Publications by authors named "Peter Downey"

28 Publications

  • Page 1 of 1

Timing of Coronary Artery Bypass Grafting in Acute Coronary Syndrome: A National Analysis.

Ann Thorac Surg 2021 Jun 11. Epub 2021 Jun 11.

Cardiovascular Outcomes Research Laboratories, Division of Cardiac Surgery, Department of Surgery, University of California, Los Angeles, Los Angeles, California. Electronic address:

Background: Timing of surgical revascularization for acute coronary syndrome (ACS) remains debated. We assessed the impact of timing to CABG on mortality and resource utilization in a national cohort.

Methods: Adults admitted for ACS in the 2009-2018 National Inpatient Sample were grouped by time from coronary angiography to CABG (Δt): 0, 1-3, 4-7, and >7 days. Generalized linear models were fit to evaluate associations between Δt and in-hospital mortality and hospitalization costs. Timing and mortality of CABG for ACS was compared between high-performing hospitals (below the median risk adjusted mortality for all CABG and valve operations) and others.

Results: Of 444,065 patients, time to CABG was Δt=0 in 12.3%, Δt=1-3 in 57.3%, Δt=4-7 in 26.3%, and Δt>7 in 4.2%. Risk-adjusted mortality was greatest at Δt=0 (4.5%, 95% confidence interval, CI, 4.1-4.9) and Δt>7 (4.0%, 95% CI 3.4-4.7), but similar for operations performed at Δt=1-3 (1.8%, 95% CI 1.7-1.9) and Δt=4-7 (2.1%, 95% CI 1.9-2.3). Compared to Δt=1-3, hospitalization costs were greater by $6,400 (95% CI 5,900-6,900) for Δt=4-7 and $21,200 (95% CI 19,800-22,600) for Δt>7. High-performing hospitals had similar time to CABG as others (2 vs 2 days, p=0.17), but lower mortality (0.9% vs 3.3%, p<0.001).

Conclusions: Revascularization on day 1-3 and 4-7 led to comparable in-hospital mortality, with greater rates on day 0 and after day 7. Costs were greater for revascularization at day 4-7 compared to day 1-3. These findings support the reduction of time to revascularization to 1-3 days when deemed clinically appropriate and feasible.
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http://dx.doi.org/10.1016/j.athoracsur.2021.05.057DOI Listing
June 2021

A Case of Leadless Pacemaker in the Left Ventricle With Cardioembolic Stroke.

JACC Clin Electrophysiol 2021 04;7(4):563-564

Department of Cardiovascular Medicine, University of Kansas, Kansas City, Kansas, USA. Electronic address:

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http://dx.doi.org/10.1016/j.jacep.2021.01.002DOI Listing
April 2021

Impact of Postoperative Infections on Readmission and Resource Use in Elective Cardiac Surgery.

Ann Thorac Surg 2021 Apr 18. Epub 2021 Apr 18.

Cardiovascular Outcomes Research Laboratories, Division of Cardiac Surgery, Department of Surgery, University of California, Los Angeles, Los Angeles, California. Electronic address:

Background: Efforts to reduce postoperative infections have garnered national attention, leading to practice guidelines for cardiac surgical perioperative care. The present study characterized the impact of healthcare-acquired infection (HAI) on index hospitalization costs and post-discharge healthcare utilization.

Methods: Adults undergoing elective coronary artery bypass grafting (CABG) and/or valve operations were identified in the 2016-2018 Nationwide Readmissions Database. Infections were categorized into bloodstream, gastrointestinal, pulmonary, surgical site, or urinary tract infections. Generalized linear or flexible hazard models were used to assess associations between infections and outcomes. Observed-to-expected (O/E) ratios were generated to examine inter-hospital variation in HAI.

Results: Of an estimated 444,165 patients, 8.0% developed HAI. Patients with HAI were older, had a greater burden of chronic diseases, and more commonly underwent CABG/valve or multi-valve operations (all p<0.001). HAI was independently associated with mortality (odds ratio 4.02, 95% CI 3.67-4.40), non-home discharge (3.48, 95% CI 3.21-3.78), and a cost increase of $23,000 (95% CI 20,900-25,200). At 90 days, HAI was associated with greater hazard of readmission (1.29, 95% CI 1.24-1.35). Pulmonary infections had the greatest incremental impact on patient-level ($24,500, 95% CI 23,100-26,00) and annual cohort costs ($121.8 million, 95% CI 102.2-142.9 million). Significant hospital level variation in HAI was evident, with O/E ranging from 0.17 to 4.3 for cases performed in 2018.

Conclusions: Infections following cardiac surgery remain common and are associated with inferior outcomes and increased resource use. The presence of inter-hospital variation in this contemporary cohort emphasizes the ongoing need for systematic approaches in their prevention and management.
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http://dx.doi.org/10.1016/j.athoracsur.2021.04.013DOI Listing
April 2021

Supercritical-CO extraction, identification and quantification of polyprenol as a bioactive ingredient from Irish trees species.

Sci Rep 2021 Apr 2;11(1):7461. Epub 2021 Apr 2.

Department of Applied Science, Limerick Institute of Technology, Moylish Park, Moylish, Co Limerick, Ireland.

This study ascertained the accumulation of polyprenol from four Irish conifer species Picea sitchensis, Cedrus atlantica 'Glauca', Pinus sylvestris and Taxus baccata and one flowering tree Cotoneaster hybrida using supercritical fluid extraction with carbon dioxide (SFE-CO) and solvent extraction. The effects of SFE-CO parameters such as temperature (ranged from 40 to 70 [Formula: see text]), pressure (ranged from 100 to 350 bars) and dynamic time (from 70 min to 7 h) were analysed on the extraction efficiency of polyprenol. Qualitative and quantitative analysis of polyprenol was examined using high-performance liquid chromatography. Results showed that P. sylvestris accumulated the highest polyprenol yield of 14.00  ± [Formula: see text]mg g DW when extracted with hexane:acetone (1:1 v/v). However, with SFE-CO conditions of 200 bars, 70 [Formula: see text], 7 h, with absolute ethanol as a cosolvent with a flow rate of 0.05 ml min, P. sitchensis accumulated the highest polyprenol yield of 6.35 ± [Formula: see text] mg gDW. This study emphasised the potential application of SFE-CO in the extraction of polyprenol as an environmentally friendly method to be used in pharmaceutical and food industries.
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http://dx.doi.org/10.1038/s41598-021-86393-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8018978PMC
April 2021

Trends in utilization, mortality, and resource use after implantation of left ventricular assist devices in the United States.

