JNC: Dual assessment of coronary artery calcium and exercise ability enhances mortality prediction in stress single-photon emission computed tomography—myocardial perfusion imaging patients-JNC: Dual assessment of coronary artery calcium and exercise ability enhances mortality prediction in stress single-photon emission computed tomography

JNC: Dual assessment of coronary artery calcium and exercise ability enhances mortality prediction in stress single-photon emission computed tomography—myocardial perfusion imaging patients

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This retrospective study evaluated whether combining coronary artery calcium (CAC) burden with stress test performance improves long-term mortality prediction in patients undergoing stress SPECT myocardial perfusion imaging (MPI). Investigators analyzed 2,435 Cedars-Sinai patients (2000–2019) who had both SPECT-MPI and a non-contrast CAC scan within six months (most on the same day), excluding those with known coronary artery disease or incomplete follow-up. Patients were categorized by decreasing functional stress performance: treadmill exercise ≥9 minutes, treadmill exercise <9 minutes, pharmacologic stress with low-level walking, and pharmacologic stress without walking. Mean follow-up was 9.0±6.4 years; 291 patients (12.0%) died.<br /><br />Mortality rose stepwise with both worsening stress performance and higher CAC scores. Across every CAC category, poorer stress performance was associated with higher death rates; similarly, within each stress-performance group, increasing CAC corresponded to greater mortality risk. Notably, patients with very high CAC (≥400) who could exercise ≥9 minutes had mortality rates comparable to patients with CAC=0 who required pharmacologic stress and could not walk (8.8 vs 8.0 deaths per 1,000 person-years), illustrating the strong, complementary prognostic impact of functional capacity.<br /><br />In multivariable Cox modeling, stress test performance was the strongest predictor of all-cause mortality, followed by age and CAC score. CAC ≥400 conferred more than a threefold adjusted mortality hazard versus CAC=0, while inability to walk during pharmacologic stress conferred more than a fourfold hazard versus exercising ≥9 minutes. Inducible ischemia was not independently predictive, likely due to “post-treatment bias” from subsequent revascularization and intensified therapy.<br /><br />The authors conclude that dual assessment of exercise/stress performance and CAC provides synergistic risk stratification and supports the clinical value of hybrid SPECT/CT to integrate anatomic atherosclerotic burden with functional status for guiding prevention and management.

Keywords

coronary artery calcium

CAC score

stress SPECT myocardial perfusion imaging

SPECT-MPI

stress test performance

exercise capacity

pharmacologic stress testing

all-cause mortality prediction

Cox proportional hazards model

hybrid SPECT/CT risk stratification