Percutaneous Coronary Intervention versus Coronary Artery Bypass Grafting for Chronic Total Occlusion of Coronary Arteries: A Systematic Review and Meta-Analysis

Chronic total occlusion (CTO) is defined as complete coronary artery occlusion with TIMI 0 flow persisting for more than three months. CTO is identified in 15–20% of patients undergoing coronary angiography. While many patients receive guideline-directed medical therapy, others undergo revascularization with PCI or CABG. CTO-PCI has historically been challenging, but success rates in experienced centers now reach 80–90% due to advances in devices, techniques, and operator expertise. Randomized and observational data indicate successful CTO-PCI can improve symptoms, quality of life, and may be associated with better clinical outcomes versus failed PCI. However, its effect on long-term prognosis remains uncertain. Given ongoing controversy regarding the optimal revascularization strategy for CTO, this study compares outcomes of PCI versus CABG using a systematic review and meta-analysis of available cohort studies.

The authors note evolving evidence supporting CTO-PCI with improved success rates and symptom relief. Prior multicenter trials and registries have shown CTO-PCI can improve angina and quality of life and that success is associated with lower mortality, stroke, repeat revascularization, and recurrent angina compared with failed PCI. Advances such as improved guidewire design, hybrid CTO techniques, and use of intravascular ultrasound (IVUS) have enhanced PCI outcomes; meta-analyses suggest IVUS guidance reduces MACE, mortality, MI, revascularization, and stent thrombosis compared with angiography guidance. Conversely, trials in multivessel disease (e.g., BEST, SYNTAX) have shown higher MI rates after PCI versus CABG without increased mortality. Use of internal mammary artery grafts in CABG is associated with excellent long-term patency, potentially lowering repeat revascularization. These data frame the rationale to directly compare PCI and CABG outcomes specifically in CTO populations.

Design: Systematic review and meta-analysis registered in PROSPERO (CRD42022326498). Data sources: PubMed, Embase, and Web of Science searched from 2000 to March 2023 using MeSH terms and text words for chronic total occlusion, percutaneous coronary intervention, coronary artery bypass grafting, and revascularization; no language restrictions; abstracts and full texts included. Selection criteria: Included studies compared outcomes of PCI versus CABG in CTO patients and reported at least one endpoint (all-cause mortality, MI, cardiac death, repeat revascularization, or MACE). Exclusions: studies comparing successful vs unsuccessful PCI only; studies combining CTO with other illnesses as a subgroup; single-strategy reports; animal studies. Study selection: 3,938 records identified; 3,922 excluded at screening; 16 full texts assessed; 9 studies met criteria (1 RCT, 3 prospective cohorts, 5 retrospective cohorts). Data extraction: Two reviewers (W.C.Y., L.S.) independently extracted study characteristics, demographics, design, and outcomes; disagreements resolved by discussion. Outcomes: Primary endpoints were MACE (composite of cardiac death, cerebrovascular accident, MI, or repeat revascularization) and all-cause mortality. Secondary endpoints were MI, cardiac death, and repeat revascularization. Quality assessment: Newcastle–Ottawa Scale; reporting adhered to MOOSE guidelines. Statistical analysis: Pooled risk ratios (RRs) with 95% confidence intervals (CIs) for categorical outcomes. Heterogeneity assessed using Cochrane Q and I2; fixed-effects model used if I2<50%, random-effects otherwise. Sensitivity analyses performed by leave-one-out approach. Publication bias assessed with funnel plots. Analyses conducted with RevMan 5.3. Sample: 8,674 patients (PCI n=4,466; CABG n=4,208); mean follow-up 4.3 years; overall internal validity moderate.

- All-cause mortality: PCI associated with lower risk versus CABG (RR 0.78; 95% CI 0.66–0.92; P=0.003) among 7,723 patients; 558 deaths (7.0%). - Cardiac death: Lower with PCI (RR 0.55; 95% CI 0.31–0.96; P=0.03) across 6 studies reporting 231 events. - MACE: No significant difference between PCI and CABG (RR 1.11; 95% CI 0.69–1.81; P=0.66) across 6 studies with 368 events. - Repeat revascularization: Higher after PCI (RR 7.42; 95% CI 5.78–9.53; P<0.00001) in 4 studies with 540 events. - Myocardial infarction: Reported as higher in the PCI group versus CABG; pooled effect showed heterogeneity across studies (figures indicate significant overall effect in some models), though exact RR not explicitly stated in the main text. - Sensitivity analyses: Leave-one-out analyses showed stable pooled RRs without material change. - Publication bias: Funnel plot assessments did not suggest significant publication bias.

This meta-analysis directly addresses whether PCI or CABG provides better outcomes for patients with CTO. PCI was associated with lower all-cause mortality and cardiac death compared with CABG, despite higher rates of repeat revascularization and myocardial infarction, and no difference in MACE. The mortality benefit may reflect advances in PCI techniques, devices, operator experience, and broader adoption of adjuncts such as IVUS, which optimize stent selection and deployment. Selection patterns likely influence outcomes: PCI is more often used in lower-risk, single-vessel CTOs, whereas CABG is chosen for complex multivessel or left main disease, potentially contributing to differences in mortality and cardiac death. The higher repeat revascularization with PCI aligns with known superior long-term patency of internal mammary artery grafts used in CABG. The finding of similar MACE supports the notion that while event profiles differ (more MI and revascularization after PCI), overall composite outcomes are comparable. These results can inform heart-team deliberations and patient-centered decision-making in CTO revascularization, though residual confounding and heterogeneity across studies must be considered.

In CTO patients, PCI appears superior to CABG in reducing all-cause mortality and cardiac death, while being inferior in limiting myocardial infarction and repeat revascularization. No significant difference in MACE was observed between strategies. Further high-quality randomized studies are warranted to define the optimal revascularization approach for CTO.

- Limited randomized evidence; most included studies were observational, introducing potential selection bias and residual confounding (e.g., patient risk profiles, operator and patient preferences). - Heterogeneity across studies in follow-up duration, endpoints, and inclusion criteria may affect generalizability. - Lack of subgroup analyses by clinical risk scores (ACEF, SYNTAX I/II) due to unavailable source data. - Number of CTO vessels and other anatomical factors were not analyzed but may influence outcomes. - Publication bias cannot be entirely excluded despite funnel plot assessments.