Renal artery stenosis: Duplex US after angioplasty and stent placement

PURPOSE: To evaluate the hemodynamic outcome of technically successful percutaneous transluminal renal artery angioplasty and stent placement (PTRAS) with duplex ultrasonography (US). MATERIALS AND METHODS: Eighteen patients who underwent PTRAS in 22 renal arteries were prospectively examined. All had abnormal preprocedural duplex US findings. Those who had significant renal artery stenosis (> 70%) at angiography and underwent technically successful percutaneous interventions were enrolled. Standard intrarenal duplex US parameters (acceleration index [Al], acceleration time, waveform morphology grade, and resistive index) were compared before and after interventions. RESULTS: A significant Al increase occurred after PTRAS (9.02 m/sec(2) +/- 4.85 [SD]), as compared with before intervention (2.34 m/sec(2) +/- 2.03; P < .001). Acceleration time significantly decreased from 0.084 second +/- 0.049 to 0.032 second +/- 0.008 (P < .01). There was also a significant resistive index increase from 0.69 +/- 0.12 to 0.79 +/- 0.12 (P < .01). Abnormal waveform morphology (modified Malpern waveform grade 3-6) was present in 19 (86%) of 22 intrarenal arteries prior to intervention, as compared with one (5%) after PTRAS (P < .001). In the instance in which an abnormal waveform persisted after intervention, waveform morphology improved from grade 6 to grade 3, with a concomitant Al increase from 0.96 to 5.1 m/sec2. CONCLUSION: The findings suggest an important potential role for duplex US in noninvasive assessment of the immediate hemodynamic outcome and long-term follow-up of PTRAS.