Publications by authors named "Kenichi Hashizume"

27 Publications

  • Page 1 of 1

Coronary Occlusion During Transcatheter Aortic Valve Replacement With an Anomalous Origin of Left Coronary Artery.

JACC Cardiovasc Interv 2021 Aug 28;14(16):e217-e218. Epub 2021 Jul 28.

Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.

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http://dx.doi.org/10.1016/j.jcin.2021.04.041DOI Listing
August 2021

Total aortic arch replacement using the J-graft open stent graft for distal aortic arch aneurysm: report from two centres in Japan.

Interact Cardiovasc Thorac Surg 2021 Jul 30. Epub 2021 Jul 30.

Department of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Tochigi, Japan.

Objectives: The open-style stent graft technique has been changing the strategy for true distal arch aneurysms extending to the descending aorta. Our mid-term results of surgical repair using a J-graft open stent graft are presented.

Methods: Between May 2015 and June 2020, 69 patients with a distal arch aneurysm (53 males, median age 74 years) underwent total arch replacement combined with J-graft open stent deployment. All 59 surviving patients were followed for a median follow-up period of 1.8 (0.6-3.6) years.

Results: Antegrade deployment was successfully performed in all patients without any difficulties. The deployed device was securely fixed at the target area, and it initiated thrombus formation. The diameter of the excluded aneurysm was decreased in 54 patients (91.5%) during the follow-up period. There were no type I endoleaks, but there were 3 type II endoleaks; 2 of the 3 type II endoleaks disappeared during the follow-up period. Additional endovascular operations were performed in 3 patients. There were 10 in-hospital deaths (14.5%), and the incidences of stroke, spinal cord injury and distal embolism were 11.6%, 5.8% and 2.9%, respectively. The 1- and 3-year survival rates were 84.8% and 79.4%, respectively, and the 1- and 3-year freedom from reintervention rates were 97.2% and 81.3%, respectively.

Conclusions: The J-graft open stent graft was easy to deploy, and it could shift the distal anastomosis to a more proximal side. The mid-term performance of this device was good. It has the potential to provide one-stage repair.
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http://dx.doi.org/10.1093/icvts/ivab114DOI Listing
July 2021

The provisional extension to induce complete attachment technique is associated with abdominal aortic remodeling and reduces aorta-related adverse events after aortic dissection.

J Vasc Surg 2021 07 16;74(1):45-52.e1. Epub 2020 Dec 16.

Department of Cardiovascular Surgery, School of Medicine, Keio University, Tokyo, Japan.

Objective: This study evaluated the efficacy of the provisional extension to induce complete attachment (PETTICOAT) technique for type B and postoperative residual type B aortic dissections compared with the conventional thoracic endovascular aortic repair (TEVAR) technique.

Methods: In this retrospective study, we compared sequential aortic morphologic changes in consecutive patients with type B and postoperative residual type B aortic dissections treated with the PETTICOAT technique between January 2016 and December 2017 with patients treated with the conventional TEVAR between January 2013 and December 2015. Outcomes included aortic remodeling and aorta-related adverse events for 2 years postoperatively.

Results: Forty-eight patients were included in this study (24 in the PETTICOAT group, 24 patients in the conventional TEVAR group). Although both groups showed aortic remodeling in the descending thoracic aorta, the PETTICOAT group developed significantly better aortic remodeling in the abdominal aorta compared with the conventional TEVAR group during the observation period. The PETTICOAT group had significantly fewer aorta-related adverse events compared with the conventional TEVAR group (8% vs 54%; P < .001). Aorta-related adverse events more commonly occurred in the poor remodeling group compared with in the good remodeling group (P = .001; hazard ratio, 8.32; 95% confidence interval, 2.26-30.64).

Conclusions: This study suggests that the PETTICOAT technique for aortic dissection may promote aortic remodeling and decrease the incidence of aorta-related adverse events. Additional studies are required to confirm these preliminary findings.
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http://dx.doi.org/10.1016/j.jvs.2020.11.038DOI Listing
July 2021

Full PETTICOAT in acute type B aortic dissection with patent false lumen may offer positive remodeling for the distal aorta.

Gen Thorac Cardiovasc Surg 2021 Jun 17;69(6):926-933. Epub 2020 Nov 17.

Department of Cardiovascular Surgery, School of Medicine, Keio University, Tokyo, Japan.

Objective: The provisional extension to induce complete attachment (PETTICOAT) technique is a unique thoracic endovascular aortic repair (TEVAR) for aortic dissection, which consists of proximal descending aortic endografting plus distal bare-metal stenting. This study aimed to investigate the efficacy of the PETTICOAT technique in patients with acute-sub-acute complicated type B aortic dissections. In particular, we compared the remodeling effect of full PETTICOAT covering down to the abdominal aorta with that of simple entry closure.

