Noninvasive analysis of coronary artery poststenotic flow characteristics by using transthoracic echocardiography.

This study was performed (1) to test whether transthoracic echocardiography may detect coronary flow velocity in the left anterior descending coronary artery distal to stenoses; and (2) to noninvasively assess coronary artery hemodynamics distal to coronary artery stenoses. High-frequency transthoracic echocardiography was used to assess blood velocity patterns in the distal segment of the left anterior descending coronary artery of 128 consecutive patients (mean age, 58 +/- 9 years; 97 men and 31 women) who underwent cardiac catheterization for investigation of angina. Biphasic, diastolic predominant Doppler velocity patterns were obtained in 67 patients (52%). There was no significant difference in any measurements of systolic blood velocity between patients with unobstructed (less than 30% stenosis) left anterior descending coronary artery, moderate stenosis (30% to 70% obstruction), or severe stenosis (more than 70% obstruction). Patients with severe stenosis demonstrated a reduction in the diastolic component of blood flow velocity in the distal left anterior descending coronary artery compared with patients in the other two groups. This technique may be useful for the noninvasive assessment of the significance of stenotic left anterior descending coronary artery disease or the outcome of interventional procedures.