Using dipyridamole-thallium imaging to reduce cardiac risk in aortic reconstruction

Cardiac morbidity and mortality remain the major operative risk following aortic reconstruction (AR) performed for aneurysmal and occlusive disease. We reviewed the preoperative cardiac evaluation and outcome in 209 patients who had AR between 1987 and 1992. Dipyridamole-thallium stress test (DTST) was performed in 147 (70.3%) patients. Fifty-six of these patients had a normal DTST and only 1 (1.8%) had a perioperative myocardial infarction (MI). Forty-six patients had a fixed defect on their DTST and 3 (6.5%) had perioperative MI. Forty-five patients had reversible defects on their DTST and 2 (4.4%) had perioperative MI with 1 cardiac death. Following DTST, 29 coronary catheterizations were performed. Ten catheterizations were normal or had minimal one-vessel coronary artery disease with an associated postoperative death in 1 patient due to cardiac dysrhythmia. Nineteen patients had abnormal coronary angiography, 1 of whom had a perioperative myocardial infarction and 5 of whom underwent coronary artery revascularization (CABG) (3) or percutaneous transluminal angioplasty (2) prior to AR without subsequent cardiac events. Forty-three (20.6%) had either no cardiac symptoms (40) or prior CABG (3) precluding invasive cardiac evaluation. There was one fatal perioperative myocardial infarction (2.3%), resulting in a cardiac mortality of 2.3% in this group. The remaining 19 patients who did not have a DTST (9.1%) had coronary angiography based on evidence of significant cardiac disease resulting in one CABG and one percutaneous transluminal angioplasty. There was one (5.3%) perioperative myocardial infarction in this group and no cardiac deaths. Thirty-day mortality was 3.8%, perioperative MI rate was 3.8%, and perioperative cardiac mortality was 1.0%. During the follow-up period (median, 18 months; range, 1-89), there were 19 deaths (10%) and the 5-year cumulative survival was 76%.

Selective use of DTST can direct further evaluation, intervention, and subsequent perioperative care. This algorithm has enabled us to perform AR even in patients with defined perfusion abnormalities with acceptable morbidity. The true sensitivity, specificity, and predictive value of DTST can only be determined by a prospective trial.