Introduction: Pre-infarct angina (PIA) in patients with non-ST elevation myocardial infarction (NSTEMI) is associated with better outcomes. However, the association of invasive strategy, as compared with ischemia-guided strategy, on health status outcomes for patients with PIA is not well studied.
Methods: TRIUMPH and PREMIER are prospective myocardial infarction registries that collected the Seattle Angina Questionnaire (SAQ) at baseline, 1, 6 and 12 months. PIA was defined as a score of <100 on the SAQ Angina Frequency score at the time of patients’ acute myocardial infarction admission. Invasive strategy was defined as undergoing coronary angiography within 72 hours of admission without a preceding stress test. Propensity-adjusted mixed effect multivariable models were used to compare follow-up health status in patients with and without PIA based on treatment strategy.
Results: Among 3,544 patients with NSTEMI, 1,839 (52%) had PIA, of whom 1,230 (67%) had an invasive strategy of whom 75% underwent revascularization. While patients who underwent invasive strategy had better health status at baseline than those who underwent ischemia-guided strategy, after propensity adjustment, patients’ comorbidities and characteristics were well balanced (all standardized differences <10%). An invasive strategy was associated with an improvement in SAQ angina frequency and SAQ summary score at 1 month only among patients with PIA (mean difference of 4 and 4.4 points, respectively, p <0.005), but this difference was not sustained at 6 or 12 months (Figure). However, among patients with no PIA, there was no significant difference in health status among patients who underwent an invasive or conservative strategy at all time points (mean difference at 1 month of 0.4 and 0.5 points on SAQ angina frequency and summary score, respectively, p >0.5).
Conclusion: An invasive strategy for NSTEMI was associated with significantly better 30-day health status among patients with PIA, but not in those without. No health status benefits of an invasive strategy were observed at 6 or 12 months, regardless of PIA status.