Methods: In this retrospective pre-post study, we compared the clinical course of consecutive patients undergoing TEVAR with the PETTICOAT technique in which proximal entry tear was excluded with a covered stent, and extension bare stents were placed down to the abdominal segment for acute-sub-acute complicated type B aortic dissections, between 2015 and 2017, with a control group treated with TEVAR with entry closure between 2011 and 2015. Outcomes included the aortic remodeling rate and the aortic diameter up to 1 year after surgery.

Results: Subjects consisted of 47 patients (21 in full PETTICOAT group, 26 in the simple entry closure group). The remodeling rate of the abdominal aorta in the full PETTICOAT group was significantly higher than in the simple entry closure group (p < 0.05), while that of the thoracic aorta was comparable between the two groups.

Conclusions: This study suggests that the full PETTICOAT technique achieves better aortic remodeling compared to entry closure alone, and might lead to less reintervention.
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http://dx.doi.org/10.1007/s11748-020-01548-3DOI Listing
June 2021

Ventricular pulling sign on computed tomography in mediastinitis-a predictor for right ventricular rupture at surgery.

Indian J Thorac Cardiovasc Surg 2020 Nov 10;36(6):629-631. Epub 2020 Jul 10.

Departments of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Takebayashicho 911-1, Utsunomiya, Tochigi 321-0974 Japan.

Mediastinitis is an unusual but potentially life-threatening complication of cardiac surgery. Open drainage is one of the standard therapies, but there could sometimes be potential complications. We had a patient who underwent open drainage surgery for postoperative mediastinitis, and right ventricular rupture occurred subsequently to extubation in an operation room. Retrospectively reviewed, computed tomography showed strong adhesions between the right ventricle and the posterior margin of sternum, pulling his right ventricle to the right side of his sternum. We should have noticed the risk of leaving the sternum open and performed adhesiolysis of the right ventricle and the posterior margin of sternum to prevent the devastating complication. This case illustrates the importance of recognizing the rare computed tomography sign of ventricular pulling-a predictor for right ventricular rupture after open drainage for mediastinitis.
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http://dx.doi.org/10.1007/s12055-020-00990-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7572949PMC
November 2020

Efficacy of extracorporeal membrane oxygenation before surgery of a post-infarction ventricular septal rupture in cardiogenic shock.

Interact Cardiovasc Thorac Surg 2020 11;31(5):727-728

Department of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Tochigi, Japan.

A 73-year-old man with an acute myocardial infarction experienced severe cardiogenic shock due to an inferior ventricular septal rupture with a massive left-to-right shunt. Emergency surgery was considered a too high mortality risk. The patient was implanted with an extracorporeal membrane oxygenation system as a bridge to surgery. On the seventh day after admission, the ventricular septal defect was successfully repaired. Our case study demonstrates that extracorporeal membrane oxygenation could be an option in cases of ventricular septal rupture as a bridge for stabilizing patients.
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http://dx.doi.org/10.1093/icvts/ivaa159DOI Listing
November 2020

Emergency surgery for left main disease: with and without cardioplegic arrest.

Asian Cardiovasc Thorac Ann 2019 Mar 19;27(3):157-162. Epub 2019 Jan 19.

1 Division of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Tochigi, Japan.

Background: The aims of this study were to evaluate the on-pump beating-heart technique of coronary artery bypass in patients with acute myocardial infarction and left main disease, and to retrospectively compare the early postoperative results with those of conventional on-pump arrested-heart coronary surgery.

Methods: Eighty-five patients with acute myocardial infarction caused by left main disease, who underwent emergency surgery between January 1998 and April 2017 at Saiseikai Utsunomiya Hospital, were enrolled in this study. Of these patients, 56 were evaluated using propensity-matched analysis. The patients were divided into two groups according to the surgical procedure: group A ( n = 28) had on-pump surgery on the arrested heart, and group B ( n = 28) had on-pump surgery on the beating heart. Early postoperative results were compared between the two groups.

Results: Preoperative and intraoperative characteristics showed no significant differences between the two groups. The peak creatine kinase myocardial band level was significantly lower in group B (group A 151 vs. group B 91 IU·L, p = 0.01). The early mortality rate was higher in group A than group B, but the difference was not significant (group A 28.6% vs. group B 17.9%, p = 0.53).

Conclusions: There was no significant advantage based on surgical procedure between on-pump beating-heart surgery and on-pump surgery on the arrested heart. On-pump beating-heart coronary artery bypass grafting significantly reduced the peak creatine kinase myocardial band level, but there were no significant differences in the early postoperative data, including the mortality rate and left ventricular function.
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http://dx.doi.org/10.1177/0218492319826434DOI Listing
March 2019

Aortic dissection occurring while driving and road traffic accidents.

Am J Emerg Med 2019 07 18;37(7):1374-1376. Epub 2018 Dec 18.

Department of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Utsunomiya, Japan.

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http://dx.doi.org/10.1016/j.ajem.2018.12.026DOI Listing
July 2019

Stepwise Total Aortic Repairs With Fenestrated Endografts in a Patient With Loeys-Dietz Syndrome.

