Assessment of Myocardial Viability in Patients With Chronic Coronary Artery Disease

Abstract

Background To date, late redistribution after resting 201 Tl injection has not been evaluated. In addition, the concordance between resting 201 Tl imaging and dobutamine echocardiography in identifying viable myocardium has not been assessed. Methods and Results Forty patients with coronary artery disease underwent rest–4-hour–24-hour 201 Tl tomography and dobutamine echocardiography (5 to 10 μg·kg −1 ·min −1 ). Late redistribution occurred in 46 (21%) of 219 persistent defects at 4 hours. Systolic function and contractile reserve were similar among persistent defects at 4 hours with and without late redistribution. Contractile reserve was more frequent in segments with normal 201 Tl uptake (59%), completely reversible defects (53%), or mild to moderate defects at 4 hours (56%) compared with severe defects (14%; P <.02 versus all). Of 105 hypokinetic segments, 99 (94%) were viable by 201 Tl, and 88 (84%) showed contractile reserve. In contrast, of 155 akinetic segments, 119 (77%) were viable by 201 Tl, but only 34 (22%) had contractile reserve. Concordance between 201 Tl and dobutamine was 82% in hypokinetic segments but 43% in akinetic segments. In 109 revascularized segments, positive accuracy for functional recovery was 72% for 201 Tl and 92% for dobutamine, whereas negative accuracy was 100% and 65%, respectively. Sensitivity was 100% for 201 Tl and 79% for dobutamine. Conclusions Late redistribution occurs in one fifth of persistent defects at 4 hours, and it does not correlate to systolic function or contractile reserve. Dobutamine and 201 Tl yield concordant information in the majority of hypokinetic segments, whereas concordance is low in akinetic segments. Dobutamine demonstrates higher positive accuracy and sensitivity in predicting recovery of dysfunctional myocardium, whereas 201 Tl shows higher negative predictive accuracy but reduced positive accuracy.