J Thorac Cardiovasc Surg 2021 Jun 19;161(6):2083-2091.e4. Epub 2020 Feb 19.

Cardiovascular Outcomes Research Laboratories (CORELAB), University of California Los Angeles, Los Angeles, Calif; Division of Cardiac Surgery, University of California Los Angeles, Los Angeles, Calif. Electronic address:

Objectives: Adoption of implantable left ventricular assist devices has dramatically improved survival and quality of life in suitable patients with end-stage heart failure. In the era of value-based healthcare delivery, assessment of clinical outcomes and resource use associated with left ventricular assist devices is warranted.

Methods: Adult patients undergoing left ventricular assist device implantation from 2008 to 2016 were identified using the National Inpatient Sample. Hospitals were designated as low-volume, medium-volume, or high-volume institutions based on annual institutional left ventricular assist device case volume. Multivariable logistic regression was used to evaluate adjusted odds of mortality across left ventricular assist device volume tertiles.

Results: Over the study period, an estimated 23,972 patients underwent left ventricular assist device implantation with an approximately 3-fold increase in the number of annual left ventricular assist device implantations performed (P for trend <.001). In-hospital mortality in patients with left ventricular assist devices decreased from 19.6% in 2008 to 8.1% in 2016 (P for trend <.001) and was higher at low-volume institutions compared with high-volume institutions (12.0% vs 9.2%, P < .001). Although the overall adjusted mortality was higher at low-volume compared with high-volume institutions (adjusted odds ratio, 1.66; 95% confidence interval, 1.28-2.15), this discrepancy was only significant for 2008 and 2009 (low-volume 2008 adjusted odds ratio, 5.5; 95% confidence interval, 1.9-15.8; low-volume 2009 adjusted odds ratio, 2.3; 95% confidence interval, 1.4-3.8).

Conclusions: Left ventricular assist device use has rapidly increased in the United States with a concomitant reduction in mortality and morbidity. With maturation of left ventricular assist device technology and increasing experience, volume-related variation in mortality and resource use has diminished. Whether the apparent uniformity in outcomes is related to patient selection or hospital quality deserves further investigation.
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http://dx.doi.org/10.1016/j.jtcvs.2019.12.121DOI Listing
June 2021

Method to Evaluate the Age of Groundwater Inputs to Surface Waters by Determining the Chirality Change of Metolachlor Ethanesulfonic Acid (MESA) Captured on a Polar Organic Chemical Integrative Sampler (POCIS).

J Agric Food Chem 2020 Feb 14;68(8):2297-2305. Epub 2020 Feb 14.

Pasture Systems & Watershed Management Research , US Department of Agriculture (USDA), Agricultural Research Service (ARS) , Curtin Road, Building 3702 , University Park , Pennsylvania 16802 , United States.

We previously discovered a method to estimate the groundwater mean residence time using the changes in the enantiomeric ratio of metolachlor ethanesulfonic acid (MESA), (2-[(2-ethyl-6-methylphenyl)(2-methoxy-1-methylethyl)amino]-2-oxoethanesulfonic acid), a metabolite of the herbicide metolachlor. However, many grab samples would be needed for each watershed over an extended period, and this is not practical. Thus, we examined the use of a polar organic chemical integrative sampler (POCIS) deployed for 28 days combined with a modified liquid chromatography-mass spectrometry LC-MS/MS method to provide a time-weighted average of the MESA enantiomeric ratio. POCISs equipped with hydrophilic-lipophilic-balanced (HLB) discs were deployed at five sites across the United States where metolachlor was used before and after 1999 and compared the effectiveness of the POCIS to capture MESA versus grab samples. In addition, an in situ POCIS sampling rate () for MESA was calculated (0.15 L/day), the precision of MESA extraction from stored POCIS discs was determined, and the effectiveness of HLB to extract MESA was examined. Finally, using molecular modeling, the influence of the asymmetric carbon of metolachlor degradation on the MESA enantiomeric ratio was predicted to be negligible. Results of this work will be used in projects to discern the groundwater mean residence times, to evaluate the delivery of nitrate-N from groundwater to surface waters under various soil, agronomic, and land use conditions, and to examine the effectiveness of conservation practices.
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http://dx.doi.org/10.1021/acs.jafc.9b06187DOI Listing
February 2020

Ambulatory central veno-arterial extracorporeal membrane oxygenation in lung transplant candidates.

J Heart Lung Transplant 2019 12 11;38(12):1317-1319. Epub 2019 Sep 11.

Division of Cardiac Surgery, Department of Surgery, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California. Electronic address:

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http://dx.doi.org/10.1016/j.healun.2019.09.006DOI Listing
December 2019

National Study of Index and Readmission Mortality and Costs for Thoracic Endovascular Aortic Repair in Patients With Renal Disease.

Ann Thorac Surg 2020 02 20;109(2):458-464. Epub 2019 Jul 20.

Division of Cardiac Surgery, Cardiovascular Outcomes Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, California. Electronic address:

Background: In the current era of value-based health care delivery, an understanding of patient populations at greatest risk for mortality, complications, and readmissions after thoracic endovascular aortic repair (TEVAR) is warranted. Thus, the present study aimed to evaluate outcomes after TEVAR for patients with varying degrees of renal dysfunction.

Methods: All patients who underwent TEVAR from 2010 to 2015 in the Nationwide Readmissions Database were identified. These patients were further stratified into four groups: no chronic kidney disease (NCKD), chronic kidney disease (CKD) stages 1 to 3 (CKD1-3), CKD 4 to 5 (CKD4-5), and end-stage renal disease (ESRD) requiring dialysis. Multivariable regression analysis was used to study index mortality, early (30 days) and intermediate (31-90 days) readmissions, costs, and length of stay. Kaplan-Meier analyses were performed to compare readmission performance among all four groups.

