Taira Yamamoto

Coronary artery bypass grafting in patients on chronic hemodialysis: surgical outcome in diabetic nephropathy versus nondiabetic nephropathy patients

BACKGROUND The presence of diabetes mellitus adversely affects the late survival of patients undergoing coronary artery bypass grafting (CABG). The purpose of this study is to clarify the role of diabetic nephropathy on outcomes of a group of patients on chronic hemodialysis undergoing CABG. METHODS Between April 1984 and July 1999, 45 patients on chronic hemodialysis underwent CABG. Forty-three had conventional CABG and 2 had off-pump CABG. There were 37 males and 8 females, and the mean age was 57 years (43 to 76 years). Twenty-one patients had diabetic nephropathy (group D) and 24 had nondiabetic nephropathy (group ND). Early and late results were determined in both groups. RESULTS Early outcome was not significantly different between the groups. There was no hospital mortality, stroke, or requirement for prolonged mechanical ventilation (>24 hours) in either group. No patients in group D, and only 1 (4.2%) in group ND had low cardiac output syndrome. The difference in the incidence of arrhythmias (23.8% in group D and 25% in group ND), wound infections (9.5% in group D and 8.3% in group ND), and delayed tamponade (5% in group D and 12.5% in group ND) was not statistically significant. However, late results differed significantly between the two groups. Actuarial survival (Kaplan-Meier) at 5 and 9 years was 22.9% and 11.5% in group D and 89.1% and 45.7% in group ND (p = 0.01), respectively. Similarly, the cardiac event-free rate at the same intervals was 50.4% and 0% for group D and 100% and 65.8% for group ND (p = 0.001), respectively. CONCLUSIONS Using present technology, CABG can be done in patients on chronic hemodialysis with acceptable early mortality and morbidity. Late results in patients with diabetic nephropathy on hemodialysis are not as favorable as their nondiabetic cohort.

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.

Relationship between exercise tolerance and muscle strength following cardiac rehabilitation: Comparison of patients after cardiac surgery and patients with myocardial infarction

BACKGROUND AND PURPOSE Previous studies have demonstrated that cardiac rehabilitation (CR) improves exercise tolerance and muscle strength in patients with myocardial infarction (MI) and in patients after cardiac surgery. However, the association between exercise tolerance and muscular strength following CR and the comparison of relationships among various disease categories has not been fully examined. The purpose of the present study was to assess the relationship between exercise tolerance and muscle strength following CR in patients after cardiac surgery and patients with MI. METHODS AND RESULTS One hundred and four patients who participated in CR for 6 months were enrolled [post-cardiac valve surgery (VALVE), n=28; post-coronary artery bypass grafting (CABG), n=42; post-acute MI, n=34]. The exercise tolerance, thigh/calf circumferences, and muscle strength were measured before and after CR. At the baseline, the thigh circumference was significantly smaller in the VALVE group than in the MI group. There were significant positive correlations between peak VO(2) and muscle torques of the lower muscles in all groups. After 6 months, peak VO(2) and muscle torque were significantly increased in all groups (p<0.001). A positive significant correlation between percent increases in peak VO(2) and muscular strength was observed in the VALVE group (r=0.51, p<0.01), but not in the other groups. In addition, the changes in peak VO(2) and calf circumference after CR were significantly higher in the VALVE group than in the MI group. CONCLUSIONS These data suggest that exercise intolerance in patients after heart valve surgery may in part depend on decreased muscular strength. Further studies are needed to assess whether the strategy of increasing muscular strength of lower limb by programmed resistance training could be effective for improving exercise intolerance in patients after heart valve surgery and symptomatic patients with heart failure.

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.

Metal allergy to stainless steel wire after coronary artery bypass grafting.

Abstract To our knowledge, this is the first reported case of a manganese metal allergy to stainless steel wire. A 51-year-old man suffered from a refractory pruritic erythematous wheal after the insertion of a stainless steel wire. The patch test showed strong reactions to manganese, one of the constituents of stainless steel wire. After the removal of all stainless steel wires, the symptoms were much improved, except for mild pruritus on his face.

Metabolic syndrome is an independent risk factor for stroke and acute renal failure after coronary artery bypass grafting.

OBJECTIVES Metabolic syndrome is common among patients having coronary artery bypass grafting. However, it remains unclear whether it has a significant impact on postoperative complications. We aimed to determine whether metabolic syndrome negatively influences the postoperative outcomes of coronary artery bypass grafting. METHODS We enrolled 1183 patients who had coronary artery bypass grafting at Juntendo University Hospital between 1984 and 1992. Patients were categorized by the presence or absence of metabolic syndrome using the modified National Cholesterol Education Program Adult Treatment Panel III definition with body mass index in the place of waist circumference. Multivariate analysis was performed to assess the relationships between preoperative presence of metabolic syndrome and postoperative outcomes. RESULTS Metabolic syndrome was present in 551 (46.6%) patients and absent in 632 (53.4%). Postoperative stroke occurred in 4.7% of patients with metabolic syndrome and 2.1% of patients without metabolic syndrome (P < .0001). Postoperative acute renal failure occurred in 3.8% of patients with metabolic syndrome and 1.1% of patients without metabolic syndrome. On multivariate analysis, metabolic syndrome had odds ratios of 2.47 (95% confidence interval 1.22-4.99; P = .012) for postoperative stroke and 3.81 (95% confidence interval 1.42-10.3; P = .008) for postoperative acute renal failure. CONCLUSIONS This study showed the clinical importance of metabolic syndrome with respect to postoperative stroke and acute renal failure in patients having coronary artery bypass grafting. Like many established risk factors for postoperative complications, metabolic syndrome should be recognized as a novel risk factor for adverse events.

