Establishing an approach for patients with recent coronary occlusion: identification of viable myocardium

Revascularization of occluded coronary arteries after myocardial infarction (MI) may restore flow to viable myocardium and improve ventricular function. The aim of this pilot study was to determine the potential utility of thallium-201 viability imaging for the prediction of recovery of regional ventricular function in patients undergoing revascularization of total or subtotal occlusion of infarct-related arteries (TIMI 0-2 flow) during the convalescent period after MI.

Twenty-three patients were identified < 6 weeks after MI and underwent Tl-201 viability imaging (rest imaging, n = 16; stress/reinjection imaging, n = 7) and radionuclide angiography. Patients were revascularized with percutaneous transluminal coronary artery in 10, stent in 10, and bypass in 3. Follow-up radionuclide angiography at 3 months was used to assess recovery of regional wall motion.

Among 41 abnormal wall motion segments in the infarct territories, the sensitivity, specificity, and accuracy for Tl-201 imaging in the prediction of recovery of regional function were 89% (25/28), 54% (7/13), and 78% (32/41), respectively. When 8 segments supplied by vessels with restenosis to >70% were excluded, specificity improved to 70%. Wall motion scores improved in those with adequate revascularization (1.6+/-1.4 vs 2.7+/-1.6; P < .001) but not in those with restenosis or occlusion (1.8+/-1.0 vs 2.0+/-1.6; P = NS).

In patients with an occluded artery after MI, Tl-201 viability imaging can detect recoverable myocardium with reasonable accuracy and may help select which patients will most benefit from revascularization.