Single-Photon Emission Computed Tomography Myocardial Perfusion Defects Are Associated With an Increased Risk of All-Cause Death, Cardiovascular Death, and Sudden Cardiac Death

Abstract

Background— Single-photon emission computed tomography myocardial perfusion imaging defects are associated with increased all-cause mortality and cardiovascular death. However, it is unknown whether single-photon emission computed tomography myocardial perfusion imaging can identify patients at increased risk of sudden cardiac death (SCD). Methods and Results— We analyzed a cohort of 6383 patients with angiographically documented coronary artery disease who underwent single-photon emission computed tomography imaging. Cox proportional hazards modeling was used to examine the relationship between patient characteristics and SCD. Among patients who died, the median time to SCD was 2.7 years (25 th , 75 th percentiles 0.9, 4.9, respectively). The incidence of SCD was 3.4% (n=215) over 6.1 years (25 th , 75 th percentiles 3.7, 9.2, respectively) of follow-up. Patients with SCD had more severe heart failure symptoms, greater comorbidity (Charlson index), and higher summed stress perfusion scores (all P <0.001). After adjusting for left ventricular ejection fraction and other clinical factors in the multivariable model, the summed stress perfusion score (fixed plus reversible defects) remained significantly associated with the occurrence of SCD: summed stress perfusion score (hazard ratios per 3 U: 1.16 [95% CI, 1.08 to 1.25], P <0.001), left ventricular ejection fraction (hazard ratios per 5 U: 0.90 [95% CI, 0.85 to 0.95], P <0.001), and Charlson index (hazard ratios 1.35 [95% CI, 1.23 to 1.49], P <0.001). Conclusions— Myocardial perfusion imaging is a significant predictor of SCD and provides information independent of clinical history and left ventricular ejection fraction. Gated single-photon emission computed tomography imaging, which evaluates both myocardial perfusion and function, may represent a more effective means of risk stratification than solitary left ventricular ejection fraction determination and should be evaluated in prospective trials.

Impaired Hyperemic Myocardial Blood Flow Is Associated With Inducibility of Ventricular Arrhythmia in Ischemic Cardiomyopathy

“…Global CFR was an independent strong risk factor for total cardiac mortality. Consistent with the results of Piccini et al, 37 these findings were superior to the prognostic value of LVEF and independent of the extent of qualitatively assessed ischemia or scar size. The question arises, however, whether the value of impaired quantitatively assessed hyperemic MBF and CFR in risk stratification holds true for VAs specifically.…”

“…by guest on May 10, 2018 http://circimaging.ahajournals.org/ Downloaded from et al 37 performed a study of >6000 patients with coronary artery disease with a median follow-up time of 2.7 years. The summed stress perfusion defect score was an independent risk factor for SCD and provided incremental prognostic value over LVEF.…”

Heart rate response during vasodilator stress myocardial perfusion imaging: Mechanisms and implications

“…The Duke investigators have examined the predictors of sudden death using the largest database available and have carefully crafted the criteria of defining sudden death. 22,23 Impressively, a blunted HR response to dipyridamole in the Mathur study was independently associated with increased cardiac death even after controlling for myocardial perfusion, LVEF, age, abnormal electrocardiogram and a history of DM, myocardial infarction, and heart failure. The HR response was thus predictive of cardiac death in subgroups of patients with low, intermediate, and high summed stress score and whether or not patients were receiving beta-blocker therapy.…”

Novel Imaging Approaches for Predicting Arrhythmic Risk

“…Its strength is visualization and quantification of underlying pathophysiological processes predisposing to arrhythmias. 25 Although indirect radionuclide assessment of arrhythmic risk has been described through determination of the extent and severity of perfusion imaging defects, 26 cardiac autonomic innervation imaging is a promising method for directly assessing arrhythmic risk. [27][28][29][30][31][32] Innervation abnormalities can contribute to initiating and sustaining arrhythmias by creating substrate abnormalities resulting in heterogeneity of sympathetic innervation, 28 increasing systemic autonomic tone that can trigger an arrhythmia in denervated hypersensitive myocardium, 29 and via modulation of central and regional autonomic tone that can accentuate electric heterogeneities of primary arrhythmic conditions.…”