Background: Annual mortality rate can range from <1% for patients with normal myocardial perfusion by SPECT to >5% based on a high-risk Duke treadmill score (DTS). Information on the prognosis of patients with the combination of HRDTS and normal SPECT is limited and is the purpose of this study.
Methods: Data from a large nuclear cardiology registry (n = 17,972 patients) were reviewed. A total of 340 had HRDTS (score ≤ -11) while undergoing SPECT. Combined cardiovascular mortality and non-fatal myocardial infarction (MI) and cardiovascular mortality alone were available in 310 patients at a mean follow-up of 4.01 ± 1.5 years.
Results: The majority of the patients had abnormal SPECT (n = 270, 71%). The abnormal SPECT patients compared to the normal were older (65.6 vs 62.8 years of age; P = .025), more likely to have abnormal left ventricular ejection fraction (26.1% vs 0%; P < .0001), known coronary artery disease (CAD, 35.9% vs 7.8%; P < .0001) and lower DTS (-14.5 vs -13.2; P = .0006), Kaplan-Meier survival analysis demonstrated a significantly lower cardiovascular mortality (5.4% vs 0%, P = .02) and combined outcome of MI and cardiovascular mortality (15% vs 4.4%, P = .009) in patients with normal versus abnormal SPECT.
Conclusions: High-risk DTS is associated with abnormal perfusion SPECT in most patients, but nearly one-third of the patients had normal perfusion. Patients with a normal SPECT had a lower cardiovascular event rates.
Keywords: Duke treadmill score; exercise testing; mortality; myocardial perfusion imaging; outcome; prognosis.