Background: In the present study, the safety and diagnostic accuracy of a modified protocol with accelerated high-dose dipyridamole-atropine stress echocardiography, utilized in an attempt to significantly shorten the test imaging time with respect to the standard protocol, were evaluated.
Methods: Three hundred and thirty-seven patients (231 men, 106 women, mean age 63 +/- 9 years) with known or suspected coronary artery disease underwent 404 tests. The ECG and blood pressure were continuously monitored during constant infusion of 0.21 mg/kg/min of dipyridamole over 4 min; atropine (0.50 mg at 5 and 6 min) was given in order to reach > or = 85% of the age-predicated heart rate. The wall motion score index and the 16-segment model were used to evaluate contractility. Eighty-nine patients underwent selective coronary angiography. Coronary artery stenosis was considered significant if the vessel diameter was < 50% of the normal value.
Results: Eight-eight out of 404 tests were positive: 72 for echocardiographic criteria, 11 for ECG criteria, 2 for clinical symptoms, and 3 for combined criteria. Three hundred and sixteen tests were negative. In 303 tests atropine was administered and 380 tests were performed in pharmacological wash-out. The maximal heart rate was 105.8 +/- 9 b/min and the maximal blood pressure was 128 +/- 19/78 +/- 9 mmHg. No major side effects nor life-threatening complications were observed. In 24 tests (5.9%) only minor side effects occurred and in no case did these effects cause premature suspension of the test. The sensitivity, specificity and diagnostic accuracy of angiographically assessed coronary artery disease were 56, 86 and 73% respectively.
Conclusions: Accelerated high-dose dipyridamole echocardiography is practical, feasible and safe and allows for a significant reduction in the imaging time, with an increased cost-effectiveness and tolerance of the patients. In our experience the diagnostic accuracy of this new protocol was quite good and similar to that of the standard test.