Assessment of Coronary Collaterals Among Patients With ST-segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention and its Impact on In-hospital and 30-day Mortality: A Prospective Observational Study.

Objectives: This study aimed to determine the distribution of coronary collaterals (CC) as per the Rentrop Collateral Score (RCS) among patients with ST-segment elevation myocardial infarction (STEMI) and its impact on in-hospital and 30-day mortality after primary percutaneous coronary intervention (PCI).

Methods: In this study, a selected sample of consecutive STEMI patients was assessed for the development of CC as per the RCS classification. An RCS grade of 2 or 3 was taken as the presence of CC with either partial or complete filling of the infarct-related artery (IRA). Patients were followed during the hospital stay and up to 30 days, and the incidence of major adverse cardiovascular events (MACE) was recorded, which included mortality, re-infarction, stroke, and hospitalization due to heart failure.

Results: This study was conducted on a sample of 347 patients; 81.6% (283) were male, and the mean age was 56.2 ± 10.3 years. CC was not visible (RCS-0) in 206 (59.4%) patients, visible but without filling of the IRA (RCS-1) in 39 (11.2%) patients, and visible with partial (RCS-2) and complete (RCS-3) filling of the IRA in 72 (20.7%) and 30 (8.6%) patients, respectively. No significant differences were observed in the incidence of in-hospital mortality and short-term MACE between patients with and without CC, with an in-hospital mortality rate of 2% vs. 4.9% (p = 0.248) and a MACE rate of 7% vs. 6.4% (p = 0.850), respectively.

Conclusion: Good CC with either partial or complete filling of the IRA was observed in more than one-fourth of the patients with STEMI. However, no significant benefits of good CC were observed.