C Caiati1, P Aragona, S Iliceto, P Rizzon. 1. Division of Cardiology, "Clinica del Lavoro" Foundation IRCCS Medical Center of Rehabilitation, Cassano Murge, Italy.
Abstract
OBJECTIVE: This study was designed to verify the usefulness of transesophageal Doppler recording of blood flow velocity in the proximal left anterior descending coronary artery, after a peripheral injection of a lung-crossing contrast agent (SHU 508A), in detecting and locating a hemodynamically significant stenosis (vessel narrowing > or = 50%) affecting this portion of the vessel. BACKGROUND: Transesophageal Doppler echocardiography has a limited diagnostic impact on the evaluation of proximal left anterior descending coronary artery stenoses. Peripheral injection of SHU 508A, a lung-crossing contrast agent enhancing Doppler signal to noise ratio in coronary arteries, may allow recording of localized disturbed blood flow velocity at the stenosis site even in the absence of a clear B-mode visualization of the vessel. METHODS: Transesophageal Doppler echocardiography, before and after echo contrast injection, was performed in 31 patients who underwent coronary angiography. Using color Doppler as a guide, pulsed wave Doppler recording of blood flow velocity in the left anterior descending coronary artery was attempted to detect a localized increase in blood flow velocity. B-mode evaluation of the vessel was also performed. RESULTS: Angiography showed a significant proximal left anterior descending coronary artery stenosis in 16 patients (group 1) and no stenosis in 15 patients (group 2). In 15 of 16 group 1 patients, Doppler after contrast injection revealed a localized velocity increase of at least 50% of the reference value; mean (+/-SD) percent increase in velocity was 150 +/- 89% (range 367% to 0%). In group 2 Doppler after contrast injection revealed a mild localized increase in velocity in four patients and no increase in velocity in the remaining 11 patients; mean (+/-SD) percent increase in velocity was 5 +/- 7% (range 21% to 0%, p < 0.001 vs. percent increase in group 1). When a percent velocity increase > or = 50% of the reference value was considered a positive criterion for detecting significant stenosis, the sensitivity and specificity were 92% and 100% respectively. The sensitivity of the evaluation before contrast injection or considering B-mode imaging alone was much lower (25% and 19%, respectively, p < 0.001 vs. evaluation after contrast injection). In addition, color Doppler after contrast injection correctly located the stenosis along the vessel, as compared with angiography. CONCLUSIONS: Blood flow evaluation of the proximal left anterior descending coronary artery by transesophageal Doppler echocardiography after contrast injection is a feasible and reliable method for detecting and locating significant stenoses affecting this part of the vessel and is an improvement over the traditional ultrasound approach.
OBJECTIVE: This study was designed to verify the usefulness of transesophageal Doppler recording of blood flow velocity in the proximal left anterior descending coronary artery, after a peripheral injection of a lung-crossing contrast agent (SHU 508A), in detecting and locating a hemodynamically significant stenosis (vessel narrowing > or = 50%) affecting this portion of the vessel. BACKGROUND: Transesophageal Doppler echocardiography has a limited diagnostic impact on the evaluation of proximal left anterior descending coronary artery stenoses. Peripheral injection of SHU 508A, a lung-crossing contrast agent enhancing Doppler signal to noise ratio in coronary arteries, may allow recording of localized disturbed blood flow velocity at the stenosis site even in the absence of a clear B-mode visualization of the vessel. METHODS: Transesophageal Doppler echocardiography, before and after echo contrast injection, was performed in 31 patients who underwent coronary angiography. Using color Doppler as a guide, pulsed wave Doppler recording of blood flow velocity in the left anterior descending coronary artery was attempted to detect a localized increase in blood flow velocity. B-mode evaluation of the vessel was also performed. RESULTS: Angiography showed a significant proximal left anterior descending coronary artery stenosis in 16 patients (group 1) and no stenosis in 15 patients (group 2). In 15 of 16 group 1 patients, Doppler after contrast injection revealed a localized velocity increase of at least 50% of the reference value; mean (+/-SD) percent increase in velocity was 150 +/- 89% (range 367% to 0%). In group 2 Doppler after contrast injection revealed a mild localized increase in velocity in four patients and no increase in velocity in the remaining 11 patients; mean (+/-SD) percent increase in velocity was 5 +/- 7% (range 21% to 0%, p < 0.001 vs. percent increase in group 1). When a percent velocity increase > or = 50% of the reference value was considered a positive criterion for detecting significant stenosis, the sensitivity and specificity were 92% and 100% respectively. The sensitivity of the evaluation before contrast injection or considering B-mode imaging alone was much lower (25% and 19%, respectively, p < 0.001 vs. evaluation after contrast injection). In addition, color Doppler after contrast injection correctly located the stenosis along the vessel, as compared with angiography. CONCLUSIONS: Blood flow evaluation of the proximal left anterior descending coronary artery by transesophageal Doppler echocardiography after contrast injection is a feasible and reliable method for detecting and locating significant stenoses affecting this part of the vessel and is an improvement over the traditional ultrasound approach.