Hiroe Tanaka

Minimal cardiopulmonary bypass attenuates neutrophil activation and cytokine release in coronary artery bypass grafting.

The minimal cardiopulmonary bypass (mini-CPB) circuit, a closed system with neither cardiotomy suction nor an open venous reservoir and thus no air–blood interface, reportedly reduces blood loss and inflammatory reactions associated with coronary bypass surgery. We evaluated the inflammatory reactions in patients in whom coronary bypass operations were performed with conventional CPB or mini-CPB (n = 15 each). Interleukin (IL)-6, IL-8, and neutrophil elastase levels; the neutrophil count; and the C-reactive protein value were measured before and immediately after surgery and on postoperative days 1 and 2. In addition, intraoperative blood loss and the transfusion volume were evaluated in these groups. Neutrophil elastase levels were lower in the mini-CPB group than in the conventional group on postoperative days 1 (127 ± 52 vs. 240 ± 100 µg/l, P = 0.013) and 2 (107 ± 17 vs. 170 ± 45 µ/l, P = 0.0001), as was the IL-8 level on postoperative day 1 (8.3 ± 6.4 vs. 19 ± 11 pg/ml, P = 0.016). The intraoperative blood loss and transfusion volumes were significantly lower in the mini-CPB group than in the conventional group (510 ± 244 vs. 1046 ± 966 ml, P = 0.012, and 691 ± 427 vs. 1416 ± 918 ml, P = 0.0033). Thus, mini-CPB appears to attenuate neutrophil activation and cytokine release after coronary bypass surgery and, in addition, has some beneficial effects on blood conservation.

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.

Beneficial effects of mini-cardiopulmonary bypass on hemostasis in coronary artery bypass grafting: analysis of inflammatory response and hemodilution.

We compared the inflammatory response, hemodilution, and blood loss in patients who underwent mini-cardiopulmonary bypass (CPB) or conventional CPB during coronary artery bypass grafting (CABG). Ninety-eight consecutive patients with ischemic heart disease were randomly assigned to mini-CPB (n = 34) or conventional CPB (n = 64). Interleukin (IL) −8 and neutrophil elastase levels were measured before and after surgery. Hemodilution during CPB, blood loss during and after surgery were also evaluated. Compared with the conventional group, the mini-CPB group had lower levels of IL-8 on postoperative day 1 (8.3 ± 6.4 vs. 19 ± 11 pg/mL, p = 0.016) and of neutrophil elastase on postoperative days 1 (127 ± 52 vs. 240 ± 100 &mgr;g/L, p = 0.013) and 2 (107 ± 17 vs. 170 ± 45 &mgr;/L, p = 0.0001). The mini-CPB group also has less blood loss during (620 ± 595 vs. 978 ± 658 mL, p = 0.012) and after the operation (578 ± 310 vs. 1,002 ± 651 mL, p = 0.0034) and a hemodilution ratio of 14 ± 2 vs. 25% ± 3%, p < 0.0001. Thus, mini-CPB attenuated the inflammatory response and hemodilution, resulting in blood conservation in patients undergoing CABG.

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.

Who needs preoperative routine chest computed tomography for prevention of stroke in cardiac surgery

Although chest computed tomography (CT) is useful for identifying ascending aortic calcification before surgery, the efficacy of routine preoperative CT in cardiac surgery is unknown. We sought to clarify the role of routine preoperative chest CT for the determination of ascending aortic calcification before cardiac surgery to aid in the prevention of stroke. Three hundred consecutive patients who underwent elective cardiac operations excluding thoracic aortic surgery had preoperative non-contrast CT. Thirteen patients (4.3%) had severe calcification in the ascending aorta which required alteration of the cannulation site. Univariate analysis showed preoperative renal dysfunction, dialysis and aortic stenosis as predictors for ascending aortic calcification, but not history of stroke, peripheral vascular disease, and age. In multivariate analysis, aortic stenosis was found as the only predictor. The prevalence of severe ascending aortic calcification was 11.9% (10/84) in patients with aortic stenosis. Stroke occurred in two (0.67%) of the patients in the entire group but none in the 13 patients with surgical modification. For patients with aortic stenosis or hemodialysis, a low postoperative stroke rate can be achieved in elective cardiac surgery by use of routine preoperative chest CT to identify patients with ascending aortic calcification who require modification of the surgical technique.

