Preoperative Statin Use Reduces Mortality in Coronary Bypass Patients

Jim Kling

October 28, 2010

October 28, 2010 (San Diego, California) — Preoperative statins reduce mortality in coronary bypass patients, according to research presented here at the American Society of Anesthesiologists 2010 Annual Meeting.

Most patients undergoing coronary artery bypass graft (CABG) surgeries are treated with beta blockers, angiotensin converting enzyme inhibitors, and 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins). The researchers investigated the relationship between preoperative statin therapy and postoperative outcome and 1-year survival in patients undergoing CABG.

The study was prospective and included 1034 patients undergoing CABG surgery at a single academic institution. Of these, 703 patients received preoperative statin therapy, and 331 did not. The researchers analyzed risk factors, postoperative complications, and mortality at 30 days and 1 year after surgery.

They used likelihood ratios with kappa optimization to build a risk model for mortality and C-statistic with area under the curve values to evaluate the performance of the risk model. The researchers used univariate and bivariate (χ2, Fisher's exact, and Student's t-test) analyses to determine the association between statin therapy and mortality. For both groups, the researchers calculated number needed to treat and odds ratios (ORs) with 95% confidence intervals (CIs).

Mean age of the population was 65 years (standard deviation, 10 years; range, 42 - 81 years), 283 were women, and 751 were men. Predictive risk factors for mortality were found to be: creatinine level, higher than 130 μmol/L; left ventricular ejection fraction percentage, lower than 40%; age, older than 75 years; New York Heart Association status, 3 or more; and no statin therapy. The model's specificity was 98.7%, its sensitivity was 40.6%, and the total error rate was 4.9% (kappa value, 0.481; 95% CI for kappa, 0.34 - 0.62; C-statistic area under the curve values, 0.83).

At 1 month, 36 patients had died (3.48%), including 19 patients in the statin group (2.7%) and 17 patients in the nonstatin group (5.14%; χ2 3.96; P < .05). At 1 year, 64 patients (6.19%) had died, including 28 in the statin group (3.98%) and 36 in the nonstatin group (10.9%).

For statin users, risk for 1-year mortality was an OR of 0.340 (95% CI, 0.208 - 0.556); among nonstatin users, the OR was 4.7 (95% CI, 2.3 - 9.8; χ2 18.40; P < .0001; Fisher's exact, 0.00003). Number needed to treat among statin users was 14.5 (95% CI, 9.5 - 30.9), and these patients had a relative risk reduction of 63.4%.

"Preoperative statin therapy may provide a significant risk reduction in the CABG patient population," the researchers wrote in the abstract.

"Statins lower lipid levels, but they also have other cardioprotective effects. The difference in mortality was already significant 1 month after the operation," Tuula Kurki, MD, PhD, a cardiac anesthesiologist at Helsinki University Hospital, in Finland, who presented the research, told Medscape Medical News.

Dr. Kurki noted that some patients discontinue statins for personal reasons, but the study results underscore the importance of patients staying on statins preoperatively. "We cannot yet make hard conclusions, but we suggest that all patients going into coronary bypass surgery should have statins at least 4 weeks before the operation, and of course after," Dr. Kurki said.

"It's an interesting observation, but the thing you have to worry about is some bias between the 2 groups. Those things can be very hard to tease out," Mark Nunnally, MD, an associate professor of anesthesiology at the University of Chicago, in Illinois, who moderated the session, told Medscape Medical News.

The use of statins is gaining momentum as a result of a number of retrospective studies, according to Dr. Nunnally. "I think a lot of people would be happy to see the data be solidified a little more in a prospective fashion, but the signal is strong, and I can attest that many providers are now using the drugs in this setting."

Dr. Kurki and Dr. Nunnally have disclosed no relevant financial relationships.

American Society of Anesthesiologists 2010 Annual Meeting: Abstract 1318. Presented October 19, 2010.

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