Impact of total occlusion of culprit artery in acute non-ST elevation myocardial infarction: a systematic review and meta-analysis

Aims Total occlusion (TO) of the culprit artery usually presents with ST-elevation myocardial infarction. A subset of patients with TO present as non-ST segment elevation myocardial infarction (NSTEMI) without classic ST-elevation on the electrocardiogram. This may lead to delay in identification of these patients and further management. We performed a meta-analysis to estimate the difference in outcomes between totally occluded and non-occluded culprit arteries in patients with NSTEMI. Methods and results Our literature search yielded seven studies with 40 777 patients. The outcomes assessed were clinical presentation (Killip class), left ventricular ejection fraction, time to angiography, major cardiac adverse events (MACE) and all-cause mortality. The generic inverse or Mantel-Haenszel method was used to pool relevant outcomes and the mean difference (MD) or relative risk (RR) was calculated. A total of 10 415 (25.5%) patients had an occluded culprit artery with a predominant infero-lateral distribution (40% right coronary and 33% left circumflex artery). There was an increased risk of both MACE (short-term RR: 1.41; CI: 1.17, 1.70; P = 0.0003; I-2 = 26%; medium-to long-term RR: 1.32; CI: 1.11, 1.56; P = 0.001; I-2 = 25%) and all-cause mortality (short-term RR: 1.67; CI: 1.31, 2.13; P < 0.0001; I-2 = 41%; medium to long-term RR: 1.42; CI: 1.08, 1.86; P = 0.01; I-2 = 32%) with TO of the culprit artery. Conclusion Our meta-analysis suggests that patients with NSTEMI who demonstrate a totally occluded culprit vessel on coronary angiography are at higher risk of mortality and major adverse cardiac events. Better risk stratification tools are needed to identify such high-risk acute coronary syndrome patients to facilitate earlier revascularization and potentially to improve outcomes.