COMPARISON OF TRANSESOPHAGEAL DOPPLER CORONARY FLOW RESERVE MEASUREMENTS WITH TL-201 SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY IMAGING IN ASSESSMENT OF LEFT ANTERIOR DESCENDING ARTERY STENOSES

Background and hypothesis: Recent studies demonstrate the feasibility of coronary flow reserve measurements by transesophageal echocardiogra phic (TEE) Doppler recordings of coronary sinus or left anterior desce nding (LAD) coronary artery flow velocity for detecting stenoses of th e LAD artery. This study compares coronary flow reserve measure ments by Doppler TEE with thallium-201 (Tl-201) single-photon emission compu ted tomography (SPECT) in patients with proximal single-vessel LAD ste nosis. Methods: Nineteen patients with various degrees of LAD stenosis (mean area stenosis 71+/-24%; range 24-96%) were studied. Area stenos is by quantitative coronary angiography was <75% in 7 patients and >75 % in 12 patients. Transesophageal LAD and coronary sinus Doppler measu rements were performed at baseline and after intravenous dipyridamole. Coronary flow reserve was calculated as the ratio of hyperemic to bas eline average peak velocities. Predefined coronary flow reserve cut-of f values of 1.8 for the coronary sinus method and of 2.0 for the LAD m ethod were used for diagnosis of significant LAD stenosis. Results wer e compared with qualitative Tl-201 dipyridamole SPECT. Results: Overal l predictive accuracy for diagnosis of >75% LAD stenosis was 79% for T l-201 SPECT, 77% for the transesophageal LAD and 79% for the transesop hageal coronary sinus technique. Concordant results between Tl-201 SPE CT and the LAD and coronary sinus Doppler methods were observed in 79% and 71% of patients, respectively. Conclusions: Thallium-201 SPECT an d transesophageal Doppler assessment of coronary flow reserve have sim ilar accuracy for diagnosing significant proximal LAD stenosis. Theref ore, both transesophageal Doppler techniques might constitute another widely available, noninvasive method for assessment of left coronary a rtery disease, if disease location is proximal.