Ann Thorac Surg 2017 Jul;104(1):e39-e42

Department of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Utsunomiya, Tochigi, Japan.

Loeys-Dietz syndrome (LDS) is a rare connective tissue disorder (CTD) caused by mutations in the gene encoding transforming growth factor-β receptors Ⅰ and Ⅱ. Patients with LDS manifest spontaneous aneurysms and dissections of the aorta and peripheral artery. We report a successful treatment with a hybrid endovascular repair for a rapidly expanding thoracoabdominal aneurysm in a 41-year-old woman affected by LDS. To overcome the difficulties of anatomical and surgical repair, we applied an original strategy using surgeon-modified fenestrated endografts.
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http://dx.doi.org/10.1016/j.athoracsur.2017.02.017DOI Listing
July 2017

[Surgeon-modified Fenestrated Thoracic Endovascular Aortic Repair for the Treatment of Aortic Aneurysm].

Kyobu Geka 2017 Apr;70(4):261-265

Department of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Utsunomiya, Japan.

Thoracic endovascular aortic repair( TEVAR) for thoracic aortic aneurysm has been established as a 1st-line therapy, especially in high-risk cases, with device improvements and the appearance of various procedures, but there are still cases of anatomical adaptation. On the other hand, several countermeasures have been developed, but there are no commercially available devices for fenestrated or branched stent grafts in Japan. Moreover, complications such as cerebral infarction, organ ischemia and bypass occlusion and infection are pointed out in popular debranch TEVAR. However the surgeon-modified fenestrated TEVAR can extend the landing zone without open thoracotomy and laparotomy, and can reduce the operation time by decreasing debranch branches. And by the use of a commercially available device, is an urgent correspondence is possible surgical procedures. We report our treatment strategies including experience of 29 cases( Relay Plus:13 cases, Cook TX2:16 cases) of surgeon-modified fenestrated TEVAR that we implemented.
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April 2017

A Permanent Epicardial Pacemaker Lead That Penetrated the Esophageal Wall 26 years After Implantation.

Ann Thorac Surg 2016 Sep;102(3):e185-e186

Department of Surgery, Saiseikai Utsunomiya Hospital, Utsunomiya, Tochigi, Japan.

We treated a patient in whom a permanent epicardial pacemaker lead penetrated the esophageal wall 26 years after the index pacemaker implantation. A 28-year-old man with loss of appetite and weight loss underwent upper gastrointestinal endoscopy and was found to have a foreign body protruding into the esophagus. Computed tomography revealed an epicardial lead penetrating the esophageal wall. He had undergone pacemaker implantation with permanent epicardial leads when he was 2 years old. The lead was surgically removed.
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http://dx.doi.org/10.1016/j.athoracsur.2016.02.022DOI Listing
September 2016

Natural history of the ascending aorta after aortic valve replacement: risk factor analysis for late aortic complications after aortic valve replacement.

Gen Thorac Cardiovasc Surg 2016 May 24;64(5):243-50. Epub 2015 Dec 24.

Division of Cardiovascular Surgery, Hiratsuka Municipal Hospital, Hiratsuka, Kanagawa, Japan.

Background: The purpose of this study was to clarify the natural history of the ascending aorta and to identify risk factors for late ascending aortic events after first isolated aortic valve replacement (AVR).

Methods: A total of 287 patients undergoing AVR were enrolled. The patients were categorized into two groups based on the diameter of the ascending aorta at the time of AVR, as determined by computed tomography: Group A (n = 233) was defined as an ascending aortic diameter <40 mm, and Group B (n = 54) was defined as an ascending aortic diameter ≥40 mm.

Results: The mean follow-up period was 7.6 years. The baseline diameter of the ascending aorta was 31.4 ± 4.8 mm in Group A and 44.7 ± 4.2 mm in Group B. These values increased to 35.9 ± 7.4 mm in Group A and 50.1 ± 7.3 mm in Group B during the follow-up period (P < 0.001). Ten patients had acute type A aortic dissection (Group A: 1 patient vs. Group B: 9 patients; P < 0.001), and three patients had enlargement of the ascending aorta to ≥55 mm in diameter (Group A: 1 patient vs. Group B: 2 patients). Multivariate analysis revealed that the baseline ascending aortic diameter was the only significant risk factor for developing late ascending aortic events (P < 0.001).

Conclusions: AVR alone may not prevent further enlargement of the ascending aorta. An ascending aorta ≥40 mm in diameter at the time of AVR increased the risk of late ascending aortic events.
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http://dx.doi.org/10.1007/s11748-015-0617-9DOI Listing
May 2016

Endovascular aneurysm repair using the periscope graft technique for thoracic aortic anastomotic pseudoaneurysm.

Interact Cardiovasc Thorac Surg 2013 Apr 19;16(4):553-5. Epub 2012 Dec 19.