Results: An estimated 121,046 patients underwent TEVAR with 26,653 (22.1%) being elective. Patients with ESRD comprised 2.7% of elective and 5.4% of nonelective TEVAR operations. Patients with CKD4-5 (17.8%; P = .01) and with ESRD (21.1%; P < .001), but not with CKD1-3 (14.1%; P = .12), had remarkably higher early readmission rate than the NCKD cohort (9.2%). Patients with ESRD had remarkably higher hospitalization costs than the NCKD group ($7456; 95% confidence interval, $2629-$12,283). Cardiovascular, infectious, and vascular complications were the most prevalent diagnoses on readmission, with no remarkable difference among the NCKD and CKD4-5/ESRD groups.

Conclusions: Nearly 10% of all patients with TEVAR have evidence of chronic kidney disease of varying severity. Only patients with ESRD are at risk of substantially higher odds of mortality, readmissions, index length of stay, and costs compared with the non-CKD cohort.
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http://dx.doi.org/10.1016/j.athoracsur.2019.05.071DOI Listing
February 2020

Rehospitalization and resource use after inpatient admission for extracorporeal life support in the United States.

Surgery 2019 11 2;166(5):829-834. Epub 2019 Jul 2.

Cardiovascular Outcomes Research Laboratories (CORELAB), Division of Cardiac Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA. Electronic address:

Background: With increasing dissemination and improved survival after extracorporeal life support, also called extracorporeal membrane oxygenation, the decrease in readmissions after hospitalization involving extracorporeal life support is an emerging priority. The present study aimed to identify predictors of early readmission after extracorporeal life support at a national level.

Methods: This was a retrospective cohort study using the Nationwide Readmissions Database. All patients ≥18 years who underwent extracorporeal life support from 2010 to 2015 were identified. Patients were stratified into the following categories of extracorporeal life support: postcardiotomy, primary cardiogenic shock, cardiopulmonary failure, respiratory failure, transplantation, and miscellaneous. The primary outcome of the study was the rate of 90-day rehospitalization after extracorporeal life support admission. A multivariable logistic regression model was developed to predict the odds of unplanned 90-day readmission. Kaplan-Meier analyses were also performed.

Results: An estimated 18,748 patients received extracorporeal life support with overall mortality of 50.2%. Of the patients who survived hospitalization, 30.2% were discharged to a skilled nursing facility, and 21.1% were readmitted within 90 days after discharge. After adjusting for patient and hospital characteristics, cardiogenic shock was associated with the greatest odds of mortality (adjusted odds ratio 1.6; 95% confidence interval, 1.09-1.46; C-statistic, 0.64). The cohort with respiratory failure had decreased odds of readmission (adjusted odds ratio 0.76; 95% confidence interval, 0.58-0.99). Discharge to skilled nursing facility (adjusted odds ratio 1.64; 95% confidence interval, 1.36-1.97) was independently associated with readmission. Cardiac and respiratory-related readmissions comprised the majority of unplanned 90-day rehospitalizations.

Conclusion: In this large analysis of readmissions after extracorporeal life support in adults, 21% of extracorporeal life support survivors were rehospitalized within 90 days of discharge. Disposition to a skilled nursing facility, but not advanced age nor female sex, was associated with readmission.
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http://dx.doi.org/10.1016/j.surg.2019.05.013DOI Listing
November 2019

A Febrile, Hypotensive Patient With Bilateral Lung Crackles.

JAMA 2019 Jun;321(24):2460-2461

Department of Cardiac Surgery, University of California, Los Angeles.

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http://dx.doi.org/10.1001/jama.2019.6546DOI Listing
June 2019

National trends in volume-outcome relationships for extracorporeal membrane oxygenation.

J Surg Res 2018 11 31;231:421-427. Epub 2018 Jul 31.

Division of Cardiac Surgery, Cardiovascular Outcomes Research Laboratories (CORELAB), David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California. Electronic address:

Background: The use of extracorporeal membrane oxygenation (ECMO) has emerged as a common therapy for severe cardiopulmonary dysfunction. We aimed to describe the relationship of institutional volume with patient outcomes and examine transfer status to tertiary ECMO centers.

Materials And Methods: Using the National Inpatient Sample, we identified adult patients who received ECMO from 2008 to 2014. Individual hospital volume was calculated as tertiles of total institutional discharges for each year independently.

Results: Of the total 18,684 adult patients placed on ECMO, 2548 (13.6%), 5278 (28.2%), and 10,858 (58.1%) patients were admitted to low-, medium-, and high-volume centers, respectively. Unadjusted mortality at low-volume hospitals was less than that of medium- (43.7% versus 50.3%, P = 0.03) and high-volume hospitals (43.7% versus 55.6%, P < 0.001). Length of stay and cost were reduced at low-volume hospitals compared to both medium- and large-volume institutions (all P < 0.001). In high-volume institutions, transferred patients had greater postpropensity-matched mortality (58.5% versus 53.7%, P = 0.05) and cost ($190,299 versus $168,970, P = 0.009) compared to direct admissions. On exclusion of transferred patients from propensity analysis, mortality remained greater in high-volume compared to low-volume centers (50.2% versus 42.8%, P = 0.04). Predictors of mortality included treatment at high-volume centers, respiratory failure, and cardiogenic shock (all P < 0.001).

Conclusions: Our findings show increased in-hospital mortality in high-volume institutions and in patients transferred to tertiary centers. Whether this phenomenon represents selection bias or transfer from another facility deserves further investigation and will aid with the identification of surrogate markers for quality of high-risk interventions.
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http://dx.doi.org/10.1016/j.jss.2018.07.012DOI Listing
November 2018

Trends in mortality and resource utilization for extracorporeal membrane oxygenation in the United States: 2008-2014.

Surgery 2019 02 22;165(2):381-388. Epub 2018 Sep 22.

Division of Cardiac Surgery, Department of Surgery, University of California at Los Angeles, Los Angeles, CA. Electronic address:

Background: Extracorporeal membrane oxygenation is used as a life-sustaining measure in patients with acute or end-stage cardiac or respiratory failure. We analyzed national trends in extracorporeal membrane oxygenation use and outcomes and assessed the influence of hospital demographics.

