Efficacy of intravenous dipyridamole with exercise in thallium-201 myocardial perfusion scintigraphy

To assess the feasibility and the value of thallium–201myocardial perfusion imaging with intravenous dipyridamole incombination with low-level exercise, 81 patients with suspectedor proven coronary artery disease were studied. All patientsunderwent coronary arteriography. Significant coronary arterydisease (stenoses 50%) was present in 59 patients (73%); multivesseldisease (double- and triple-vessel desease) was observed in33 patients (42%). The overall sensitivity and specificity ofthe test were 78% and 86%, respectively. Sensititvity and specificityfor detection of multivessel disease were 70% and 92%, respectively.The sensitivity for detecting coronary artery disease in theRCA, LAD, and LCX was 74%, 82% and 48%, respectively, and thespecificity was 85%, 88% and 88%, respectively. With the combinedprocedure no serious side effects were observed. Mild side effectslike headche, vertigo and uausea were seen in 12 patients (15%). Twenty volunteers with a 1% likelihood of significant coronaryartery disease were examined in the same manner to determinethe maximal specificity of the procedure (100%). Thus, the combinationof two different stress procedures (exercise testing and dipyridamoleinfusion) can be performed safely without serious side effects.The presence, location and extent of significnt coronary arterydisease can be assessed to a similar degree as with conventionalexercise thallium-201 scintigraphy, which has major implicationsfor the detection of coronary artery disease in patients whoare unable to perform maximal exercise.