Publications by authors named "Guy DeRose"

64 Publications

Onyx versus coil embolization for the treatment of type II endoleaks.

J Vasc Surg 2021 Jun 27;73(6):1966-1972. Epub 2020 Nov 27.

Department of Vascular Surgery, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada; Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada. Electronic address:

Objective: Little evidence is available supporting the optimal treatment of type II endoleaks associated with aortic sac growth. Previous studies have lacked comparisons between treatment methods and long-term follow-up. The purpose of the present study was to review our center's experience with the treatment of type II endoleaks comparing Onyx (a liquid embolization agent consisting of ethylene vinyl alcohol; Medtronic, Minneapolis, Minn) embolization and coil embolization.

Methods: A retrospective review of prospectively collected data from a vascular surgery database was performed to identify all patients who had undergone embolization of a type II endoleak for aortic sac growth after endovascular aneurysm repair from 2005 to 2018. The Onyx and coil embolization groups were compared using univariate statistics.

Results: A total of 58 patients had undergone 77 embolization procedures for type II endoleaks with either Onyx (27 patients; 37 procedures) or coils (31 patients; 40 procedures). The average aneurysm size at embolization was larger in the Onyx group (77.9 ± 15.1 mm) compared with coil embolization (73.4 ± 11.9 mm). The mean follow-up was 57 months for the Onyx group and 74 months for the coil embolization group. Of the 27 patients who had undergone Onyx embolization, 2 (7.4%) had required graft explantation compared with 5 of the 31 patients (16.1%) who had undergone coil embolization (P = .33). The results of the per-patient analysis showed that the coil embolization group had a significantly greater rate of the need for further reintervention compared with the Onyx group (55% vs 19%; P < .01). Clinical success was observed in 13 patients (48%) in the Onyx embolization group compared with 10 patients (32%) in the coil embolization group (P = .04). Two patients in each group had presented with secondary rupture of the aneurysm sac after attempted embolization.

Conclusions: Type II endoleaks associated with sac growth treated with Onyx were less likely to require further reinterventions than were those treated with coil embolization. A trend was found toward a greater need for endovascular aneurysm repair explant after coil embolization. With a high rate of further reintervention and potential for sac rupture, diligent follow-up is required after attempted type II embolization, regardless of the technique used.
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http://dx.doi.org/10.1016/j.jvs.2020.10.069DOI Listing
June 2021

The efficacy of a topical formulation of selamectin plus sarolaner in preventing the development of a macrocyclic lactone-resistant strain of Dirofilaria immitis in cats.

Vet Parasitol 2020 Jun 11;282:109122. Epub 2020 May 11.

Zoetis, Veterinary Medicine Research and Development, 333 Portage Street Kalamazoo, MI 49007, USA.

Revolution®/Stronghold® Plus, a topical endectocide incorporating 6 mg/kg selamectin plus 1 mg/kg sarolaner, is approved for use in cats to prevent heartworm disease. The efficacy of selamectin has not previously been evaluated against any macrocyclic lactone (ML)-resistant heartworm strains in cats for prevention of heartworm disease. In this study, an experimental combination formulation of selamectin (6 mg/kg) plus sarolaner (2 mg/kg) was assessed for preventing the development of a ML-resistant strain of Dirofilaria immitis in cats. Forty purpose-bred domestic shorted-haired cats (20 males; 20 females) from 7-9 months of age and negative for heartworm antigen prior to study inclusion were used. On Day -30, cats were inoculated with 100 D. immitis L (ZoeMO strain) subcutaneously in the inguinal area. Cats were randomly allocated to one of the following four treatments with associated dosing regimens: T01 (vehicle-treated control on Days 0, 28, and 56), T02 (single dose of selamectin plus sarolaner combination on Day 0 only), T03 (selamectin plus sarolaner combination on Days 0, 28, and 56) or T04 (single dose of selamectin on Day 0 only). All treatments were administered topically in an isopropyl alcohol-based formulation. Selamectin was administered at 6 mg/kg in both standalone and combination formulations. Sarolaner was administered at 2 mg/kg. Cats were necropsied on Day ∼145 (∼175 days post infection) and adult worms were counted. Nine of ten cats in the control group (T01) were infected with adult worms (range, 1-23; geometric mean, 3.5). In contrast, all cats in T03 had zero heartworms. Only two cats in T02 (0-3; 0.2) and a single cat in the T04 (0-1; 0.1) had heartworms. Compared to T01 (control cats), all treated cats had significantly (p < 0.0001) reduced worm burdens, with treatment efficacies of 100% (T03), 93.5% (T02) and 98% (T04). A topical combination of selamectin (6 mg/kg) plus sarolaner (2 mg/kg) was 100% efficacious in preventing the development of an ML-resistant strain of D. immitis (ZoeMO) in cats when administered as three consecutive monthly treatments. A single dose was highly (93.5%) but incompletely effective.
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http://dx.doi.org/10.1016/j.vetpar.2020.109122DOI Listing
June 2020

Long-term outcomes comparing endovascular and open abdominal aortic aneurysm repair in octogenarians.

J Vasc Surg 2020 04 10;71(4):1162-1168. Epub 2019 Sep 10.

Division of Vascular Surgery, Department of Surgery, London Health Sciences Centre, Western University, London, Ontario, Canada; Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada. Electronic address:

Objective: Patients older than 80 years have significantly lower early mortality with endovascular aneurysm repair (EVAR) compared with open repair for abdominal aortic aneurysms (AAAs), but long-term results remain poorly studied. We analyzed the results of both emergent and elective AAA repair in patients aged 80 years or older who had at least 5 years of follow-up.

Methods: Retrospective review of a prospectively collected vascular surgery database was performed to identify all patients who underwent elective repair of an AAA between 2007 and 2012 and were 80 years of age or older at the time of surgery. Open and EVAR groups were compared using univariate statistics.

Results: The study cohort was composed of 314 patients 80 years of age or older (median, 83 years; interquartile range, 5 years) who underwent repair (96 open, 218 EVAR). The groups had similar comorbidities, except that EVAR patients were more likely to be male and open repair patients were more likely to have larger aneurysms. Compared with open repair, elective early postoperative mortality was significantly lower for EVAR patients (1% vs 14%; P < .001). Overall mean life expectancy was 5.9 years (EVAR, 5.8 years; open repair, 5.8 years; P = .98). The 1-year survival was significantly higher for EVAR (92.9%) than for open repair (84.1%; P = .02). The 2-year survival (EVAR, 83.4%; open repair, 74.6%; P = .07) and 5-year survival (EVAR, 57.8%; open repair, 60.3%; P = .98) did not differ between EVAR and open repair. Reintervention rates (EVAR, 18%; open repair, 2%; P = .05) were higher in the endovascular treatment group.

Conclusions: EVAR results in an improved 1-year mortality in octogenarians compared with open repair, although 5-year survival is similar between the groups. With average life expectancies of >5 years and an 18% reintervention rate, diligent follow-up is required after EVAR even in elderly patients.
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http://dx.doi.org/10.1016/j.jvs.2019.06.207DOI Listing
April 2020

Plasma-Etched Pattern Transfer of Sub-10 nm Structures Using a Metal-Organic Resist and Helium Ion Beam Lithography.

Nano Lett 2019 Sep 27;19(9):6043-6048. Epub 2019 Aug 27.

School of Chemistry and Photon Science Institute , The University of Manchester , Oxford Road , Manchester M13 9PL , United Kingdom.

