Update on cardiopulmonary bypass

Statin therapy in the primary prevention of early atrial fibrillation after coronary artery bypass grafting

OBJECTIVE

Assessment of the role of statin therapy in the prevention of postoperative atrial fibrillation (POAF) after coronary artery bypass grafting (CABG) in patients without prior atrial fibrillation.

METHODS

A retrospective analysis of 206 patients, aged 57.2±7.9 years (mean±SD), who underwent isolated CABG is carried out. All patients are divided into two groups. The first group (nSt-patients) includes the patients who did not receive statin therapy prior to CABG (n=82). The second group (St-patients) includes the patients who received statin therapy prior to CABG (n=124). Both groups received the statin therapy from the first day after CABG. The risk of occurrence of POAF is evaluated using the Cox-regression model.

RESULTS

The rate of POAF was 25.6% in nSt-patients and 6.5% in St-patients (P=0.020). On the 4th day after CABG, white blood cells (WBC) count was 11.0 (9.0, 13.0)×10⁹/mL (medians with inter-quartile ranges) in nSt-patients and 9.0 (7.6, 10.2)×10⁹/mL in St-patients (P<0.001). The peak WBC numbers occurred on the day of POAF onset. The Cox-regression analysis shows that only two factors (statin therapy and number of grafts) had significant influence on the POAF onset. Odds ratio of POAF event prediction by statin therapy was 0.20 (95%CI: 0.08-0.51), P<0.001. Each subsequent graft increased the risk of POAF in 2.1 times.

CONCLUSION

Statin therapy carried out prior to the CABG is an effective approach to primary prevention of POAF in early postoperative period. Statin therapy after CABG in nSt-patients does not give prophylactic effect observed in St-patients.

Does preoperative statin therapy improve outcomes in patients undergoing isolated cardiac valve surgery?

Preoperative statins have been associated with decreased mortality after coronary artery bypass grafting. Data are limited on whether these benefits extend to patients undergoing cardiac valve surgery. We examined whether preoperative statins decrease morbidity and mortality in patients undergoing isolated cardiac valve surgery. In a retrospective cohort analysis of consecutive patients who underwent surgical valve repair or replacement (excluding concomitant coronary artery bypass grafting, aortic root replacement, or ventricular assist device placement) at St. Luke's Episcopal Hospital, the primary outcome was 30-day mortality. Secondary outcomes included 30-day major adverse events (composite of early mortality, postoperative myocardial infarction, or stroke). Of 825 patients, 31% received preoperative statins (n = 255). Logistic regression analysis revealed that age >65 years (p = 0.02), history of congestive heart failure (p = 0.001), and total bypass time >80 minutes (p = 0.01) were independent predictors of increased 30-day mortality. Preoperative statin therapy was not associated with decreased 30-day mortality (odds ratio 0.89, 95% confidence interval 0.38 to 2.03), major adverse events (odds ratio 1.09, 95% confidence interval 0.61 to 1.96), postoperative myocardial infarction (p = 0.70), or stroke (p = 0.57). At a mean follow-up of 1.57 years, preoperative statin therapy was not associated with decreased mortality (p = 0.81). In the analysis using propensity score matching (354 propensity-matched patients, 177 in each group), preoperative statin was not associated with improved primary or secondary outcomes. In conclusion, preoperative statin therapy was not associated with a decrease in morbidity or mortality in patients undergoing isolated cardiac valve surgery.

Preoperative statin therapy is not associated with a decrease in the incidence of postoperative atrial fibrillation in patients undergoing cardiac surgery

BACKGROUND

Atrial fibrillation (AF) after cardiac surgery is associated with significant morbidity. We investigated whether preoperative statin therapy was associated with decreased incidence of postoperative AF in patients undergoing cardiac surgery, including isolated valve surgery and patients with low ejection fraction (EF).

METHODS

A retrospective study of consecutive patients without history of AF (n = 4044) who underwent cardiac surgeries at St. Luke's Episcopal Hospital (Houston, TX), from January 1, 2003, through April 30, 2006, was conducted. Postoperative AF was assessed by continuous telemetry monitoring during hospitalization for cardiac surgery.

RESULTS

A total of 2096 patients (52%) received preoperative statins. Atrial fibrillation occurred in 1270 patients (31.4% in both the statin and nonstatin groups). In multivariate regression analysis, age >65 years, history of valvular heart disease, rheumatic disease, pulmonary disease, and New York Heart Association class III/IV were independent predictors of increased risk, whereas female sex was associated with decreased risk. Preoperative statin therapy was not associated with decreased risk in the entire cohort (odds ratio [OR] 1.13, 95% confidence interval [CI] 0.98-1.31) or in subgroups undergoing isolated coronary artery bypass grafting (OR 1.16, 95% CI 0.97-1.43), isolated valve surgery (OR 1.09, 95% CI 0.81-1.46), or both (OR 1.09, 95% CI 0.72-1.65), or the subgroup with EF <35% (OR 1.23, 95% CI 0.84-1.82). After propensity score analysis (n = 867 patients in each group), preoperative statin therapy was not associated with decreased AF incidence (OR 1.14, 95% CI 0.92-1.41).

CONCLUSIONS

Preoperative statin therapy was not associated with decreased incidence of postoperative AF in patients undergoing cardiac surgery, including patients with low EF.

Aprotinin in Cardiac Surgery: A Review of Conventional and Novel Mechanisms of Action

Induction of the coagulation and inflammatory cascades can cause multiorgan dysfunction after cardiopulmonary bypass (CPB). In light of these observations, strategies that can stabilize the coagulation process as well as attenuate the inflammatory response during and after cardiac surgery are important. Aprotinin has effects on hemostasis. In addition, aprotinin may exert multiple biologically relevant effects in the context of cardiac surgery and CPB. For example, it decreases neutrophil and macrophage activation and chemotaxis, attenuates release and activation of proinflammatory cytokines, and reduces oxidative stress. Despite these perceived benefits, the routine use of aprotinin in cardiac surgery with CPB has been called into question. In this review, we examined this controversial drug by discussing the classical and novel pathways in which aprotinin may be operative in the context of cardiac surgery.