Department of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Takebayashi, Utsunomiya, Tochigi, Japan.

Replacement of an artificial graft in a redo lateral thoracotomy is extremely difficult with a high risk of lung injury. Endovascular intervention may be an ideal option in such conditions, as in the following case. A 75-year old man with a history of coronary artery bypass graft surgery developed a proximal anastomotic pseudoaneurysm 1 year after undergoing artificial proximal descending aorta replacement surgery. Thoracic endovascular aneurysm repair was performed successfully using the periscope graft technique to preserve the flow into the left subclavian artery from the distal side of the aortic stent graft. Since the patient had coronary artery bypass grafting, debranching of the left subclavian artery was considered too risky. Using the periscope graft technique, the pseudoaneurysm was successfully repaired preserving the left subclavian artery patency, thus obviating a side-to-side subclavian artery crossover bypass.
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http://dx.doi.org/10.1093/icvts/ivs519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3598029PMC
April 2013

Brain swelling in acute superior vena cava syndrome due to aortic dissection: unusual and lethal manifestation aggravated by induction of general anesthesia.

Gen Thorac Cardiovasc Surg 2012 Dec 26;60(12):815-7. Epub 2012 May 26.

Division of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, 911-1 Takebayashi-cho, Utsunomiya, Tochigi, 321-0974, Japan.

A 32-year-old woman with Marfan syndrome experienced acute superior vena cava syndrome due to aortic dissection. The patient had previously undergone a Bentall operation. The aneurysm from the ascending to the transverse aorta compressed the superior vena cava, the right pulmonary artery, and the trachea. The rare and life-threatening neurological complication in this patient may have been related to brain edema, which was revealed by preoperative computed tomography. The induction of general anesthesia aggravated the symptoms of the superior vena cava syndrome and led to a fatal condition. Additional cannulation in the right subclavian vein was mandatory to alleviate the symptoms because the venous drainage from the upper half of the body created only by the femorofemoral bypass was not adequate. Total arch replacement was performed. The postoperative course was uneventful.
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http://dx.doi.org/10.1007/s11748-012-0079-2DOI Listing
December 2012

Giant pseudoaneurysm at the proximal vein graft anastomosis after Bentall procedure for Takayasu arteritis.

J Thorac Cardiovasc Surg 2011 Nov 25;142(5):1272-3. Epub 2011 Jun 25.

Department of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Tochigi, Japan.

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http://dx.doi.org/10.1016/j.jtcvs.2011.05.025DOI Listing
November 2011

Risk factor analysis for acute type A aortic dissection after aortic valve replacement.

Gen Thorac Cardiovasc Surg 2010 Dec 18;58(12):601-5. Epub 2010 Dec 18.

Department of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, 911-1 Takebayashi-machi, Utsunomiya, Tochigi, 321-0974, Japan.

Purpose: Previous aortic valve replacement (AVR) is considered to be an independent risk factor for late acute type A aortic dissection (AAAD). However, the predictors of late AAAD at the time of AVR have not been characterized.

Methods: A total of 285 patients who underwent isolated AVR were followed for 7.6 ± 8.1 years (mean ± SD). These 285 patients were divided into two groups. Group A consisted of 275 patients who did not develop late aortic complications after AVR, and group B consisted of 10 patients (3.5%) who developed late AAAD after AVR.

Results: The mean time interval between initial AVR and developing late AAAD was 6.1 ± 5.2 years. The diameter of the ascending aorta at the time of AVR was significantly greater in group B than those of group A (47.7 ± 4.6 vs. 35.6 ± 6.3 mm; P < 0.001). Univariate analysis identified other predictors as well: aortic regurgitation (P = 0.029), systemic hypertension (P < 0.001), thinning or fragility of the aortic wall (P < 0.001), and male sex (P = 0.039).

Conclusion: Aortic regurgitation combined with systemic hypertension, male sex, and thinned or fragile aortic walls in patients with ascending aortic dilatation (≥45 mm diameter) at the time of AVR may be predisposing factors for postsurgical aortic complications. These patients should be considered for concomitant replacement of the ascending aorta unless the patient has a high operative risk or older age.
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http://dx.doi.org/10.1007/s11748-010-0658-zDOI Listing
December 2010

Current density distribution by ring and diagonally arranged half-ring electrodes in bipolar and overlapping biphasic impulse stimulation.

Pacing Clin Electrophysiol 2010 Sep;33(9):1063-73

Department of Cardiovascular Surgery, Hiratsuka City Hospital, Hiratsuka, Kanagawa, Japan.

Background: We have studied the acute and long-term efficacy of overlapping biphasic impulse (OLBI) stimulation for atrial pacing with VDD pacemakers and demonstrated the feasibility of DDD pacing in OLBI with diagonally arranged half-ring (Half-Ring) electrodes. We made two three-dimensional computational analysis models to verify our clinical studies.