Decreasing sternum microcirculation after harvesting the internal thoracic artery.

OBJECTIVE The effect of harvesting the internal thoracic artery (ITA) on blood supply to the sternum is not completely understood. Using a novel laser Doppler flow meter, we evaluated changes in sternum microcirculation prior to and after ITA harvesting. METHODS Forty-six patients (37 males, 69.4 ± 7.9 years) scheduled for coronary artery bypass grafting were enrolled into the study and divided into skeletonized (n = 23) and pedicled (n = 23) groups of patients with a left ITA. All right ITA were harvested using the skeletonized method. Sternal blood flow was measured presternally and retrosternally in the upper, middle, and lower sternal parts with a novel laser Doppler flow meter that measures blood flow at 1-mm depth using a 780-nm laser. Following median sternotomy, blood flow was measured before and after ITA harvesting. RESULTS In all patients (46 left and 16 right ITA cases), the middle part of the retrosternal microcirculation deteriorated (middle: pre- 2.71 ± 1.49, post- 2.43 ± 1.01 ml min(-1)100 g(-1); p < 0.05), while blood flow of other parts did not change. In patients with left ITA divided into skeletonized and pedicled groups, although middle retrosternal blood flow decreased after harvesting in both groups, there was no difference in deterioration between the groups. In patients with right ITA, the middle and lower retrosternal blood flow also deteriorated. CONCLUSIONS The degree of sternal microcirculation damage after ITA harvesting is not different between skeletonized and pedicled group patients, suggesting that skeletonization is not advantageous for maintaining sternal microcirculation.

Successful Repair of Unruptured Aneurysm of the Right Sinus of Valsalva

Patch closure of the orifice of an aneurysm is a common operation for sinus of Valsalva aneurysms. Recently, there have been reports of aortic valve-sparing operations for multisinus of Valsalva aneurysms. However, repair would be difficult if only one sinus of Valsalva was dilated. We report a patient with a single unruptured sinus of Valsalva aneurysm successfully treated using the patch repair technique.

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.

Long-term results of mitral valve replacement: biological xenograft versus mechanical valves

Abstract We studied 279 patients who underwent mitral valve replacement at the Department of Thoracic and Cardiovascular Surgery, Hyogo College of Medicine, between November 1973 and December 1998. The patients were divided into two groups based on the type of replacement valve (154 patients in the biological xenograft group and 125 patients in the mechanical valve group), and the long-term results were compared. Clinically satisfactory results were obtained in both the biological xenograft group and the mechanical valve group according to the surgical results, long-term survival, and incidence of prosthetic valve endocarditis. At 15 years, fewer patients in the mechanical valve group than in the biological xenograft group were free of bleeding events (92.5 ± 3.7% vs 100% P < 0.05). At 15 years, the biological xenograft group was lower than the mechanical valve group with respect to freedom from thromboembolism (72.2 ± 4.6% vs 93.5 ± 3.6% P < 0.01), freedom from valve failure (22.0 ± 5.2% vs 87.0 ± 4.1% P < 0.005) and freedom from cardiac events (16.5 ± 3.9% vs 47.2 ± 14.5% P < 0.01). Though it has previously been suggested that biological xenografts used in mitral valve replacement do not need anticoagulation, the current study suggests the need for anticoagulation with the use of biological xenografts. Mechanical valves require close monitoring of anticoagulation, but their use has decreased the incidence of valve failure and thromboembolism, as compared with the use of biological xenografts. Therefore, mechanical valves are currently the preferred choice for mitral valve replacement. We believe that biological xenografts are indicated only for the older patient (≧65 years).