Perioperative statins: More than lipid-lowering?
ABSTRACTPreliminary evidence indicates that statin drugs may be beneficial when given in the perioperative period. Although more studies are needed to draw firm conclusions, the acute nonlipid pleiotropic effects of statins may improve patient outcomes, especially for patients at the highest risk.
KEY POINTS
- Experiments in animals suggest that statins, given shortly before or after a cardiovascular event, confer benefit before any changes in lipids are measurable.
- Retrospective and prospective studies indicate that patients with either acute myocardial infarction or acute coronary syndrome who are already receiving statins should not have them stopped, and those who had not been receiving statins should receive them immediately.
- Most patients undergoing coronary artery bypass grafting or noncardiac vascular surgery should already be receiving a statin. These drugs can also be considered in patients undergoing intermediate-risk nonvascular surgery. Patients who have been receiving statins prior to surgery should not have them stopped for surgery.
Dogma of withdrawing statins before major surgery is challenged
Le Manach et al33 reviewed the outcomes for all patients of a single hospital in Paris who underwent nonemergency infrarenal aortic procedures between January 2001 and December 2004. In January 2004, the hospital instituted guidelines to ensure that patients on statins continue taking them up to the evening before surgery and that statins be restarted on the first postoperative day (via nasogastric tube if necessary). Before 2004, there had been no specific guidelines, and patients on statins did not receive them for a median of 4 days postoperatively. Types of procedures were similar during the two time periods, as were the rates of beta-blocker use, preoperative revascularization, venous thromboembolism prophylaxis, and perioperative blood pressure control. After surgery, topononin I levels were measured in all patients as surveillance for cardiac events, and were defined as elevated when greater than 0.2 ng/mL.
Compared with patients not on statins at all, those treated with statins continuously throughout the perioperative period (after January 2004) had a lower rate of elevated troponin (relative risk 0.38). In contrast, those who had their statins transiently discontinued perioperatively (prior to 2004) had troponin elevations more often than those who had never been treated (relative risk 2.1). This suggested an over fivefold risk reduction (P < .001) conferred by not discontinuing statins in the immediate postoperative period. This finding was maintained after multivariate adjustment: statin withdrawal was associated with a 2.9-fold (95% CI 1.6–5.5) increase in the risk of cardiac enzyme elevations postoperatively. No fewer deaths were noted, but the study was not powered to detect a mortality difference.
Comment. Although secular trends cannot be entirely discounted as contributing to these findings, the prompt increase in cardiac events after just 4 days of statin withdrawal adds to the growing body of evidence suggesting that statin discontinuation can have harmful acute effects. It also brings up the question: Can starting statins benefit patients in the same time period?
Should statins be started before vascular surgery?
Schouten et al32 evaluated the effects of newly started or continued statin treatment in patients undergoing major elective vascular surgery. Patients were screened before surgery and started on statins if they were not already receiving them and their total cholesterol levels were elevated; new users received the medication for about 40 days before surgery. Of the 981 screened patients, 44 (5%) were newly started on statins and 182 (19%) were continued on their therapy. Perioperative death or myocardial infarction occurred in 22 (8.8%) of the statin users and 111 (14.7%) of the nonusers, a statistically significant difference. Temporary discontinuation (median 1 day) of statins in this study due to the inability to take an oral medication did not appear to affect the likelihood of a myocardial infarction.
Durazzo et al23 performed a single-center, randomized, prospective, placebo-controlled, double-blind clinical trial of atorvastatin (Lipitor) 20 mg daily vs placebo in 100 patients undergoing noncardiac arterial vascular surgery. Patients were excluded if they had previously used medications to treat dyslipidemia, recently had a cardiovascular event, or had contraindications to statin treatment such as a baseline creatinine level greater than 2.0 mg/dL or severe hepatic disease. The intervention group received atorvastatin starting at least 2 weeks before surgery for a total of 45 days. Patients were then continued or started on a statin after surgery if their LDL-C level was greater than 100 mg/dL. Beta-blocker use was recommended “on the basis of current guidelines.”
One month after surgery, the LDL-C level was statistically significantly lower in the atorvastatin group. Since most patients did not continue or start statin therapy after the 45-day treatment period, the LDL-C levels were not statistically different at 3 and 6 months after surgery.
At 6 months, the rate of the primary end point (death from cardiovascular causes, nonfatal acute myocardial infarction, ischemic stroke, or unstable angina) was 26.0% in the placebo group and 8.0% in the atorvastatin group, a statistically significant difference. Three patients in the atorvastatin group had cardiac events in the first 10 days after surgery, compared with 11 patients in the placebo group. Thirteen of the 17 total cardiac events took place within 10 days after surgery.
One of the atorvastatin patients developed rhabdomyolysis and elevated aminotransferase levels.
Major noncardiac surgery
Lindenauer et al2 performed a retrospective cohort study of surgical patients who were at least 18 years old and survived beyond the second hospital day. Patients were divided into a group receiving any form of lipid-lowering treatment (of whom more than 90% were taking statins) and a group that had never never received a lipid-lowering drug or only started one on the third day of the hospitalization or later. The period of study was from January 1, 2000, to December 31, 2001.
In all, 780,591 patients from 329 hospitals throughout the United States were included, of whom only 77,082 (9.9%) received lipid-lowering therapy. Eight percent of the patients underwent vascular surgery. Not surprisingly, the treated patients were more likely to have a history of hypertension, diabetes, ischemic heart disease, or hyperlipidemia. They also were more likely to have a vascular procedure performed, to have two or more cardiac risk factors (high-risk surgery, ischemic heart disease, congestive heart failure, cerebrovascular disease, renal insufficiency, or diabetes mellitus), and to be treated with beta-blockers and angiotensin-converting enzyme inhibitors, but they were less likely to have high-risk and emergency surgery performed.
The primary end point, perioperative death, occurred in 2.13% of the treated patients and 3.05% of the nontreated group. Compared with the rate in a propensity-matched cohort, the odds ratio adjusted for unbalanced covariates was 0.62 (95% CI 0.58–0.67) in favor of lipid treatment. Stratification by cardiac risk index revealed a number needed to treat of 186 for those with no risk factors, 60 for those with two risk factors, and 30 for those with four or more risk factors.
Unfortunately, this analysis was not able to take into account whether and for how long patients were receiving lipid-lowering therapy before hospitalization. It therefore does not answer the questions of whether starting lipid-lowering therapy before surgery is beneficial or whether stopping it is harmful. It also does not shed light on whether perioperative lipid-lowering increases the risk of rhabdomyolysis or liver disease.