Methods And Results: Model I was composed of a heart, a pacemaker, and a human body. Model II was a cube with dimensions of 20 by 20 by 20 mm quarried from Model I for the detailed study of current density distributions. Laplace's equation was solved using the finite element method and the current density J was calculated. For Model I, the distal and proximal voltages were -10 V, 0 V in bipolar and -5 V, +5 V in OLBI, using Ring electrodes. In Model II, the actual measurements of electrode impedances obtained from the clinical study (1,180 Ω for Ring and 630 Ω for Half-Ring) were added to the analysis conditions. Model I showed that OLBI produced more concentrated current density distributions than those by bipolar. According to Model II, at the atrial myocardium position current density produced by Half-Ring was larger than that by Ring electrodes, 70 μA/mm(2) versus 30 μA/mm(2) in OLBI configuration. It also indicated that even if electrode impedances were equal between Half-Ring and Ring electrodes, the maximum current density produced by Half-Ring would be greater than that by Ring electrodes.

Conclusions: It was considered that OLBI configuration with Half-Ring electrodes provides more effective current density distributions.
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http://dx.doi.org/10.1111/j.1540-8159.2010.02778.xDOI Listing
September 2010

Chronic occlusion of an abdominal aortic aneurysm.

Ann Vasc Dis 2010 2;3(3):240-3. Epub 2010 Dec 2.

Division of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Tochigi, Japan.

A 67-year-old woman with peripheral arterial occlusive disease in both lower extremities, secondary to an abdominal aortic aneurysm, developed chronic total occlusion of the abdominal aortic aneurysm during the 3-year follow-up period. She suffered from sudden onset of paraplegia 3 months after palliative axillobifemoral bypass grafting and died of pneumonia. The paraplegia was considered to have been caused by thrombosis of lumbar arteries that might have served as an important collateral pathway in the distal spinal cord, due to proximally propagated infrarenal aortic thrombosis. It is necessary to recognize that chronically thrombosed abdominal aortic aneurysm (AAA) still has a risk of causing serious complications with a high mortality rate, especially in cases treated medically or with palliative operations.
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http://dx.doi.org/10.3400/avd.cr01026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3595788PMC
April 2013

High-frequency ultrasound-guided late surgical revascularisation of chronically occluded left anterior descending coronary artery.

Eur J Cardiothorac Surg 2010 Jan 19;37(1):239-41. Epub 2009 Aug 19.

Department of Cardiovascular Surgery, Saiseikai Utsunomiya Hospital, Utsunomiya, Tochigi, Japan.

A few successful reports exist of late revascularisation of an 'occluded' left anterior descending coronary artery (LAD) with no angiographically visible collateral circulation. Epicardial high-frequency ultrasound and colour Doppler mapping can directly provide accurate anatomical landmarks and also detect very slow coronary flow velocities, with greater sensitivity than coronary angiograms. Late revascularisation of a chronically occluded LAD was performed successfully in two diabetic patients using high-frequency epicardial echo guidance. This had a positive effect on the left ventricular ejection fraction in the hibernating myocardial segments, and there were no subsequent cardiac events as well. These results indicate that the poor prognosis in diabetic patients with very severely reduced left ventricular function and reduced myocardial viability may be improved by late surgical revascularisation of chronic total occlusion (CTO) with no retrograde collateral channel.
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http://dx.doi.org/10.1016/j.ejcts.2009.07.007DOI Listing
January 2010

Effect of the free radical scavenger MCI-186 on spinal cord reperfusion after transient ischemia in the rabbit.

Jpn J Thorac Cardiovasc Surg 2005 Aug;53(8):426-33

Division of Cardiovascular Surgery, Saitama Municipal Hospital, Saitama, Japan.

Objective: Paraplegia remains a serious complication of aortic operations. The production of free radicals during reperfusion after transient ischemia is believed to induce secondary spinal neuronal injury, resulting in paraplegia. The aim of the present study was to clarify the protective effect and method of administration of antioxidants on the neurological and histological outcome in the animal model for reperfusion injury after transient spinal cord ischemia.

Methods: New Zealand white rabbits underwent surgical exposure of the abdominal aorta that was clamped for 15 minutes to achieve spinal cord ischemia. Group A animals received two 10 mg/kg doses of 3-methyl-1-phenyl-2-pyrazolin-5-one (MCI-186) at the time of release of the aortic clamp and 30 minutes later. In group B, MCI-186, 5 mg/kg, was given three times, at the time of aorta clamp release, 30 minutes and 12 hours later. In group C (control group), one dose of vehicle was administered. Neurological status was assessed using modified Tarlov's score until 168 hours after operation. Spinal cord sections were examined microscopically to determine the extent of ischemic neuronal damage.

Results: Groups A and B animals had better neurological function than group C (p < 0.001). In contrast, group C animals exhibited paraplegia or paraparesis with marked neuronal necrosis. The number of surviving neurons within examined sections of the spinal cord was significantly greater in group B than in group C (p < 0.001).

