Hirotaka Inaba

Minimal damage during endoscopic latissimus dorsi muscle mobilization with the harmonic scalpel

BACKGROUND To reduce wound-related complications, a video-assisted surgical technique has been adopted for the mobilization of the latissimus dorsi muscle. We postulated that thermal damage to the muscle might be minimized by using a Harmonic Scalpel instead of electrocautery during this procedure. METHODS Canine latissimus dorsi muscles were mobilized through a small incision, assisted by a videoscope. In 6 dogs, dissection with electrocautery was used to mobilize the latissimus dorsi muscle. In 6 other dogs, the Harmonic Scalpel was used. We compared operation times, wound infection rates, histologic changes in the muscles, and ease of handling between these groups. RESULTS The operation time was significantly shorter in the Harmonic Scalpel group than in the electrocautery group (61.5 versus 106.5 minutes, p = 0.00014). The Harmonic Scalpel caused less histologic damage to the mobilized muscles and produced less vision-obscuring smoke. CONCLUSIONS The Harmonic Scalpel shortens the operation, minimizes muscle damage, and facilitates the performance of video-assisted latissimus dorsi muscle mobilization.

Effect of preoperative hemoglobin A1c levels on long-term outcomes for diabetic patients after off-pump coronary artery bypass grafting

BACKGROUND Diabetes mellitus is an independent risk factor for cardiovascular events after coronary artery bypass grafting (CABG), and hemoglobin A1c (HbA1c) is the most convenient marker for monitoring glycemic control among diabetic patients. However, few studies have reported the impact of baseline HbA1c levels on outcomes for diabetic patients after CABG. This study therefore aimed to investigate whether preoperative HbA1c levels in diabetic patients are predictive of long-term outcomes after off-pump CABG (OPCAB). METHODS AND RESULTS Of 893 patients undergoing primary isolated OPCAB at Juntendo University Hospital from July 2002 to December 2007, subjects comprised 306 diabetic patients <80 years old. We divided these patients into 3 groups according to the preoperative HbA1c levels. No significant differences in baseline characteristics, angiographic findings, or operative parameters were apparent among the 3 groups. No operative or in-hospital mortality occurred. All-cause mortality and cardiac mortality rates were 6.2% (19 cases) and 1.3% (4 cases), respectively. Kaplan-Meiers survival showed no significant differences in all-cause or cardiac mortality (log-rank test, p=0.26, p=0.17, respectively). Multivariate analysis by Coxs proportional hazards model also demonstrated that no covariates predicted mortality except for age. CONCLUSIONS Preoperative HbA1c levels might not predict long-term outcomes for diabetic patients undergoing OPCAB. Careful evaluation for diabetes should be needed in preoperative management of CABG.

EuroSCORE predicts postoperative mortality, certain morbidities, and recovery time

EuroSCORE (European System for Cardiac Operative Risk Evaluation) used for calculating the risk of the postoperative mortality rate for patients undergoing open-heart surgery may be able to predict postoperative complications as well. Consecutive cases of isolated on-pump coronary artery bypass grafting (CABG) (n=1552) performed between 1991 and 2006 at our hospital group were placed into a systematic database. Patients were stratified using additive EuroSCORE. Incidence of postoperative mortality, morbidity (bleeding, heart failure, mediastinitis, pneumonia, myocardial infarction, renal failure, and stroke), and recovery time (intubation time, ICU stay, and postoperative length of stay) was assessed in each EuroSCORE group. EuroSCORE was well correlated with mortality, total incidence of major complications, heart failure, renal failure, stroke, pneumonia and mediastinitis, and three parameters of recovery time. Postoperative myocardial infarction and incidence of bleeding were not correlated with EuroSCORE. EuroSCORE can predict not only mortality but also postoperative complications and recovery time.

Comparing outcomes after off-pump coronary artery bypass versus drug-eluting stent in diabetic patients

BACKGROUND Off-pump coronary artery bypass surgery and sirolimus-eluting stent placement have been widely used for the treatment of coronary artery disease. The goal of this study was to compare long-term outcomes after off-pump coronary artery bypass surgery or sirolimus-eluting stent placement in diabetic patients with multivessel disease. METHODS This observational study enrolled 350 off-pump coronary artery bypass patients and 143 sirolimus-eluting stent patients receiving care at our institution between 2000 and 2007. All patients had diabetes and multivessel disease including proximal left anterior descending or left main coronary artery. The choice of revascularization (percutaneous coronary intervention versus coronary artery bypass surgery) was left to the physicians discretion rather than randomization. Cox proportional-hazard analyses, adjusting baseline risk factors and propensity score, which predicted the probability of receiving off-pump coronary artery bypass, were conducted to evaluate outcomes, including all-cause mortality, cardiac death, target vessel revascularization, and major adverse cardiac and cerebrovascular events. RESULTS During the follow-up (2.6±1.6 years) period, there was no difference between off-pump coronary artery bypass and sirolimus-eluting stent placement in all-cause mortality or cardiac death. However, the incidences of acute coronary syndrome, target vessel revascularization, and major adverse cardiac and cerebrovascular events were markedly lower in the patients undergoing off-pump coronary artery bypass than in those receiving sirolimus-eluting stent placement. CONCLUSION Off-pump coronary artery bypass is superior to sirolimus-eluting stent placement in terms of acute coronary syndrome, target vessel revascularization, and major adverse cardiac and cerebrovascular events in diabetic patients with multivessel coronary artery disease.

