Pattern and prognosis by localization of culprit lesions in coronary arteries of patients undergoing primary percutaneous coronary intervention with first ST-segment elevation myocardial infarction

Purpose: The aim of this study is to evaluate (1) the distribution of culprit lesions in the left (LCA) and right coronary arteries (RCA) and (2) prognosis related to the pattern of culprit lesions in patients undergoing primary percutaneous coronary intervention (PCI) after their first ST-segment elevation myocardial infarctions (STEMIs). Methods: Between November 2005 and November 2011, 857 patients (634 men; mean age = 62.8±12.0 year-old) without previous coronary heart disease were analyzed in this study. Coronary segments were identified according to the Coronary Artery Surgery Study vessel classification. An infarct-related culprit lesion was defined as the site of acute coronary occlusions or, for nonoccluded arteries, as the site of greatest narrowing within an angiographically significant stenosis corresponding to the electrocardiographic changes. Patients were divided into two groups according to the pattern of culprit lesions; bifurcation versus non-bifurcation. Propensity score (PS) indicating the likelihood of having bifurcation lesions was calculated using a multivariable logistic regression model, and was used to 1:1 match the patients with or without bifurcation lesions. The 6-months MACEs were defined as death, non-fatal MI, and revascularizations. Results: Overall, 49.5% of culprit lesions were located in left anterior descending artery (LAD), 9.4% in left circumflex artery (LCx), and 39.2% in RCA. Of LAD culprit lesions, 55.3% were located in proximal portion, 41.4% in mid-portion, and 2.6% in distal portion. Compared with those in the LAD, 35.9% were located in mid-portion, 29.7% in proximal portion, and 25.9% in distal portion of RCA. Overall, 42.7% of culprit lesions were located in bifurcation including 50.2% in LAD, 34.1% in LCx, and 32.9% in RCA. In LAD, bifurcation lesions are more prevalent in proximal portion (54.2%), whereas bifurcation lesions are more prevalent in distal portion of RCA (39.3%) and LCx (39.3%). Before PS match, the 6-month MACEs (14.3% versus 6.9%, p=0.023) and mortality (12.9% versus 5.9%, p=0.024) were significantly higher in patients with bifurcation lesions in the proximal portion of culprit artery. After PS match, bifurcation lesions in the proximal portion showed a trend of worse prognosis in terms of 6-month MACEs (14.2% versus 7.4%, p=0.070) and mortality (12.7% versus 6.1%, p=0.062). Conclusions: In patients with first STEMI, a bifurcation lesion which is located in proximal portion of culprit coronary artery showed a trend of worse 6-month clinical outcome.