Prognostic Value of Myocardial Blush Grade in Patients With ST-Segment Elevation Myocardial Infarction (STEMI) Undergoing Primary Percutaneous Coronary Intervention (PCI): Association With Reperfusion Success and In-Hospital Outcomes.

BACKGROUND

Myocardial blush grade (MBG) is a simple angiographic tool for assessing microvascular perfusion in patients with ST-segment elevation myocardial infarction (STEMI). While restoration of epicardial flow by primary percutaneous coronary intervention (PCI) is critical, microvascular reperfusion determines true myocardial salvage. Limited data are available from Pakistan regarding the prognostic value of MBG in predicting in-hospital outcomes.

OBJECTIVE

This study aimed to evaluate the prognostic significance of MBG in STEMI patients undergoing primary PCI, with emphasis on reperfusion success and in-hospital adverse events.

METHODS

This prospective observational study was conducted at Lady Reading Hospital Medical Teaching Institution, Peshawar, Pakistan, from January to December 2024. A total of 200 consecutive STEMI patients treated with primary PCI were included. MBG was assessed by two independent interventional cardiologists, and patients were stratified into low MBG (0-1) and high MBG (2-3) groups. Baseline demographics, angiographic findings, and in-hospital outcomes were compared using appropriate statistical tests. Multivariate logistic regression was applied to adjust for confounders.

RESULTS

Among 200 patients, 80 (40%) had MBG 0-1 and 120 (60%) had MBG 2-3. Patients with low MBG were older, were more likely to present with anterior wall myocardial infarction (MI), and had longer door-to-balloon times. Post-PCI Thrombolysis in Myocardial Infarction grade 3 (TIMI 3) flow was achieved in 72.5% of MBG 0-1 versus 96.7% of MBG 2-3 patients (p<0.001). In-hospital mortality was significantly higher in the low MBG group (8.8% vs. 1.7%; OR: 5.58; 95% CI: 1.09-28.4; p=0.037). Low MBG was also associated with recurrent ischemia, acute heart failure, and reduced reperfusion success. On multivariate analysis, MBG 0-1 independently predicted in-hospital adverse outcomes (adjusted OR: 3.42; 95% CI: 1.48-7.91; p=0.004), along with prolonged door-to-balloon time and anterior wall MI.

CONCLUSION

MBG is a powerful and independent predictor of reperfusion success and in-hospital outcomes in STEMI patients undergoing primary PCI. Its routine use in clinical practice can aid in early risk stratification, especially in resource-limited settings such as Pakistan. Future multicenter studies with long-term follow-up are warranted to confirm these findings.