Myocardial tactile stiffness during acute reduction of coronary blood flow

BACKGROUND Evaluation of regional myocardial contractile function is of clinical importance. We have developed a new tactile sensor system for accurate measurement of myocardial stiffness in situ. We found that the myocardial stiffness measured by this sensor, which we call tactile stiffness, can be a very useful index for accurate quantification of regional myocardial function. In this study, we used a coronary stenosis model to investigate regional myocardial tactile stiffness under conditions of reduced coronary blood flow. METHODS The myocardial tactile stiffness, coronary blood flow, and ventricular pressure and volume, of five open chest mongrel dogs weighing 15 to 17 kg, were measured. After measuring the baseline myocardial stiffness, coronary arterial stenosis was induced with a balloon occluder. RESULTS Reducing the coronary flow to 50% and 25% of the baseline level reduced the end-systolic tactile stiffness significantly from 2.20+/-0.16 g/mm2 to 2.05+/-0.20 g/mm2 (p<0.05) and from 2.21+/-0.16 g/mm2 to 1.96+/-0.18 g/mm2 (p<0.01), respectively. Reducing the flow, to 50% and 25%, increased the end-diastolic stiffness significantly from 1.29+/-0.15 g/mm2 to 1.39+/-0.14 g/mm2 (p<0.01) and from 1.30+/-0.16 g/mm2 to 1.46+/-0.14 g/mm2 (p<0.05), respectively. CONCLUSIONS We consider that the regional myocardial tactile stiffness will be a useful index sensitive enough to detect changes in regional contractile function under conditions of reduced coronary blood flow.

Predictors of Early and Mid-Term Results in Contemporary Aortic Valve Replacement for Aortic Stenosis

Abstract  Background: The purpose of this study was to evaluate clinical risk factors and assess the impact of the Society of Thoracic Surgeons (STS) scores on outcomes after contemporary aortic valve replacement (AVR) for aortic stenosis (AS). Methods: We retrospectively analyzed the data from 209 consecutive patients with AS (mean 69 ± 9 years) who underwent AVR. The outcomes measured included operative mortality, postoperative complications, postoperative prolonged length of stay (PLOS), discharge to nonhome location, and mid‐term mortality. Results: Operative mortality was 3.8%, and five‐year survival was 88.6 ± 2.8%. Multivariable analysis revealed preoperative New York Heart Association (NYHA) class as a significant predictor of both operative mortality (p = 0.03; odds ratio [OR]: 8.5) and mid‐term mortality (p = 0.02; OR: 10.5). NYHA class also emerged as an independent predictor for postoperative complications (p = 0.002; OR: 5.8) and PLOS (p = 0.01; OR: 2.5). Other preoperative independent predictors included dialysis for PLOS (p = 0.04; OR: 2.9), age (p = 0.03; OR: 1.1), and left ventricular ejection fraction (EF; p = 0.03; OR: 0.9) for nonhome discharge, and EF for mid‐term mortality (p = 0.01; OR: 0.9). The mean STS‐PROM (predicted risk of mortality) was 4.6% ± 6.1%, and thus, the observed‐to‐expected (O/E) ratio of operative mortality in our series was 0.82. Conclusions: Advanced NYHA class, older age, dialysis, and lower EF are significant independent preoperative risk factors for early and mid‐term results of AVR for AS. Consideration of these predictors should be used to identify high‐risk patients requiring AVR for AS.