Field-emission devices are promising candidates to replace silicon fin field-effect transistors as next-generation nanoelectronic components. For these devices to be adopted, nanoscale field emitters with nanoscale gaps between them need to be fabricated, requiring the transfer of, for example, sub-10 nm patterns with a sub-20 nm pitch to substrates like silicon and tungsten. New resist materials must therefore be developed that exhibit the properties of sub-10 nm resolution and high dry etch resistance. A negative tone, metal-organic resist is presented here. It can be patterned to produce sub-10 nm features when exposed to helium ion beam lithography at line doses on the order of tens of picocoulombs per centimeter. The resist was used to create 5 nm wide, continuous, discrete lines spaced on a 16 nm pitch in silicon and 6 nm wide lines on an 18 nm pitch in tungsten, with line edge roughness of 3 nm. After the lithographic exposure, the resist demonstrates high resistance to silicon and tungsten dry etch conditions (SF and CF plasma), allowing the pattern to be transferred to the underlying substrates. The resist's etch selectivity for silicon and tungsten was measured to be 6.2:1 and 5.6:1, respectively; this allowed 3 to 4 nm thick resist films to yield structures that were 21 and 19 nm tall, respectively, while both maintained a sub-10 nm width on a sub-20 nm pitch.
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http://dx.doi.org/10.1021/acs.nanolett.9b01911DOI Listing
September 2019

Editor's Choice - Infrainguinal Bypass Following Failed Endovascular Intervention Compared With Primary Bypass: A Systematic Review and Meta-Analysis.

Eur J Vasc Endovasc Surg 2019 Mar 2;57(3):382-391. Epub 2018 Nov 2.

Division of Vascular Surgery, Western University, London, Ontario, Canada; Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada. Electronic address:

Objectives: Patients with infrainguinal peripheral arterial disease often undergo multiple revascularisation procedures. Although many centres have adopted an endovascular first approach, some are reluctant to do so for fear of compromising the outcomes of any subsequent bypasses. All studies that compared the outcomes of primary infrainguinal bypass with bypass after failed endovascular intervention were analysed.

Methods: A systematic review was conducted of MEDLINE, EMBASE, and CENTRAL databases for studies comparing outcomes of primary infrainguinal bypass with bypass after failed endovascular intervention for peripheral arterial disease. Abstracts and full text studies were screened independently by two reviewers with data abstraction done in duplicate. Dichotomous outcome measures were reported using the OR and 95% CI, and pooled using random effects models.

Results: Abstracts were screened (2,528), with 50 selected for full text review. Of these, 15 studies involving 11,886 patients met the inclusion criteria. Pooling the results of studies comparing primary bypass with bypass after failed endovascular intervention showed no significant difference in 30 day mortality (OR 1.00; 95% CI 0.65-1.54), or 30 day amputation rates (OR 1.26; 95% CI 0.95-1.65). Interestingly, one year amputation free survival was higher in the patients who had primary bypass (OR 1.30; 95% CI 1.10-1.52) compared with patients who had bypass after failed endovascular therapy. There was also worse one year primary patency (OR 1.65; 95% CI 1.04-2.62) for patients with prior failed endovascular intervention. The review demonstrated a trend towards higher rates of early graft occlusion (OR 4.54; 95% CI 0.97-21.28).

Conclusions: Meta-analysis of the existing literature comparing primary bypass with bypass following failed endovascular intervention shows worse one year amputation free survival and worse primary patency in those patients who undergo bypass after failed endovascular intervention. There is also a trend towards higher rates of early graft occlusion, although these results were not statistically significant. These conclusions are limited by observational study design, inconsistent patient selection, and significant heterogeneity between studies.
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http://dx.doi.org/10.1016/j.ejvs.2018.09.025DOI Listing
March 2019

Preoperative point-of-care ultrasound and its impact on arteriovenous fistula maturation outcomes.

J Vasc Surg 2018 10 18;68(4):1157-1165. Epub 2018 May 18.

Division of Vascular Surgery, Western University, London, Ontario, Canada. Electronic address:

Objective: Duplex ultrasound as a preoperative assessment tool in the clinic may help identify anatomic factors predictive of fistula maturation. Preoperative point-of-care ultrasound (POCUS) offers surgeons an alternative to routine formal vein mapping as it can be performed by the operator during the initial clinic visit. We sought to determine the impact of POCUS as an adjunct to physical examination on arteriovenous fistula maturation.

Methods: All consecutive patients undergoing first-time dialysis access creation from December 2007 to December 2014 were retrospectively reviewed. Surgeons who routinely use POCUS to assess preoperative maximal vein diameter and quality were compared with surgeons who relied only on physical examination. All access and patency definitions were in accordance with the Society for Vascular Surgery's reporting standards. The effects of POCUS on fistula maturation rate and fistula abandonment were analyzed using logistic regression, controlling for comorbidities of the patient, anticoagulant use, and location of fistula.

Results: A total of 316 patients were included in the study; 250 patients were assessed exclusively with physical examination, and 66 patients underwent preoperative ultrasound examination by the vascular surgeon in the clinic. The primary failure rate in the ultrasound group was 18% compared with 47% (P < .001) in the group of patients who did not undergo ultrasound examination. In patients without preoperative ultrasound, there were higher rates of new access creation (31% vs 9%; P < .001) and fistula abandonment (66% vs 39%; P < .001). Multivariable analysis demonstrated that fistulas created without preoperative ultrasound were associated with a 3.56 greater risk of failure (95% confidence interval, 1.67-7.59; P = .001) compared with fistulas in the POCUS group. Similarly, the rate of fistula abandonment was 2.63 times higher (95% confidence interval, 1.38-5.05; P = .003) when ultrasound was not used preoperatively. Time to functional fistula maturation was better in the ultrasound group (P < .001). At 1 year, 12% of fistulas in the ultrasound group and 32% in the clinical examination group had yet to be cannulated. Secondary patency at 1 year was better in the POCUS group at 73% compared with 59% in the group with no preoperative ultrasound (P = .01).

Conclusions: POCUS as an adjunct to physical examination for dialysis access patients leads to decreased rates of primary failure, new access creation, and fistula abandonment compared with patients who undergo only physical examination. Ultrasound examination improved times to functional fistula maturation and secondary patency. Further studies are required to compare POCUS with formal preoperative vein mapping for arteriovenous fistula planning.
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http://dx.doi.org/10.1016/j.jvs.2018.01.051DOI Listing
October 2018

Patient satisfaction with the consent discussion is not improved by showing patients their computed tomography or angiography images before they undergo vascular surgery.

J Vasc Surg 2018 11 18;68(5):1517-1523.e3. Epub 2018 May 18.

Division of Vascular Surgery, Western University, London, Ontario, Canada; Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada. Electronic address:

Objective: Patient-based decision aids and other multimedia tools have been developed to help enrich the preoperative discussion between surgeon and patient. Use of these tools, however, can be time-consuming and logistically challenging. We investigated whether simply showing patients their images from preoperative computed tomography (CT) or angiography would improve patients' satisfaction with the preoperative discussion. We also examined whether this improved the patient's understanding and trust and whether it contributed to increased preoperative anxiety.

Methods: Patients undergoing either elective abdominal aortic aneurysm repair or lower limb revascularization were randomly assigned to either standard perioperative discussion or perioperative discussion and review of images (CT image or angiogram). Randomization was concealed and stratified by surgeon. Primary outcome was patient satisfaction with the preoperative discussion as measured by a validated 7-item scale (score, 0-28), with higher scores indicating improved satisfaction. Secondary outcomes included patient understanding, patient anxiety, patient trust, and length of preoperative discussion. Scores were compared using t-test.