Impact of diabetes on muscle mass, muscle strength, and exercise tolerance in patients after coronary artery bypass grafting

BACKGROUND The impact of diabetes mellitus (DM) on muscle mass, muscle strength, and exercise tolerance in patients who had undergone coronary artery bypass grafting (CABG) has not been fully elucidated. METHODS We enrolled 329 consecutive patients who received cardiac rehabilitation (CR) after CABG (DM group, n=178; non-DM group, n=151) and measured lean body weight, mid-upper arm muscle area (MAMA), and handgrip power (HGP) at the beginning of CR. We also performed an isokinetic strength test of the knee extensor (Ext) and flexor (Flex) muscles and a cardiopulmonary exercise testing at the same time. RESULTS No significant differences in risk factors, including age, gender, number of diseased vessels, or ejection fraction were observed between the 2 groups. The levels of Ext muscle strength, peak oxygen uptake, and anaerobic threshold were significantly lower in the DM group than in the non-DM group (all p<0.05). Both peak oxygen uptake and MAMA correlated with Ext and Flex muscle strength as well as HGP (all p<0.005). The MAMA, HGP, and Ext muscle strength were lower in patients who received insulin therapy than in those who did not. Interestingly, fasting glucose levels significantly and negatively correlated with Ext muscle strength. CONCLUSIONS These data suggest that DM patients had a lower muscle strength and exercise tolerance than non-DM patients. Moreover, a high glucose level may affect these deteriorations in DM patients after CABG.

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.

Is diabetes mellitus a major risk factor in coronary artery bypass grafting? The influence of internal thoracic artery grafting on late survival in diabetic patients.

OBJECTIVE The presence of diabetes could possibly have an adverse influence on the late results of coronary artery bypass grafting (CABG). A retrospective observational risk-unadjusted estimation study was conducted to clarify the magnitude of this unfavorable influence of diabetes based on our experience at Juntendo University. METHODS Between January 1984 and December 1995, 1,618 primary CABG operations were performed and 99.0% of these patients were followed up for a mean period of 81.2 months with a maximal follow-up of 14 years. Among the 1,610 patients who were successfully followed up, 523 patients (32.5%) were diabetic and this cohort was compared with 1,087 nondiabetic patients regarding the patient profiles, perioperative outcome, and the long-term outcome. RESULTS Diabetic patients included a higher proportion of females, a greater preoperative presence of renal insufficiency, a higher rate of three vessel disease, and reception of a greater number of grafts (mean: 2.5 versus 2.4) and an internal thoracic artery graft (68% versus 58%). Hospital mortality was not significantly different (2.1% vs 1.0%: ns). An actuarial analysis revealed a significantly unfavorable long-term survival in the diabetic group (59.6%) at 14 years, compared with the nondiabetic group (73.4%), however diabetic patients with an internal thoracic artery graft had a favorable long-term survival (82.0%) at 13 years, and this finding was almost identical to that of nondiabetic patients with an internal thoracic artery graft (88.5%). CONCLUSION We conclude that the presence of diabetes appears to be a major risk factor in patients undergoing CABG. However, diabetic patients with an internal thoracic artery graft had a survival almost identical to that of nondiabetic patients with an internal thoracic artery graft.

Effect of cardiac rehabilitation on muscle mass, muscle strength, and exercise tolerance in diabetic patients after coronary artery bypass grafting

BACKGROUND The effects of cardiac rehabilitation (CR) on muscle mass, muscle strength, and exercise tolerance in patients with diabetes mellitus (DM) who received CR after coronary artery bypass grafting (CABG) have not been fully elucidated. METHODS We enrolled 78 consecutive patients who completed a supervised CR for 6 months after CABG (DM group, n=37; non-DM group, n=41). We measured mid-upper arm muscle area (MAMA), handgrip power (HGP), muscle strength of the knee extensor (Ext) and flexor (Flex), and exercise tolerance at the beginning and end of CR. RESULTS No significant differences in confounding factors, including age, gender, ejection fraction, or number of CR sessions, were observed between the two groups. At the beginning of CR, the levels of Ext muscle strength and peak VO2 were significantly lower in the DM group than in the non-DM group. At the end of CR, significant improvement in the levels of muscle strength, HGP, and exercise tolerance was observed in both groups. However, the levels of Ext muscle strength, HGP, peak VO2, thigh circumference, and MAMA were significantly lower in the DM group than in the non-DM group. In addition, no significant improvement in thigh circumference and MAMA was observed in the DM group. At the end of CR, the levels of thigh circumference and MAMA correlated with Ext and Flex muscle strength as well as with HGP. Percent changes in the levels of Ext muscle strength were significantly correlated with those of MAMA and hemoglobin A1c. CONCLUSIONS These data suggest that improvement in muscle strength may be influenced by changes in muscle mass and high glucose levels in DM patients undergoing CR after CABG. A CR program, including muscle mass intervention and blood glucose control, may improve deterioration in exercise tolerance in DM patients after CABG.