Prevalence and outcome of patients with non-ST segment elevation myocardial infarction with occluded culprit artery - a systemic review and meta-analysis

Background: The aim was to determine the prevalence and impact of an occluded culprit artery (OCA) in patients with non-ST segment elevation myocardial infarction (NSTEMI). Methods: We searched PubMed, EMBASE, and Web of Science, with no language restrictions, up to 1 Jul. 2016. Observational cohorts or clinical trials of adult NSTEMI were eligible for inclusion to determine the prevalence if the proportion of OCA on coronary angiography was reported. Studies were further eligible for inclusion to determine the outcome if the association between OCA and clinical endpoints was reported. Results: Among the 60,898 patients with NSTEMI enrolled in 25 studies, 17,212 were found to have OCA. The average proportion of OCA in NSTEMI was 34% (95% CI 30-37%). Patients with OCA were more likely to have left circumflex artery as their culprit artery (odds ratio (OR) 1.65, 95% CI 1.15-2.37, p = 0.007), and this was associated with lower left ventricular ejection fraction (standard mean difference -0.29, 95% CI -0.34 to -0.34, p < 0.001), higher peak enzyme level (standard mean difference 0.43, 95% CI 0.27-0.58, p < 0.001), and higher risk for cardiogenic shock (OR 1.66, 95% CI 1.35-2.04, p < 0.001), compared with patients with a non-occlusive culprit artery. Death rate (OR 1.72, 95% CI 1.49-1.98, p < 0.001) and recurrent myocardial infarction (OR 1.7, 95% CI 1.06-2.75, p = 0.029) were also higher in patients with OCA, compared with patients with a non-occlusive culprit artery. Conclusions: Patients with OCA comprised a substantial portion of the NSTEMI population. These patients present with more severe symptoms and worse clinical outcome. Whether these patients should be treated with more aggressive strategy warrants further study.