Use of intravascular Doppler velocimetry during angioplasty of failing hemodialysis shunts.

Abstract

To correlate angiographic stenoses, pressure gradients, and intravascular Doppler velocity measurements, we studied 12 patients with failing hemodialysis shunts who were undergoing percutaneous transluminal angioplasty. Seven patients had a stenosis at the site of venous anastomosis, two had a stenosis of the central vein, and three had stenoses at both sites. The mean degree of angiographic stenosis was reduced by percutaneous transluminal angioplasty from 74 +/- 8% to 23 +/- 7% diameter, and the mean pressure gradient was reduced from 48 +/- 13 to 7 +/- 3 mm Hg. The proximal to distal peak systolic velocity ratio was significantly different before and after the angioplasty (3.3 +/- 1.4 and 1.6 +/- 0.6, respectively, P < 0.001). The lesion to proximal peak systolic velocity ratio was 2.5 +/- 0.8 before and 1.2 +/- 0.2 after percutaneous transluminal angioplasty (P < 0.001). Cutoff values of 1.9 for the proximal to distal velocity ratio and 1.5 for lesion to proximal velocity ratio were used to assess hemodynamic significance of lesions in our series. Velocity gradients derived from intravascular Doppler measurements correlate with angiographic and pressure measurements in failing hemodialysis shunts treated with percutaneous transluminal angioplasty. Further studies are needed to assess the exact role of these measurements in percutaneous revascularization procedures.