Results: Overall, 51 patients were randomized, 25 to the intervention arm (discussion and imaging) and 26 to the control arm. Most patients were male (69%), and the average age was 70 years. Forty percent of patients underwent abdominal aortic aneurysm repair, whereas 60% underwent lower limb revascularization. Patient satisfaction with the discussion was generally high, with no added improvement when preoperative images were reviewed (mean score, 24.9 ± 3.02 vs 24.8 ± 2.93; P = .88). Similarly, there was no difference in the patient's anxiety, level of trust, or understanding when the imaging review was compared with standard discussion. There was a trend toward longer preoperative discussions in the group that underwent imaging review (8.18 vs 6.35 minutes; P = .07).

Conclusions: Showing patients their CT or angiography images during the preoperative discussion does not improve the patient's satisfaction with the consent discussion. Similarly, there was no effect on the patient's trust, understanding, or anxiety level. Our conclusions are limited by the lack of a standardized measure of patient understanding and not measuring outcomes postoperatively, both of which should be considered in future studies.
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http://dx.doi.org/10.1016/j.jvs.2018.02.029DOI Listing
November 2018

Higher surgeon annual volume, but not years of experience, is associated with reduced rates of postoperative complications and reoperations after open abdominal aortic aneurysm repair.

J Vasc Surg 2018 06 13;67(6):1717-1726.e5. Epub 2017 Dec 13.

Institute for Clinical and Evaluative Sciences, London, Ontario, Canada.

Objective: Volume-outcome relationships for open abdominal aortic aneurysm (AAA) repair have received less attention in publicly funded health systems. Furthermore, the roles of surgeon seniority (years of experience) and composite volume (encompassing all major arterial cases) on outcomes after open AAA repair are less well known. We sought to determine the effects of surgeon volume, surgeon years of experience, and composite volume on outcomes after elective open AAA repairs performed in Ontario, Canada.

Methods: Using a population-based, prospectively collected health administrative database, all elective open AAA repairs occurring in the province of Ontario from 2005 to 2014 were identified. Surgeon annual volume was classified by quintiles, with the highest volume quintile acting as the reference category. Multivariable logistic regression modeling was used, adjusting for patient factors (age, sex, comorbidities, year of procedure, income) to investigate the relationship between surgeon annual volume and 30-day mortality, 30-day major complications, 30-day reoperations, 1-year mortality, and 1-year reoperations (related to index procedure). The potential effects of annual surgeon composite volume and surgeon years of experience on postoperative outcomes were also explored.

Results: A total of 7211 elective open AAA repairs performed by 101 surgeons were identified between 2005 and 2014. Most of the operations were performed by vascular surgeons (81.5%), followed by cardiac (12.1%) and general surgeons (6.1%). Median number of procedures in the lowest quintile group was 3 repairs/y, whereas the highest quintile group performed 54 repairs/y. Overall 30-day mortality was 3%. No difference in mortality was detected in comparing the lowest with the highest volume groups (1.89% vs 3.01%; adjusted odds ratio [OR], 0.60; 95% confidence interval [CI], 0.27-1.33). The lowest volume group exhibited a higher 30-day complication rate (28.0% vs 20.4%; OR, 1.54; 95% CI, 1.15-2.06) and 30-day reoperation rate (10.53% vs 6.73%; OR, 1.64; 95% CI, 1.13-2.38) compared with the highest volume group. No effect of surgeon volume on 1-year mortality or 1-year reoperation was observed. Similarly, composite volume and surgeon years of experience were not associated with postoperative outcomes.

Conclusions: In a single-payer system with a relatively high number of open AAA repairs/surgeon per year, surgeon annual volume had no effect on postoperative mortality but was associated with lower postoperative complication and reoperation rates.
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http://dx.doi.org/10.1016/j.jvs.2017.10.050DOI Listing
June 2018

Randomized clinical trial of negative pressure wound therapy for high-risk groin wounds in lower extremity revascularization.

J Vasc Surg 2017 12 31;66(6):1814-1819. Epub 2017 Aug 31.

Division of Vascular Surgery, Department of Surgery, Western University. Electronic address:

Objective: The surgical site infection (SSI) rate in vascular surgery after groin incision for lower extremity revascularization can lead to significant morbidity and mortality. This trial was designed to study the effect of negative pressure wound therapy (NPWT) on SSI in closed groin wounds after lower extremity revascularization in patients at high risk for SSI.

Methods: A single-center, randomized, controlled trial was performed at an academic tertiary medical center. Patients with previous femoral artery surgical exposure, body mass index of >30 kg/m or the presence of ischemic tissue loss were classified as a high-risk patient for SSI. All wounds were closed primarily and patients were randomized to either NPWT or standard dressing. The primary outcome of the trial was postoperative 30-day SSI in the groin wound. The secondary outcomes included 90-day SSI, hospital duration of stay, readmissions or reoperations for SSI, and mortality.

Results: A total of 102 patients were randomized between August 2014 and December 2015. Patients were classified as at high risk owing to the presence of previous femoral artery cut down (29%), body mass index of >30 kg/m (39%) or presence of ischemic tissue loss (32%). Revascularization procedures performed included femoral to distal artery bypass (57%), femoral endarterectomy (18%), femoral to femoral artery crossover (17%), and other procedures (8%). The primary outcome of 30-day SSI was 11% in NPWT group versus 19% in standard dressing group (P = .24). There was a statistically significant shorter mean duration of hospital stay in the NPWT group (6.4 days) compared with the standard group (8.9 days; P = .01). There was no difference in readmission or reoperation for SSI or mortality between the two groups.

Conclusions: This study demonstrated a nonsignificant lower rate of groin SSI in high-risk revascularization patients with NPWT compared with standard dressing. Owing to a lower than expected infection rate, the study was underpowered to detect a difference at the prespecified level. The NPWT group did show significantly shorter mean hospital duration of stay compared with the standard dressing group.
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http://dx.doi.org/10.1016/j.jvs.2017.06.084DOI Listing
December 2017

Use of Supramolecular Assemblies as Lithographic Resists.

Angew Chem Int Ed Engl 2017 06 15;56(24):6749-6752. Epub 2017 May 15.

The School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.

A new resist material for electron beam lithography has been created that is based on a supramolecular assembly. Initial studies revealed that with this supramolecular approach, high-resolution structures can be written that show unprecedented selectivity when exposed to etching conditions involving plasmas.
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http://dx.doi.org/10.1002/anie.201700224DOI Listing
June 2017

Explaining endograft shortening during endovascular repair of abdominal aortic aneurysms in severe aortoiliac tortuosity.

J Vasc Surg 2017 05 19;65(5):1297-1304. Epub 2016 Nov 19.

Division of Vascular Surgery, Western University, London, Ontario, Canada.

Objective: During endovascular aneurysm repair (EVAR), severely tortuous aortoiliac anatomy can alter the deployment and conformability of the endograft. The accuracy of treatment length measurements is commonly recognized to be affected by severe tortuosity. However, the exact mechanism of the postintervention length discrepancy is poorly understood. The objective of this study was to determine the mechanism of how severe aortoiliac tortuosity influences the endograft and native aorta during EVAR and its impact on the distal sealing zone.

Methods: A prospectively collected vascular surgery database was retrospectively reviewed at a university-affiliated medical center to identify the study patients. Patients who underwent EVAR with the main body device deployed on the side of the severely tortuous iliac artery were selected. Severe aortoiliac tortuosity was defined as having either aortoiliac or common iliac angulation <90 degrees.

