Comparison of steerable continuous-wave versus pulsed-wave Doppler ultrasonography to renal artery angiography in diagnosing renal artery stenosis.

Pulsed-wave Doppler ultrasonography is widely used to noninvasively diagnose renal artery stenosis. The use of steerable continuous-wave Doppler has never been tested. We compared pulsed and steerable continuous-wave Doppler ultrasonography, demonstrating that although both methods are highly sensitive for severe stenoses, continuous-wave Doppler shows a better sensitivity for mild to moderate stenoses.

[Doppler flow-velocity analysis of the renal arteries in left ventricular dysfunction]. / Analisi della curva di flusso-velocità doppler delle arterie renali nella disfunzione ventricolare sinistra.

AIM OF THE STUDY: Chronic heart failure leads to renal hypoperfusion. Clinical methods for monitoring renal artery flow have several limitations. We analyzed the renal artery flow-velocity in patients with left ventricular dysfunction and normal controls by pulsed-wave (PW) color-guided Doppler technique. The relation between PW Doppler quantitative indexes and left ventricular ejection fraction (LVEF), creatinine clearance, and age, was also assessed. METHODS: We studied 53 patients with left ventricular dysfunction (LVEF by 2D echo < or = 40%) and no systemic hypertension, diabetes, parenchymal nephropathy, serum creatinine levels > 150 mmol/l, nor renal artery stenosis. Five patients were excluded for suboptimal renal artery PW Doppler recordings. Thus, the study group was constituted of 48 patients (mean age: 64 +/- 13 years). Twenty-eight normal subjects (mean age: 61 +/- 9 years) were the control group. By PW Doppler we measured the maximum (Vmax), the minimum (Vmin) and the mean (Vmean) velocities of both renal arteries. The resistivity index (RI), obtained from the formula (Vmax-Vmin)/ Vmax, and the pulsatility index (PI), obtained from the formula (Vmax-Vmin)/Vmed were calculated. Creatinine clearance was determined in each patient. RESULTS: RI and PI were greater in patients with left ventricular dysfunction than in normal controls. In normal controls, RI and PI were related to age (r: 0.63, p < 0.001; and r: 0.45, p < 0.05) and creatinine clearance (r: -0.44 and -0.40, respectively; both: p < 0.05), not to LVEF. In patients with left ventricular dysfunction, RI and PI were related to LVEF (r: -0.67 and -0.59; both: p < 0.001), other than to age (r: 0.57 and 0.55; both: p < 0.001) and creatinine clearance (r: -0.59, p < 0.001, and r = -0.46, p < 0.01, respectively). In this group, however, there was no sharp separation of RI and PI between patients with different degree of left ventricular dysfunction (LVEF < or = 30% and > 30%). CONCLUSIONS: In patients with left ventricular dysfunction, by renal artery PW Doppler analysis it is possible to detect noninvasively a reduction in regional flow-velocity and an increase in Doppler-derived vascular resistance indexes. These Doppler changes mainly depend on severity of left ventricular dysfunction and less on age of patients.