Usefulness of echocardiographic myocardial work in evaluating the microvascular perfusion in STEMI patients after revascularization

Abstract

Background: Left ventricular myocardial work (MW) assessed by echocardiography has recently been introduced as a new index of global and regional myocardial performance. The presence of microvascular obstruction after revascularization in ST-segment elevation myocardial infarction (STEMI) patients predicts poor clinical outcomes. This study aimed to explore the usefulness of MW in identifying impaired microvascular perfusion (MVP) in the patients with STEMI after revascularization.

Methods: One hundred and sixty STEMI patients who underwent myocardial contrast echocardiography (MCE) within 48 h after percutaneous coronary intervention (PCI) were included. Patients were divided into normal MVP and impaired MVP groups according to the myocardial perfusion score. The clinical data, coronary angiography results and echocardiographic data including Global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were collected.

Results: Impaired MVP was found in 60% of patients. Compared with the normal MVP group, GWI (909.2 ± 287.6 mmHg% vs. 1191.2 ± 378.2 mmHg%), GCW (1198.3 ± 339.6 mmHg% vs. 1525.9 ± 420.5 mmHg%), GWE (82.7 ± 7.8% vs. 86.8 ± 5.6%) and GLS (- 11.0 ± 3.4% vs. - 14.4 ± 3.8%) were significantly reduced in the impaired MVP group. Whereas there was no statistically significant difference in left ventricular ejection fraction (LVEF) and GWW, multivariate logistic regression analysis showed that peak troponin I (OR 1.017, 95% CI 1.006-1.029; P = 0.004), final TIMI flow ≤ 2 (OR 16.366, 95% CI 1.998-134.06; P = 0.009), left ventricular end-diastolic volume index (LVEDVi) (OR 1.139 95% CI 1.048-1.239; P = 0.002), and GWI (OR 0.997 95% CI 0.994-1.000; P = 0.029) were independently associated with impaired MVP. GWI showed a good sensitivity (86.8%) but low specificity (53.7%) in identifying impaired MVP (AUC 0.712, 95% CI 0.620-0.804; P < 0.001). Combination with GWI can improve the diagnostic value of TNI or LVEVi for impaired MVP.

Conclusion: Impaired MVP is relatively common in STEMI patients after revascularization and independently associated with left ventricular GWI assessed by echocardiography. GWI confer incremental value to MVP assessment in STEMI patients.

Keywords: Left ventricular myocardial work; Microvascular perfusion; Myocardial contrast echocardiography; Myocardial infarction.