Results: A total of 469 patients between 2008 and 2014 underwent EVAR using the Endurant endograft (Medtronic Cardiovascular, Santa Rosa, Calif). Severe aortoiliac tortuosity was observed in 36% of patients; 17 patients were found to have the main body placed on the side of severe tortuosity without an extension limb. There was a significant shortening of the main body endograft length from 169 mm before EVAR to 147 mm after EVAR (P < .001). The treatment length of the main body, measured from the lowest renal artery to hypogastric artery, also significantly shortened from 179 mm to 170 mm (P < .001). There was a decrease in tortuosity at the most angulated portion of the aneurysm after EVAR, in which angulation changed from 86 degrees to 114 degrees (P < .001). There was no significant change in treatment length (P = .859) and angulation (P = .195) on the nontortuous side of the aneurysm.

Conclusions: The study observed significant shortening of endografts and native aorta and iliac arteries in patients with severe aortoiliac tortuosity during EVAR. This shortening effect can have a negative impact on the distal sealing zone during EVAR. A longer main body or an extension limb should be considered when one is faced with severely tortuous aneurysms.
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http://dx.doi.org/10.1016/j.jvs.2016.09.041DOI Listing
May 2017

Negative pressure wound therapy for high-risk wounds in lower extremity revascularization: study protocol for a randomized controlled trial.

Trials 2015 Nov 4;16:504. Epub 2015 Nov 4.

Division of Vascular Surgery, Department of Surgery, Western University, 800 Commissioners Road East, London, ON, N6A 4G5, Canada.

Background: Rates of surgical site infections (SSIs) following groin incision for femoral artery exposure are much higher than expected of a clean operation. The morbidity and mortality is high, particularly with the use of prosthetic grafts. The vascular surgery population is at an increased risk of SSIs related to peripheral vascular disease (PVD), diabetes, obesity, previous surgery and presence of tissue loss. Negative pressure wound therapy (NPWT) dressings have been used on primarily closed incisions to reduce surgical site infections in other surgical disciplines. We have not come across any randomized controlled trials to support the prophylactic use of negative pressure wound therapy in high-risk vascular patients undergoing lower limb revascularization.

Methods/design: In this single-center, prospective randomized controlled trial, patients scheduled for a lower limb revascularization requiring open femoral artery exposure who are at a high risk (BMI > 30 kg/m(2), previous femoral cutdown or Rutherford V or VI category for chronic limb ischemia) will be eligible for the study. A total of 108 groin incisions will be randomized to the use of a negative pressure wound device or standard adhesive gauze dressing. Patients will be followed in hospital and reassessed within the first 30 days postoperatively. The primary outcome is SSI within the first 30 days of surgery and will be determined using the intention-to-treat principle. Secondary outcomes include length of stay, emergency room visits, reoperation, amputation and mortality. A cost analysis will be performed.

Discussion: The trial is expected to define the role of NPWT in SSI prophylaxis for lower limb revascularization in high-risk vascular patients. The results of the study will be used to inform current best practice for perioperative care and the minimization of SSIs.

Trial Registration: NCT02084017 , March 2014.
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http://dx.doi.org/10.1186/s13063-015-1026-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4634141PMC
November 2015

Fibrinogen Level and Bleeding Risk During Catheter-Directed Thrombolysis Using Tissue Plasminogen Activator.

Vasc Endovascular Surg 2015 Oct 13;49(7):175-9. Epub 2015 Oct 13.

Division of Vascular Surgery, London Health Sciences Centre, Western University, London, Ontario, Canada

Purpose: The purpose of this study was to determine whether low fibrinogen levels (fibrinogen level <1.5 g/L) during catheter-directed thrombolysis are associated with an increased bleeding risk.

Methods: A retrospective review was performed on patients undergoing extremity arterial or venous thrombolysis between 2005 and 2013.

Results: Patients in the low fibrinogen group were younger (P = .006) and had a higher number of venous occlusive events (P = .004). The low fibrinogen group received a larger dose of tissue plasminogen activator (tPA; P = .009) and had a longer duration of thrombolysis (P = .010). The rates of major bleeding were not significantly different (P = .139). Univariate analysis showed that larger total dose and longer duration of tPA infusion were associated with increased bleeding complications (P < .01 and P = .03).

Conclusion: A fibrinogen level <1.5 g/L during thrombolysis was not associated with an increased bleeding risk. However, larger dose and longer duration of thrombolysis were associated with increased bleeding risk.
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http://dx.doi.org/10.1177/1538574415611234DOI Listing
October 2015

Similar failure and patency rates when comparing one- and two-stage basilic vein transposition.

J Vasc Surg 2015 Mar;61(3):809-16

Division of Vascular Surgery, London Health Sciences Centre and Western University, London, Ontario, Canada; Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada. Electronic address:

Objective: Basilic vein transposition is recommended in patients who are not candidates for a radial or brachial artery to cephalic vein fistula for dialysis access. Both one-stage and two-stage procedures have their advantages and disadvantages. Which procedure results in improved outcomes remains unclear.

Methods: A systematic review was conducted of the MEDLINE and EMBASE databases for studies that compared one-stage and two-stage brachial-basilic vein transpositions. Abstracts and full-text studies were screened independently by two reviewers with data abstraction done in duplicate. Random-effects meta-analysis was used to identify differences in primary failure rates and 1-year primary and secondary patency rates. Study quality was assessed by a previously described tool designed for observational studies reporting on dialysis access outcomes.

Results: Of 1662 abstracts screened, 97 were selected for full-text review. Of these, eight studies (one randomized trial, seven observational studies) involving 882 patients met the inclusion criteria. The pooled odds ratio estimate for primary failure was 1.21 (95% confidence interval [CI], 0.73-1.98; P = .46), suggesting no difference in failure rate between one-stage and two-stage transpositions. Similarly, the estimated odds ratio for 1-year primary patency rate of 1.39 (95% CI, 0.71-2.72; P = .33) and 1-year secondary patency rate of 1.02 (95% CI, 0.36-2.87; P = .98) indicated no difference between the two groups. Study quality was limited by unclear outcome definitions, minimal control for confounding, and variable selection criteria. The decision to pursue a one-stage vs a two-stage procedure was often based on size of the basilic vein, with a two-stage procedure reserved for patients with smaller veins.

Conclusions: Meta-analysis of the existing literature comparing one-stage and two-stage basilic vein transposition suggests no difference in failure and patency rates, despite the two-stage procedure's being used in patients with smaller basilic veins. These findings are limited by the small size, observational design, and inconsistent quality of included studies. Reserving a two-stage procedure for patients with smaller basilic veins appears justified, although the strength of the evidence is limited.
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http://dx.doi.org/10.1016/j.jvs.2014.11.083DOI Listing
March 2015

Anatomic and procedural determinants of fluoroscopy time during elective endovascular aortic aneurysm repair.

Vascular 2016 Feb 16;24(1):19-24. Epub 2015 Feb 16.

Division of Vascular Surgery, London Health Sciences Centre & Western University, London, ON, Canada Department of Epidemiology and Biostatistics, Western University, London, ON, Canada

Objective: To identify both the procedural and anatomic factors which determine duration of fluoroscopy during elective endovascular aortic aneurysm repair (EVAR).

Methods: We retrospectively analyzed our prospectively maintained EVAR database for the relationship between fluoroscopy time and both procedural (type of graft, configuration, number of components, surgeon) and anatomic factors reflective of aneurysm complexity (15 variables).

