THE VALUE OF DIPYRIDAMOLE-ECHOCARDIOGRAPHY IN RISK STRATIFICATION BEFORE VASCULAR-SURGERY - A MULTICENTER STUDY

Purpose Patients undergoing major vascular surgery are at relatively high risk of cardiac events, and pharmacological stress echocardiography is increasingly used for peri-operative risk stratification. Patients and Methods One hundred and twenty-one patients under going vascular surgery (age 65 +/- 7 years) were studied by dipyridamole echocardiography testing in six different centres. Of the total 136 patients, 15 were subsequently excluded because surgery was either cancelled (n=8) or postponed pending cardiac revascularizatian (n=7) because of the presence of a 'high-risk' stress echo response (identified 'a priori as a positive dipyridamole echocardiography testing with a dipyridamole-time <5 min and/or a peak wall motion score index >2, upon scoring each segment from 1=normal to 4=dyskinetic in an Ii-segment model). Results No major complications occurred during dipyridamole echocardiography testing. Technically adequate images were obtained in all patients; however, in one patient only the low dipyridamole dose (56 mg. kg(-1) over 4 minj was given to limit side effects. Of the 121 patients undergoing surgery 28 (23%) had a positive test. Peri-operative events occurred in nine patients (8%): two deaths, two myocardial infarctions, five cases of unstable angina. Sensitivity and specificity of dipyridamole echocardiography testing for predicting cardiac events were 78% and 81% respectively, with a positive predictive value of 25% and a negative predictive value of 98%. Dipyridamole echocardiography testing effectively singled out patients with, from those without, events, but neither clinical parameters, such as Detsky score, nor baseline echo parameters, such as resting wall motion score index or ejection fraction were able to distinguish between such patients. Conclusion In conclusion, dipyridamole echocardiography testing is safe and well tolerated inpatients undergoing major vascular surgery and provides an effective pie-operative screening test for risk stratification of these patients mainly due to the extremely high negative predictive value. Stress echocardiography is a better discriminator than clinical and rest echocardiographic variables.