Conclusion: In a 15-minute ischemia-reperfusion model using rabbits, systemic repetitious administration of MCI-186, a free radical scavenger, was found to have a protective effect on the spinal cord neurons both neurologically and histologically. We postulate that the drug minimizes the delayed neuronal cell death for reperfusion injury after transient ischemia by reducing the free radical molecules. Moreover, it was thought that we could protect delayed neuronal cell death more effectively by administering MCI-186 12 hours later.
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http://dx.doi.org/10.1007/s11748-005-0078-7DOI Listing
August 2005

Effect of delayed induction of postischemic hypothermia on spinal cord damage induced by transient ischemic insult in rabbits.

Jpn J Thorac Cardiovasc Surg 2004 Sep;52(9):411-8

Department of Cardiovascular Surgery, Keio University School of Medicine, Tokyo, Japan.

Objective: This study was performed to determine the effect of delayed induction of mild hypothermia after transient spinal cord ischemia in rabbits.

Methods: Abdominal aortic occlusion was performed for 15 minutes to induce spinal cord ischemia at a rectal temperature of 37.3 +/- 0.3 degrees C. Four groups of rabbits were investigated: Group 1 (n = 8) was subjected to ischemia and reperfused at the same temperature for 7 hours; Group 2 (n = 8) was subjected to ischemia and reperfused at the same temperature for 1 hour, followed by 6 hours of systemic hypothermia (32.5 +/- 0.5 degrees C); Group 3 (n = 8) was subjected to ischemia, reperfusion at the same temperature for 3 hours and then 6 hours of systemic hypothermia (32.5 +/- 0.5 degrees C); and Group 4 (n = 8) comprised non-ischemic controls. Neurological status of all rabbits in Groups 1-3 was recorded and animals were sacrificed 1 week after ischemic injury. Spinal cord sections were examined microscopically to determine the extent of ischemic neuronal damage.

Results: Mean modified Tarlov's score at 1 week after ischemic insult was 0.5 +/- 0.8 in Group 1, compared to 43 +/- 1.5 in Group 2 and 2.9 +/- 1.8 in Group 3. Mean total number of surviving neurons within examined sections of spinal cord was significantly greater for Groups 2 and 3 compared with Group 1 (Group 1, 81 +/- 66.1; Group 2, 293.4 +/- 110.9; Group 3, 227.1 +/- 105.5; p < 0.001).

Conclusions: Delayed postischemic hypothermia induced within 3 hours after reperfusion significantly reduces ischemia-induced spinal cord neuronal damage in rabbits.
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http://dx.doi.org/10.1007/s11748-004-0034-yDOI Listing
September 2004

Mortality and morbidity after total arch replacement using a branched arch graft with selective antegrade cerebral perfusion.

Ann Thorac Surg 2003 Dec;76(6):1951-6

Section of Cardiovascular Surgery, School of Medicine, Keio University, Tokyo, Japan.

Background: The early outcome after aortic arch surgery has improved. However, some operative survivors have died as a result of postoperative problems soon after discharge. This study determines the factors affecting mortality within 1 year of total arch replacement.

Methods: Between July 1993 and November 2001, 103 patients (mean age 65 +/- 11 years, 26 women, 35 dissections) underwent total arch replacement through a median sternotomy using a branched arch graft with selective cerebral perfusion. Eighteen operations including 14 acute dissections were performed on an emergency basis. Concomitant procedures were root replacement in 5 patients, mitral valve replacement in 1, coronary artery bypass in 14, and open endovascular stent-graft in 9. The average time (minutes) for bypass, aortic cross-clamp, selective cerebral perfusion, and distal arrest were respectively 273 +/- 79, 163 +/- 54, 145 +/- 36, and 69 +/- 22.

Results: Mechanical heart support was necessary in 3 patients. Stroke occurred in 9 patients, transient neurologic dysfunction in 7, and paraplegia/paraparesis in 4. The only independent determinant for postoperative stroke was a history of stroke (odds ratio 16.3, 95% confidence interval: 2.8 to 93.8). Thirty-one patients required ventilator support for more than 5 days. Hemodialysis was needed in 5 patients. Sternal infection or mediastinitis occurred in 6 patients. The in-hospital mortality was 12% (12 of 103). The actuarial survival rate at 1 year was 83%, and was 67% at 5 years. For the 1-year mortality independent determinants were emergency surgery (odds ratio 5.3, 95% confidence interval: 1.6 to 17.9) and age 75 years or older (odds ratio 4.0, 95% confidence interval: 1.1 to 13.9).

Conclusions: Total arch replacement using a branched arch graft with selective antegrade cerebral perfusion has a favorable 1-year mortality rate except for patients undergoing emergency surgery and for elderly patients.
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http://dx.doi.org/10.1016/s0003-4975(03)01136-6DOI Listing
December 2003

Liberal use of tricuspid valve detachment for transatrial ventricular septal defect closure.

