Myocardial perfusion imaging with adenosine triphosphate predicts the rate of cardiovascular events

Adenosine triphosphate (ATP) has effects similar to adenosine, including a very short half-life, with the advantage of a much lower cost. Our aim was to evaluate whether myocardial single photon emission computed tomography (SPECT) with ATP can predict the rate of hard events.

We studied 299 patients (188 men; mean age, 64 +/- 10 years) with known or suspected coronary disease with thallium 201 SPECT during ATP infusion and at rest. Perfusion defects were divided into the following: absent/mild reversible, moderate/severe reversible, and mixed/fixed. During a maximum follow-up of 87 months (mean, 32.7 +/- 20.3 months), the rate of cardiovascular events was studied. The prognostic value of different variables that can influence survival was calculated with the Cox proportional hazards model. The total number of cardiovascular events was 115 (43 hard events). The annual rate of hard events according to type of perfusion defect was 3.44% (95% confidence interval [CI], 2.12-5.26) for absent/mild reversible, 6.06% (95% CI, 2.23-13.20) for moderate/severe reversible, and 15.12% (95% CI, 8.64-24.55) for mixed/fixed. In the Cox model the variables that significantly predicted hard events were age greater than 55 years (P = .0293), diabetes (P = .0036), and severe perfusion defects (P = .0008).

ATP can be used for pharmacologic stress testing. SPECT with ATP has a stronger correlation with the rate of hard events than clinical variables.