[Effect of left ventricular ejection fraction on clinical long-term follow-up outcomes in patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention].

OBJECTIVE: To evaluate the effect of left ventricular ejection fraction (LVEF) on clinical outcomes in patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.

METHODS: A total of 158 patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention between January 2005 to December 2007 were enrolled. They were divided into three groups: LVEF≤40% (n=14), LVEF 41%-55% (n=46) and LVEF>55% group (n=98). The clinical follow-up end-point was major adverse cardiac event (MACE) including death, acute myocardial infarction, stent thrombosis and stent restenosis. The clinical follow-up duration was 43.1±15.2 months. MACE occurred in 15 patients.

RESULTS: The rates of infarction site, infarction relative artery, 1-vessel disease, 2-vessel disease, hypertension, diabetes, hyperlipidemia, smoking, obesity and aspirin use were not different in three groups (P>0.05). Average CTnI, CK, CK-MB and duration of clopidogrel use were not different in three groups (P>0.05). The rate of 3-vessel disease was significantly higher in the LVEF≤40% group than that in the LVEF 41%-55% and LVEF>55% groups (P=0.0036). The rates of TIMI flow grades (Grade III) and complete revascularization were significantly higher in the LVEF 41%-55% and LVEF>55% groups than that in the LVEF≤40% group (P=0.0099, P=0.0010). The rates of Killip classification (classes II, III, IV) and average symptom-onset-to balloon-time (SOTB) were significantly lower in the LVEF 41%-55% and LVEF>55% groups than that in the LVEF≤40% group (P=0.0100, P=0.0087). The rate of drug-eluting stents was significantly lower in the LVEF≤40% group and LVEF 41%-55% group than that in LVEF>55% group (P=0.0242). Logistic regression analysis showed that LVEF was independent predictor for MACE in the follow-up period (P=0.0029). With LVEF decrease, incidence of MACE in the follow-up period significantly increased in LVEF>55% group, LVEF 41%-55% group and LVEF≤40% group (6.12% vs 8.7% vs 35.71%, P=0.0019). Incidence of total death and cardiac death in the follow-up period significantly increased in LVEF>55% group, LVEF 41%-55% group and LVEF≤40% group (1.02% vs 4.35% vs 21.43%, P=0.0090; 1.02% vs 2.17 vs 14.29%, P=0.0060).

CONCLUSION: In patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention, LVEF was independent predictor for MACE in the follow-up period. With LVEF decrease, incidence of MACE in the follow-up period significantly increased.