On-pump versus off-pump coronary artery bypass surgery in high-risk patients: operative results of a prospective randomized trial (on-off study).

OBJECTIVE: To analyze the risk reduction of cardiopulmonary bypass complications between on-pump and off-pump coronary artery bypass grafting in high-risk patients. METHODS: This multicenter, prospective, randomized, parallel trial enrolled patients for elective or urgent isolated coronary artery bypass grafting with an additive European System for Cardiac Operative Risk Evaluation of 6 or more. The patients in cardiogenic shock were excluded. The composite primary end point included operative mortality, myocardial infarction, stroke, renal failure, reoperation for bleeding and adult respiratory distress syndrome within 30 days after surgery. The total sample size was 693 patients, according to a scheduled interim analysis at 400 patients enrolled (α-spending = 0.029, Pocock method). RESULTS: A total of 411 patients were included in the interim analysis. Randomization assigned 203 patients to on-pump and 208 patients to off-pump treatment. Of the 411 patients, 24 crossed over; thus, 195 patients were actually treated on-pump and 216 off-pump. According to the intention to treat analysis, the rate of the composite primary end point was significantly lower (unadjusted P = .009, adjusted P = .010) in the off-pump group (5.8% vs 13.3%). The risk of experiencing the primary end point was significantly greater for the on-pump group (unadjusted odds ratio, 2.51; 95% confidence interval, 1.23-5.10; P = .011; adjusted odds ratio, 3.07; 95% confidence interval, 1.32-7.14; P = .009). CONCLUSIONS: Off-pump coronary artery bypass grafting reduces early mortality and morbidity in high-risk patients.

Myocardial injury after off-pump coronary artery bypass grafting operation.

OBJECTIVE: Perioperative myocardial ischemia is less pronounced in off-pump coronary artery bypass (OPCAB) compared to on-pump coronary artery bypass; however, the threshold over which the postoperative release of cardiac troponin I (cTnI) release and creatine kinase-MB (CK-MB) after OPCAB should be considered clinically relevant is unknown. The study was designated to evaluate if perioperative myocardial damage, measured by means of postoperative release of cTnI and CK-MB, has an influence on short- and mid-term outcome after OPCAB operations. METHODS: Two hundred and sixty-one unselected patients undergoing OPCAB had cTnI and CK-MB measured preoperatively and nine times postoperatively. Postoperative peak values were evaluated and the 80th percentiles were used to segregate the population into two groups for each marker. The following cut-offs were used: 7.1 ng/dl for cTnI peak and 36.3 ng/dl for CK-MB peak. RESULTS: Patients with cTnI>7.1 ng/ml (n=51) and CK-MB>36.3 ng/ml (n=48) had a longer mechanical ventilation and ICU length of stay. Nevertheless, hospital mortality did not differ between groups. Survival after 3 years was 92.8+/-2.3% and 81.8+/-6.2 for patients with postoperative cTnI peak7.1 ng/ml, respectively (p=0.003). It was 93+/-2.2% and 80+/-6.8% for patients with CK-MB36.3 ng/ml, respectively (p=0.005). Adjusted hazard ratios for mid-term mortality were HR 2.7 (CI 1-7.6), p=0.05 for cTnI>7.1 ng/dl and HR 3.1 (CI 1-9.1), p=0.04 for CK-MB>36.3 ng/ml. CONCLUSION: Perioperative myocardial damage should not be considered an innocuous event following OPCAB operations since the survival rate over 3 years is significantly worse in patients with the highest postoperative peak release of cTnI and CK-MB.

Hemodynamics in off-pump surgery: normal versus compromised preoperative left ventricular function.

OBJECTIVE: Off-pump coronary surgery (OPCABG), avoiding cardiopulmonary bypass and cardioplegic arrest, seems to be a better choice in patients with poor baseline cardiac function. Since cardiocirculatory collapse could be induced by heart displacement in this group of patients at high risk, a greater pathophysiologic understanding of the hemodynamic derangements occurring in such patients is needed. METHODS: Twenty-eight elective OPCABG patients were evaluated for hemodynamic changes induced by heart displacement, using arterial thermodilution to measure cardiac output and global end-diastolic volume. Hemodynamic parameters were recorded: at baseline; during proper exposure and stabilization of each vessel; and at the end of surgery. Patients were divided into two groups, according to baseline ejection fraction (EF): group A (EF>30%; N=16), group B (EF< or =30%; N=12). RESULTS: Heart displacement induced a significant drop in the cardiac and stroke index, with a lesser decrease of mean arterial pressure because of raised systemic vascular resistance. Preload, measured as global end diastolic volume, significantly decreased in group A, while it remained unchanged or increased in group B. Linear regression between the preload index and left ventricular stroke work was significant only in group A. CONCLUSIONS: Patients with poor baseline cardiac function can well tolerate OPCABG. However, the pathophysiologic modifications underlying the hemodynamic changes are different compared to those in patients with good preoperative cardiac performance.

Midterm evaluation of the Sorin Bicarbon heart valve prosthesis: single-center experience.

BACKGROUND: The purpose of this study was to perform midterm evaluation of the clinical performance of the Sorin Bicarbon mechanical heart valve prosthesis. METHODS: From November 1992 to December 2002, 328 patients underwent isolated aortic (AVR; 156) or mitral (MVR; 172) valve replacement with the Sorin Bicarbon mechanical valve. Concomitant surgery was performed in 83 patients (25.2%). RESULTS: Total hospital mortality was 5.2%. Survival at 7 years was 79.5% for AVR and 82.4% for MVR. Kaplan-Meier freedoms from valve-related complications were as follows: thromboembolism 92.7% (AVR 94.8%, MVR 92.1%); bleeding 93% (AVR 91.9%, MVR 94.5%); nonstructural dysfunction 96.6% (AVR 94.7%; MVR 97.9%); endocarditis 97.7% (AVR 97.4%, MVR 98.1%); and reoperation 95.7% (AVR 96.6%, MVR 93.9%). Overall freedom from valve-related death was 93.2% (AVR 99.3%, MVR 91.2%). At the end of follow-up, 88.9% of survivors were in New York Heart Association class I or II. CONCLUSIONS: The Sorin Bicarbon valve is a satisfactory mechanical valve prosthesis with low mortality and morbidity and good functional results.