Preoperative dipyridamole-thallium scanning, selective coronary revascularization and long-term survival in patients with critical lower limb ischemia

Background. A large proportion of patients with critical limb ischemia have advanced, often asymptomatic coronary artery disease which is associated with increased perioperative risk and decreased long-term survival. Methods. We evaluated retrospectively the short and long-term effect of routine dipyridamole-thallium cardiac scanning (DTS) and selective coronary revascularization in 113 consecutive patients who were scheduled for revascularization of the lower extremity. Results. DTS was abnormal in 60 (53.1%) patients and demonstrated a moderate-severe reversible defect in 26 (23.0%) patients. On the basis of DTS and clinical evaluation 33 (29.2%) patients were referred for coronary catheterization. Of these, 9 underwent PTCA and 4 underwent coronary artery bypass, without complications. Surgical revascularization of the limbs was performed in all but two patients. Two (1.8%) patients died postoperatively, three (2.7%) sustained nonfatal postoperative myocardial infarctions. None of the patients who underwent preoperative coronary revascularization suffered a cardiac complication after the peripheral vascular operation. During mean follow-up of 31.7 months, 30 (28.0%) patients died. A moderate-severe reversible defect on DTS was the strongest predictor for shortened survival (Exp(β)=0.61, CI 95%=0.42-0.88; p=0.006). Patients who underwent preoperative coronary revascularization followed a survival curve approaching those without a reversible defect on DTS (mean survival 61±8 vs 63±4 months; NS) which was significantly better than those with such a defect who did not undergo coronary revascularization (mean survival 34±5 months; p=0.03). Conclusions. While the perioperative benefits of routine preoperative DTS screening in patients with critical limb ischemia, remain debatable, it provides an opportunity for identification and treatment of life-limiting coronary artery disease and improving survival.