Risk of death associated with incident heart failure in patients with known or suspected chronic coronary syndrome

AIMS: Traditional adverse events in chronic coronary syndrome (CCS) include atherothrombotic events but usually exclude heart failure (HF). Data are scarce about how new‐onset HF modifies mortality risk. We aimed to determine the incidence of HF and compare its long‐term mortality risk with myocardial infarction (MI) and stroke in patients with known or suspected CCS. METHODS: We prospectively evaluated 5811 consecutive HF‐free patients submitted to vasodilator stress cardiac magnetic resonance (CMR) for known or suspected CCS. Ischaemic burden and left ventricular ejection fraction were assessed by CMR. HF included outpatient diagnosis or acute HF hospitalization. The mortality risk for the incident events and their cross‐comparisons were evaluated using a Markov illness–death model with transition‐specific survival models. RESULTS: The mean age was 55 ± 11 years, and 38.9% were female. At a median follow‐up of 5.44 (IQR = 2.53–8.55) years, 591 deaths were registered (1.79 per 100 P‐Y). The rates of new‐onset HF were higher compared with MI and stroke [1.02, 0.62, and 0.51, respectively (P < 0.05)]. The adjusted association between new‐onset HF, MI, and stroke, and subsequent mortality was time dependent. The risk increased almost linearly for HF and became significant by the third year. By Year 10, the mortality risk attributable to new‐onset HF was more than 2.5‐fold (HR: 2.68, 95% CI = 1.74–4.12). For MI, there was a significant increase in mortality risk up to the second year, followed by a monotonic decrease. For stroke, the mortality risk increased for the entire follow‐up but became significant by the third year. A cross‐comparison among incident endpoints HF outnumbers risk for those with MI by the sixth year (HR(year6.3): 1.88, 95% CI = 1.03–3.43). There was no difference in mortality risk between incident HF and stroke. CONCLUSIONS: In patients with CCS, long‐term rates of incident HF were higher than MI and stroke. Patients with new‐onset HF showed a higher risk of long‐term mortality.