Risk of major adverse cardiovascular events based on myocardial perfusion SPECT in patients with suspected ischemia: an 8-year retrospective cohort study from a reference cardiology center

Introduction Single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) is validated for ischemia detection and risk stratification; however, long-term prognostic data derive predominantly from North American and European cohorts. Evidence from Latin America remains limited, particularly regarding the prognostic impact of combined ischemia and infarction. Objective To evaluate the association between SPECT-MPI findings and 8-year MACE risk in a Latin American cohort with suspected myocardial ischemia, incorporating hierarchical analyses of individual components. Methods We conducted a retrospective cohort study of adults undergoing SPECT-MPI for suspected myocardial ischemia at a national referral center in 2017. Of 1,998 patients, 789 met inclusion criteria and were followed for a median of 8 years (Figure 1). Perfusion was categorized as normal, ischemia, infarction, or combined defects. The primary endpoint was MACE, defined as cardiovascular death, nonfatal myocardial infarction, or late coronary revascularization. Adjusted Cox models accounted for age, sex, trivessel disease, and cardiovascular risk factors. Kaplan–Meier, standardized incidence, inverse probability weighting, and hierarchical Win Ratio analyses were performed. Results Among 789 included patients, median age was 62 years, and 65% were male. Perfusion was normal in 38% of patients, while 15% had ischemia, 17% had infarction, and 29% had combined defects. Over 8 years, 94 patients (12%) experienced MACE, predominantly late revascularization. Standardized MACE incidence increased stepwise from 11.3 events/1,000 person-years in normal studies to 90.5 in patients with combined ischemia and infarction, paralleled by progressively reduced event-free survival across perfusion categories on IPTW-adjusted Kaplan–Meier analysis (Figure 2). In multivariable Cox models, ischemia (HR 4.36), infarction (HR 3.83), and combined defects (HR 7.66; p<0.001) independently predicted MACE, with consistent hierarchical Win Ratio results (WR 4.62; p<0.001). Conclusion In this Latin American referral cohort, SPECT-MPI abnormalities were strongly and consistently associated with long-term MACE, particularly when ischemia and infarction coexisted. Hazard ratios exceeded those reported in international cohorts. These findings support the integration of imaging and clinical parameters and underscore the need for local validation in high-risk populations.Figure 1.Patient selection flowchartFigure 2.