Methods: Adult extracorporeal membrane oxygenation patients in the 2008-2014 National Inpatient Sample were evaluated. Patient and hospital characteristics, extracorporeal membrane oxygenation indication, mortality, and hospital costs were analyzed.

Results: A total 17,020 adult extracorporeal membrane oxygenation patients were considered: 47.4% respiratory failure, 38.6% postcardiotomy, 5.5% lung transplantation, 5.5% cardiogenic shock, and 3.2% heart transplantation. Admissions rose 361% from 1,026 in 2008 to 4,815 in 2014 (P < .0001), and the fraction of respiratory failure increased 40.5%-49.8% (P < .001). Elixhauser scores rose from 3.1 to 4.1 (P < .0001). Mortality decreased among total admissions from 62.4% to 42.7% (P < .0001) associated with an observed decline in postcardiotomy mortality. Mean hospital costs and length of stay remained stable throughout the study period. Although extracorporeal membrane oxygenation occurred most frequently at large hospitals, small and medium-sized hospitals showed significant expansion (P < .001). The Northeast exhibited a sustained three-fold per capita increase in extracorporeal membrane oxygenation rate (P < .0001).

Conclusion: The past decade has seen an exponential growth of ECMO extracorporeal membrane oxygenation in the United States, with the fraction for respiratory failure displaying considerable growth. Overall extracorporeal membrane oxygenation patients experienced substantially reduced mortality, driven by improved outcomes for postcardiotomy patients, along with a trend toward an increased risk profile. Disproportionate use of extracorporeal membrane oxygenation in the Northeast warrants investigation of access to this technology across the United States.
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http://dx.doi.org/10.1016/j.surg.2018.08.012DOI Listing
February 2019

Using a Vegetative Environmental Buffer to Reduce the Concentrations of Volatile Organic Compounds in Poultry-House Atmospheric Emissions.

J Agric Food Chem 2018 Aug 30;66(31):8231-8236. Epub 2018 Jul 30.

U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS) , 10300 Baltimore Avenue , Beltsville , Maryland 20705 , United States.

Ground-level ozone is formed when volatile organic compounds (VOCs) react with hydroxyl radicals and nitrogen oxides in the presence of ultraviolet light. Research has typically focused on the release and control of VOCs from hydrocarbon processing; however, agricultural activities, such as poultry production, can also be VOC sources and potentially contribute to ozone pollution. Therefore, this study examines the emission of C-C VOCs from poultry houses and the use of a vegetative environmental buffer (VEB) as a potential mitigation strategy. Sampling campaigns were conducted at two farms, one with and one without a VEB. Of the nine compounds measured, methanol, ethanol, and acetone were the primary VOCs emitted and had the largest ozone-formation potential (OFP). A significantly larger decrease in the OFP for methanol as a function of distance from the poultry house was observed at the farm with the VEB as compared with at the farm without the VEB. These results suggest that besides being a visual barrier and particulate screen, VEBs can provide some control of VOCs emitted from poultry production.
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http://dx.doi.org/10.1021/acs.jafc.8b00088DOI Listing
August 2018

Assessment of particulate matter and ammonia emission concentrations and respective plume profiles from a commercial poultry house.

Environ Pollut 2018 Jul 9;238:10-16. Epub 2018 Mar 9.

US Department of Agriculture, Agricultural Research Service (USDA-ARS), 10300 Baltimore Avenue, Beltsville, MD, 20705, USA. Electronic address:

Poultry-emitted air pollutants, including particulate matter (PM) and ammonia, have raised concerns due to potential negative effects on human health and the environment. However, developing and optimizing remediation technologies requires a better understanding of air pollutant concentrations, the emission plumes, and the relationships between the pollutants. Therefore, we conducted ten field experiments to characterize PM (total suspended particulate [TSP], particulate matter less than 10 μm in aerodynamic diameter [PM], and particulate matter less than 2.5 μm in aerodynamic diameter [PM]) and ammonia emission-concentration profiles from a typical commercial poultry house. The emission factors of the poultry house, which were calculated using the concentrations and fan speed, were 0.66 (0.29-0.99) g NH-N birdd for ammonia, 52 (44-168) g dAU (AU = animal unit = 500 kg) for TSP, 3.48 (1.16-9.03) g dAU for PM, and 0.07 (0.00-0.36) g dAU for PM. PM and ammonia emission concentrations decreased as distance from the fan increased. Although emission concentrations were similar in the daytime and nighttime, diurnal and nocturnal plume shapes were different due to the increased stability of the atmosphere at night. Particle size distribution analysis revealed that, at a given height, the percentage of PM and PM was consistent throughout the plume, indicating that the larger particles were not settling out of the airstream faster than the smaller particles. Overall, the direction of the measured air pollutant emission plumes was dominated by the tunnel fan ventilation airflow rate and direction instead of the ambient wind speed and direction. This is important because currently-available air dispersion models use ambient or modeled wind speed and direction as input parameters. Thus, results will be useful in evaluating dispersion models for ground-level, horizontally-released, point sources and in developing effective pollutant remediation strategies for emissions.
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http://dx.doi.org/10.1016/j.envpol.2018.02.039DOI Listing
July 2018

Recurrent and congenital tracheoesophageal fistula in adults.

Eur J Cardiothorac Surg 2017 Dec;52(6):1218-1222

Division of Thoracic Surgery, Department of Surgery, New York Presbyterian Hospital and Columbia University, New York, NY, USA.

Objectives: Recurrent congenital tracheoesophageal fistula (TEF) is well documented in infancy but may also present later in life. This study reviews our experience with the clinical presentation, diagnosis and management of 5 recurrent and 2 primary congenital tracheoesophageal fistulas (TEF) in adult patients. There are no literature series of late recurrence of TEF (repaired in childhood and recurring in adulthood) and relatively few reported cases of initial adult presentation of TEF. In this series, we aim to provide the first large series description of late recurrence of congenital TEF following repair in infancy or childhood. We also present management considerations for this unique group of patients.

