🔎︎
Patients with stable angina whose coronary disease was focal rather than diffuse got substantially more angina relief from percutaneous coronary intervention (PCI) than patients whose disease was spread along the length of the vessel, according to an analysis of the ORBITA-2 trial published in the Journal of the American College of Cardiology by Kayla Chiew, Rasha Al-Lamee, and colleagues at Imperial College London.
The question had been unsettled. Unblinded studies reported better procedural and clinical outcomes with PCI in focal disease, but the first placebo-controlled study to examine it found no differential effect of disease pattern on symptom endpoints.
ORBITA-2 randomized patients with stable angina to PCI or a placebo procedure, with antianginal medications stopped before randomization so that the effect of the stent could be isolated. Patients underwent prerandomization nonhyperemic pressure wire pullback assessments, and 245 patients with 300 target vessel pullbacks were analyzed here. Seven blinded interventional cardiologists independently reviewed each trace and categorized the pattern as focal, diffuse, or mixed, assigning values of 1, 0, and 0.5. The mean across reviewers produced an overall score, with above 0.5 counted as focal and 0.5 or below as diffuse. The team used Bayesian proportional odds modeling and adjusted for the prerandomization nonhyperemic pressure ratio.
PCI in focal compared with diffuse disease produced greater improvement in the angina symptom score, with an odds ratio of 1.80 (95% credible interval, 1.48-2.18) and a probability of benefit above 99.9%, and in daily episodes of angina, with an odds ratio of 1.55 (95% credible interval, 1.26-1.89) and a probability of benefit above 99.9%.
Focal disease predicted greater placebo-controlled benefit across other measures as well. The probability of interaction exceeded 99.9% for exercise treadmill time, reached 99.5% for Seattle Angina Questionnaire angina frequency, 99.0% for Canadian Cardiovascular Society class, and 95.1% for the EuroQol Group 5-Dimensions 5-Level questionnaire. Evidence was weaker for improvement in dobutamine stress echocardiography score, at 83%.
The authors concluded that PCI produced greater placebo-controlled symptom improvement in focal than in diffuse disease, and that physiological patterns of disease may be useful in guiding treatment decisions about PCI for symptom relief.
That selection question carries into daily practice. Patients in ORBITA-2 were identified for PCI from the angiogram. Al-Lamee has told TCTMD that angiography has poor sensitivity for distinguishing focal from diffuse patterns, and that diffuse disease may be better left alone and treated with medical therapy. Pressure wire pullback is a separate step in the catheterization laboratory, with its own device and procedural time requirements.
