Canadian multicenter chronic total occlusion registry: ten-year follow-up results of chronic total occlusion revascularization

Background — Chronic total occlusions (CTO) occur in nearly 20% of coronary angiograms. CTO revascularization, either by percutaneous coronary intervention (PCI) or coronary artery bypass grafting surgery (CABG), is infrequently performed, approximately one-third of cases. Long-term outcomes are unknown. The objective of the study was to determine whether early CTO revascularization of patients, either by CABG or PCI, was associated with improved clinical outcomes.

Methods — One thousand six hundred twenty-four patients from the Canadian CTO registry were followed for at least 9.75 years. Revascularization was performed according to routine clinical practice. Patients were grouped according to CTO revascularization status (PCI or CABG of CTO vessel, CTO revasc) or no CTO revasc (medical therapy only, or PCI/CABG of non-CTO vessels only), within 3 months of initial angiogram. Patients were followed for mortality, revascularization procedures (PCI and CABG), and hospitalizations for acute coronary syndromes and heart failure.

Results — Early CTO revasc was performed in 28.2% of patients (17.5% CABG, 10.7% PCI). The CTO revasc group was younger, with more males and generally fewer comorbidities. There was a significantly lower mortality probability at 10 years in the CTO revascularization group (22.7% [95% CI, 19.0%–26.9%]) compared with the no CTO revasc group (36.6% [95% CI, 33.8%–39.5%]). At 10 years, revascularization rates (14.0% versus 22.8%) and acute coronary syndrome hospitalization rates (10.0% versus 16.6%) were significantly lower in the CTO revasc group. Baseline-adjusted analysis showed CTO revasc was associated with significantly lower all-cause mortality (hazard ratio, 0.67 [95% CI, 0.54–0.84]). In both landmark and time varying analyses, association with lower mortality was particularly robust for CTO revascularization by CABG (hazard ratio 0.56 and 0.60, respectively), with a marginally significant result for PCI in the time varying analysis (hazard ratio 0.711 [95% CI, 0.51–0.998]).

Conclusions — Early CTO revascularization was associated with significantly lower all-cause mortality, revascularization rates, and hospitalization for acute coronary syndrome at 10 years, and mainly driven by outcomes in patients with CABG.