Methods: We performed a computer-based search of the adult thoracic surgery departmental operative database at our institution from 2002 to 2014. Patients with iatrogenic TEF or malignant TEF were excluded.

Results: Seven patients are included in our series. Five patients (71%) had recurrent congenital TEF and 2 (29%) had initial diagnosis of congenital TEF. All presented with severe coughing symptoms, and most (86%) had a history of recurrent aspiration pneumonia. Repair technique was dictated by the location of the TEF and the specific tracheoesophageal pathology. Four patients underwent repair via cervical approach with or without a tracheal resection. Three patients with distal recurrence underwent repair via right thoracotomy with partial oesophagectomy for significant tissue compromise and cervical reconstruction. Patients were followed for at least 1 year. All 7 patients experienced full resolution of symptoms. One patient required postoperative placement of a retrievable tracheal stent for tracheomalacia. There were no mortalities.

Conclusions: Adult presentation of congenital TEF is a rare but recognizable clinical entity. Recurrent TEF in adulthood is a possible late complication of TEF repair performed in childhood that has not previously been described. Adult patients experiencing symptoms of cough and recurrent aspiration pneumonia should be evaluated for congenital TEF. Surgical repair of congenital TEF in the adult is feasible and effective with acceptable morbidity.
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http://dx.doi.org/10.1093/ejcts/ezx164DOI Listing
December 2017

In Vivo Post-Cardiac Arrest Myocardial Dysfunction Is Supported by Ca2+/Calmodulin-Dependent Protein Kinase II-Mediated Calcium Long-Term Potentiation and Mitigated by Alda-1, an Agonist of Aldehyde Dehydrogenase Type 2.

Circulation 2016 09 31;134(13):961-977. Epub 2016 Aug 31.

Division of Cardiovascular Medicine, Stanford University, Stanford, CA.

Background: Survival after sudden cardiac arrest is limited by postarrest myocardial dysfunction, but understanding of this phenomenon is constrained by a lack of data from a physiological model of disease. In this study, we established an in vivo model of cardiac arrest and resuscitation, characterized the biology of the associated myocardial dysfunction, and tested novel therapeutic strategies.

Methods: We developed rodent models of in vivo postarrest myocardial dysfunction using extracorporeal membrane oxygenation resuscitation followed by invasive hemodynamics measurement. In postarrest isolated cardiomyocytes, we assessed mechanical load and Ca(2) (+)-induced Ca(2+) release (CICR) simultaneously using the microcarbon fiber technique and observed reduced function and myofilament calcium sensitivity. We used a novel fiberoptic catheter imaging system and a genetically encoded calcium sensor, GCaMP6f, to image CICR in vivo.

Results: We found potentiation of CICR in isolated cells from this extracorporeal membrane oxygenation model and in cells isolated from an ischemia/reperfusion Langendorff model perfused with oxygenated blood from an arrested animal but not when reperfused in saline. We established that CICR potentiation begins in vivo. The augmented CICR observed after arrest was mediated by the activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). Increased phosphorylation of CaMKII, phospholamban, and ryanodine receptor 2 was detected in the postarrest period. Exogenous adrenergic activation in vivo recapitulated Ca(2+) potentiation but was associated with lesser CaMKII activation. Because oxidative stress and aldehydic adduct formation were high after arrest, we tested a small-molecule activator of aldehyde dehydrogenase type 2, Alda-1, which reduced oxidative stress, restored calcium and CaMKII homeostasis, and improved cardiac function and postarrest outcome in vivo.

Conclusions: Cardiac arrest and reperfusion lead to CaMKII activation and calcium long-term potentiation, which support cardiomyocyte contractility in the face of impaired postarrest myofilament calcium sensitivity. Alda-1 mitigates these effects, normalizes calcium cycling, and improves outcome.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.116.021618DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5040468PMC
September 2016

Watch what happens: using a web-based multimedia platform to enhance intraoperative learning and development of clinical reasoning.

Am J Surg 2016 Feb 1;211(2):384-9. Epub 2015 Dec 1.

Department of Surgery, Columbia University Medical Center, 177 Fort Washington Avenue, MHB-7GS 313, New York, NY 10032, USA.

Background: We aim to determine whether observed operations or internet-based video review predict improved performance in the surgery clerkship.

Methods: A retrospective review of students' usage of surgical videos, observed operations, evaluations, and examination scores were used to construct an exploratory principal component analysis. Multivariate regression was used to determine factors predictive of clerkship performance.

Results: Case log data for 231 students revealed a median of 25 observed cases. Students accessed the web-based video platform a median of 15 times. Principal component analysis yielded 4 factors contributing 74% of the variability with a Kaiser-Meyer-Olkin coefficient of .83. Multivariate regression predicted shelf score (P < .0001), internal clinical skills examination score (P < .0001), subjective evaluations (P < .001), and video website utilization (P < .001) but not observed cases to be significantly associated with overall performance.

Conclusions: Utilization of a web-based operative video platform during a surgical clerkship is an independently associated with improved clinical reasoning, fund of knowledge, and overall evaluation. Thus, this modality can serve as a useful adjunct to live observation.
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http://dx.doi.org/10.1016/j.amjsurg.2015.09.007DOI Listing
February 2016

Effectiveness of core biopsy for screen-detected breast lesions under 10 mm: implications for surgical management.

ANZ J Surg 2017 Sep 16;87(9):725-731. Epub 2015 Mar 16.

BreastScreen SA, Adelaide, South Australia, Australia.

Background: Technical advances have improved the detection of small mammographic lesions. In the context of mammographic screening, accurate sampling of these lesions by percutaneous biopsy is crucial in limiting diagnostic surgical biopsies, many of which show benign results.

Methods: Women undergoing core biopsy between January 1997 and December 2007 for <10-mm lesions are included. Patient demographics, imaging features and final histology were tabulated. Performance indices were evaluated.

