Predictors and Prognostic Implications of Well-Matured Coronary Collateral Circulation in Patients with a Chronic Total Occlusion (CTO)

The predictors and prognostic implications of well-matured collaterals in those with a chronic total occlusion (CTO) are unknown. We sought to identify the determinants of collateral maturation and to determine its effects on procedural outcomes and prognosis.Patients presenting for CTO percutaneous coronary intervention (PCI) between April 2010 and July 2019 were included. Patients with a previous coronary artery bypass (CABG) to the CTO and those with only bridging collaterals were excluded. The degree of collateral maturation was determined by the Rentrop grading classification. Demographic, biochemical, and anatomical factors and procedural and longer-term outcomes were identified.A total of 212 patients were included in the study. Patients with well-matured collaterals were more likely to be females (29.7% versus 15.2% versus 0%, P < 0.005 for Rentrop grade 3, 2, and 0 or 1, respectively), less likely to have chronic kidney disease (CKD) (8.8% versus 4.5% versus 19.2%, P < 0.05) and less likely to have had a prior CABG (15.6% versus 18.7% versus 19.2%). Patients with well-matured collaterals had lower neutrophil-to-leukocyte ratio (NLR) (2.8 versus 4.0 versus 5.7, P < 0.0001). Patients with well-matured collaterals were more likely to have procedural success (90.5% versus 62.5% versus 34.6%, P < 0.0001). The degree of collateral maturation was not associated with longer-term mortality.Improved collateral maturation was associated with female sex and lower rates of CKD and CABG and a lower NLR. Those with well-matured collaterals had a significantly higher rate of procedural success but not improved prognosis.