Allahwala UK, Nour D, Bhatia K, et al. - This meta‐analysis was performed to determine prognostic impact of the degree of coronary collaterals in patients with a chronic total occlusion (CTO). Studies describing coronary collaterals and risk of all‐cause mortality, acute myocardial infarction (AMI) and successful percutaneous coronary intervention (PCI) were selected from EMBASE, MEDLINE, and Cochrane Library. Poor collaterals were defined as patients with Rentrop grade 0 or 1 collaterals and those with Rentrop grade 2 or 3 were robust collaterals. Overall 12 studies with a total of 3,369 were analyzed. Findings showed that robust collaterals, when present, were not related to lower rates of AMI or mortality, but did raise the possibility of successful CTO PCI. These observations carry crucial implications regarding the indications for CTO PCI as well as choosing suitable patients to receive the procedure.