Results: This audit includes 803 lesions <10 mm. Based on core histology, 345 women (43.0%) were immediately cleared of malignancy and 300 (37.4%) were referred for definitive cancer treatment. A further 157 women (19.6%) required diagnostic surgical biopsy because of indefinite or inadequate core results or radiological-pathological discordance, and one woman (0.1%) needed further imaging in 12 months. The open biopsies were malignant in 46 (29.3%) cases. The positive predictive value of malignant core biopsy was 100%. The negative predictive value for benign core results was 97.7%, and the false-negative rate was 2.6%. The lesion could not be visualized after core biopsy in 5.1% of women and in 4.0% of women with malignant core biopsies excision specimens did not contain residual malignancy. Excessive delays in surgery because of complications of core biopsy were not reported.

Conclusion: Even at this small size range, core biopsy evaluation of screen-detected breast lesions is highly effective and accurate. A lesion miss rate of 3.1% and under-representation of lesions on core samples highlight the continued need for multidisciplinary collaboration and selective use of diagnostic surgical biopsy.
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http://dx.doi.org/10.1111/ans.13037DOI Listing
September 2017

A novel ECMO circuit using a SYNERGY circulite pump in a swine model.

ASAIO J 2014 Sep-Oct;60(5):519-23

From the *Department of General Surgery, Columbia University Medical Center, New York, NY; and †Department of Cardiothoracic Surgery, Columbia University Medical Center, New York, NY.

Extracorporeal membrane oxygenation (ECMO) is used in the management of refractory cardiopulmonary failure. With improvements in technology, patients can be transferred between hospitals, ambulated, and supported for extended periods of time while on ECMO. The SYNERGY CircuLite micropump is a blood pump that has been used as a ventricular assist device for partial support. In this study, we assessed the blood biocompatibility of the SYNERGY blood pump in conjunction with a Quadrox D oxygenator for use in a novel ECMO circuit in a swine model. This clinical design was used to demonstrate early feasibility of this pump system. Four pigs were placed on venovenous ECMO circuit, which consisted of a SYNERGY pump, Quadrox D oxygenator, and Cobe E Pack 3/8 inch tubing. All animals survived the 6 hour ECMO run without catastrophic biocompatibility issues. There was no statistically discernible change from baseline in hematologic parameters, including hemoglobin, plasma-free hemoglobin, total bilirubin, lactate dehydrogenase, D-dimer, fibrinogen, platelets, and P-selectin. We believe that this study serves as a proof of concept and basis for further studies using the SYNERGY pump as a component of ECMO systems.
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http://dx.doi.org/10.1097/MAT.0000000000000115DOI Listing
June 2015

Bilateral embolic protection devices for high-risk cardiac surgery in a patient with recent embolic stroke.

Circ Cardiovasc Interv 2014 Jun;7(3):414-6

From the Center for Interventional Vascular Therapy, Division of Cardiology, New York Presbyterian Hospital and Columbia University (P.D., A.Z., H.T., A.K., A.P., W.G., Z.A.A.); and Cardiovascular Research Foundation, New York, NY (A.K., W.G., Z.A.A.).

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http://dx.doi.org/10.1161/CIRCINTERVENTIONS.114.001223DOI Listing
June 2014

Impact of major bleeding on long-term mortality in anemic versus nonanemic patients undergoing percutaneous coronary intervention using bivalirudin.

Am J Cardiol 2014 May 12;113(9):1481-6. Epub 2014 Feb 12.

Cardiac Catheterization Laboratory, Cardiovascular Institute, Division of Cardiology, Mount Sinai Hospital and School of Medicine, New York, New York.

Bleeding complications after percutaneous coronary intervention (PCI) have been associated with higher short and long-term mortality. Bivalirudin has been shown to reduce bleeding complications in patients who underwent PCI; however, the impact of anemia on bleeding complications and long-term mortality has not been studied. A total of 11,991 patients who underwent PCI over a period of 8 years with bivalirudin as the primary antithrombotic agent were included. Anemia was defined according to the World Health Organization definition. Bleeding complications were prospectively collected. Survival analysis was performed using multivariable Cox proportional hazards models. Of the 11,991 patients, 4,815 patients (40%) had baseline anemia. Major bleeding occurred in 3.3% of patients with anemia compared with 0.7% of patients without anemia (p <0.001) driven largely by transfusion events. In the overall study population, major bleeding was a significant predictor of mortality (hazard ratio [HR] 1.4, 95% confidence interval [CI] 1.04 to 1.8, p = 0.027) at a mean follow-up of 2.6 years (interquartile range 1.4 to 3.5). In patients with anemia, major bleeding remained an independent predictor of mortality (HR 1.5, 95% CI 1.1 to 2.0, p = 0.008); however, in patients without anemia, it did not (HR 1.25, 95% CI 0.52 to 3.03, p = 0.62). In patients who underwent PCI with bivalirudin therapy, major bleeding is associated with early and long-term mortality, which is more pronounced in patients with baseline anemia.
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http://dx.doi.org/10.1016/j.amjcard.2014.01.427DOI Listing
May 2014

Rat model of veno-arterial extracorporeal membrane oxygenation.

J Transl Med 2014 Feb 7;12:37. Epub 2014 Feb 7.

Center for Interventional Vascular Therapy, Division of Cardiology, New York Presbyterian Hospital and Columbia University, 161 Fort Washington Avenue, Herbert Irving Pavilion, 6th Floor, New York, NY 10032, USA.

Background: We aim to develop a rat model of veno-arterial extracorporeal membrane oxygenation (VA-ECMO).

Methods: VA-ECMO was established in twelve Male Sprague-Dawley rats (250-350 g) through cannulation of the right jugular vein for venous drainage and the right femoral artery for arterial reinfusion. Arterial blood pressure was measured using a conductance catheter through cannulation of the left carotid artery. Heart rate was monitored by electrocardiography and arterial blood gas parameters with a blood gas analyzer. The VA-ECMO circuit was tested by subjecting the rats to hypoxic cardiac arrest with resuscitation using VA-ECMO. Both load-dependent and load-independent measures of myocardial contractility were measured using pressure-volume loop analysis to confirm restoration of myocardial function post-resuscitation.

Results: Following hypoxic cardiac arrest VA-ECMO provided sufficient oxygenation to support the circulation. The haemodynamic and blood gas parameters were maintained at transition and during ECMO. All animals were resuscitated, regained cardiac function and were able to be weaned off ECMO post-resuscitation.

