Comparison of clinical outcomes between proximal and non-proximal right coronary artery occlusion in patients with inferior ST-segment elevation myocardial infarction

Background

The clinical outcomes of ST-segment elevation myocardial infarction (STEMI) due to the occlusion of left coronary artery are worse in patients with proximal occlusion than in those with non-proximal occlusion. However, there are few reports that focus on the comparison of clinical outcomes in patients with STEMI between proximal and non-proximal right coronary artery (RCA) occlusions.

Methods

We included 356 patients with STEMI whose infarct-related artery is RCA and divided them into the proximal group (n = 129) and the non-proximal group (n = 227). We defined segment 1 of RCA as proximal, and segments 2, 3, and 4 as non-proximal according to the reporting system of the American Heart Association. The primary endpoint was major cardiovascular events (MACE), which was defined as the composite of all-cause death, non-fatal myocardial infarction, readmission for heart failure, and ischemia-driven target vessel revascularization.

Results

Incidence of shock at admission, requirement for catecholamine during percutaneous coronary intervention (PCI), or mechanical support during PCI tended to be higher in the proximal group (42.6 %) than in the non-proximal group (33.5 %) (p = 0.088). Although the incidence of right ventricular infarction tended to be higher in the proximal group (17.8 %) than in the non-proximal group (10.6 %) without reaching statistical significance (p = 0.072), the incidence of in-hospital death was similar between the 2 groups (1.6 % versus 1.8 %, p = 1.000). The MACE-free survival curves were not different between the 2 groups (p = 0.400). Multivariate Cox hazard analysis revealed that proximal RCA occlusion was not associated with MACE (HR 1.095, 95%CI 0.691–1.737, p = 0.699).

Conclusions

Although the acute phase conditions such as shock or right ventricular infarction tended to be more severe in patients with proximal occlusion, overall clinical outcomes including long-term outcomes were comparable between the proximal and distal RCA occlusions. Furthermore, multivariate analysis showed that the proximal RCA occlusion was not associated with MACE after hospital discharge.