Junjiro Kobayashi

Failure to Prevent Progressive Dilation of Ascending Aorta by Aortic Valve Replacement in Patients With Bicuspid Aortic Valve: Comparison With Tricuspid Aortic Valve

Background—Patients with bicuspid aortic valve (BAV) have been frequently complicated with ascending aortic dilation possibly because of hemodynamic burdens by aortic stenosis (AS) or regurgitation (AR) or congenital fragility of the aortic wall. Methods and Results—To clarify if the aortic dilation could be prevented by aortic valve replacement (AVR) in BAV patients, we studied 13 BAV (8 AR dominant, 5 AS dominant) and 14 tricuspid aortic valve (TAV) patients (7 AR, 7 AS) by echocardiography before and after AVR (9.7±4.8 years). We also studied 18 BAV (11 AR, 7 AS) without AVR. Diameters of the sinuses of Valsalva, sinotubular junction and the proximal aorta were measured. The annual dilation rate was calculated by dividing changes of diameters during the follow-up period by the body surface area and the observation interval. We found that aortic dilation in BAV patients tended to be faster than that in TAV patients, although a significant difference was found only at the proximal aorta (0.18±0.08 versus −0.08±0.08 mm/(m2/year), P =0.03). BAV patients with and without AVR showed similar progressive dilation. AR dominant group showed tendency of more progressive dilation than AS dominant group in BAV, although it did not reach statistical significance. TAV patients did not show further aortic dilation after AVR. Conclusions—AVR could not prevent progressive aortic dilation in BAV. Since the aorta did not dilate in TAV, progressive aortic dilation in BAV seems mainly due to the fragility of the aortic wall rather than hemodynamic factors.

The electrophysiologic mechanism of ST-segment elevation in Brugada syndrome.

OBJECTIVES We sought to demonstrate the electrophysiologic (EP) mechanism of the ST-T change in Brugada syndrome. BACKGROUND Brugada syndrome is characterized by various electrocardiographic manifestations (e.g., right bundle branch block, ST-segment elevation, and terminal T-wave inversion in the right precordial leads) and sudden cardiac death caused by ventricular fibrillation. Direct evidence in support of the EP mechanism underlying this intriguing syndrome has been lacking. METHODS Monophasic action potentials (MAPs) were obtained from three patients with the coved-type ST-segment elevation (Brugada patients) and five control patients using the contact electrode method. Epicardial MAPs were recorded during open-chest surgery in all patients. RESULTS A spike-and-dome configuration was documented from epicardial sites of the right ventricular (RV) outflow tract in all Brugada patients but not in control patients. Monophasic action potential recordings from the endocardium with special focus on the RV outflow tract could not demonstrate any morphological abnormalities in three Brugada patients. CONCLUSIONS The presence of a deeply notched action potential in the RV epicardium, but not in endocardium, would be expected to induce a transmural current that would contribute to elevation of the ST-segment in the right precordial leads. The spike-and-dome configuration may also prolong the epicardial action potential, thus contributing to a rapid reversal of the transmural gradients and inscription of an inverted T-wave.

Early and late stroke after mitral valve replacement with a mechanical prosthesis: risk factor analysis of a 24-year experience

OBJECTIVE We evaluated risk factors for mortality and stroke after mechanical mitral valve replacement between May 1977 and December 2001. METHODS Early and late mortality and stroke were assessed. Potential predictors of mortality and stroke were entered into a Cox proportional hazards model. Actuarial survival and freedom from stroke were determined by a log-rank test. RESULTS Mitral valve replacement was performed in 812 patients. Concomitant procedures included left atrial appendage closure in 493 (61%) patients, tricuspid annuloplasty-replacement in 348 (43%) patients, maze procedure in 185 (23%) patients, plication of the left atrium in 148 (18%) patients, and other procedures in 151 (19%) patients. Five-year actuarial survival was 91.1% +/- 2.3%. Freedom from stroke at 8 years was significantly better in patients with sinus rhythm versus atrial fibrillation (P <.001). Ninety-nine percent of patients with mitral valve replacement combined with a maze procedure were free from stroke, whereas only 89% of patients with mitral valve replacement alone were free from stroke at 8 years after surgical intervention. Seventy-two patients had late stroke; sixty-five patients (90%) were in atrial fibrillation, and 47 (65%) patients had the left atrial appendage closed. Multivariate analysis showed that late atrial fibrillation (odds ratio, 3.39; 95% confidence interval, 1.72-6.67; P =.0001) and omission of the maze procedure (odds ratio, 3.40; 95% confidence interval, 1.14-10.14; P =.003) were the significant risk factors for late stroke. CONCLUSIONS Persistent atrial fibrillation was the most significant risk factor for late stroke after mechanical mitral valve replacement. Restoration of sinus rhythm with a maze procedure nearly eliminated the risk of late stroke, whereas neither closure of the left atrial appendage nor therapeutic anticoagulation prevented this complication.