Conclusion: We have established a safe, high-throughput, economical, functioning rat model of VA-ECMO.
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http://dx.doi.org/10.1186/1479-5876-12-37DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3925959PMC
February 2014

Metolachlor metabolite (MESA) reveals agricultural nitrate-N fate and transport in Choptank River watershed.

Sci Total Environ 2014 Mar 2;473-474:473-82. Epub 2014 Jan 2.

United States Department of Agriculture, Agricultural Research Service (USDA-ARS), Henry A. Wallace Beltsville Agricultural Research Center, 10300 Baltimore Avenue, Beltsville, MD 20705, USA.

Over 50% of streams in the Chesapeake Bay watershed have been rated as poor or very poor based on the index of biological integrity. The Choptank River estuary, a Bay tributary on the eastern shore, is one such waterway, where corn and soybean production in upland areas of the watershed contribute significant loads of nutrients and sediment to streams. We adopted a novel approach utilizing the relationship between the concentration of nitrate-N and the stable, water-soluble herbicide degradation product MESA {2-[2-ethyl-N-(1-methoxypropan-2-yl)-6-methylanilino]-2-oxoethanesulfonic acid} to distinguish between dilution and denitrification effects on the stream concentration of nitrate-N in agricultural subwatersheds. The ratio of mean nitrate-N concentration/(mean MESA concentration * 1000) for 15 subwatersheds was examined as a function of percent cropland on hydric soil. This inverse relationship (R(2)=0.65, p<0.001) takes into consideration not only dilution and denitrification of nitrate-N, but also the stream sampling bias of the croplands caused by extensive drainage ditch networks. MESA was also used to track nitrate-N concentrations within the estuary of the Choptank River. The relationship between nitrate-N and MESA concentrations in samples collected over three years was linear (0.95 ≤ R(2) ≤ 0.99) for all eight sampling dates except one where R(2)=0.90. This very strong correlation indicates that nitrate-N was conserved in much of the Choptank River estuary, that dilution alone is responsible for the changes in nitrate-N and MESA concentrations, and more importantly nitrate-N loads are not reduced in the estuary prior to entering the Chesapeake Bay. Thus, a critical need exists to minimize nutrient export from agricultural production fields and to identify specific conservation practices to address the hydrologic conditions within each subwatershed. In well drained areas, removal of residual N within the cropland is most critical, and practices such as cover crops which sequester the residual N should be strongly encouraged. In poorly drained areas where denitrification can occur, wetland restoration and controlled drained structures that minimize ditch flow should be used to maximize denitrification.
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http://dx.doi.org/10.1016/j.scitotenv.2013.12.017DOI Listing
March 2014

Relating nutrient and herbicide fate with landscape features and characteristics of 15 subwatersheds in the Choptank River watershed.

Sci Total Environ 2011 Sep 5;409(19):3866-78. Epub 2011 Jul 5.

United States Geological Survey, Eastern Geographic Research Center, Reston, Virginia, USA.

Excess nutrients and agrochemicals from non-point sources contribute to water quality impairment in the Chesapeake Bay watershed and their loading rates are related to land use, agricultural practices, hydrology, and pollutant fate and transport processes. In this study, monthly baseflow stream samples from 15 agricultural subwatersheds of the Choptank River in Maryland USA (2005 to 2007) were characterized for nutrients, herbicides, and herbicide transformation products. High-resolution digital maps of land use and forested wetlands were derived from remote sensing imagery. Examination of landscape metrics and water quality data, partitioned according to hydrogeomorphic class, provided insight into the fate, delivery, and transport mechanisms associated with agricultural pollutants. Mean Nitrate-N concentrations (4.9 mg/L) were correlated positively with percent agriculture (R(2)=0.56) and negatively with percent forest (R(2)=0.60). Concentrations were greater (p=0.0001) in the well-drained upland (WDU) hydrogeomorphic region than in poorly drained upland (PDU), reflecting increased denitrification and reduced agricultural land use intensity in the PDU landscape due to the prevalence of hydric soils. Atrazine and metolachlor concentrations (mean 0.29 μg/L and 0.19 μg/L) were also greater (p=0.0001) in WDU subwatersheds than in PDU subwatersheds. Springtime herbicide concentrations exhibited a strong, positive correlation (R(2)=0.90) with percent forest in the WDU subwatersheds but not in the PDU subwatersheds. In addition, forested riparian stream buffers in the WDU were more prevalent than in the PDU where forested patches are typically not located near streams, suggesting an alternative delivery mechanism whereby volatilized herbicides are captured by the riparian forest canopy and subsequently washed off during rainfall. Orthophosphate, CIAT (6-chloro-N-(1-methylethyl)-1,3,5-triazine-2,4-diamine), CEAT (6-chloro-N-ethyl-1,3,5-triazine-2,4-diamine), and MESA (2-[(2-ethyl-6-methylphenyl) (2-methoxy-1-methylethyl)amino]-2-oxoethanesulfonic acid) were also analyzed. These findings will assist efforts in targeting implementation of conservation practices to the most environmentally-critical areas within watersheds to achieve water quality improvements in a cost-effective manner.
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http://dx.doi.org/10.1016/j.scitotenv.2011.05.024DOI Listing
September 2011

Predictors of malignancy in screen-detected breast masses with indeterminate/equivocal (grade 3) imaging features.

Breast 2011 Feb 9;20(1):56-61. Epub 2010 Aug 9.

Pathology, BreastScreen SA, 1 Goodwood Road, Wayville, SA 5065, Australia.

Background: The mammographic grading system used by BreastScreen Australia accredited programs requires needle biopsy of lesions with indeterminate features (grade 3). We wished to determine the predictors of malignancy for these common lesions, so as to reduce surgery for benign lesions.

Design: Grade 3 masses assessed between Jan 1996-Dec 2005 are included. New or changing lesions were identified through film review. Imaging, demographic and final outcome data were tabulated. Statistical analysis was performed to determine the predictors of malignancy.

