Evaluation of coronary artery disease by dipyridamole echocardiography test.

Role of oral dipyridamole echocardiography test (DET) was evaluated in 50 patients with effort angina. All patients underwent coronary angiography, the day after oral DET. The echo studies were performed at rest and 65 +/- 15 minutes after 300 mg of oral dipyridamole. Segmental wall motion was analysed in a 16 segment model and a wall motion score index (WMSI) was generated for the entire left ventricle both at rest and following the drug. WMSI was significantly higher after oral dipyridamole, (p < 0.001) compared to resting condition with increased sensitivity (86% vs 74%). When results of DET were compared with coronary angiography, the correlation of WMSI was statistically significant in three vessel disease (p < 0.001), two vessel disease (p < 0.001) as well as for left anterior descending lesions (p < 0.001). However, it was insignificant for single vessel disease, viz, right coronary artery and circumflex artery. Thus we conclude that oral DET is a safe, inexpensive, sensitive and non-exercise dependent method for demonstrating myocardial ischaemia with high diagnostic accuracy.

Dipyridamole radionuclide ventriculography for localisation of coronary artery disease.

Nineteen consecutive patients who had coronary arteriography underwent dipyridamole stress testing with 0.14 mg/kg/min infusion over 4 minutes during computer assisted radionuclide ventriculography. Global ejection fraction, diastolic function and regional ejection fraction were calculated by a semiautomatic method. There were 17 patients with severe left anterior descending disease of which 12 involved the proximal segment of the LAD, 15 patients with left circumflex disease and 13 patients with right coronary artery disease. Abnormalities in resting or stress induced regional ejection fraction was used for localisation of severe coronary artery disease. The overall sensitivity was 75 per cent with a specificity of 75 per cent, a positive predictive value of 90 per cent and a negative predictive value of 45 per cent. For LAD disease the sensitivity was 94 per cent with a 100 per cent specificity while proximal segment of LAD had a sensitivity of 100 per cent and a specificity of 57 per cent. Identification of left circumflex disease had a sensitivity of 47 per cent and a 100 per cent specificity and right coronary artery had a 85 per cent sensitivity and a 50 per cent specificity. Four patients developed ST changes, 6 developed chest discomfort and 1 patient developed giddiness. All 7 were promptly reversed with intravenous aminophylline. Thus dipyridamole radionuclide ventriculography is a highly sensitive and specific method for localisation of CAD.

Comparison of exercise and dipyridamole equilibrium blood pool scintigraphy (EBPS) in angina pectoris.

Twelve patients with exertional angina underwent exercise treadmill testing, exercise equilibrium blood pool scintigraphy (Ex EBPS). Dipyridamole equilibrium blood pool scintigraphy (Dip EBPS) and coronary angiography by the Judkin's technique. Dipyridamole was infused through a venous cannula placed in the antecubital vein, in a dose of 0.56 mg/kg over four minutes. Four patients had single vessel disease, three double vessel disease, four triple vessel disease, and one had normal coronary arteries. Exercise equilibrium blood pool scintigraphy was found to have a sensitivity of 81%, and a positive predictive value for significant coronary artery disease of 100%. Dipyridamole EBPS had a sensitivity of 72% with a positive predictive value of 100%. The occurrence of regional wall motion abnormalities, following dipyridamole infusion, occurs up to fifteen minutes after exercise, and, therefore, serial acquisition for up to 20 minutes after the infusion is recommended. In patients with angina, who are unable to exercise because of orthopaedic disabilities or peripheral vascular disease, dipyridamole stress blood pool scintigraphy is a feasible alternative.