Clinical Context
Percutaneous coronary intervention for CTO is commonly performed to improve angina and quality of life. However, prior evidence has largely been derived from unblinded studies, limiting the ability to isolate the true symptomatic benefit of the procedure.
The ORBITA-CTO trial evaluated the efficacy of CTO PCI using a randomized, double-blind, placebo-controlled design in patients with angina due to single-vessel CTO.

Study Design
ORBITA-CTO was a multicenter, randomized, double-blind, placebo-controlled trial conducted at two hospitals in the United Kingdom.
Participants: 50 patients with symptomatic single-vessel CTO
Median age: 64 years
Male: 74%
Baseline status: Majority with moderate-to-severe angina (CCS class II or III)
 

Eligible patients had a CTO of at least 3 months’ duration, with evidence of inducible ischemia and viability in the affected myocardial territory, and no significant disease in non-CTO vessels.
Patients were randomized in a 1:1 ratio to CTO PCI or a placebo procedure. Blinding was maintained using auditory isolation and deep conscious sedation. Antianginal therapy was optimized before randomization and withdrawn at the time of the procedure, with reintroduction guided by symptoms.

Key Findings

Between October 2021 and October 2025, 50 patients were randomized to CTO PCI (n = 25) or placebo (n = 25). One patient assigned to PCI was withdrawn during the procedure, and all patients were included in the primary analysis.

At 6 months, CTO PCI significantly improved angina symptom score compared with placebo (OR: 4.38; 95% credible interval: 1.57 to 12.69; probability of benefit 0.996). This effect was driven by a reduction in daily angina episodes (OR: 4.38; 95% credible interval: 1.55 to 11.78).

Patients undergoing CTO PCI experienced an additional 30.6 angina-free days during follow-up (95% credible interval: 11.1 to 50.7; probability of benefit >0.999).

Improvements were also observed across Seattle Angina Questionnaire domains, including angina frequency (+10.7), physical limitation, quality of life, and summary score. Canadian Cardiovascular Society angina class also improved with CTO PCI.

Blinding of patients, clinical staff, and research personnel was maintained throughout the trial.

Safety Profile

One patient in the CTO PCI group experienced coronary perforation requiring intervention during the procedure.

No deaths or myocardial infarctions were reported during follow-up.

Procedural duration, radiation exposure, and contrast use were higher in the CTO PCI group, reflecting the technical complexity of the procedure.

Study Limitations

• Small sample size of 50 patients
• Conducted at two high-volume centers with experienced operators
• Exclusion of patients with more complex CTO anatomy

Withdrawal of antianginal therapy may not reflect routine clinical practice

Clinical Perspective

In this placebo-controlled trial, CTO PCI reduced angina burden and increased angina-free days compared with a simulated procedure in patients with symptomatic single-vessel CTO.
Improvements were observed in both patient-reported outcomes and physician-assessed angina class. These findings provide controlled evidence supporting the symptomatic benefit of CTO PCI and highlight the importance of patient selection and procedural expertise.
 

Key Takeaway

CTO PCI improved angina symptoms and increased angina-free days compared with placebo in a blinded trial setting, supporting its role in selected patients with symptomatic CTO.

Author

Vivek Pathak is Founder and Editorial Lead at MedApt, a physician-focused platform covering clinical updates, congress insights, and expert perspectives.