Early, middle and long-term clinical outcomes of coronary artery bypass grafting for left main coronary stenosis

Abstract

To evaluate the early, middle and long-term clinical outcomes of coronary artery bypass grafting (CABG) for a special subset of left main coronary stenosis (LMS). A total of 626 LMS patients, recruited at our hospital between January 1998 and March 2008, were classified them into the statin therapy group (Group A, n = 322) or the non-statin therapy group (Group B, n = 304) according to whether or not taking statins pre-operatively. Then their clinical data were retrospectively analyzed. The inhospital mortality was 4.31% (n = 27). And the mortality was 1.90% (n = 6) for Group A and 6.91% for Group B (n = 21) (χ² test, χ² = 9.642, P = 0.002). Preoperative statin therapy could lower the all-cause mortality rate (1.90% vs 6.91%, P = 0.002), the prevalence of new atrial fibrillation or flutter (14.69% vs 19.61%, P = 0.016, χ ²= 5.780) and disabling stroke (2.50% vs 4.58%, P = 0.047, χ(2) = 3.94). Among 599 CABG survivors, 565 cases (94.3%) were actually followed up with a mean duration of 55.5 ± 26.1 months (range: 2 - 98). During the follow-up period, there were 29 (4.63%) cardiac events, including 12 deaths and 17 myocardial infarctions. There were 43 (7.18%) cases with relapsing angina pectoris. The univariate analysis showed that emergency procedure, abnormal C-reactive protein (CRP), abnormal troponin I(TnI), complicated LMS pathology, preoperative IABP (intra-aortic balloon pump) support, preoperative cardiac arrest, preoperative history of myocardium infarction and no preoperative statin therapy were the risk factors for perioperative death while complicated LMS pathology, preoperative IABP support, preoperative cardiac arrest, preoperative myocardium infarction and no preoperative statin therapy were the risk factor for late cardiac events. The multivariate binary logistic regression showed that emergency procedure, preoperative IABP support, no preoperative statin therapy and preoperative IABP support were independent predictors for peri-operative death. And preoperative IABP support, preoperative cardiac arrest, no preoperative statin therapy and complicated LMS pathology were independent predictors for late cardiac events. There was no statistical significance in inhospital mortality between on pump CABG and OPCAB (off pump coronary artery bypass). The CABG procedure for LMS carries a relative high mortality. However preoperative statin therapy may offer such protective effects as lowering the all-cause mortality rate and reducing the prevalence of new atrial fibrillation or flutter and disabling stroke.