Definition of flow parameters in proximal nonstenotic coronary arteries using transesophageal Doppler echocardiography

Transesophageal echocardiography (TEE) enables the visualization of proxima l coronary arteries. We investigate the feasibility of coronary flow evalua tion using TEE, as well as to define flour parameters found in normal proxi mal coronary arteries. The subgroups of patients with normal proximal segme nts of coronary arteries were selected from the cohort of 210 patients unde rgoing routine coronary angiography. The left main coronary artery (LMCA), proximal segment of left anterior descending coronary artery (LAD), left ci rcumflex: artery (LCx) and right coronary artery (RCA) were analyzed separa tely in 147, 64, 53, and 70 patients, respectively. Proximal coronary arter ies were evaluated in the transverse plane using a 5-MHz TEE probe, and the flow in normal arteries was registered using pulsed-wave Doppler The regis tration of flow with pulsed-wave Doppler was feasible in 88% of studies for the LMCA, 85% for the LAD, 58% for the LCx, and 65% for the RCA. Normal fl ow was laminar with distinct phasic character (diastolic predominance). Mea n +/- SD values of peak coronary flow velocity were (systole/diastole) for the LMCA, 36 +/- 11/71 +/- 19 cm/sec; the LAD, 31 +/- 9/67 +/- 19 cm/sec; t he LCx, 36 +/- 13/75 +/- 24 cm/sec; and the RCA, 25 +/- 8/39 +/- 12 cm/sec. Peak diastolic coronary flow velocity was most significantly correlated wi th heart rate. Doppler evaluation of proximal coronary flow is feasible usi ng TEE in the majority of patients. The knowledge of normal flow values, wh ich is different for the left and the right coronary artery, provides the b ackground for proper interpretation of flow in diseased coronary arteries.