Ischemia on dobutamine stress echocardiography predicts efficacy of PCI: results from the ORBITA-2 trial

Background: ORBITA-2 (The Placebo-Controlled Trial of Percutaneous Coronary Intervention for the Relief of Stable Angina) found that percutaneous coronary intervention (PCI) relieved angina in patients with single-vessel and multivessel stable coronary artery disease (CAD) on little or no antianginal medication. Whereas symptom characteristics and invasive physiological assessments can predict PCI efficacy, the role of noninvasive imaging with dobutamine stress echocardiography (DSE) remains unclear.

Objectives: This DSE-stratified secondary analysis of ORBITA-2 investigates the relationship between ischemia, assessed by DSE, and the placebo-controlled efficacy of PCI.

Methods: Participants with angina, single-vessel or multivessel CAD, and ischemia were enrolled. Following discontinuation of antianginal medications, patients were evaluated prerandomization using the ORBITA-app, questionnaires, DSE, and exercise treadmill testing. Stress echocardiography scores were calculated for each left ventricular segment at peak stress, with normal, hypokinetic, akinetic, dyskinetic, and aneurysmal segments scoring 0 to 4, respectively. Bayesian proportional odds modeling was used.

Results: Prerandomization DSE data were available for 262 patients. The median age was 65.5 years (Q1-Q3: 59-71 years), and 208 (79.4%) were male. At baseline, the median stress echocardiography score was 1.42 in the PCI group (n = 133) and 1.00 in the placebo group (n = 129), with an overall median score of 1.25 (Q1-Q3: 0.33-2.92). Higher stress echocardiography scores were strongly associated with greater placebo-controlled improvements in angina symptom score following PCI (OR: 1.23; 95% credible interval [CrI]: 1.13-1.35; Pr(interaction) > 99.9%). Higher scores also predicted significant reduction in daily angina episodes (OR: 1.36; 95% CrI: 1.24-1.49; Pr(interaction) > 99.9%), as well as improvement in the Seattle Angina Questionnaire angina frequency score (8.22; 95% CrI: 0.96-15.50; Pr(interaction) = 98.7%), and Seattle Angina Questionnaire quality of life score (8.95; 95% CrI: 2.05-16.00; Pr(interaction) = 99.3%). The relationship between stress echocardiography score and reduction in daily angina episodes remained consistent, irrespective of symptom characteristics.

Conclusions: In patients with single- and multivessel stable CAD on little or no antianginal medication, the placebo-controlled efficacy of PCI was predicted by the degree of ischemia detected on DSE. The greater the burden of baseline ischemia, the greater the improvement in symptoms and quality of life with PCI.