Association Between Age and PCI Effectiveness in Stable CAD: Secondary Analysis of ORBITA-2

Background: ORBITA-2 (Objective Randomized Blinded Investigation With Optimal Medical Therapy of Angioplasty in Stable Angina) was the first randomized placebo-controlled trial to show the efficacy of percutaneous coronary intervention (PCI) in patients with stable angina and single- or multivessel coronary artery disease without background antianginal medication. Whether the effect is consistent across age groups is unknown. Objectives: The authors sought to evaluate the interaction between age and symptom and stenosis severity, and the efficacy of PCI on the ORBITA-2 primary and secondary endpoints. Methods: All patients from the primary ORBITA-2 trial contributed data to this post hoc analysis. For daily symptoms, a bayesian longitudinal Markov model was constructed. For treadmill exercise time, stress echocardiography, and questionnaires, a bayesian ordinal proportional odds model was used, including the prerandomization value and treatment arm, which were allowed to interact with age. Results: The mean age was 64 ± 9 years, ranging from 40 to 82 years. There was little relationship between age and symptom and stenosis severity. In older patients, PCI was more effective for symptom relief (OR: 2.03; 95% CrI: 1.67-2.45; Pr > 0.99) than in younger patients (OR: 1.70; 95% CrI: 1.38-2.15; Pr > 0.99; Pr [interaction] = 0.99). In contrast, the effect of PCI on treadmill exercise time was far greater in younger than in older patients (50-year-old: +125 s [95% CrI: 35.8-215.0 s; Pr > 0.99]; 70-year-old: +31.9s [95% CrI: −12.6 to 78.3; Pr = 0.92]; Pr [interaction] = 0.96). Conclusions: PCI was effective across all ages in reducing angina frequency. Notably, there was limited improvement in treadmill exercise time in the elderly, challenging its role as a primary endpoint in many antianginal trials. These data should inform cardiovascular clinical trial design to ensure applicability across all ages.