Critical LVEF and Possible Mechanism in Patients with Supra-normal Ejection Fraction after Primary PCI for STEMI

Objective To explore the critical value of supra-normal ejection fraction after acute myocardial infarction primary PCI and possible mechanism. METHODS A total of 272 patients with acute ST-segment elevation myocardial infarction admitted to the Heart Center of Hebei General Hospital from November 2016 to June 2018 who underwent primary PCI and transthoracic echocardiographic measurement of left ventricular ejection fraction ≥ 50% were included. All transthoracic ultrasound data of the patients were collected. The correlation between LVEF and hospital outcomes (death, cardiogenic shock) was analyzed. The ROC curve was drawn and the area under the ROC curve was measured. The critical value of the correlation between LVEF and in-hospital death was obtained by drawing the ROC curve. Clinical indicators between the two groups[the supra-normal EF group(LVEF༞critical value) and the control group(LVEF < critical value)] were analyzed. RESULTS Logsitic univariate regression analysis (OR) between LVEF and in-hospital death was 1.350(95%CI 1.078–1.691, P = 0.009). The area under the ROC curve between LVEF and in-hospital death was 0.846(95%CI 0.628-1.000, P = 0.018); The maximum Youden index was 0.701, corresponding to the critical LVEF of 67.5%, and the sensitivity and specificity of predicting nosocomial death were 75% and 95.1%. The proportion of women in the abnormal ejection fraction group [7(43.80%) vs 42(16.40%), P = 0.015] and the application of IABP [2(12.50%) vs 2(0.80%), P = 0.018] were significantly higher than those in the control group. The pulse rate [65.00(14.75) vs 79.00(20.00), P = 0.004], postoperative blood flow grade 2–3 proportion [13(81.30%) vs 253(98.80%), P = 0.003], and left ventricular end-systolic diameter [28.00(4.25) vs 32.00(4.00), P < 0.001] were significantly lower than those in the control group. Other results were not statistically significant between the two groups. CONCLUSIONS There is a subgroup named supra-normal EF with a higher mortality in patients with ST-segment elevation myocardial infarction after primary PCI, with a cut-off value of 67.5%. Sex and coronary microcirculation disorder may be the promoting factors for occurrence and development of supra-normal ejection fraction.