Tolerance and safety of pharmacologic coronary vasodilation with adenosine in association with thallium-201 scintigraphy in patients with suspected coronary artery disease

Adenosine thallium-201 myocardial scintigraphy is a promising test for coronary artery disease detection, but its safety has not been reported in large patient cohorts. Accordingly, the tolerance and safety profile of adenosine infusion were analyzed in 607 patients (351 men, 256 women, mean age 63 ± 11 years) undergoing this test either because of suspected coronary artery disease (Group I, n = 482) or for risk stratification early (5.2 ± 2.8 days) after myocardial infarction (Group II, n = 125). Adenosine increased the heart rate from 74.5 ± 14.0 to 91.8 ± 15.9 beats/mill (p < 0.001) and decreased systolic blood pressure from 137.8 ± 26.8 to 120.7 ± 26.1 mm Hg (p < 0.001). Side effects were frequent and similar in both groups. Flushing occurred in 35%, chest pain in 34%, headache in 21% and dyspnea in 19% of patients. Only 35.6% of Group I patients with chest pain during adenosine infusion had concomitant transient perfusion abnormalities, compared with 60.7% of Group II patients (p < 0.05). First-and second-degree AV block occurred in 9.6% and 3.6% of patients, respectively, and ischemic ST changes in 12.5% of cases. Concomitance of chest pain and ischemic ST depression was uncommon (6%) but, when present, predicted perfusion abnormalities in 73% of patients. Most side effects ceased rapidly after stopping the adenosine infusion. The side effects were severe in only 1.6% of patients and in only six patients (1%) was it necessary to discontinue the infusion. No serious adverse reactions such as acute myocardial infarction or death occurred. These data attest to the excellent safety of adenosine infusion as an adjunct to thallium-201 scintigraphy in humans even within a few days of acute myocardial infarction.