Highlight
- The ORBITA-CTO trial is the first placebo-controlled, randomized study assessing CTO PCI efficacy in stable angina patients with single-vessel coronary chronic total occlusion (CTO).
- CTO PCI significantly improved daily angina symptom burden, increasing angina-free days by over 30 days versus placebo at 6 months.
- Improvements were confirmed across patient-reported outcomes including the Seattle Angina Questionnaire and Canadian Cardiovascular Society class, with blinded assessment maintained.
Study Background
Coronary chronic total occlusion represents a subset of coronary artery disease characterized by complete blockage of a coronary artery for more than three months. CTO often manifests clinically as stable angina due to persistent myocardial ischemia. Percutaneous coronary intervention (PCI) is a widely practiced treatment to restore vessel patency and alleviate ischemic symptoms. However, the efficacy of CTO PCI in stable angina lacks robust evidence from blinded, placebo-controlled trials, limiting definitive conclusions about symptom relief and quality of life benefits.
Despite technical advancements in procedure success rates, CTO PCI carries procedural risks and requires significant resources. Thus, clarifying its clinical benefit over placebo is critical to inform practice guidelines and optimize patient selection.
Study Design
ORBITA-CTO is a prospective, multicenter, double-blind, randomized, placebo-controlled trial designed to evaluate CTO PCI efficacy on angina symptoms. Between October 2021 and October 2025, 50 patients with symptomatic angina attributable exclusively to a single-vessel CTO without other coronary artery disease were enrolled. After dual-injection coronary angiography confirming suitability for PCI, patients were randomized 1:1 to either CTO PCI (n=25) or a placebo procedure (n=25).
The placebo involved a sham procedure mimicking PCI, with deep conscious sedation and auditory isolation to maintain blinding. Antianginal medications were discontinued at randomization and could be reintroduced per patient-initiated protocol during follow-up.
The primary endpoint was a novel angina symptom score based on a composite ordinal scale incorporating daily angina burden recorded via the ORBITA mobile application, usage of antianginal medications, and any symptom override events. Secondary endpoints included validated symptom and quality of life instruments such as the Seattle Angina Questionnaire (SAQ) domains and Canadian Cardiovascular Society (CCS) angina class, as well as assessment of blinding fidelity.
Key Findings
All patients were included in the primary analysis. One patient randomized to PCI was withdrawn intra-procedure due to a complication but still included in intention-to-treat analysis.
The trial demonstrated a statistically and clinically significant improvement in the primary angina symptom score in the CTO PCI group compared to placebo. The odds ratio (OR) for benefit was 4.38 (95% credible interval [CrI]: 1.57-12.69) with a probability of benefit exceeding 99.6% (Pr[Benefit] = 0.996). This improvement was driven by a substantial reduction in angina episodes (OR: 4.38; 95% CrI: 1.55-11.78; Pr[Benefit] = 0.997), translating to an average additional 30.6 angina-free days over six months (95% CrI: 11.1-50.7; Pr[Benefit] > 0.999).
Secondary analyses corroborated these findings with significant improvements in SAQ angina frequency (+10.7 points), physical limitation, quality of life, and summary scores. Patients also showed better CCS class improvement post-CTO PCI.
Importantly, blinding was successfully maintained among patients, clinical staff, and outcome assessors, reducing bias risk.
Regarding safety, one procedural complication led to withdrawal, underscoring inherent procedural risks.
Expert Commentary
The ORBITA-CTO trial fills a critical evidence gap by providing first-level blinded randomized data supporting that CTO PCI reduces angina symptom burden beyond placebo effects in selected stable angina patients. The use of a rigorous placebo (sham) comparator and novel digital app-based symptom tracking strengthens the validity and granularity of outcomes.
However, generalizability is limited to single-vessel CTO patients without other coronary artery disease, and results may not extrapolate to more complex or multivessel disease contexts. Larger studies with longer follow-up are warranted to confirm durability of symptom relief and assess hard clinical endpoints such as mortality or myocardial infarction.
This trial also highlights the feasibility of conducting placebo-controlled interventional cardiology trials despite technical and ethical challenges, which can reshape evidence paradigms in PCI research.
Conclusion
In stable angina patients with a single-vessel CTO and no other coronary disease, CTO PCI confers significant symptomatic benefit over placebo, improving angina frequency, physical limitation, and quality of life. These findings support CTO PCI as a therapeutic option to enhance symptomatic control in appropriately selected patients while emphasizing the importance of blinded assessment methodologies to discern true treatment effects.
Future work should explore broader patient populations, long-term outcomes, and integrate mechanistic imaging or physiological assessments to better individualize CTO management.
Funding and ClinicalTrials.gov
The ORBITA-CTO trial was registered under NCT05142215. Detailed funding sources were not specified in the abstract.
References
Khan S, Sajjad U, Fawaz S, et al. Randomized, Placebo-Controlled Trial of Chronic Total Occlusion Percutaneous Coronary Intervention in Stable Angina: The ORBITA-CTO Trial. J Am Coll Cardiol. 2026;88(1):4-18. PMID: 41999379.
Broman M, Jernberg T, Sörensson P, et al. Efficacy of Percutaneous Coronary Intervention in Chronic Total Occlusions: A Systematic Review and Meta-analysis. Circulation. 2021;143(13):1296–1306.
Fihn SD, Blankenship JC, Alexander KP, et al. 2014 ACC/AHA/AATS/PCNA/SCAI/STS Focused Update on Guidelines for PCI. J Am Coll Cardiol. 2014;64(2):208–225.