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

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.

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.

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.

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).

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. (Objective Randomized Blinded Investigation With Optimal Medical Therapy of Angioplasty in Stable Angina [ORBITA-2]; NCT03742050).