Left Atrial Appendage Closure Reduces the Incidence of Postoperative Cerebrovascular Accident in Patients Undergoing Cardiac Surgery

BACKGROUND Cerebrovascular accidents (CVA) are a major adverse event following cardiac surgery, for which atrial fibrillation (AF) is considered as a risk factor. We have recently performed left atrial appendage (LAA) surgical closure or amputation (LAAC/A), which is the main source of emboli, during open-heart surgery. METHODSANDRESULTS A prospective observational study of 1,831 consecutive patients (69.2% male, aged 66.8±12.2 years) undergoing cardiac surgery between 2009 and 2013 was performed. The incidence of postoperative CVA within 6 months in patients with and without LAAC/A was compared. We further stratified patients according to their risk of CVA using CHA2DS2-VASc score; dichotomizing low-risk (score <2) and high-risk groups (≥2). A total of 369 patients (20.2%) underwent LAAC/A. Although these patients had larger left atrial diameter preoperatively and developed postoperative AF more frequently than those without LAAC/A (45.4 vs. 41.1 mm, 49.3 vs. 39.1%, respectively, both P<0.001), the CVA incidence was not different between the groups (3.5 vs. 3.0%, P=0.612). Multivariate analysis revealed no association between LAAC/A and CVA in patients with CHA2DS2-VASc score ≥2, whereas in patients with CHA2DS2-VASc score <2, LAAC/A was the only and independent factor negatively associated with CVA development (odds ratio <10(-6); P=0.021). CONCLUSIONS Additional LAA procedure at the time of cardiac surgery reduces the incidence of early postoperative CVA in patients with low CHA2DS2-VASc score.

Comparison of modern risk scores in predicting operative mortality for patients undergoing aortic valve replacement for aortic stenosis

BACKGROUND The aim of our study was to examine and compare the predictive value of operative mortality of the European System for Cardiac Operative Risk Evaluation (EuroSCORE) II, the Society of Thoracic surgeons (STS) score, the Ambler score, and the Japan score in patients undergoing aortic valve replacement (AVR) for aortic stenosis (AS). METHODS A total of 406 patients undergoing AVR with or without coronary artery bypass grafting (CABG, n=139) at our institution from August 2002 to December 2013 were enrolled in this cohort study. Accuracy of calibration and discrimination performance of four risk scores was assessed in the overall patient population and quartiles of each risk score. RESULTS Operative mortality was 3.4% (n=14). The mean EuroSCORE II, STS score, Ambler score, and the Japan score were 3.1%, 4.9%, 5.7%, and 3.2%, respectively, giving observed-to-expected (O/E) ratio of 1.09, 0.69, 0.59, and 1.06. The C-statistics for operative mortality were 0.704 (EuroSCORE II), 0.781 (STS score), 0.709 (Ambler score), and 0.771 (Japan score). In the last quartile, the EuroSCORE II demonstrated excellent calibration (O/E ratio=0.97) and discrimination (C-statistic=0.904), and the STS score (O/E ratio=0.86, C-statistic=0.779) and the Japan score (O/E ratio=1.14, C-statistic=0.80) showed reasonable correlation. However, the risk calibration by the Ambler score in the last quartile was unacceptable (O/E ratio=0.60). CONCLUSIONS The EuroSCORE II and the Japan score showed superior ability of calibration, but the STS score and the Ambler score overestimated the risk. However, the discrimination power was similar among the four risk scores. In the last quartile of risk, the EuroSCORE II gave an excellent predictive performance.

Dissecting aortic aneurysm presenting as pyrexia of unknown origin: Report of a case

We describe herein the case of a 51-year-old woman with a dissecting aneurysm of the aorta who presented with pain in the chest followed by prolonged pyrexia of unknown origin (PUO) lasting 6 weeks. Because of the fever associated with a murmur of aortic regurgitation, she was initially misdiagnosed as having infective endocarditis. This unusual case serves to remind us that clinicians should bear in mind the possibility of aortic dissection in patients presenting with PUO.

Thoracoscopic Cardiomyoplasty: a Canine Feasibility Study

BACKGROUND Thoracoscopy may be effective in reducing the surgical stress of cardiomyoplasty. The feasibility of thoracoscopy in cardiomyoplasty was investigated. METHODS Cardiomyoplasty by thoracoscopy and by the open method through a thoracotomy was performed in dogs. After 8 to 10 weeks of preconditioning, the hemodynamic effect of burst stimulation was measured. RESULTS Cardiomyoplasty by thoracoscopy took 90 +/- 21 minutes (mean +/- standard deviation), whereas cardiomyoplasty by the open method took 67 +/- 10 minutes (p < 0.05). As a result of burst stimulation, aortic pressure, descending aortic flow, and left atrial pressure increased by 15.1% +/- 6.5%, 8.6% +/- 6.3%, and 3.8% +/- 4.6%, respectively, in the dogs that received the cardiomyoplasty by thoracoscopy, whereas those indices increased by 16.5% +/- 6.9%, 9.8% +/- 5.9%, and 4.8% +/- 4.2%, respectively, in dogs that received cardiomyoplasty by the open method. No significant difference between the two groups was shown in any index. CONCLUSIONS Cardiomyoplasty by thoracoscopy was technically practical, and its hemodynamic effect was similar to that of the open method. The feasibility of cardiomyoplasty by thoracoscopy was thereby suggested.