Coronary microcirculation dysfunction evaluated by myocardial contrast echocardiography predicts poor prognosis in patients with ST-segment elevation myocardial infarction after percutaneous coronary intervention

Background The mortality rate of acute ST-segment elevation myocardial infarction (STEMI) remains substantial, despite advances in treatment strategies. Coronary microcirculation dysfunction (CMD) persists after percutaneous coronary intervention (PCI) in a substantial proportion of STEMI patients. The association between CMD assessed using myocardial contrast echocardiography (MCE) and prognosis requires further elucidation. This study aimed to evaluate the impact of CMD after successful PCI on the prognosis of patients with STEMI. Methods We enrolled 167 patients with STEMI after PCI who underwent MCE during hospitalization between January 2018 and March 2022. Patients were classified into the CMD and non-CMD groups according to the results of MCE. The clinical data and MCE results of both groups were analyzed. Follow-up was conducted for major adverse cardiac events. Results MCE detected CMD in 105 patients (62.9%). The CMD group contained fewer hypertensive patients (55.2% versus 74.2%, P = 0.015). Patients with CMD exhibited significantly higher levels of plasma troponin I (TnI) [73.2 (23.0–124.0) versus 28.9 (12.7–80.2) ng/mL, P = 0.004], higher levels of plasma B-type natriuretic peptide [255 (99–641) versus 193 (59–389) pg/mL, P = 0.004], poorer Killip classification ( P = 0.038), and different culprit vessels ( P < 0.001) compared to the non-CMD group. Patients with CMD exhibited lower left ventricular ejection fraction [50 (43–58) versus 61 (54–67) %, P < 0.001], poorer wall motion score index values (1.68 ± 0.4 versus 1.31 ± 0.26, P < 0.001) and poorer left ventricular global longitudinal strain [–11.2 (–8.7 to –14.1) versus –13.9 (–11.0 to –17.2) %, P < 0.001] compared to the non-CMD group. Patients underwent follow-up for 13 (7–20) months. After adjusting for hypertension, peak TnI level, culprit vessel, and Killip classification, CMD was an independent predictor of total major adverse cardiac events at 13 months’ follow-up [adjusted odds ratio (OR), 2.457; 95% confidence interval (CI), 1.042–5.790; P = 0.040], and patients with CMD had a higher risk of hospitalization for heart failure (adjusted OR, 5.184; 95% CI, 1.044–25.747; P = 0.044) and repeat myocardial infarction (adjusted OR, 2.896; 95% CI, 1.109–7.565; P = 0.030). Conclusions MCE is a safe and effective method for detecting CMD in patients with STEMI. CMD detected by MCE after successful PCI in patients with STEMI is a common occurrence, which is associated with a significantly worse prognosis, especially hospitalization for heart failure and repeat myocardial infarction.