Mode of onset of ventricular fibrillation in patients with Brugada syndrome detected by implantable cardioverter defibrillator therapy

OBJECTIVES We sought to demonstrate the mode of spontaneous onset of ventricular fibrillation (VF) in patients with Brugada syndrome. BACKGROUND The electrophysiologic mechanisms of VF in Brugada syndrome have not been fully investigated. METHODS Nineteen patients (all male, mean age 47 +/- 12 years) with Brugada syndrome were treated with an implantable cardioverter defibrillator (ICD). The implanted devices were capable of storing electrograms during an arrhythmic event. We investigated the mode of spontaneous onset of VF according to the electrocardiographic features during the episode of VF, which were obtained from stored electrograms of ICDs and/or electrocardiographic (ECG) monitoring. RESULTS During a follow-up of 34.7 +/- 19.4 months (range 14 to 81 months), 46 episodes of spontaneous VF attacks were documented in 7/19 (37%) patients. The event-free period between ICD implantation and the first spontaneous occurrence of VF was 14.6 +/- 12.1 months (range 3.7 to 27.4 months). We investigated 33/46 episodes of VF, for which electrocardiographic features (10 to 20 s before and during VF) were obtained from ICDs and/or ECG monitoring in five patients. A total of 22/33 episodes of VF were preceded by premature ventricular contractions (PVCs), which were almost identical to the initiating PVCs of VF. Furthermore, in three patients who had multiple VF episodes, VF attacks were always initiated by the same respective PVC. The coupling interval of the initiating PVCs of VF was 388 +/- 28 ms. CONCLUSIONS Spontaneous episodes of VF in patients with Brugada syndrome were triggered by specific PVCs. These findings may provide important insights into the pathophysiological mechanisms causing VF in Brugada syndrome.

Thoracic and cardiovascular surgery in Japan during 2012

The Japanese Association for Thoracic Surgery has conducted annual surveys of thoracic surgery throughout Japan since 1987 to determine the statistics regarding the number of procedures according to operative category. Here, we have summarized the results from our annual survey of thoracic surgery performed during 2012. The incidence of hospital mortality was added to the survey to determine the nationwide status, which has contributed to the Japanese surgeons to understand the present status of thoracic surgery in Japan and to make progress to improve operative results by comparing their work with those of others. The Association was able to gain a better understanding of the present problems as well as future prospects, which has been reflected to its activity including education of its members. Thirty-day mortality (so-called ‘‘operative mortality) is defined as death within 30 days of operation regardless of the patient’s geographic location and even though the patient had been discharged from the hospital. Hospital mortality is defined as death within any time interval after an operation if the patient had not been discharged from the hospital. Hospital-to-hospital transfer is not considered discharge: transfer to a nursing home or a rehabilitation unit is considered hospital discharge unless the patient subsequently dies of complications of the operation. The definitions of the Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity of the Society of Thoracic Surgeons and Annual report by The Japanese Association for Thoracic Surgery: Committee for Scientific Affair

Overview of Late Outcome of Medical and Surgical Treatment for Takayasu Arteritis