Ann Thorac Surg 2003 Oct;76(4):1073-7

Division of Cardiovascular Surgery, Keio University, Tokyo, Japan.

Background: Although temporary tricuspid valve detachment is useful for improved visualization of ventricular septal defect through right atriotomy, liberal use of this adjunct is not widely supported, mainly because of concerns about iatrogenic complications such as heart blocks and tricuspid valve dysfunction. The objective of this study was to determine whether liberal use of this adjunct can improve operative outcome.

Methods: Between January 1997 and March 2002, trans-atrial closure of isolated ventricular septal defect (conoventricular or canal type) was performed in 87 consecutive patients. Tricuspid valve detachment was used in 4 out of 44 patients (prudent-use group) and 19 out of 43 patients (liberal-use group) in the first and second half of this period, respectively (p = 0.0002). Patient demographics and use of other surgical and cardiopulmonary bypass techniques remained virtually unchanged during this period.

Results: In the prudent-use group, there was one operative death with prolonged bypass time and one residual defect that required reoperation; neither of these patients underwent tricuspid valve detachment. All other patients (both groups) were free from mortality and clinically significant complications, including heart block, tricuspid regurgitation, and residual defect. The liberal-use group had shorter cardiopulmonary bypass time than the prudent-use group (59 +/- 14 vs 67 +/- 22 minutes, p = 0.037).

Conclusions: Tricuspid valve detachment should be used liberally for moderate- or even low-difficulty exposure of ventricular septal defect, regardless of patient background, because it is a safe and effective adjunct that can improve speed, programmability, reproducibility, and reliability.
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http://dx.doi.org/10.1016/s0003-4975(03)00723-9DOI Listing
October 2003

The limitation of staged repair in the surgical management of congenital complex heart anomalies with aortic arch obstruction.

Jpn J Thorac Cardiovasc Surg 2003 Jul;51(7):302-7

Division of Cardiovascular Surgery, Keio University, Tokyo, Japan.

Objective: Severe aortic arch obstruction including an interrupted aortic arch in congenital complex heart anomalies remains a challenge in surgical management.

Methods: Treatment and outcomes in 75 consecutive patients who underwent an aortic arch repair as the first step of the staged repair protocol between 1975 and 2000 were reviewed. Their ages at repair ranged from 1 day to 8.5 months.

Results: Cross-sectional postoperative follow-up data were available in all the patients. The follow-up period ranged from 0 to 27.6 years (mean: 7.3 +/- 7.3 years). There were 20 postoperative hospital deaths (27%) and 7 late deaths. The Kaplan-Meier estimate of survival was 81.3% +/- 4.5% at 1 month, 68.0% +/- 5.4% at 1 year, 65.0% +/- 5.5% at 5 years, 63.1% +/- 5.7% at 10 years, 63.1% +/- 5.7% at 20 years. By Cox regression analysis, body weight of 2.5 kg or less is the only independent determinant of postoperative mortality (p = 0.04, multivariable odds ratio: 2.50, [95% confidence interval: 1.02-6.1]). The aortic arch morphology, the primary cardiac lesion, or date of operation did not reach a statistically significant level to show correlation with mortality. Reintervention to reconstruct the aortic arch was performed at 9 occasions in 8 of the 55 patients who survived the primary operation (14.5%). The Kaplan-Meier estimate of the reintervention-free rate was 91.3% +/- 4.2% at 5 years, 85.5% +/- 5.6% at 10 years, 75.6% +/- 8.2% at 20 years. Using multivariable Cox regression analysis, interrupted aortic arch (versus aortic coarctation) was the only independent predictor of a shorter time to reintervention (p = 0.001, multivariable odds ratio: 16.1, [95% confidence interval: 3.2-80.2]).

Conclusions: The staged repair protocol was associated with significant limitations in patient survival and with the development of recurrent aortic arch obstruction. Thus, a primary repair protocol may serve as an alternate approach, especially in patients with low weight or with an interrupted aortic arch.
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http://dx.doi.org/10.1007/BF02719382DOI Listing
July 2003

Effects of atrial fibrillation on coronary artery bypass graft flow.

Eur J Cardiothorac Surg 2003 Feb;23(2):175-8

Division of Cardiovascular Surgery, Department of Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.

Objectives: No detailed studies exist of coronary artery bypass graft flow during atrial fibrillation. We examined the effects on bypass graft flow of atrial fibrillation following coronary artery bypass grafting.

Methods: Immediately after surgical revisualization, atrial fibrillation was induced in 18 patients by high frequency atrial pacing. Hemodynamic variables were measured in sinus rhythm and atrial fibrillation. The graft flow in pedicled left internal thoracic artery grafts and in saphenous vein grafts was also measured using transit-time flowmetry.

