Increased thallium lung uptake after exercise in isolated left anterior descending coronary artery disease

Increased thallium lung uptake during exercise correlates with an exercise-induced elevation In left ventricular filling pressure. This finding was analyzed in 48 patients with 1-vessel left anterior descending (LAD) coronary artery disease (CAD) before and after percutaneous transiuminal coronary angioplasty. Patients were separated into 2 groups: 13 (27%) patients with Increased (group 1) and 35 patients with normal thallium lung uptake (group 2). Compared with group 2, group 1 patients had more severe LAD luminal diameter narrowing (90 ± 6% vs 81 ± 11 % [mean ± standard deviation], p <0.003); slower clearance of thallium from the LAD territory segments (half-life 13.5 ± 8.0 vs 6.5 ± 5.0 hours, p <0.007); and more abnormal thallium segments per patient by quantitative criteria (p <0.02). After angioplasty, thallium lung uptake became normal in 12 of 13 patients in whom it was previously elevated. Increased thallium lung uptake after exercise occurs in 1-vessel LAD disease, and is related to the severity of ischemia by thallium scan and the severity of stenosis by angiography. Therefore, increased thallium lung uptake identifies a subset of patients with 1-vessel CAD with a greater amount of myocardium at risk.