Association Between Segmental Noninvasive Myocardial Work and Microvascular Perfusion in ST-Segment Elevation Myocardial Infarction: Implications for Left Ventricular Functional Recovery and Clinical Outcomes.

ABSTRACT

BACKGROUND: Predicting left ventricular recovery (LVR) after acute ST-segment elevation myocardial infarction (STEMI) is of prognostic importance. This study aims to explore the prognostic implications of segmental noninvasive myocardial work (MW) and microvascular perfusion (MVP) after STEMI. METHODS: In this retrospective study, 112 patients with STEMI who underwent primary percutaneous coronary intervention and transthoracic echocardiography after percutaneous coronary intervention were enrolled. Microvascular perfusion was analyzed by myocardial contrast echocardiography, and segmental MW was analyzed by noninvasive pressure-strain loops. A total of 671 segments with abnormal function at baseline were analyzed. The degrees of MVP were observed following intermittent high-mechanical index impulses replenishment within 4 seconds (normal MVP), replenishment >4 seconds and within 10 seconds (delayed MVP), and persistent defect (microvascular obstruction). The correlation between MW and MVP was analyzed. The correlation of the MW and MVP with LVR (normalization of wall thickening, >25%) was assessed. The prognostic value of segmental MW and MVP for cardiac events (cardiac death, admission for congestive heart failure, or recurrent myocardial infarction) was evaluated. RESULTS: Normal MVP was seen in 70 segments, delayed MVP in 236, and microvascular obstruction in 365. The segmental MW indices were independently correlated with MVP; 244 (36.4%) segments had segmental LVR at 3-month follow-up. Segmental MW efficiency and MVP were independently associated with segmental LVR (P < .05). The χ2 of combination of segmental MW efficiency and MVP was higher than either index alone for identifying segmental LVR (P < .001). At a median follow-up of 42.0 months, cardiac events occurred in 13 patients; all regional MW parameters, high sensitivity troponin I, regional longitudinal strain, and so on were associated with cardiac events. CONCLUSIONS: Segmental MW indices are associated with MVP within the infarct zone following reperfused STEMI. Both are independently associated with segmental LVR, and regional MW is associated with cardiac events, providing prognostic value in STEMI patients.