Cardiac complications in noncardiac surgery: Value of dobutamine stress echocardiography versus dipyridamole thallium imaging

Abstract

The objective of this study was to determine the relative value of dobutamine stress echocardiography (DSE) and dipyridamole thallium imaging (DT) in the preoperative assessment of cardiovascular risk before noncardiac surgery. Prospectively DSE was performed in patients who had undergone DT as a part of their preoperative evaluation. A large urban veterans' affairs medical center. Thirty-seven patients undergoing major noncardiac surgery were assessed for complications during a 1-month follow-up period. Both DSE and DT were performed before surgery. The medium interval between the two tests were 15.5 days. Left ventricular wall motion was assessed at baseline and peak dobutamine dose in a standard fashion. Wall motion was scored and indexed using a 16-segment model. A positive DSE was defined as failure of augmentation, new or worsening of baseline wall motion abnormalities in two or more contiguous segments. Myocardial perfusion studies after DT were performed according to conventional method. A positive DT was defined as a reversible perfusion defect, increased lung uptake, and/or transient left ventricular dilatation. Complications were defined as myocardial infarction or cardiac death occurring as a result of the operation, or need for revascularization before surgery. DSE was positive in 19 patients, whereas DT was positive in 25 patients. Fourteen patients had both an abnormal DSE and DT. Five patients had major postoperative cardiac complications: fetal myocardial infarction (1); fatal cardiac arrest (1); and severe coronary artery disease necessitating coronary artery bypass surgery (2) or percutaneous transluminal coronary angioplasty (1). DSE was positive in all 5 (100%), whereas DT was positive in 4 of 5 (80%) patients with complications. The sensitivity for each test was comparable: for DSE it was 100% (95% C.I. 56% to 100%) and for DT 80% (37% to 96%). Specificity for DSE (60%, 43%-74%) was somewhat higher than DT (38%, 24% to 54%), although this did not reach statistical significance (p = 0.06). The ability of DSE to predict major cardiac complications related to noncardiac surgery appears to be similar to DT and may be used as an alternative to DT imaging in the preoperative risk assessment of patients undergoing noncardiac surgery.