[Evaluation of renal artery stenosis by echocardiography]

Renovascular hypertension and renal hypertension are two major secondary forms of hypertension due to renal disease. Diagnosis of renovascular hypertension is important because revascularization therapy is an effective treatment for patients with renal artery stenosis. Doppler echocardiogaphy is a useful noninvasive test to detect renal artery stenosis. There are two Doppler echocardiographic methods to detect renal artery stenosis. The first is to measure flow velocity at the stenotic area. Pulse-Doppler and/or continuous Doppler methods are used to measure flow velocity. Significant stenosis is diagnosed by maximum flow velocity (Vmax) at the stenotic area: > 1.5m/sec or > 1.8-2.0m/sec. Flow waves of segmental and interlober arteries are assessed by the pulse-Doppler method. Decreased Vmax, early systolic acceleration, resistive index and pulsatility index indicate decreased renal artery blood flow and hence, renal artery stenosis.