Prediction of residual angina after percutaneous coronary intervention

Abstract

Aims: Angina relief is a major goal of percutaneous coronary intervention (PCI); however, about one in five patients continue to have angina after PCI. Understanding patient factors associated with residual angina would enable providers to more accurately calibrate patients' expectations of angina relief after PCI, may support different follow-up strategies or approaches to coronary revascularization, and could potentially serve as a marker of PCI quality.

Methods and results: Among 2573 patients who had PCI at 10 US hospitals for stable angina, unstable angina, or non-ST-elevation myocardial infarction (NSTEMI), 24% reported angina 6 months after PCI, as assessed with the Seattle Angina Questionnaire angina frequency score (categorized as none vs. any angina; score = 100 vs. <100). Post-PCI angina was more common in those patients treated for unstable angina (30 vs. 20% stable angina and 21% NSTEMI, P < 0.001). Using a hierarchical logistic regression model, eight variables were independently associated with angina after PCI, including younger age, poor economic status, depression, and greater number of antianginal medications at the time of PCI (c-index = 0.75). The amount of angina at the time of PCI was more predictive of post-PCI angina in patients with stable or unstable angina when compared with NSTEMI (pinteraction = 0.01). The model demonstrated excellent calibration, both in the original sample (slope 1.04, intercept -0.01, r = 0.98) and in bootstrap validation.

Conclusion: Based on a large, multicentre cohort of PCI patients, we created a model of residual angina 6 months after PCI that can provide patients realistic expectations of angina relief, guide follow-up strategies, support the use of residual angina as a means of comparing PCI quality, and enable comparative effectiveness research.

Figures

Figure 1

Factors independently associated with angina 6 months after PCI.

Figure 2

Calibration plot for prediction of angina at 6 months after PCI. Intercept of −0.01 [P-value (for difference from 0) = 0.63], a slope of 1.04 [P-value (for difference from 1) = 0.69], and R2 of 96%.

Figure 3

Observed rates of angina by decile of predicted risk, stratified by complete revascularization at the time of PCI.