Results: A total of 128 patients underwent elective EVAR with a mean fluoroscopy time of 5.7 ± 3.4 min. The type of grafts used consisted of 41 (32%) Zenith, 85 (66.4%) Endurant and 2 (1.6%) Anaconda, with 105 (82%) being bifurcated and 23 (18%) being aorto-uni-iliac (AUI) in configuration. Both the surgeon performing the procedure (p = 0.001) and graft configuration (bifurcated vs. AUI, p = 0.03) were found to be predictive of fluoroscopy time; while procedural and anatomic variables were not.

Conclusions: The surgeon's efficiency in the use of fluoroscopy during EVAR is the most important determinant of total fluoroscopy time. Anatomic complexity, make of device, and number of components inserted have minimal impact on duration of fluoroscopy. An endovascular surgeon's ability to curtail fluoroscopy duration is the key component in minimizing radiation exposure to both the surgical team and the patient.
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http://dx.doi.org/10.1177/1708538115573395DOI Listing
February 2016

Durability and survival are similar after elective endovascular and open repair of abdominal aortic aneurysms in younger patients.

J Vasc Surg 2015 Mar 25;61(3):636-41. Epub 2014 Nov 25.

Division of Vascular Surgery, London Health Sciences Centre and The University of Western Ontario, London, Ontario, Canada. Electronic address:

Objective: The role of endovascular repair (EVAR) of aortic aneurysms in young patients is controversial. The purpose of this study was to determine the long-term outcomes and reintervention rates in patients 60 years of age or younger who underwent elective open or endovascular repair of an abdominal aortic aneurysm.

Methods: Retrospective review of a prospectively collected vascular surgery database at a university-affiliated medical center was performed to identify all patients who underwent elective repair of an abdominal aortic aneurysm between 2000 and 2013 and were 60 years of age or younger at the time of the repair. Preoperative anatomic measurements were performed and compared with instructions for use (IFU) criteria for the endografts.

Results: The study cohort comprised 169 patients 60 years of age or younger (mean age, 56.7 ± 2.8 years) who underwent elective repair (119 open repair, 50 EVAR). Patients treated with open repair and EVAR had similar comorbidities, except that EVAR patients were more likely to have hypertension (P = .03) and poor left ventricular function (P = .04). The open repair group had significantly larger suprarenal (P = .004) and infrarenal (P = .005) neck angles, shorter neck lengths (P < .001), and larger maximum aneurysm diameter (P = .02) compared with the EVAR group. Only five patients (13%) in the EVAR group did not meet all IFU criteria. The overall in-hospital mortality rate was 1.8% (0% EVAR, 2.5% open repair; P = .56). Overall mean life expectancy was 11.5 years (9.8 years EVAR, 11.9 years open repair; P = .09). The 1-year (98% EVAR, 96% open repair), 5-year (86% EVAR, 88% open repair), and 10-year (54% EVAR, 75% open repair) survival did not differ between EVAR and open repair (P = .16). Long-term survival (78% EVAR, 85% open repair; P = .09) and reintervention rates (12% EVAR, 16% open repair; P = .80) did not differ. No late aneurysm rupture or aneurysm-related deaths were observed. The most common causes of long-term mortality were malignant disease and cardiovascular events. Reinterventions in the open repair group were exclusively laparotomy related (incisional hernia repairs), whereas all reinterventions in the EVAR group were aortic related, including one conversion to open repair.

Conclusions: After elective aneurysm repair, younger patients have a moderate life expectancy related to malignant disease and cardiovascular health. EVAR offers durability and long-term survival similar to those with open repair in these younger patients as long as aneurysm anatomy and IFU are adhered to.
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http://dx.doi.org/10.1016/j.jvs.2014.10.012DOI Listing
March 2015

Endograft conformability and aortoiliac tortuosity in endovascular abdominal aortic aneurysm repair.

J Endovasc Ther 2014 Oct;21(5):728-34

Division of Vascular Surgery, Western University, London, Ontario, Canada.

Purpose: To determine conformability of stent-grafts in endovascular aneurysm repair (EVAR) using centerline of flow measurements and to compare conformability in patients with severe aortoiliac tortuosity.

Methods: From 2012 to 2013, 111 consecutive patients (98 men; mean age 75.4±7.7 years) underwent endovascular aneurysm repair with Endurant I and II and Zenith Flex, LP, and Spiral Z stent-grafts; their pre- and post-EVAR computed tomography (CT) studies were retrospectively analyzed using quantitative 3-dimensional imaging software. The length between the lowest renal artery and the iliac bifurcation was measured using centerline of flow and was defined as the treatment length (TL). The difference in TLs pre and post EVAR were compared as a surrogate to evaluate endograft conformability.

Results: A total of 203 pre and post EVAR aortoiliac TLs were measured (99 Endurant I, 20 Endurant II, 32 Flex, 6 LP, and 42 Spiral Z). Overall, there was a mean difference of 5.0±7.3 mm or 2.6%±3.9% between the pre- and post-EVAR TLs (p<0.001). No statistically significant difference in TLs was observed among the various stent-grafts (p=0.115). In 40 patients with severe aortoiliac tortuosity, the post-EVAR TL was 16.2±5.5 mm or 8.0%±2.7% shorter than the pre-EVAR TL (p<0.001); again, there was no difference in TLs among the various devices implanted (p=0.737).

Conclusion: Overall, there was no difference in treatment lengths before and after EVAR among different stent-grafts, suggesting similar conformability. Interestingly, patients with severe aortoiliac tortuosity were found to have significantly shorter post-EVAR treatment lengths compared to before EVAR, which should be considered when planning EVAR.
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http://dx.doi.org/10.1583/14-4663MR.1DOI Listing
October 2014

Canadian vascular surgery residents' perceptions regarding future job opportunities.

Vascular 2015 Jun 25;23(3):253-9. Epub 2014 Jun 25.

Division of Vascular Surgery, London Health Sciences Centre & Western University London, Canada

The objective was to determine the employment environment for graduates of Canadian vascular surgery training programs. A cross-sectional survey of residents and graduates (2011-2012) was used. Thirty-seven residents were invited with a response rate of 57%, and 14 graduates with a response rate of 71%; 70% of graduates felt the job market played an important role in their decision to pursue vascular surgery as a career compared to 43% of trainees. The top three concerns were the lack of surgeons retiring, the overproduction of trainees, and saturation of the job market. The majority (62%) of trainees see themselves extending their training due to lack of employment. All of the graduates obtained employment, with 50% during their second year (of two years) of training and 30% after training was completed. Graduates spent an average of 12 ± 10.6 months seeking a position and applied to 3.3 ± 1.5 positions, with a mean of 1.9 ± 1.3 interviews and 2 ± 1.2 offers. There was a discrepancy between the favorable employment climate experienced by graduates and the pessimistic outlook of trainees. We must be progressive in balancing the employment opportunities with the number of graduates. Number and timing of job offers is a possible future metric of the optimal number of residents.
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http://dx.doi.org/10.1177/1708538114541112DOI Listing
June 2015

Identification of patient-derived outcomes after aortic aneurysm repair.

J Vasc Surg 2014 Jun 18;59(6):1528-34. Epub 2014 Jan 18.

Division of Vascular Surgery, London Health Sciences Centre and Western University, London, Ontario, Canada.

