New Hemodynamic Test for Assessment of Failing Hemodialysis Grafts: The Saline Infusion Test

Abstract

To validate the saline infusion test, a new hemodynamic test for assessment of failing hemodialysis access grafts. Over a 12-month period, 31 procedures were performed in 25 patients with synthetic forearm loop grafts for hemodialysis. Pre- and postangioplasty measurements of static graft pressures and infusion pressures were obtained. For the saline infusion test, graft pressure was measured while saline was infused at a rate of 600 mL/min for 10 seconds with arterial inflow occluded. Comparison was made to percent outflow stenosis as determined with pre- and postangioplasty angiograms. There was no correlation between either the static intragraft pressure (r = .085, P = .654) or the normalized pressure ratio (r = .136, P = .4676) and venous outflow stenosis in the preangioplasty group. When pressure was measured during infusion, a significant Pearson correlation was observed between infusion pressure and percent of angiographic stenosis (r = .60, P = .0002). All three pressure tests were significantly correlated to the percent stenosis identified after angioplasty. Pressure measured in the graft during the saline infusion test at a standard rate that simulates optimal graft flow correlates with the angiographic degree of stenosis and warrants further investigation as a useful adjunct to the assessment of revascularization results.