Results: 1181 lesions, including 623 new or changing masses are assessed. Of these 98 (8.3%) were malignant. Malignancy was found in 3% first round masses versus 13% of new or changing lesions. Withholding needle biopsy results, interval change (OR 2.85, p = 0.0001), increasing age (p = 0.0001) and diameter were independent predictors of malignancy, lesion diameter having an inverse relationship with malignancy. Once needle biopsy results were included, this parameter became the sole predictor of malignancy as other factors lost significance in a multivariate model.

Conclusion: Surgical biopsy is not indicated in well-sampled grade 3 masses with benign needle biopsy results. Surgery is valuable for diagnosis or treatment of the remaining such masses without benign needle biopsy results.
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http://dx.doi.org/10.1016/j.breast.2010.07.002DOI Listing
February 2011

Atypical presentations of screen-detected DCIS Implications for pre-operative assessment and surgical intervention.

Breast 2007 Apr 13;16(2):161-71. Epub 2006 Nov 13.

BreastScreen SA and Division of Tissue Pathology, Institute of Medical and Veterinary Science, Frome Road, Adelaide 5000, South Australia.

Few series are published on DCIS that forms parenchymal lesions on screening mammograms. The implications of these unusual presentations for pre-operative assessment and surgical intervention are of interest. In the setting of a large, population-based breast cancer screening program, the diagnostic and management implications of DCIS presenting as parenchymal lesions on screening mammograms are investigated. A total of 125 lesions (20.1% of all DCIS) presented as a mass (n=99) or microcalcifications with an associated parenchymal lesion (n=26). Cytology was positive in 47.1% of cases. Core biopsy diagnosed DCIS in 68.4% of cases. Breast surgery after a definite preoperative diagnosis achieved negative initial margins in 69.4% case, versus 54.7% without a pre-operative malignant diagnosis. The mastectomy rate was 26.4%. Axillary surgery was carried out in 32.8% cases, including axillary clearance in 26.4% of cases. One in five cases of DCIS detected during mammographic screening has features other than pure microcalcifications. This has implications for pre-operative assessment and surgical management.
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http://dx.doi.org/10.1016/j.breast.2006.08.003DOI Listing
April 2007

Combined use of imaging and cytologic grading schemes for screen-detected breast abnormalities improves overall diagnostic accuracy.

Cancer 2005 Oct;105(5):282-8

BreastScreen SA, Wayville, South Australia.

Background: Numeric grading systems have been validated for the reporting of mammographic abnormalities and for breast cytology. The impact of integrating lesion grades from both disciplines on the accuracy of assessment of screen-detected lesions has not been investigated.

Methods: In the current study, all lesions were prospectively classified using the Tabar radiologic grading system, as well as the National Health Service Breast Screening Programme (NHSBSP) cytologic reporting system. For lesions assessed between January 1996 and January 2003, based on final histology or 12 months of follow-up, positive predictive values (PPV) were calculated for each imaging grade and for each cytologic grouping. After integration of the data, changes in the PPV and the negative predictive values (NPV) of cytology among lesions with varying imaging grades were tracked.

Results: Data were retrieved for 4806 lesions. The differences in the rates of malignancy for lesions in the different imaging grades were significant (Grade 5, 95.8%; Grade 4, 54.6%; Grade 3, 11.6%) (P < 0.001). Similarly, the cytologic categories stratified lesions into groups with significantly different rates of malignancy (positive, 99.5%; suspicious, 89.2%; atypical, 43.4%; benign, 5.7%; inadequate, 33.3%) (P < 0.001). Integration of cytologic results with the imaging grade of lesions led to significant improvements in the PPV and NPV. Positive smears were likely to represent malignant lesions in 99.9% of Grade 5 lesions, 99.2% of Grade 4 lesions, and 95.2% of Grade 3 lesions (P < 0.0001). Similarly, negative cytology corresponded to a nonmalignant lesion in 99% of Grade 3 lesions, 81.6% of Grade 4 lesions, and in only 45.5% of Grade 5 lesions (P < 0.001).

Conclusions: The integration of numeric grading schemes for breast imaging and cytology improves the accuracy of assessment of screen-detected lesions. Because 99.9% of Grade 5 lesions with positive cytology are malignant, core biopsy confirmation may not be required in this group.
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http://dx.doi.org/10.1002/cncr.21280DOI Listing
October 2005

Changes in gallbladder motility and gallstone formation following laparoscopic gastric banding for morbid obestity.

Can J Gastroenterol 2003 Mar;17(3):169-74

Departmentof General and Digestive Surgery, Flinders University of South Australia, Adelaide, Australia.

Unlabelled: Morbid obesity is associated with cholesterol gallstone formation, a risk compounded by rapid weight loss. Laparoscopic gastric banding allows for a measured rate of weight loss, but the subsequent risk for developing gallstones is unknown.

Method: Twenty-six normal-weight volunteers (body mass index [BMI] less than 30) were compared with 14 morbidly obese patients (BMI greater than 40). Gallbladder volumes were measured ultrasonographically, after fasting and following stimulation with intravenous cholecystokinin-octapeptide (CCK-8)

Results: Preoperatively, fasting gallbladder volume and residual volume after CCK stimulation were both two times greater in the obese group (P<0.02 versus controls). Per cent gallbladder emptying was not different. Gallbladder refilling was four times higher in the obese patients (P<0.01). By six weeks postoperatively, the obese patients lost 1.4+/-0.1% body weight per week. Gallbladder emptying decreased 18.4% (80.3+/-3.9% to 65.5+/-6.9%; P<0.05); residual volume rose one-third (not significant), and refilling fell 60.5% (0.43+/-0.09 to 0.26+/-0.04 mL/min; P=0.07). Three patients with weight losses of greater than 1.7% per week developed gallstones; gallbladder emptying fell outside the 95 percentile. By six months, weight loss slowed to 0.5+/-0.1% per week; gallbladder motility improved modestly. No further stones developed.

Conclusion: Rapid weight loss following laparoscopic gastric banding impairs gallbladder emptying and when pronounced, gallstones form by six weeks postoperatively. The accompanying reduction in gallbladder emptying, increased gallbladder residual volume and decreased refilling promote gallbladder stasis and hence stone formation.
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http://dx.doi.org/10.1155/2003/392719DOI Listing
March 2003