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Cardiovascular outcomes after pharmacologic stress myocardial perfusion imaging


Background — While pharmacologic stress single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) is used for noninvasive evaluation of patients who are unable to perform treadmill exercise, its impact on net reclassification improvement (NRI) of prognosis is unknown.

Methods — We evaluated the prognostic value of pharmacologic stress MPI for prediction of cardiovascular death or non-fatal myocardial infarction (MI) within one-year at a single-center university-based laboratory. We examined continuous and categorical NRI of pharmacologic SPECT-MPI for prediction of outcomes beyond clinical factors alone.

Results — 6240 patients (median 66 years [IQR 56-74], 3466 men) were studied and followed for 5963 person-years. SPECT-MPI variables associated with increased risk of cardiovascular death or non-fatal MI included summed stress score (SSS), stress ST-shift, and post-stress resting left ventricular ejection fraction (LVEF) ≤50%. Compared to a clinical model which included age, sex, cardiovascular disease, risk factors, and medications, model χ2 (210.5 vs. 281.9, p < 0.001) and c-statistic (0.74 vs. 0.78, p < 0.001) were significantly increased by addition of SPECT-MPI predictors (SSS, stress ST-shift and stress resting LVEF). SPECT-MPI predictors increased continuous NRI by 49.4% (p < 0.001), reclassifying 66.5% of patients as lower risk and 32.8% as higher risk of cardiovascular death or non-fatal MI. Addition of MPI predictors to clinical factors using risk categories, defined as <1%, 1-3%, and >3% annualized risk of cardiovascular death or non-fatal MI, yielded a 15.0% improvement in NRI (95%CI; 7.6-27.6%, p < 0.001).

Conclusions — Pharmacologic stress MPI substantially improved net reclassification of cardiovascular death or MI risk beyond that afforded by clinical factors.



Lee DS, Husain M, Wang X, Austin PC, Iwanochko RM. Am Heart J. 2016; 174:138-46. Epub 2016 Jan 23.

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