Background:
Myocardial perfusion single photon emission computed tomography (spect) occasionally fails to detect coronary stenosis in patients with coronary artery disease (cad). we evaluated coronary flow reserve (cfr) using oxygen 15-labeled water in areas with and without ischemia on technetium 99m tetrofosmin stress perfusion spect in patients with angiographically documented cad.
Methods and results:
Twenty-seven patients with cad and eleven age-matched normal subjects were studied. baseline myocardial blood flow (mbf) and mbf during hyperemia induced by intravenous adenosine triphosphate infusion (0.16 mg. kg(-1). min(-1)) were determined with the use of o-15-labeled water positron emission tomography, and the cfr was calculated. tc-99m tetrofosmin stress/rest spect was performed for comparison. on the basis of the results of coronary angiography and spect, coronary segments were divided into 3 types: segments with coronary stenosis and a perfusion abnormality on stress spect imaging (group a, n = 16), segments with coronary stenosis without a perfusion abnormality (group b, n = 42), and remote segments with no coronary stenosis or perfusion abnormality (group c, n = 18). baseline mbf values were similar among the 3 groups. cfr in group a was lower (1.82 +/- 0.54) than in group b (2.22 +/- 0.87, p <.05), in group c (2.92 +/- 1.21, p <.01), and in normal segments (3.86 +/- 1.24, p <.001). cfr in group b was lower than in group c (p <.02) and in normal segments (p <.001). cfr in group c was lower than in normal segments (p <.02).
Conclusions:
Areas with a perfusion abnormality on stress spect had reduced cfr. in the areas without a perfusion abnormality and with coronary stenosis, lowering of cfr was intermediate between the areas with a perfusion abnormality and remote segments. moreover, cfr was slightly, but significantly, lower in remote segments in patients with cad compared with normal segments.