Takayasu arteritis (TA), which is a nonspecific inflammatory disease of unknown origin, causes various types of aortoarterial stenosis/occlusion or dilatation (Figure). Historically, Mikito Takayasu, a Japanese ophthalmologist, described a peculiar wreathlike arteriovenous anastomosis around the papillae of the retina (Takayasu disease) in 1908.1 In the first necropsy case reported in 1940, this ophthalmologic finding was related to cervical vessel occlusion.2,3 Subsequently, this nonspecific panarteritis that affects the intima and the adventitia of the aorta and its main branches was called Takayasu arteritis . Its clinical manifestations are varied and related to the vessel that presents the stenotic or occlusive lesions, such as the aortic arch (pulseless disease),4 descending thoracic or abdominal aorta (atypical coarctation),5 renal arteries,6 coronary arteries,7 and pulmonary arteries. Aortic aneurysm8 and aortic valve regurgitation with ascending aortic dilatation9 may also develop in some instances. Pharmacological treatment with corticosteroids is usually the initial treatment. Some patients require surgical treatment such as bypass grafting and graft replacement or endovascular repair including percutaneous transluminal angioplasty (PTA) and stent grafting, even in the active phase or in the inactive chronic phase with adequate control of the inflammation. Since the 1960s, acceptable early and midterm outcomes of medical and/or surgical treatment have been published. However, the long-term outcome, including that of recently developed endovascular treatment, has not been discussed. In this article, we describe an overview, particularly focusing on the late outcome of treatment for TA. Figure. Three-dimensional computed tomographic findings of an active phase of Takayasu arteritis (21 years, female). Three-dimensional computed tomographic findings include multiple stenotic lesions on the carotid and subclavian arteries (A), aneurysmal dilatation of the ascending aorta to the aortic arch and of the main pulmonary artery (B), aneurysmal dilatation of the descending aorta, stenosis of the right renal …

Early Outcome of a Randomized Comparison of Off-Pump and On-Pump Multiple Arterial Coronary Revascularization

Background—Previous randomized comparisons of off-pump and on-pump coronary artery bypass grafting (CABG) have yielded controversial results about the cardiac and neurological events and graft patency. In addition, these randomized studies were composed of CABG with a few arterial grafts. We performed a prospective randomized controlled study to compare off-pump and on-pump CABG with multiple arterial grafts. Methods and Results—Between July, 2002, and September, 2004, 167 consecutive unselected patients referred for elective primary CABG were randomly assigned to undergo multiple arterial off-pump CABG (n=81) or on-pump CABG (n=86). The clinical outcomes and S-100 protein, neuron-specific enolase, and maximum creatine kinase-MB levels were compared. Early graft patency was examined within 3 weeks after the operation by angiography. The number of grafts performed per patient (3.5±1.0 for off-pump CABG and 3.6±0.9 for on-pump CABG) and the number of arterial grafts performed per patient (3.3±1.0 for off-pump CABG and 3.4±0.9 for on-pump CABG) were similar. Completeness of revascularization (completed grafts/planned grafts) was 98% in both procedures. There were no hospital deaths in either group. The operation time was significantly (P<0.001) shorter in the off-pump group than in the on-pump group (267±60 minutes versus 307±59 minutes). The incidence of perioperative complications was similar. The frequency of no need for transfusion was higher in the off-pump group than in the on-pump group (80% versus 55%, P<0.001). The S-100 protein levels at the admission into the intensive care unit were significantly (P<0.001) lower in the off-pump group than in the on-pump group (0.20±0.11 ng/mL versus 0.34±0.22 ng/mL). The neuron-specific enolase levels at the intensive care unit admission were significantly (P<0.001) lower in the off-pump group than in the on-pump group (10.4±9.0 ng/mL versus 16.9±6.9 ng/mL). Maximum creatine kinase-MB levels were significantly (P=0.046) lower in the off-pump group than in the on-pump group (17.1±16.7 IU/L versus 21.5±10.6 IU/L). The overall early graft patency rate with or without stenosis was the same (98%) in both groups, but the rate without stenosis was slightly worse in the off-pump group (93%) than in the on-pump group (96%) (P=0.093). The stenosis-free patency rate in the right coronary area was significantly (P=0.028) worse in the off-pump CABG group (90%) than in the on-pump group (99%). Conclusions—Off-pump CABG with multiple arterial grafts was as safe as the conventional on-pump CABG, with similar completeness of revascularization and early graft patency.

