Enhanced hepatic uptake of thallium-201 in patients with severe narrowing of the right coronary artery.

To assess the hepatic uptake of thallium-201 after exercise treadmill testing and to investigate whether hepatic uptake of thallium-201 may be a useful marker of right coronary artery (RCA) disease, 43 patients were studied: 17 with RCA disease (9 with 1-vessel disease, 8 with multivessel disease including the RCA), 8 with left coronary system disease alone, and 18 with a low probability (< 5%) of coronary disease. All subjects were studied with symptom-limited exercise and redistribution thallium-201 single-photon emission computed tomographic (SPECT) scintigraphy. Two indexes of hepatic uptake were derived: a liver-to-heart ratio after stress, and a stress-to-rest hepatic ratio. The low-probability group had a liver/heart ratio of 0.48 +/- 0.02. In the group with RCA disease alone, liver/heart ratio was 1.29 +/- 0.20 (p < 0.005 vs low-probability group). Patients with multivessel coronary artery disease involving the RCA had a ratio of 1.19 +/- 0.16 (p < 0.005 vs low-probability group), and patients with only left coronary system disease had a liver/heart ratio of 0.87 +/- 0.15 (p < 0.05 vs low-probability group). The stress/rest ratio of the low-probability group was 0.83 +/- 0.04. Patients with RCA disease alone had a stress/rest ratio of 1.49 +/- 0.25 (p < 0.05 vs low-probability group), and patients with multivessel disease involving the RCA had a stress/rest ratio of 1.16 +/- 0.08 (p < 0.005 vs low-probability group).(ABSTRACT TRUNCATED AT 250 WORDS)