Cardiac risk in vascular surgery. The oral dipyridamole-thallium stress test
M. S. Makaroun, N. Shuman-Jackson, A. Rippey, D. Schreiner and S. Arvan
Department of Surgery, Veterans Affairs Medical Center, Pittsburgh, PA 15240.
The value of the oral dipyridamole-thallium stress test in identifying
patients at high risk of myocardial infarction after vascular procedures
has not been documented. We studied prospectively 46 patients who underwent
an oral dipyridamole-thallium stress test before undergoing vascular
operations. Twenty patients (43%) had a positive test result, defined by a
thallium defect with reperfusion, while 26 patients had a negative test
result. Myocardial infarctions were documented postoperatively in 5 (25%)
of 20 of the group with positive results and 1 (4%) of 26 of the group with
negative results. Three of the six myocardial infarctions were clinical;
all three were in the group with positive results. No correlation was
identified between dipyridamole-thallium stress test results and clinical
cardiac history. A positive dipyridamole-thallium stress test result is a
more sensitive predictor of postoperative myocardial infarction than
ejection fraction or history of coronary artery disease. The oral
dipyridamole-thallium stress test is as useful as the intravenous test in
this setting.