Objective: Relatively few outcomes have been examined in randomized comparisons of endovascular and open aortic aneurysm repair, and no patient input was obtained in the selection of these outcomes. The aim of this study was to identify patient-derived, potentially novel outcomes that may be used to guide future clinical trials in aneurysm surgery.

Methods: Focus group interviews were conducted with patients who had undergone endovascular or open aortic aneurysm repair. The discussions were transcribed and the transcript was analyzed by two indexers using constant-comparison analysis and grounded theory to identify potentially novel, patient-derived outcomes. Other potential themes relating to the patients' experience and their decision-making were also sought.

Results: Six focus groups were conducted (three with endovascular aneurysm repair patients and three with open aortic aneurysm repair patients), with a median of six participants, 2 to 12 months from surgery. Functional outcomes were most commonly mentioned and emphasized by patients. Recovery time and energy level were most frequently verbalized as important in the decision-making process between endovascular and open aneurysm repair. Other potential outcomes identified as important to patients included postoperative pain, time to walking normally, loss of appetite, extent and location of incisions, impact on cognition, being able to go home after surgery, and impact on caregivers. In addition to these outcomes, we identified three themes relating to the patient's experience: undervaluing or underappreciating the risk of death during surgery, differing informational needs and level of involvement in decision-making, and unrealistic patient expectations about the risks of and recovery after the procedure.

Conclusions: Functional outcomes emerged as most important during qualitative analysis of patients' experiences with aneurysm repair. Perceived differences in recovery time were identified as an important consideration for aneurysm patients in deciding between open and endovascular repair. More work needs to be done clarifying the concept of recovery and other related functional outcomes for the development of methods to assess and to evaluate these in prospective clinical trials.
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http://dx.doi.org/10.1016/j.jvs.2013.12.033DOI Listing
June 2014

Socioeconomic and geographic disparities in access to endovascular abdominal aortic aneurysm repair.

Ann Vasc Surg 2013 Nov 5;27(8):1061-7. Epub 2013 Sep 5.

Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada.

Background: Within Southwestern Ontario, abdominal aortic aneurysm (AAA) surgery has been centralized to a single university-affiliated medical center. The referral area serves 1.9 million people and includes community hospitals with limited vascular surgery capabilities. We reviewed the role of patients' travel distance, geographic location, and socioeconomic status (SES) to determine if centralization of endovascular programs results in disparity in access to endovascular surgery. We hypothesized that patients would travel a longer distance to specifically seek elective endovascular surgery while having open and emergent surgery closer to home.

Methods: All patients who underwent AAA repair (July 2005-June 2010) at London Health Science Centre were identified from the vascular surgery database. Method of repair, clinical presentation, and in-hospital mortality were recorded. Travel distance from each patient's home to our hospital and rural versus urban status was determined for each patient. SES was determined by using a previously validated, locally developed deprivation index.

Results: During this 5-year period, 1,243 patients were included in our analysis; 46.8% (n=581) underwent endovascular repair (EVAR) and 53.2% (n=662) underwent open repair. For elective cases, the in-hospital mortality rate was 2.0% (n=11) for EVAR and 3.6% (n=20) for open repair (P=0.1). There was no difference in clinical presentation between SES groups, but open repair was more frequently used in patients of lower SES compared to higher SES (odds ratio=1.32; 95% confidence interval: 1.02-1.72). Travel distance and rural/urban status were not associated with increased odds of EVAR. When ruptured aneurysms were excluded, elective patients of lower SES continued to have a higher rate of open surgery.

Conclusion: Despite the centralization of endovascular programs in Canada, patients do not appear to be traveling a longer distance for EVAR while having open repairs closer to home as we expected. We did note that higher SES was associated with increased odds of EVAR, which may suggest a health care access bias for EVAR for patients of higher SES. Larger, population-based studies at the provincial or national level could confirm these initial findings.
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http://dx.doi.org/10.1016/j.avsg.2013.02.020DOI Listing
November 2013

Determination of patient preference for location of elective abdominal aortic aneurysm surgery.

Vasc Endovascular Surg 2013 May 10;47(4):288-93. Epub 2013 Apr 10.

Division of Vascular Surgery, London Health Sciences Centre & Western University, London, Ontario, Canada.

Objective: Aneurysm repair is centralized in higher volume centers resulting in reduced mortality, with longer travel distances. The purpose of this study is to explore patients' preference between local care versus longer distances and lower mortality rates.

Methods: Patients with abdominal aortic aneurysm (AAA) measuring 4 to 5 cm and living at least a 1-hour drive from our hospital were asked to assume it had grown to 5.5 cm, and repair was recommended with a mortality risk of 2%. The level of additional risk they would accept to undergo surgery locally was determined.

Results: A total of 67 patients were surveyed. If mortality risk was equivalent at the local and regional hospitals, 44% preferred care at our tertiary center, while 56% preferred surgery locally. If perioperative mortality was increased at the local hospital, 9% preferred local surgery.

Conclusions: The vast majority of patients with AAA will accept longer travel distances for care as long as it results in a reduction in perioperative mortality.
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http://dx.doi.org/10.1177/1538574413485648DOI Listing
May 2013

Technical factors are strongest predictors of postoperative renal dysfunction after open transperitoneal juxtarenal abdominal aortic aneurysm repair.

J Vasc Surg 2013 Mar 9;57(3):648-54. Epub 2013 Jan 9.

Division of Vascular Surgery, London Health Sciences Centre & Western University, London, Ontario, Canada.

Objective: Juxtarenal abdominal aortic aneurysms (AAAs) have predominantly been repaired using an open technique. We present a series of patients with juxtarenal AAAs and analyze multiple factors predictive of postoperative renal dysfunction.

Methods: Between March 2000 and September 2011, all patients in our prospectively maintained database undergoing juxtarenal AAA repair were evaluated for demographics, operative details, and in-hospital outcomes. Postoperative renal dysfunction was classified using the RIFLE (risk, injury, failure, loss, end-stage renal disease) criteria (glomerular filtration rate decrease >25%). The relationship between perioperative factors and postoperative renal dysfunction was explored using both univariate and multivariate analysis (logistic regression).

Results: Of 169 patients, 76 (45%) required clamping above one renal artery, whereas 93 patients (55%) required clamping above both renal arteries. Mean (standard deviation) renal ischemia time was 29.2 (8.9) minutes (range, 12-65 minutes). Twenty-seven patients (16%) underwent adjunctive renal procedures, 19 (11.3%) required left renal vein division, and 130 (76.9%) received intraoperative mannitol. Postoperative renal dysfunction occurred in 63 patients (37.3%), with the majority (69%) resolving during hospital stay. Seven patients (4.1%) required postoperative dialysis, which was permanent in two cases. Patients who developed postoperative renal dysfunction had significantly longer mean renal ischemia times (34.7 [9.3] minutes vs 25.9 [6.6] minutes; P < .001), a higher rate of bilateral suprarenal aortic clamping (68.3% vs 47.2%; P = .008), higher rates of adjunctive renal artery procedures (26.7% vs 8.8%; P = .002), and higher rates of left renal vein division (20.6% vs 5.7%; P = .003). Logistic regression identified left renal vein division, renal ischemia time, and aortic clamp position as the strongest predictors of renal dysfunction. The use of mannitol was seen to be protective. Overall in-hospital mortality was 4.1% and was 9.5% among patients with postoperative renal dysfunction.