Thoracic and cardiovascular surgery in Japan during 2014

The Japanese Association for Thoracic Surgery has conducted annual surveys of thoracic surgery throughout Japan since 1986 to determine the statistics regarding the number of procedures according to operative category. Here, we have summarized the results from our annual survey of thoracic surgery performed during 2014.

Late Aortic Insufficiency Related to Poor Prognosis During Left Ventricular Assist Device Support

BACKGROUND Management of native aortic insufficiency (AI) during left ventricular assist device (LVAD) support is challenging. We investigated the occurrence of de novo AI during long-term LVAD support to identify its effect on late clinical and echocardiographic outcomes. METHODS Left ventricular assist devices were implanted in 99 patients with dilated cardiomyopathy, of whom 47 without preoperative AI were investigated using serial echocardiography examinations for more than 1 year after the operation. RESULTS The mean duration of LVAD support was 838±327 days, and 26 patients (55%) were supported for more than 2 years. Twenty-nine patients (62%) had no AI (group A), whereas de novo AI developed in the remaining 18 (38%; group B) at 1 year after LVAD implantation (≥grade 2 in 5, grade 1 in 13). The LV end-diastolic diameter was significantly reduced after LVAD implantation in both groups, with no significant difference between them. Overall survival was better in group A (p=0.0195). Multivariate analysis revealed that preoperative mitral regurgitation of more than grade 2 (odds ratio, 7.8; 95% confidence interval, 1.2 to 48.6; p=0.028) and an aortic valve that remained closed at 1 month after implantation (odds ratio, 6.7; 95% confidence interval, 1.0 to 43.9; p=0.048) were significant independent predictors of de novo AI at 1 year after LVAD implantation. CONCLUSIONS Survival was significantly worse when de novo AI developed in patients during long-term LVAD. Our findings indicate that preoperative functional mitral regurgitation and postoperative aortic valve opening are related to the progression of AI during long-term LVAD support.

Twenty-Five-Year Outcome of Pediatric Coronary Artery Bypass Surgery for Kawasaki Disease

Background— The long-term outcome of pediatric coronary artery bypass for patients with severe inflammatory coronary sequelae secondary to Kawasaki disease is unknown. Methods and Results— One hundred fourteen children and adolescents ranging in age from 1 to 19 (median, 10) years at operation were followed up for as long as 25 years with a median of 19 years. The number of distal anastomoses was 1.7±0.8 per patient, and the internal thoracic artery was used in all but 3, most frequently for left anterior descending artery lesions. Saphenous vein grafts were used in 24 patients, mostly for non–left anterior descending artery lesions. Patients underwent multiple angiograms to evaluate their coronary and graft status. There was no operative or hospital mortality. Both 20- and 25-year survival rates were 95% (95% confidence interval [CI], 88 to 98). Five deaths occurred, all cardiac in origin. Cardiac event–free rates at 20 and 25 years were 67% and 60% (95% CI, 46 to 72), respectively. Percutaneous coronary intervention and reoperation were the most common events. Overall, the 20-year graft patency rate was 87% (95% CI, 78 to 93) for internal thoracic artery grafts (n=154) and 44% (95% CI, 26 to 61) for saphenous vein grafts (n=30) (P<0.001), and the rate for non–left anterior descending artery lesions was also significantly better for arterial grafts (87% [95% CI, 73 to 94]; n=59) than for saphenous vein grafts (42% [95% CI, 23 to 60]; n=27) (P=0.002). Eighty-eight patients (77%) remain on medications, but all 109 survivors are presently symptom free in their daily activities. Conclusions— Although the 25-year survival was excellent after pediatric coronary bypass for Kawasaki disease, the event-free rate declined progressively. This reality mandated continued follow-up. Reinterventions successfully managed most cardiac events. An internal thoracic artery graft was the most favorable for children.