Tetsuya Kajiyama

Is physiologic annular dynamics preserved after mitral valve repair with rigid or semirigid ring

BACKGROUND Various rings are available to achieve more physiologic mitral valve repair from viewpoints of physiologic mitral annular structure or dynamics. We evaluated preoperative and postoperative mitral annular structures and dynamics. METHODS Thirty-six patients underwent mitral valve repair for degenerative mitral insufficiency. Carpentier-Edwards Physio II ring (semirigid [Edwards Lifesciences, Irvine, CA]), St. Jude Medical Rigid Saddle Ring (RSR [St. Jude Medical, St. Paul, MN]), and MEMO 3D ring (semirigid [Sorin SpA, Milan, Italy]) were implanted in 13, 12, and 11 patients, respectively. Intraoperative real-time three-dimensional transesophageal echocardiography was performed before and after repair. RESULTS The postoperative anteroposterior diameter reduction rate from end diastole to end systole was significantly (p<0.0001) larger in MEMO (9.58%±2.91%) than in Physio II (0.98%±1.04%) and RSR (1.94%±1.95%). There were no significant differences in the commissure-to-commissure diameter reduction rates among the groups: 0.81%±1.98% for Physio II, 0.12%±0.53% for RSR, and 0.51%±1.98% for MEMO. The postoperative end-systolic annular height commissure width ratio was significantly (p<0.0001) larger in both Physio II (17.9%±3.0%) and RSR (18.5%±1.6%) than in MEMO (13.6%±3.0%). The postoperative annular height commissure width ratio increase rate from end diastole to end systole was significantly larger in MEMO (5.1%±2.3%) than in Physio II (0.1%±0.6%) and RSR (0.3%±0.5%). CONCLUSIONS Physio II and RSR could restore the physiologic three-dimensional annular shape, but the annular motion was diminished. Conversely, MEMO could preserve both the anteroposterior movement and folding dynamics, but no three-dimensional restoration of the mitral annulus was obtained.

Analysis of collateral blood flow to the lower body during selective cerebral perfusion: is three-vessel perfusion better than two-vessel perfusion? §

OBJECTIVE During selective cerebral perfusion (SCP), only the upper body is perfused. However, blood actually returns into the descending aorta through collaterals during SCP. This collateral blood flow (CBF) is thought to be important to protect the visceral organs and spinal cord from ischemia. The left subclavian artery is postulated to be important as a collateral source to the lower body. Therefore, we measured CBF and examined whether a perfusion technique (three- or two-vessel perfusion) affects CBF to the lower body during SCP. METHODS CBF was measured in 49 patients who underwent aortic arch surgery with SCP between August 2006 and July 2008. CBF, the amount of blood returning into the descending aorta during SCP, was measured under conditions of constant flow during SCP, with three-vessel cannulation that included the left subclavian artery, or with two-vessel cannulation that excluded the left subclavian artery. To prove visceral perfusion during SCP, hepatic (n=22) and stomach (n=5) tissue blood flows were measured using a laser-Doppler flowmeter. RESULTS The mean perfusion flow rate during SCP was 804+/-91ml/min. The mean CBF under three-vessel perfusion (53+/-34ml/min, 6.5+/-3.8% of SCP) was significantly (p<0.0001) higher compared with that under two-vessel perfusion (43+/-29ml/min, 5.3+/-3.1% of SCP). There was substantial perfusion in the visceral organs during SCP as determined by laser-Doppler flowmeter. CONCLUSION Visceral organs were perfused to some extent through collaterals and protected from ischemia during SCP. Left subclavian arterial perfusion enabled significant CBF to the lower body. Considering this CBF, three-vessel perfusion appears to be better than two-vessel perfusion during SCP; however, the choice of perfusion technique may not be so important under conditions of hypothermia because the difference in CBF between the two methods was small.

