Prognostic utility of 99mTc-MIBI single photon emission computerized tomography myocardial perfusion imaging in patients with ischemia and non-obstructive coronary artery disease

Abstract

Abstract Purpose The prognosis of patients with ischemia and non-obstructive coronary artery disease (INOCA) remains controversial; most do not undergo accurate disease evaluation and treatment, and the symptoms recur. Here, we used single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) to evaluate patients with INOCA. We sought to stratify patients more accurately and thus derive more reliable prognostic information. Materials and methods In total, 167 patients with INOCA were enrolled. All underwent invasive coronary angiography (CAG) and SPECT MPI within 1 week. The patients were divided into different groups according to their test results. Patients were followed-up regularly in terms of major adverse cardiovascular events (MACEs), including cardiac death, nonfatal myocardial infarction, stroke, re-hospitalization with angina pectoris, and recurrent angina pectoris. Kaplan-Meier curves and Cox’s proportional hazards models were used to analyze survival and identify predictive factors. Results Adverse cardiac events occurred in 33 cases (19.8%). The rate of MACEs was higher in the summed stress score (SSS) ≥ 4 group than in the SSS 0–3 group (30.1% vs 9.5%, respectively, P = 0.001) and event-free survival was lower (annual survival of 87.5% vs 96.2%, respectively, P = 0.003). Event-free survival was consistently higher in patients with normal arteries than in those with non-obstructive coronary artery disease (annual survival rates of 96.1% and 88.4%, P = 0.035). When the SSS scores and the CAG results were combined, patients with normal coronary arteries (SSS 0–3) had the best prognosis and those with non-obstructive coronary artery stenosis (SSS ≥ 4) had the worst. However, the early prognosis of patients with non-obstructive coronary artery disease and SSS scores of 0–3 was comparable to that of patients with normal coronary arteries and SSS scores ≥ 4 (annual survival rates of 100%, 94.6%, 93.1%, and 78.2%, respectively). Multivariate Cox’s regression indicated that the SSS score (hazard ratio [HR] = 1.126, 95% confidence interval [CI] 1.042–1.217, P = 0.003) and non-obstructive coronary artery disease (HR = 2.559, 95% CI 1.249–5.246, P = 0.01) were predictors of adverse cardiac events. Conclusion SPECT MPI data were prognostic for INOCA patients, thus identifying groups at high risk. The long-term predictive efficacy of such data exceeded that of CAG data. A combination of the two measures more accurately stratified INOCA patients in terms of risk.