Background: The influence of coexisting collateral circulation between chronic total occlusion (CTO) and infarct-related artery (IRA) in patients with acute ST segment elevation myocardial infarction (STEMI) remains unclear. We aimed to investigate the impact of coexisting collateral circulation between CTO and IRA on early clinical outcomes in patients with acute STEMI.
Methods: A total of 1488 consecutive acute STEMI patients who underwent primary percutaneous coronary intervention were prospectively included in the study. After restoration of antegrade flow, the patients who had coexisting CTO and collateral supply from IRA were defined as the CTO-IRA-related (CIR) group (n=56). Patients with coexisting CTO but with no collateral supply from IRA were defined as the CTO-IRA-unrelated (CIUR) group (n=104). Patients without coexisting CTO were defined as the non-CTO group (n=1328).
Results: Compared with the CIUR and non-CTO groups, the CIR group was significantly associated with higher Killip class of at least 2 (P<0.001) at presentation, a lower rate of postprocedural thrombolysis in myocardial infarction 2/3 flow (P<0.001), and myocardial perfusion grade 3 (P<0.001). Moreover, the CIR group had significantly higher in-hospital (P<0.001) and 30-day mortality (P<0.001). On multivariate regression analysis, the CIR group (odds ratio=15.96, 95% confidence interval=4.94-51.54; P<0.001) as well as age, post-PCI TIMI, Killip and NT-proBNP levels were independently associated with 30-day mortality. However, the CIUR group was not an independent predictor of early clinical outcomes.
Conclusion: After restoration of antegrade flow, coexisting CTO supplied by IRA collaterals has unfavourable effects on procedural success, enzymatic infarct size and postprocedural haemodynamic conditions. These collaterals are also independent predictors of 30-day mortality in acute STEMI patients.