Risk factors for open heart surgery in hemodialysis patients

PurposeThere have been many reports on open heart surgery in hemodialysis patients; however, the mortality rates in these patients are higher than those in nonhemodialysis patients. The purpose of this study was to identify the risk factors for mortality following open heart surgery in hemodialysis patients.MethodsWe evaluated 76 consecutive patients (76/2030 total open heart surgeries, 3.7%) who required hemodialysis before open heart surgery between January 1990 and January 2008. There were 46 men and 30 women (mean age 63 ± 11 years). The mean duration of hemodialysis was 9 years 5 months (8 months to 30 years). Chronic glomerulonephritis (25 cases, 33%) and diabetic nephropathy (17 cases, 22%) were the most common diseases leading to a requirement for hemodialysis. Operations included 36 coronary artery bypass grafting (CABG) cases (48%; emergency/elective 22: 14), 24 aortic valve replacements (AVR) (34%), and 9 cases of concomitant AVR plus CABG (12%). Multivariate logistic analyses were performed to identify the risk factors. No patient was lost during follow-up.ResultsThe overall in-hospital mortality rate was 17.1% (13/76). The 5-year survival rate was 39% ± 8%. Univariate logistic analysis showed that age (>70 years), low-output syndrome (ejection fraction <40% and/or intraaortic balloon pump support), and concomitant surgery were significant risk factors for mortality. Multivariate logistic analysis suggested that only concomitant surgery was the significant risk factor (odds ratio 4.37, P = 0.007).ConclusionConcomitant surgery is a significant risk factor for mortality following open heart surgery in hemodialysis patients.

Patient-prosthesis mismatch after aortic valve replacement in the elderly

PurposeThe aim of this study was to analyze the effect of patient-prosthesis mismatch (PPM) on survival and left ventricular mass regression in elderly patients after aortic valve replacement (AVR).Materials and methodsData on patients >65 years old who underwent isolated AVR from 1990 and 2007 were analyzed retrospectively. A bioprosthesis was used in 42 cases and a mechanical valve in 59. The mean follow-up period was 3.1 years (0.1–14.2 years). The indexed effective orifice area (i-EOA) was determined from echocardiographic data in clinical reports in the literature and indexed to body surface area (cm2/m2). Mild PPM was defined as an i-EOA between 0.65 and 0.85. We also evaluated the New York Heart Association (NYHA) classification and the left ventricular mass (LVM) index.ResultsA total of 34 patients (33.6%) had PPM. No patient had an i-EOA <0.65. Freedom from valve-related death was 86.3% ± 6.7% in the PPM-negative group and 85.7% ± 7.9% in the PPM-positive group at 5 years after AVR. The mean LVM index (g/m2) decreased significantly (P < 0.01), from 239.2 to 167.4 in the PPMnegative group and from 229.1 to 154.4 in the PPMpositive group, respectively. NYHA functional status was excellent at late follow-up in both groups.ConclusionMild PPM occurred in a large proportion of elderly patients undergoing AVR but did not affect midterm survival or LV mass regression.

Evaluation of closed cardiopulmonary bypass circuit for aortic valve replacement.

Since 2005, we have used a novel technique based on the closed cardiopulmonary bypass system without cardiotomy suction (minimal cardiopulmonary bypass [mini-CPB]) for aortic valve replacement (AVR). In this study, we investigated the clinical advantages of this approach. We prospectively studied 32 patients who underwent isolated AVR using the mini-CPB (group M, n = 13) or conventional CPB (group C, n = 19). We compared the hemodilution ratio, serum interleukin (IL)-6 and IL-8 levels, and blood transfusion volume between the two groups. The characteristics, duration of CPB, and aortic cross-clamping time did not differ between the two groups. The hemodilution ratio was significantly lower in group M just after starting CPB (M vs. C: 14% ± 2% vs. 25% ± 3%, p = 0.0009). IL-6 levels increased significantly after surgery in both groups, but the postoperative levels were significantly lower in group M at 6 (84.9 ± 24.9 pg/ml vs. 152 ± 78 pg/ml, p = 0.042) and 12 (72.7 ± 36.1 pg/ml vs. 123 ± 49.6 pg/ml, p = 0.029) hours after CPB. There were no differences in IL-8 or blood transfusion volume after CPB. Mini-CPB offers an alternative to conventional CPB for AVR and has some advantages regarding hemodilution and serum IL-6 levels. However, it is unlikely to become the standard approach for AVR because there are no marked clinical advantages of mini-CPB.

