Statins Win Again! A New Study Confirms that Statins Improve Coronary Bypass Outcomes
Published Oct 1, 2013
Statins are a class of medications used to lower cholesterol levels, particularly the “bad cholesterol” called low density lipoprotein or LDL. Increased cholesterol or LDL levels are associated with increased risk for cardiovascular disease, and statins have been shown to prevent cardiovascular disease in people with high cholesterol or LDL levels who are at high risk (like those with diabetes or high blood pressure). Statins are also very effective in decreasing mortality in people with pre-existing cardiovascular disease.
Statins have benefits other than just lowering cholesterol. Statins have anti-inflammatory properties. These properties may help stabilize the plaques in blood vessels, which cause heart attacks and strokes. Statins make the plaques less likely to rupture, thus reducing the chance of a heart attack or stroke.
While the data are less clear, statins may also reduce risk of:
- Blood clots forming in the veins (venous thromboembolism)
- Some forms of cancer
- Arthritis and bone fractures
- Dementia and Alzheimer’s disease
- Kidney disease
- Certain types of infections
Current guidelines from the American College of Cardiology and the American Heart Association recommend statins before and after coronary artery bypass surgery or angioplasty, and following certain types of strokes, regardless of the cholesterol or LDL level. A new study strongly supports this recommendation. In a study published today in the Annals of Thoracic Surgery, investigators at the University of Cologne in Germany report the results of a meta-analysis of patients taking statins before two types of heart surgery, coronary artery bypass surgery and aortic valve surgery. This pooled analysis of prior studies included 36,053 coronary artery bypass graft surgery patients from 32 studies receiving either statins or no statins and 3,091 patients undergoing aortic valve replacement from 4 trials receiving either statins or no statins.
The results in the coronary artery bypass group were definitive. Patients treated with statins were 33% less likely to die, 19% less likely to have a stroke, and 28% less likely to develop an irregular rhythm of the heart called atrial fibrillation, which is common following heart surgery. Statin use was also associated with a shorter length of stay in the hospital. Statin therapy did not reduce the risk of subsequent heart attack or renal failure.
The results were less definitive in the patients undergoing aortic valve replacement. There were no significant benefits associated with statin therapy. This finding may indicate that statins are not effective in the setting of aortic valve replacement surgery. Alternatively, the analysis may have simply been underpowered. By that, I mean that the number of patients studied was too small to show a definite benefit. In comparison to the analysis of coronary artery bypass surgery patients, the number of aortic valve replacement patients in this analysis was very small. The trends in outcomes favored statin use in the patients undergoing aortic valve replacement. While statistically insignificant, there were trends toward a 28% reduction in mortality, 23% reduction in stroke, and a 32% reduction in kidney failure with stain therapy in these patients. The incidence of atrial fibrillation and length of stay were not reported in any of the included aortic valve replacement studies.
The study’s authors conclude that their findings strengthen the mandate for statin use before and after coronary artery bypass surgery. They also conclude that their data do not support the general use of statins for aortic valve surgery patients. As a clinical scientist, I agree with these conclusions. However, given the trend toward improvement with statins in patients undergoing aortic valve surgery, it is tempting to consider the use of these agents in this setting too. Statins are generally safe, with the major side effects being elevations in liver function enzymes and muscle aches and a very rare form of muscle breakdown.