Long Term Outcome of Patients with High -Risk Exercise Testing and Normal Myocardial Perfusion Imaging

Background: The prognosis of patients with high risk Duke treadmill score (HRDTS) and normal myocardial perfusion imaging by SPECT is unknown. Mean annual mortality rate can range from 0.45% to 5% based on an isolated normal SPECT or a HRDTS. The purpose of this study was to determine the mortality rate in patients with HRDTS without myocardial perfusion defects on SPECT. Methods: A large database from a single center in Brazil was reviewed. A total of 340 patients referred for a SPECT and with a HRDTS (score <-10) were identified. An abnormal SPECT was defined as having ischemia and/or fibrosis. Total and cardiovascular mortality data were obtained and Kaplan-Meier method was applied. A mean follow-up time of 1466.3 (SD 562) days was completed in 310 (91%) patients. Results: Two hundred and twenty patients (70.9%) had an abnormal SPECT. The group with abnormal SPECT was older (mean 65.6 vs 62.8y; p =0,025), had higher rates of abnormal ejection fraction (26.1 vs 0%; p<0.0001), known CAD (35.9 vs 7.8%; p< 0.0001) and lower DTS (-14.5 vs -13.2; p=0.0006). Total and cardiovascular mortality rates were 6.8% and 5.4% in the abnormal and 2.2% and 0% in the normal SPECT groups (p=0.11 and 0.02). Cardiovascular mortality curves are shown (Figure 1). Figure 1 Figure 1 Conclusions: HRDTS is usually associated with an abnormal perfusion SPECT. Patients with a HRDTS and normal SPECT have very low cardiovascular mortality rates, similar to the general population referred for the method.