Prognostic impact of collaterals in patients with a coronary chronic total occlusion: A meta-analysis of over 3,000 patients.

Objectives: To assess the prognostic implications of the degree of coronary collaterals on outcomes in patients with a CTO.
Background: Coronary chronic total occlusions (CTO) are identified frequently in patients undergoing coronary angiography and have been associated with poorer prognosis. Whether the degree of coronary collaterals, the hallmark of CTOs impacts prognosis, is unknown.
Methods: A search of EMBASE, MEDLINE, and Cochrane Library was conducted to identify studies reporting on coronary collaterals and risk of all-cause mortality, acute myocardial infarction (AMI) and successful percutaneous coronary intervention (PCI). Patients with Rentrop grade 0 or 1 collaterals were defined as poor collaterals, while Rentrop grade 2 or 3 were defined as robust collaterals.
Results: Twelve studies with a total of 3,369 were included. Patients with robust collaterals did not have lower rates of AMI (OR: 0.89, 95%CI: 0.39-2.04) or lower rates of all-cause mortality (OR: 0.81, 95% CI: 0.42-1.58), however were more likely to have successful PCI (OR: 4.04, 95%CI: 1.10-14.85).
Conclusion: The presence of robust collaterals is not associated with lower rates of AMI or mortality, but does increase the likelihood of successful CTO PCI. These results have importance implications with respect to the indications for CTO PCI as well as selecting appropriate patients to undergo the procedure.
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