Intravenous Adenosine (Adenoscan) Versus Exercise in the Noninvasive Assessment of Coronary Artery Disease by SPECT

Fifteen patients at a mean age of 58 underwent adenosine and maximal exercise thallium SPECT imaging. All scans were performed 1 week apart and within 4 weeks of cardiac catheterization. SPECT imaging was performed after the infusion of 140 μg/kg/min of adenosine for 6 minutes. Mean heart rate increment during adenosine administration was 67 ± 3.7 to 77 ± 4.1. Mean blood pressure was 136 ± 7.2 to 135 ± 6.2 systolic and 78 ± 1.8 to 68 ± 2.6 diastolic. No adverse hemodynamic effects were observed. There were no changes in PR or QRS in intervals. Five stress ECGs were ischemic. No ST changes were observed with adenosine. Although 68% of the patients had symptoms of flushing, light-headedness, and dizziness during adenosine infusion, symptoms resolved within 1 minute of dosage adjustment or termination of the infusion in all but one patient, who required theophylline. Sensitivity for coronary artery detection was 77% and specificity 100%. Concordance between adenoscans and exercise thallium scintigraphy was high (13/15 = 87%). In two patients, there were minor scintigraphic differences. The authors conclude that adenosine is a sensitive, specific, and safe alternative to exercise testing in patients referred for thallium imaging and may be preferable to dipyridamole.