Ann Thorac Surg 2006;81:84
© 2006 The Society of Thoracic Surgeons
Original article: Cardiovascular
Invited commentary
Michel Carrier, MD, FRCSC
Department of Surgery, Montreal Heart Institute, 5000 Belanger St E, Montreal, PQ, H1T 1C8 Canada
(Email: michel.carrier{at}icm-mhi.org).
Pascual and colleagues studied the impact of pretreatment with statins on patients scheduled to undergo coronary artery bypass surgery (CABG) [1]. Patients with statins showed a decrease in early death and myocardial infarction rates as compared with untreated patients. Moreover, the risk of postoperative complications seems to be much higher in untreated patients with positive preoperative troponin T values (> 0.01 ng/mL). Although the present study has several weaknesses, including an obvious selection bias for high-risk patients as suggested by excessive mortality and myocardial infarction rates, it raises two interesting topics: First, the role of statin as an anti-inflammatory and anti-ischemia-reperfusion agent, and second, preoperative risk stratification with troponin T plasma levels.
Several authors have studied noncholesterol lowering effects (pleiotropic) of statins [2]. Briefly, statins act upon the vascular wall in stabilizing vulnerable plaques to prevent rupture; protect against ischemia-reperfusion injury; possess anti-inflammatory properties by activating e-NOS and decreasing endothelin-1; a better thrombogenic profile; reduced expression of inflammatory cytokines; and changes in the mevalonate pathway. Beyond the protective effect of statins on saphenous vein grafts as shown in the post-CABG trial [3], clinical relevance of the pleiotropic effects of statins is documented in various clinical studies [4, 5]. The present study on CABG patients adds another dimension to the complex relationship between statins and the peculiar pro-thrombogenic, inflammatory, and atherosclerotic environment to which patients who undergo CABG surgery are exposed.
The second topic of interest is the use of troponin T as a tool for preoperative risk stratification. Until now, all risk classification models based on clinical and biochemical data offer an estimate of the risk of death or myocardial infarction, or both, after cardiac surgery with little or no emphasis on interventions to modify those risks. In an earlier study, we showed that patients undergoing elective CABG with preoperative elevated troponin values have nearly tripled the risk of postoperative myocardial infarction [6]. Pascual's data suggest that this risk could be significantly reduced with preoperative statin therapy.
The logical conclusion of this discussion is that we need a prospective, randomized clinical trial to demonstrate the benefits of statin pretreatment; however, this statement is hollow because more than 80% of our patients are currently treated with a statin at the time of admission. We now know that all patients (with very few exceptions) should be on high doses of statins immediately after contacting a physician for cardiovascular problems.
This is welcome because cardiac surgeons are usually reluctant to try new pharmacologic agents. Under-use of aprotinin in current clinical practice [7] and absence of enthusiasm for Pexelizumab, a new monoclonal antibody to decrease ischemia-reperfusion injury [8], are critical examples. These drugs address the inflammatory response to CPB and ischemia-reperfusion injury. Statin pretreatment, pexelizumab, and aprotinin administration during cardiac surgery could become part of our routine treatment to prevent and control the inflammatory reaction and the ischemia-reperfusion injury related to every cardiac surgical procedure.
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References
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- Pascual DA, Arribas JM, Tornel PL, et al. Preoperative statin therapy and troponin T predict early complications of coronary artery surgery Ann Thorac Surg 2006;81:78-84.[Abstract/Free Full Text]
- Lazar HL, Bao Y, Zhang Y, Bernard SA. Pretreatment with statins enhances myocardial protection during coronary revascularization J Thorac Cardiovasc Surg 2003;125:1037-1042.[Abstract/Free Full Text]
- The Post Coronary Artery Bypass Graft Trial Investigators The effect of aggressive lowering of low-density lipoprotein cholesterol levels and low-dose anticoagulation on obstructive changes in saphenous-vein coronary-artery bypass grafts N Engl J Med 1997;336:153-162.[Abstract/Free Full Text]
- Durazzo AE, Machado FS, Ikeoka DT, et al. Reduction in cardiovascular events after vascular surgery with atrovastatin: a randomized trial J Vasc Surg 2004;39:967-975.[Medline]
- Almong Y, Shefer A, Novack V, et al. Prior statin therapy is associated with a decreased rate of severe sepsis Circulation 2004;110:880-885.[Abstract/Free Full Text]
- Carrier M, Pelletier LC, Martineau R, Pellerin M, Solymoss BC. In elective coronary artery bypass grafting, preoperative troponin T level predicts the risk of myocardial infarction J Thorac Cardiovasc Surg 1998;115:1328-1334.[Abstract/Free Full Text]
- Sedrakyan A, Treasure T, Eleftriades JA. Effect of aprotinin on clinical outcomes in coronary artery bypass graft surgery: a systematic review and meta-analysis of randomized clinical trials J Thorac Cardiovasc Surg 2004;128:442-448.[Abstract/Free Full Text]
- Verrier ED, Shernan SK, Taylor KM, et al. Terminal complement blockade with pexelizumab during coronary artery bypass graft surgery requiring cardiopulmonary bypass: a randomized clinical trial JAMA 2004;291:2319-2327.[Abstract/Free Full Text]
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