Thallium-201 Scintigraphy for Detection of Multivessel Disease in Patients with Prior Inferior Myocardial Infarction

Abstract

In order to compare the effectiveness of thallium-201 (201Tl) myocardial perfusion scintigraphy and the exercise electrocardiogram for identifying patients with multivessel coronary artery disease, these noninvasive tests and coronary arteriography were performed in 89 patients with prior inferior wall myocardial infarction. Eighty patients performed an adequate exercise test (angina, ST-segment depression or achievement of 85 percent maximum age-predicted heart rate). Of these 80 patients, coronary angiography documented multivessel disease in 57 and single-vessel disease in the remaining 23. Of the 57 patients with multivessel disease, 203Tl correctly predicted multivessel disease in 58 percent and the exercise ECG was positive in 63 percent. Of the 23 patients with single vessel disease 201Tl was negative for multivessel disease in 91 percent, while the exercise ECG was negative in only 52 percent For detecting multivessel disease, combining the two tests increased the sensitivity to 82 percent, but decreased the specificity to 48 percent. The predictive value of positive 201Tl for multivessel disease was 94 percent as compared to 76 percent for the exercise ECG. Thallium-201 identified disease of the left anterior descending vessel in only 33 percent of 42 patients with disease in this vessel. These data suggest that in patients with previous inferior myocardial infarction, both 201Tl and exercise ECG have limited clinical value for predicting multivessel disease. However, unlike exercise ECG, 201Tl is highly specific and, when positive (perfusion defects in more than one vascular segment), highly predictive for multivessel disease. In order to compare the effectiveness of thallium-201 (201Tl) myocardial perfusion scintigraphy and the exercise electrocardiogram for identifying patients with multivessel coronary artery disease, these noninvasive tests and coronary arteriography were performed in 89 patients with prior inferior wall myocardial infarction. Eighty patients performed an adequate exercise test (angina, ST-segment depression or achievement of 85 percent maximum age-predicted heart rate). Of these 80 patients, coronary angiography documented multivessel disease in 57 and single-vessel disease in the remaining 23. Of the 57 patients with multivessel disease, 203Tl correctly predicted multivessel disease in 58 percent and the exercise ECG was positive in 63 percent. Of the 23 patients with single vessel disease 201Tl was negative for multivessel disease in 91 percent, while the exercise ECG was negative in only 52 percent For detecting multivessel disease, combining the two tests increased the sensitivity to 82 percent, but decreased the specificity to 48 percent. The predictive value of positive 201Tl for multivessel disease was 94 percent as compared to 76 percent for the exercise ECG. Thallium-201 identified disease of the left anterior descending vessel in only 33 percent of 42 patients with disease in this vessel. These data suggest that in patients with previous inferior myocardial infarction, both 201Tl and exercise ECG have limited clinical value for predicting multivessel disease. However, unlike exercise ECG, 201Tl is highly specific and, when positive (perfusion defects in more than one vascular segment), highly predictive for multivessel disease.