ABSTRACT
Dipyridamole Thallium-201 (201Tl) scintigraphy has been used widely for assessment of patients prior to vascular surgery. Recently, Adenosine has been reported to be a safe and useful alternative to Dipyridamole. The purposes of this study were to evaluate the safety and feasibility of the use of Adenosine, to evaluate the correlation of Adenosine 201Tl scans with coronary angiograms (when available) and to evaluate the effect of scan results on clinician management style. Fifty adults with abdominal aortic aneurysm or other vascular disease underwent an intravenous infusion of Adenosine in conjunction with initial and delayed planar 201Tl scans. Images were interpreted qualitatively and quantitatively by the consensus of two or more experienced observers with patients showing transient left ventricular dilatation or redistribution in one or more myocardial segments reported as being at high risk of peri-operative cardiac events. Of the 50 subjects studied, 49 tolerated the maximum infusion dose with 60% experiencing minor transient symptoms. Low (n = 30) and high risk (n = 20) patients were defined according to Adenosine 201Tl scans. Age, gender and clinical characteristics were similar in both groups. Thirteen (65%) high risk subjects had coronary angiography compared with only three (10%) low risk patients. Patients with high-risk 201Tl scans were also more likely to proceed to coronary revascularization prior to non-cardiac surgery [5/20 (25%) vs 1/30 (3%)]. The positive predictive value of high risk 201Tl scans for coronary artery disease was 85%. Thus, Adenosine is considered a useful and safe alternative to Dipyridamole.(ABSTRACT TRUNCATED AT 250 WORDS)
