Comparison of prognostic outcome between left circumflex artery-related and right coronary artery-related acute inferior wall myocardial infarction undergoing primary percutaneous coronary intervention.

BACKGROUND: This study evaluated the 30-day clinical outcome of patients with acute inferior wall ST-elevation myocardial infarction (AIW-STEMI) from occlusion of the left circumflex artery (LCX) vs the right coronary artery (RCA) undergoing primary percutaneous coronary intervention (PCI).

HYPOTHESIS: The clinical outcomes of AIW-STEMI caused by RCA and LCX occlusion may be different for patients undergoing primary PCI.

METHODS: Between May 2002 and September 2009, 646 consecutive patients with AIW-STEMI undergoing primary PCI were enrolled. Of these patients, 520 (80.5%) with AIW-STEMI caused by RCA occlusion were categorized into group 1, whereas the remaining 126 (19.5%) whose AIW-STEMI was caused by LCX occlusion served as group 2.

RESULTS: The results demonstrated that the frequency of advanced congestive heart failure, respiratory failure requiring mechanical ventilatory support, and 30-day mortality were remarkably higher in group 2 than in group 1 (all P < 0.01). Conversely, the incidence of right ventricular infarction and complete heart block were notably higher in group 1 than in group 2 (all P < 0.001). Additionally, the peak level of creatine kinase-isoenzyme MB was significantly higher, whereas the left ventricular ejection fraction was notably lower in group 2 than in group 1. Multivariate analysis demonstrated that advanced CHF, high serum creatinine level, low systolic blood pressure, low left ventricular ejection fraction, and LCX as the infarct-related artery were significantly and independently predictive of 30-day mortality (all P < 0.05).

CONCLUSIONS: The 30-day prognostic outcome was less favorable in LCX-related AIW-STEMI compared with RCA-related AIW-STEMI undergoing primary PCI.