Exercise single-photon emission computed tomography provides effective risk stratification of elderly men and elderly women

Abstract

Background: In a recent study, we reported that the Duke treadmill score was unable to effectively stratify elderly patients according to risk. The purpose of this study was to evaluate the prognostic value of exercise single-photon emission computed tomography (SPECT) in this same population and to examine results by gender.

Methods and results: A cohort of 247 elderly (age > or =75 years) patients (108 women, 139 men, age 77+/-3 years) who underwent exercise thallium-201 SPECT were followed up for a median duration of 6.4 years. SPECT variables were significantly associated with cardiac death: summed stress score (SSS) chi2=19.5, P<0.001; summed difference score chi2=12.3, P<0.001; increased lung uptake chi2=9.6, P=0.002; and left ventricular enlargement chi2=8.3, P=0.004. The Duke score was not significantly associated with cardiac death (chi2<1, P=NS). The SSS classified most patients as low risk (49%) or high risk (35%); the Duke score classified the majority (68%) as intermediate risk. Annual cardiac mortality rates for patients categorized by SSS as low risk and high risk were 0.8% and 5.8%, respectively. Cardiac survival rates according to SSS risk categories were significantly different for both women (P=0.012) and men (P=0.003).

Conclusions: SPECT classified most elderly patients into clinically useful low- and high-risk categories and accurately predicted outcomes in both genders. If these results can be validated in future studies, exercise SPECT rather than standard treadmill testing may emerge as the initial noninvasive testing strategy in elderly patients who are able to exercise.