Conclusions: Postoperative transient renal dysfunction occurred in 37.3% of patients after open juxtarenal AAA repair, with a low incidence of dialysis and a low rate of permanent dysfunction. Technical factors including renal ischemia time, aortic clamp position, and left renal vein division are the strongest predictors of renal dysfunction. The use of intraoperative mannitol was associated with decreased postoperative renal dysfunction.
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http://dx.doi.org/10.1016/j.jvs.2012.09.043DOI Listing
March 2013

Outcomes after endovascular abdominal aortic aneurysm repair are equivalent between genders despite anatomic differences in women.

J Vasc Surg 2013 Feb 21;57(2):382-389.e1. Epub 2012 Dec 21.

Division of Vascular Surgery, London Health Sciences Centre and Western University, London, Ontario, Canada.

Objective: Prior work confirms gender-specific anatomic differences in patients undergoing endovascular aneurysm repair, but the clinical implications remain ill defined. The purpose of this study was to compare gender-specific early outcomes after endovascular aneurysm repair using a large international registry.

Methods: Over the 2-year period ending in 2011, 1,262 patients (131 women, 10.4%; 1,131 men, 89.6%) with infrarenal aneurysms treated with the Endurant stent graft were prospectively enrolled in the ENGAGE registry and followed clinically and radiographically.

Results: Women were older (75.5 ± 7.0 vs 72.8 ± 8.1; P = .0003) and had smaller aneurysms (57.8 ± 9.5 vs 60.6 ± 11.9 mm; P = .01). Women's infrarenal aortic necks were of narrower diameter (21.8 ± 3.4 vs 24.0 ± 3.5 mm; P < .0001), shorter length (24.3 ± 11.8 vs 27.3 ± 12.4 mm; P = .009), and greater angulation (37.7 ± 26.2° vs 29.4 ± 23.3°; P = .0002). More women had an infrarenal neck angle >60° (19.2% vs 9.1%; P = .001). Technical success was achieved in equal numbers of women and men (97.7% vs 99.2%; P = .10). On completion angiography, the incidence of any endoleak (21.5% vs 15.4%; P = .08) and type I endoleak (1.5% vs 1.1%; P = .60) did not differ between genders. At the 1-month follow-up, there were no differences between women and men with respect to endograft occlusion (2.5% vs 1.9%; P = .70), and differences observed in any endoleak (17.2% vs 11.4%; P = .08) and type I endoleaks (3.3% vs 1.2%; P = .08) did not reach statistical significance. Freedom from major adverse events was similar for women and men at 30 days (98.5% vs 95.8%; P = .23) and 1 year (85% vs 89.8%; P = .40). Survival at 30 days (100% vs 98.6%) and 1 year (92.5% vs 91.6%; P = .99) was similar for women and men.

Conclusions: This large multinational registry confirms the previously observed prevalence of suboptimal neck anatomy in women. Even though women have shorter and more angulated infrarenal necks, their technical outcomes at 30 days and clinical outcomes at 1 year were similar to those of men. Much longer follow-up is necessary to determine whether these outcomes proved durable.
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http://dx.doi.org/10.1016/j.jvs.2012.09.075DOI Listing
February 2013

Patterns of visceral and renal artery involvement in type B aortic dissections.

Vasc Endovascular Surg 2013 Jan 29;47(1):5-8. Epub 2012 Nov 29.

Division of Vascular Surgery, London Health Sciences Centre & Western University, London, ON, Canada.

Objective: The main objective of this study was to describe the visceral and renal vessel involvement and the outcomes in thoracic dissections.

Methods: Computed tomography scans of 39 patients were reviewed (30 type B, 9 type A). Visceral and renal arteries were recorded as perfused by the true lumen (TL) or false lumen (FL). Radiologic follow-up was 3.3 years (range 0-10).

Results: A total of 156 vessels were analyzed, and 49 (31%) were supplied by the FL. The most common patterns were FL supply of a renal artery (RA) with the visceral arteries and contralateral RA from the TL. In the follow-up, branch vessel compromise occurred in 12 vessels and was more likely to occur when supplied by the FL (P = .01). About 75% of the patients with at least 2 vessels supplied by the FL demonstrated aortic dilatation.

Conclusions: Branch vessel occlusion is more likely in the vessels supplied by the FL. Aortic dilatation occurred more frequently when 2 or more vessels were supplied by the FL.
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http://dx.doi.org/10.1177/1538574412467863DOI Listing
January 2013

Natural history of minimal aortic injury following blunt thoracic aortic trauma.

Can J Surg 2012 Dec;55(6):377-81

Division of Vascular Surgery, London Health Sciences Centre and the University of Western Ontario, London, Ont, Canada.

Background: Endovascular repair of blunt traumatic thoracic aortic injuries (BTAI) is common at most trauma centres, with excellent results. However, little is known regarding which injuries do not require intervention. We reviewed the natural history of untreated patients with minimal aortic injury (MAI) at our centre.

Methods: We conducted a retrospective database review to identify all patients with a BTAI between October 2008 and March 2010. The cohort comprised patients initially untreated because of the lesser degree of injury of an MAI. We reviewed initial and follow-up computed tomography (CT) scans and clinical information.

Results: We identified 69 patients with a BTAI during the study period; 10 were initially untreated and were included in this study. Degree of injury included intimal flaps (n = 7, 70%), pseudoaneurysms with minimal hematoma (n = 2, 20%) and circumferential intimal tear (n = 1, 10%). Six (60%) patients were male, and the median age was 40 years. Duration of clinical follow-up ranged from 1 month to 6 years (median 2 mo) after discharge, whereas CT radiologic follow-up ranged from 1 week to 6 years (median 6 wk). Seven (70%) patients had complete resolution or stabilization of their MAI, 1 (10%) with circumferential intimal tear showed extension of the injury at 8 weeks postinjury and underwent successful repair, and 2 (20%) were lost to follow-up.

Conclusion: There appears to be a subset of patients with BTAI who require no surgical intervention. This includes those with limited intimal flaps, which often resolve. Radiologic surveillance is mandatory to ensure MAI resolution and identify any progression that might prompt repair.
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http://dx.doi.org/10.1503/cjs.007311DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3506686PMC
December 2012

Late conversion of endovascular to open repair of abdominal aortic aneurysms.

Can J Surg 2012 Aug;55(4):254-8

Division of Vascular Surgery, London Health Sciences Centre and the University of Western Ontario, London, Ontario.

Background: Failure of endovascular repair (EVAR) of an abdominal aortic aneurysm can result in significant risk of morbidity and mortality. We review our experience with late conversions to open repair.

Methods: We conducted a retrospective database review to identify all EVAR procedures performed between 1997 and 2010 and the number converted to open repair at our university-affiliated medical centre. Late conversion was defined as those occurring at least 30 days after initial EVAR.

Results: In all, 892 EVARs took place during the study period. Six patients (0.7%) required late conversion to open repair. Their mean age was 71 (range 58-83) years, and half were women. Half of the initial EVARs were for ruptured aneurysms. The median time to conversion was 15.6 (range 1.7-61.3) months. Indications for secondary conversion (50% urgent, 50% elective) included persistent type I endoleak (n = 3), combined type II and III endoleak (n = 1), graft thrombosis (n = 1) and aneurysm rupture (n = 1). Supraceliac clamping was required in most patients (67%), and the mean transfusion requirement was 2.6 units. Total endograft explantation occurred in 2 patients (33%), whereas partial or total endograft preservation occurred in 4 (67%). Median length of stay in hospital after conversion was 7 (range 6-73) days. There were no instances of early or in-hospital mortality following conversion.

