Preoperative Intraaortic Balloon Pump Improves Early Outcomes Following High-Risk Coronary Artery Bypass Graft Surgery: A Meta-Analysis of Randomized Trials and Prospective Study Design.

BACKGROUND: Despite widespread use, evidence to support preemptive intraaortic balloon pump (IABP) insertion for patients undergoing high-risk coronary artery bypass graft (CABG) surgery remains sparse, and in need of a well-defined clinical trial. To inform the design of a prospective trial, we sought to review outcomes in randomized controlled trials (RCTs) of anticipatory IABP use vs control in patients undergoing high-risk CABG through meta-analysis. The primary endpoint was all-cause mortality within 30 days of surgery. The secondary endpoint was major adverse cardiac and cerebrovascular event (MACCE), a composite of death, myocardial infarction, stroke, or repeat revascularization. METHODS: Using Ovid MEDLINE, we systematically reviewed all RCTs comparing preoperative IABP with control in patients undergoing high-risk CABG, defined as: left ventricular ejection fraction (LVEF) ≤40%, left main stenosis ≥70%, unstable angina, recent myocardial infarction, or prior myocardial revascularization undergoing elective or emergent CABG on or off pump. RESULTS: Of 950 articles assessed for eligibility, 10 RCTs of 1261 subjects (mean age, 65.0 years; 21.8% women; mean LVEF, 35%) were included. Mortality was significantly lower in patients receiving IABP compared with control (relative risk [RR], 0.48; 95% confidence interval [CI], 0.30-0.76; P<.01). The risk of MACCE was also lower with IABP (RR, 0.67; 95% CI, 0.54-0.84; P<.001). No significant differences in major bleeding events (RR, 1.27; 95% CI, 0.44-3.72) or vascular complications (RR, 1.13; 95% CI, 0.42-3.06) were detected. CONCLUSIONS: A strategy of routine prophylactic IABP use may reduce short-term mortality and MACCE in high-risk CABG patients. A definitive, adequately powered, prospective, randomized trial is warranted to confirm these results.

Dietary flaxseed protects against ventricular fibrillation induced by ischemia-reperfusion in normal and hypercholesterolemic Rabbits.

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the (n-3) PUFA found in fish oils, exert antiarrhythmic effects during ischemia. Flaxseed is the richest plant source of another (n-3) PUFA, alpha-linolenic acid (ALA), yet its effects remain largely unknown. Our objective was to determine whether a flaxseed-rich diet is antiarrhythmic in normal and hypercholesterolemic rabbits. Male New Zealand White (NZW) rabbits (n = 14-16) were fed as follows: regular diet (REG group); diet containing 10% flaxseed (FLX group); 0.5% cholesterol (CHL group); or 0.5% cholesterol + 10% flaxseed (CHL/FLX group) for up to 16 wk. Plasma cholesterol was significantly elevated in the CHL and CHL/FLX groups. Plasma triglycerides were unchanged. ALA levels increased significantly in plasma and hearts of the FLX and CHL/FLX groups. After the feeding period, rabbit hearts were isolated and subjected to global ischemia (30 min) and reperfusion (45 min). Ventricular fibrillation (VF) occurred during ischemia in 33% of REG but in none of FLX hearts, and 28% of CHL but only 6% of CHL/FLX hearts. VF incidence during reperfusion was 28% and 26% in REG and FLX hearts, respectively. The incidence significantly increased to 64% in CHL hearts, and was significantly attenuated (18%) in CHL/FLX hearts. CHL markedly prolonged the QT interval, whereas FLX significantly shortened the QT interval and reduced arrhythmias in the FLX and CHL/FLX hearts. In vitro application of (n-3) PUFA shortened the action potential duration, an effect consistent with the QT data. This study demonstrates that dietary flaxseed exerts antiarrhythmic effects during ischemia-reperfusion in rabbit hearts, possibly through shortening of the action potential.