Clinical characteristics, myocardial perfusion deficits, and clinical outcomes of patients with non-specific chest pain hospitalized for suspected acute coronary syndrome: a 4-year prospective cohort study.
BACKGROUND
Although the prognostic role of stress SPECT MPI is generally well established, its value in predicting non-fatal cardiac events in patients with acute, non-specific chest pain (NSCP) remains unclear. The aims of this study are 1) to describe the baseline clinical characteristics and prevalence of myocardial perfusion (MP) deficits, by use of an adenosine stress SPECT MPI, in NSCP patients without known CAD discharged after hospitalization for suspected ACS; and 2) to prospectively describe the 4-year clinical outcome in terms of all-cause and cardiac mortality; hospitalization and coronary revascularization procedures; and cardio-vascular events in patients with and without MP deficits.


METHODS AND RESULTS
We evaluated a series of 272 consecutive patients with acute NSCP and aged 18-75years. ICD10-based registries were used to determine the primary outcome (a composite measure of incident CAD death, ACS, or revascularization) and two secondary outcomes (1. all-cause death; 2. a composite measure of cardiovascular death, ACS, revascularization, or stroke). Forty two (15%) participants had a MP deficit. During follow-up (median 1361days), 7 participants had a primary event, 4 died, and 20 had a secondary composite event. Annual event rates were 0.70, 0.39 and 2.07, respectively. MP deficits predicted both subsequent primary and composite secondary events (HR: 7.54; 95% CI=[1.69; 33.69] and 2.93 (95% CI=[1.10; 7.81], respectively). Usual clinical cardiac risk classification could not meaningfully differentiate between patients with and without MP deficits.


CONCLUSION
SPECT MPI substantially improved prediction of incident CAD beyond usual clinical procedures and risk classification systems among NSCP patients.