Outcomes after coronary angiography for unstable angina compared to stable angina, myocardial infarction and an asymptomatic general population

Background: The outcomes of real-world unstable angina (UA) in the high-sensitivity troponin era are unclear. We aimed to investigate the outcomes of UA referred to coronary angiography compared to stable angina (SA), non -ST-segment elevation myocardial infarction (NSTEMI), STEMI and a general population. Methods: We included the 9,694 patients with no prior coronary artery disease (CAD) referred to invasive or CT coronary angiography from 2013 to 2018 in Northern Norway (51% SA, 12% UA, 23% NSTEMI and 14% STEMI), and 11,959 asymptomatic individuals recruited from the Tromso Study. We used Cox models to estimate the hazard ratios (HR) for all-cause mortality and major adverse cardiovascular events (MACE), defined as cardiovascular death, MI or obstructive CAD. Results: The median follow-up time was 2.8 years. The incidence rate of death was 8.5 per 1000 person-years (95 % confidence interval [CI] 8.0-9.0) in the general population, 9.7 (95 % CI 8.3-11.5) in SA, 14.9 (95 % CI 11.4-19.6) in UA, 29.7 (95 % CI 25.6-34.3) in NSTEMI and 36.5 (95 % CI 30.9-43.2) in STEMI. In multivariable adjusted analyses, compared with UA, SA had a 38 % lower risk of death and a non-significant lower risk of MACE (HR 0.62, 95 % CI 0.44-0.89; HR 0.86, 95 % CI 0.66-1.11). NSTEMI had a 2.4-fold higher risk of death (HR 2.39, 95 % CI 1.38-4.14) and a 1.6-fold higher risk of MACE (HR 1.62, 95 % CI 1.11-2.38) compared tox UA during the first year after coronary angiography, but a similar risk thereafter. There was no difference in the risk of death for UA with non-obstructive CAD and obstructive CAD (HR 0.78, 95 % CI 0.39-1.57). Conclusion: UA had a higher risk of death but a similar risk of MACE compared to SA and a lower 1-year risk of death and MACE compared to NSTEMI.