Impact of screening MR angiography on referrals for percutaneous intervention in renovascular disease

PURPOSE: Concern about contrast- and catheter-induced complications inhibit s liberal use of catheter angiography to screen for renal artery stenosis. The authors evaluated the impact on interventional practice growth of offer ing magnetic resonance angiography (MRA) as an alternative screening test f or renovascular disease. MATERIALS AND METHODS: A retrospective analysis of 339 patients with renova scular disease identified with MRA from January 1, 1993 through December 31 , 1997, and the subsequent utilization of follow-up catheter angiography an d/or intervention was performed. The number of patients treated per year wi th percutaneous techniques for renovascular disease was recorded, and was c orrelated with screening MRA. The impact of screening MRA on percutaneous m anagement of renovascular disease was evaluated through comparisons of the number of percutaneous procedures performed among the individual years duri ng the 5-year period, and with the number of procedures performed during th e 5-year period (1988-1992) immediately preceding 1993, prior to the use of screening MRA RESULTS: The number of annual screening MRA examinations increased six-fold during the B-year period, from 17 per year initially to approximately 100 per year for each of the last 3 years. One hundred thirty-five (40%) of scr eening MRA examinations were positive for renal artery stenosis or occlusio n, and 111 (33%) patients had anatomy potentially suitable for percutaneous intervention. Fifty-two patients with positive screening MR angiograms und erwent arteriography: 34 underwent renal angioplasty or stent placement, se ven had surgery, seven with stenosis determined with MRA had occlusion on c atheter angiography, and four had false-positive results of MRA (<50% steno sis). Three additional patients with negative screening MR angiograms were also referred for arteriography, which confirmed the MRA findings. The perc entage of positive catheter angiograms was 50% greater among patients with a screening MRA, and the number of renal artery angioplasties performed ann ually doubled. Moreover, comparison with the 5-year period from 1988 to 199 2 (immediately prior to the use of MRA as a screening tool), demonstrates t hat the average number of renal artery percutaneous procedures performed pe r year increased nearly 350% from an average of three per year to 15 per ye ar. These findings are entirely attributable to referrals from screening MR A. CONCLUSIONS: Marketing of renal artery MRA as a safe, noninvasive outpatien t screening technique can lead to improved utilization of catheter angiogra phy in evaluation of renovascular disease, and can secondarily increase the volume of renal artery angioplasty and stent placement procedures for trea tment of renovascular disease.