Results: Left internal thoracic artery graft flow had a greater diastolic component than saphenous vein graft flow, as shown by the percent diastolic time-flow integral (86 +/- 10% in the left thoracic artery and 62 +/- 12% in the saphenous vein, P < 0.0001). The induced atrial fibrillation caused significant deterioration in hemodynamics: heart rate and central venous pressure increased, and mean arterial pressure and cardiac index decreased (all P < 0.0025). In left internal thoracic artery grafts (n = 18) and also in saphenous vein grafts (n = 20), graft flow decreased significantly with atrial fibrillation (44.3 +/- 26.2 to 26.2 +/- 20.7 ml/min in the left internal thoracic artery, P = 0.0003; 39.7 +/- 15.6 to 33.3 +/- 14.3 ml/min in the saphenous vein, P = 0.001). The reduction in graft flow due to atrial fibrillation was much larger in left internal thoracic artery grafts than in saphenous vein grafts (P = 0.0008).

Conclusions: Direct measurement of coronary artery bypass graft flow shows that atrial fibrillation after surgery significantly reduces graft flow. The effect is much larger in left internal thoracic artery grafts with their strong diastolic component than in saphenous vein grafts.
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http://dx.doi.org/10.1016/s1010-7940(02)00730-3DOI Listing
February 2003

Effect of post-ischemic hypothermia on spinal cord damage induced by transient ischemic insult in rabbits.

Jpn J Thorac Cardiovasc Surg 2002 Sep;50(9):359-65

Department of Cardiovascular Surgery, Keio University School of Medicine, Tokyo, Japan.

Objective: The effect of post-ischemic mild hypothermia applied immediately after induced transient ischemia on the extent of neuronal damage to the spinal cord was investigated in rabbit.

Subjects And Methods: A 15-minute period of transient abdominal aortic occlusion for spinal cord ischemia at a rectal temperature of 37.3 +/- 0.3 degrees C was performed just below the left renal vein via median laparotomy. Three groups of rabbits were investigated; Group 1 (n = 8) subjected to ischemia and reperfused at the same temperature for 7 hours, Group 2 (n = 8) also subjected to ischemia and then to 6 hours of systemic hypothermia (32.5 +/- 0.5 degrees C), and Group 3 (n = 8) non-ischemic controls. All the rabbits in Group 1 and Group 2 were sacrificed at 1 week after ischemic injury. Spinal cord sections were examined microscopically to determine the extent of ischemic neuronal damage.

Results: The mean modified Tarlov's score at 1 week after ischemic injury was 0.5 +/- 0.8 in Group 1, whereas it was 4.4 +/- 1.4 (p < .001) in Group 2. The mean total number of surviving neurons within examined sections of the spinal cord was significantly greater in Group 2 than in Group 1 (Group 1: 81 +/- 66.1 vs Group 2: 300.9 +/- 154.1, p < .001).

Conclusion: Post-ischemic hypothermia induced immediately after reperfusion significantly reduced ischemia-induced neuronal damage in rabbit.
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http://dx.doi.org/10.1007/BF02913184DOI Listing
September 2002

Individualized total cavopulmonary connection technique for patients with asplenia syndrome.

Ann Thorac Surg 2002 Apr;73(4):1274-80; discussion 1280-1

Division of Cardiovascular Surgery, Keio University, Tokyo, Japan.

Background: Outcomes after univentricular repair for patients with asplenia syndrome remain unsatisfactory, not only because of clinical difficulties in patient selection, but also secondary to technical difficulties in the separation of the systemic and pulmonary circulations, particularly with the rerouting technique for the inferior systemic veins.

Methods: Between February 1995 and May 2000, a total of 14 consecutive patients with asplenia syndrome underwent bidirectional cavopulmonary connection with obliteration of additional pulmonary blood flow, followed by a total cavopulmonary connection. The rerouting technique for inferior systemic venous blood flow was individualized to optimize laminar nonturbulent flow characteristics in the pathway, and to minimize prosthetic load and suture load on the atrial wall. The lateral tunnel or tube conduit technique was used in an extraatrial, intra-extraatrial, or intraatrial fashion. No fenestration was applied.

Results: No hospital mortality was observed. Systemic venous flow was evaluated using magnetic resonance angiography, revealing no signs of obstruction, turbulence, or stasis either in or near the reconstructed pathways, irrespective of the rerouting technique. Postoperative catheterization revealed favorable hemodynamics including an inferior vena cava pressure of 13 +/- 2 mm Hg and arterial oxygen saturation of 93.4% +/- 3.5% at room air. All patients have remained free of symptoms, although 1 patient died of acute septic complications 3.5 years after the procedure.

Conclusions: The complexity of cardiac anomalies in asplenia syndrome warrants individualization of the total cavopulmonary connection technique used in reconstruction of the inferior systemic venous pathway. Optimizing flow characteristics in the pathway should be a priority. A staging approach allows suitable selection of candidates for univentricular repair.
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http://dx.doi.org/10.1016/s0003-4975(01)03583-4DOI Listing
April 2002
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