PREOPERATIVE RISK STRATIFICATION BY ADENOSINE THALLIUM-201 SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY IN PATIENTS UNDERGOING VASCULAR-SURGERY

Background. Adenosine perfusion scintigraphy is a powerful technique f or diagnosing coronary artery disease and risk stratifying patients wi th recent myocardial infarction. Methods and Results. We investigated the use of adenosine Tl-201 tomography to risk stratify 106 patients u ndergoing vascular arterial reconstruction consisting lower limb arter ial grafting in 44, aortic aneurysmectomy in 36, and carotid endartere ctomy in 26 patients. Abnormal tomograms occurred in 57 patients (54%) , 47 (82%) of whom had reversible perfusion defects. There were three postoperative deaths, all in the group that underwent aortic aneurysme ctomy. Another patient with an aortic aneurysm had unstable angina and one patient who underwent lower limb arterial surgery had pulmonary e dema after surgery. No patient without transient defects had an event (negative predictive value 100%), Cardiac events occurred only in pati ents with transient perfusion defects. However, only 5 of 47 such pati ents had events (positive predictive value 11%). The perfusion defect size (23% +/- 14% vs 8.9% +/- 135; p = 0.034) and the ischemic fractio n (20% +/- 16% vs 5.6% +/- 8.9%; p = 0.009) were 2.5- and 3.5-fold lar ger, respectively, in patients with than in those without events. A hi story of diabetes mellitus or previous infarction did not enhance the predictive value of the test. Conclusion. Thus absence of reversible h ypoperfusion during adenosine scintigraphy ensures virtual absence of postoperative cardiac events. Patients undergoing aortic aneurysmectom y may be targeted preferentially for risk-stratification strategies in the future.