Open heart surgery after renal transplantation

Aim to evaluate the strategy for open heart surgery after renal transplantation performed in a single institution in Japan. Methods we reviewed 6 open heart surgeries after renal transplantation in 5 patients, performed between January 1992 and December 2012. The patients were 3 men and 2 women with a mean age of 60 ± 11 years (range 46–68 years). They had old myocardial infarction and unstable angina, aortic and mitral stenosis, left arterial myxoma, aortic stenosis, and native valve endocarditis followed by prosthetic valve endocarditis. Operative procedures included coronary artery bypass grafting, double-valve replacement, resection of left arterial myxoma, 2 aortic valve replacements, and a double-valve replacement. Renal protection consisted of steroid cover (hydrocortisone 100–500 mg or methylprednisolone 1000 mg) and intravenous immunosuppressant infusion (cyclosporine 30–40 mg day−1 or tacrolimus 1.0 mg day−1). Results 5 cases were uneventful and good renal graft function was maintained at discharge (serum creatinine 2.1 ± 0.5 mg dL−1). There was one operative death after emergency double-valve replacement for methicillin-resistant Staphylococcus aureus-associated prosthetic valve endocarditis. Although the endocarditis improved after valve replacement, the patient died of postoperative pneumonia on postoperative day 45. Conclusions careful perioperative management can allow successful open heart surgery after renal transplantation. However, severe complications, especially methicillin-resistant Staphylococcus aureus infection, may cause renal graft loss.

Development of Collaterals to the Spinal Cord after Endovascular Stent Graft Repair of Thoracic Aneurysms

OBJECTIVES In thoracic and thoraco-abdominal aortic aneurysm repair, spinal cord injury (SCI) is devastating. Detection of the Adamkiewicz artery might be important for preventing SCI. Although thoracic endovascular stent grafts often occlude the segmental artery, the incidence of SCI in thoracic endovascular aortic repair is thought to be low compared with open repair. This study aimed to evaluate how the Adamkiewicz artery is supplied after segmental arteries are occluded by stent grafts. METHODS From March 2007 to August 2015, 32 patients were enrolled whose segmental arteries that were connected to the Adamkiewicz arteries were occluded by stent grafts. Segmental arteries, Adamkiewicz arteries, collateral circulation into the Adamkiewicz arteries, and anterior spinal arteries were pre- and post-operatively evaluated by computed tomography angiography. RESULTS Post-operatively, Adamkiewicz arteries were detected in 24 (75%) patients, except for two patients with paraplegia and six without paraplegia. Post-operative Adamkiewicz arteries were the same as pre-operative Adamkiewicz arteries, except for one Adamkiewicz artery that was located at two vertebral levels below the pre-operative level. SCI occurred in two (6.3%) patients. The distribution of feeding arteries into the Adamkiewicz artery post-operatively was divided into three patterns as follows: a segmental artery below the distal landing zone of the stent graft (53%), branches of the left subclavian artery (33%), and a branch of the left external iliac artery (13%). CONCLUSIONS The length of the stent graft should be as short as possible. Blood supply to the left subclavian artery should be maintained because segmental arteries below the segmental artery occluded by the stent graft and branches of the left subclavian artery can become collaterals post-operatively.

Endovascular Aortic Arch Repair with Mini-Cardiopulmonary Bypass to Prevent Stroke

Debranching thoracic endovascular aortic repair for aortic arch pathology is an important alternative to total arch replacement. However, the problem of intraoperative stroke due to atherosclerotic changes in the aorta remains. We apply our minimally invasive mini-cardiopulmonary bypass system to prevent intraoperative stroke during the endovascular procedure. Once debranching from the right axillary artery to the left common carotid and the left axillary artery is constructed; only the brachiocephalic artery is a pathway to the brain. After mini-cardiopulmonary bypass using the debranching graft is established, all cerebral perfusions are not only maintained, but retrograde blood flow from the brachiocephalic artery to the aortic arch is secured. All endovascular procedures can be performed under this situation. Our technique could be effective for preventing intraoperative stroke for endovascular repair with the debranching method for aortic arch pathology.

Left ventricular outflow tract obstruction masked by severe aortic stenosis

An 81-year-old woman developed severe hemolytic anemia after aortic valve replacement. The anemia was not caused by paravalvular leakage, as in most cases. Instead, it occurred secondary to left ventricular outflow tract obstruction that had not been seen preoperatively and was induced by afterload reduction following aortic valve replacement. The hemolytic anemia was drug-refractory and finally treated with dual-chamber pacing, as for hypertrophic cardiomyopathy.