Key result
Abnormal stress SPECT with non-obstructive CAD carries a ~22% MACE rate over 4 years.
Why the study?
Abnormal myocardial perfusion imaging in the presence of non-obstructive coronary anatomy represents a diagnostic and prognostic challenge, as myocardial ischemia and adverse cardiovascular outcomes may occur despite the absence of obstructive epicardial CAD, while abnormal perfusion findings may also reflect technical or physiological factors.
Cohort (n=60)
No
Patients in a South Asian cohort with abnormal stress SPECT MPI despite non-obstructive coronary angiography remain at substantial risk for major adverse cardiovascular events (21.7% over 4.2 years), primarily driven by unstable angina hospitalizations and non-fatal MI.
Answers are grounded in this paper and cite their sources.
Abnormal stress SPECT MPI with non-obstructive CAD was associated with high MACE rates; leaves open whether perfusion defects warrant intensified management or prospective trials.
Objectives: Abnormal myocardial perfusion imaging (MPI) in the presence of non-obstructive coronary anatomy represents a clinically important diagnostic and prognostic challenge. Myocardial ischemia and adverse cardiovascular outcomes may occur despite the absence of obstructive epicardial coronary artery disease (CAD), although abnormal perfusion findings may also reflect technical or physiological factors. This study evaluated long-term cardiovascular outcomes among patients with abnormal stress single-photon emission computed tomography (SPECT) MPI and non-obstructive coronary angiography. Methodology: This retrospective observational cohort study included 60 consecutive patients who underwent stress SPECT MPI followed by invasive coronary angiography between January 2017 and December 2021 at Karachi Institute of Heart Diseases. Patients were eligible when SPECT MPI demonstrated a reversible or mixed perfusion defect and coronary angiography showed <50% epicardial coronary artery stenosis. Patients with previous myocardial infarction, cardiomyopathy, previous coronary revascularization, or heart failure with low ejection fraction were excluded. The primary outcome was major adverse cardiovascular events (MACE), defined as cardiac death, non-fatal myocardial infarction, hospitalization for unstable angina, or coronary revascularization. Results: The mean age of the study population was 54.6 ± 9.8 years, and 36 (60.0%) participants were men. Hypertension was present in 38 (63.3%), diabetes mellitus in 29 (48.3%), dyslipidemia in 34 (56.7%), and current smoking in 17 (28.3%) patients. During a mean follow-up of 4.2 ± 1.1 years, 13 of 60 patients (21.7%) experienced at least one MACE. Hospitalization for unstable angina occurred in 7 (11.7%), non-fatal myocardial infarction in 4 (6.7%), and coronary revascularization in 2 (3.3%) patients; no cardiac deaths were recorded. Estimated MACE-free survival was 96.7% at 1 year, 90.0% at 3 years, and 78.3% at 5 years. Conclusion: Patients with abnormal stress SPECT MPI and non-obstructive coronary angiography experienced a clinically important burden of cardiovascular events during long-term follow-up despite the absence of obstructive epicardial CAD.
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Sultana et al. (2026) conducted a cohort in Abnormal stress SPECT myocardial perfusion imaging with non-obstructive coronary artery disease (<50% stenosis) (n=60). Abnormal stress SPECT MPI (reversible or mixed perfusion defect) in the presence of non-obstructive coronary anatomy (<50% stenosis) was evaluated on Major adverse cardiovascular events (MACE), a composite of cardiac death, non-fatal myocardial infarction, hospitalization for unstable angina, or coronary revascularization. Patients with abnormal stress SPECT MPI and non-obstructive coronary anatomy experienced a 21.7% (13/60) rate of major adverse cardiovascular events over a mean 4.2-year follow-up.
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