Conclusion: Our EVAR experience includes a low rate of late conversion to open repair, with most conversions being a result of persistent aneurysm perfusion. Although technically challenging, late conversion can be safe. Our experience supports ongoing surveillance after EVAR.
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http://dx.doi.org/10.1503/cjs.038310DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3404146PMC
August 2012

Early results from a Canadian multicenter prospective registry of the Endurant stent graft for endovascular treatment of abdominal aortic aneurysms.

J Endovasc Ther 2012 Feb;19(1):58-66

Division of Vascular Surgery, McGill University Health Centre, Montreal, Quebec, Canada.

Purpose: To report the early results of a multicenter registry of endovascular aneurysm repair (EVAR) using the Endurant stent-graft.

Methods: Patients having elective treatment of infrarenal abdominal aortic aneurysm (AAA) with the Endurant stent-graft at 3 Canadian centers were enrolled in a prospective registry between September 2008 and January 2010. In the 16-month period, 111 patients (90 men; mean age 75 years, range 53-93) were registered. Thirty-seven (33.3%) patients had challenging anatomy: short proximal aortic necks (n=17), large diameter (>28 mm) aortic necks (n=4), angulated (>60°) necks (n=3), and small (<15 mm) external iliac arteries (n=21). Outcomes evaluated included survival, endoleak, aneurysm expansion >5 mm, secondary intervention, stent-graft migration, and graft thrombosis.

Results: The overall technical success rate was 100%. Nineteen (17.1%) patients experienced perioperative complications. After a mean follow-up of 6 months (range 0.1-16), mortality in the series was 4.5%: 1 perioperative death (multisystem organ failure) and 4 (3.6%) late deaths (3 cardiac, 1 cancer). Clinical and imaging follow-up past the perioperative period were available in 107 (96.4%) and 99 (89.2%) patients, respectively. Among the latter, 9 (9.1%) had a type II endoleak on the first scan; 4 resolved spontaneously. Three (3.0%) patients developed graft limb thrombosis in follow-up; one required an intervention. There was no graft migration, aneurysm expansion, secondary intervention for endoleak, aneurysm rupture, or conversion.

Conclusion: Early results from this prospective multicenter registry indicate that the Endurant stent-graft is a safe option for elective EVAR in selected AAA patients. Longer follow-up is required to determine the durability of these outcomes.
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http://dx.doi.org/10.1583/11-3622.1DOI Listing
February 2012

Trends in management of abdominal aortic aneurysms.

J Vasc Surg 2012 Apr 5;55(4):924-8. Epub 2012 Jan 5.

Division of Vascular Surgery, London Health Sciences Centre and the University of Western Ontario, London, Ontario, Canada.

Objective: The purpose of this study was to evaluate patients undergoing elective repair of infrarenal abdominal aortic aneurysms (AAAs) and the longitudinal trends in surgical management (open repair vs endovascular aneurysm repair [EVAR]), factors associated with the choice of surgical technique, and differences in the rate of in-hospital mortality at a single large-volume Canadian center.

Methods: This retrospective cohort study used data from a prospectively collected vascular surgery database and reviewed all patients undergoing elective repair of an infrarenal AAA over a recent 10-year period (June 2000-May 2010). Information was reviewed regarding surgical techniques, patient demographics, and short-term outcomes. Subsequent analysis included univariate statistics and multivariable logistic regression with data presented as odds ratios (ORs) and 95% confidence intervals (CIs).

Results: A total of 1942 patients underwent elective AAA repair over this 10-year study period, 1067 (54.9%) via open repair and 875 (45.1%) via EVAR. The proportion of patients undergoing EVAR was significantly higher in the latter half of the study period compared to the first half (55.8% vs 33.9%; P < .01). Older patients (75 vs 71; P < .01) and those with higher American Society of Anesthesiologists classifications (P < .01) were more likely to receive endovascular repair than open repair. The overall in-hospital mortality rate in the entire cohort was low (2.3% for EVAR and 3.9% for open repair), and after multivariable logistic regression and adjustment for preoperative factors, in-hospital mortality was significantly higher in patients with open AAA repair (OR, 1.8; 95% CI, 1.04-3.13; P = .04).

Conclusions: This 10-year analysis shows a significant shift toward an endovascular approach in the repair of infrarenal AAAs at our Canadian center. Similar to other jurisdictions, higher risk and older patients are more likely to be treated with an endovascular repair resulting in a survival advantage in these patients compared to standard open repair.
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http://dx.doi.org/10.1016/j.jvs.2011.10.094DOI Listing
April 2012

The role of platelet-rich plasma in inguinal wound healing in vascular surgery patients.

Vasc Endovascular Surg 2011 Apr;45(3):241-5

Division of Vascular Surgery, London Health Sciences Centre and The University of Western Ontario, London, Ontario, Canada.

The objective was to determine whether incision application of platelet-rich plasma (PRP) will decrease postoperative wound complications in vascular surgery patients. A prospective, randomized trial randomized 81 incisions in 51 patients who underwent femoral artery exposure for elective revascularization procedures or endovascular abdominal aneurysm repairs. Incidence of diabetes, chronic renal failure, prosthetic grafts, body mass index (BMI), and steroid use did not differ. Using the ASEPSIS wound classification system, we found no difference in incidence of wound infection. Wound complications occurred in 9 (23%) of 40 of PRP group and 9 (22%) of 41 of non-PRP. Severe wound complications developed in 5 (13%) PRP and 6 (5%) of non-PRP (P = NS). In multivariate analysis, there were no predictors for wound infection. Groin wound complications rates are common in this patient group. Platelet-rich plasma did not decrease the incidence of groin wound complications in our patients.
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http://dx.doi.org/10.1177/1538574411399157DOI Listing
April 2011

Midterm results of the Zenith endograft in relation to neck length.

Ann Vasc Surg 2010 Oct;24(7):859-62

Division of Vascular Surgery, London Health Sciences Centre and the University of Western Ontario, London, Ontario, Canada.

Background: Successful endovascular repair of abdominal aortic aneurysms (AAAs) requires specific infrarenal neck anatomy to allow for a durable seal and fixation. This is a single-center study reviewing outcomes in relation to neck length after placement of a Zenith endograft.

Methods: Retrospective single-center review of all AAAs electively repaired with a Zenith endograft during a recent 5-year period. Patients were divided into those with infrarenal necks 4-15 mm in length and those >15 mm using center line measurements. Clinical outcomes and follow-up computed tomography scans were reviewed.

Results: Between 2003 and 2008, 318 patients underwent elective repair of an infrarenal AAA with the Zenith endograft. Of 318 patients, 68 (21.4%) had necks measuring 4-15 mm in length and 250 (79.5%) had necks measuring >15 mm. Overall early mortality was 0.9% (p = 0.11) and the rate of type II endoleaks was 19% (p = 0.11); neither differed between the groups. Four patients in each group had immediate proximal type I endoleaks, which resolved spontaneously in two patients in each group. The remaining two in each group required further intervention (two endovascular and two conversion to open repair). Type I endoleaks and reinterventions did not differ statistically between groups (p = 0.06). On further analysis, those patients requiring reintervention or conversion for type I endoleaks had other unattractive neck features (large diameter, angulation). There have been no instances of new type I endoleaks during 5-yearfollow-up period.

Conclusion: These midterm results indicate that patients with shorter infrarenal necks can be treated as effectively as those with longer necks with the Zenith endograft unless these necks are tortuous or wide.
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http://dx.doi.org/10.1016/j.avsg.2010.05.012DOI Listing
October 2010
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