Assessment of renal artery fibromuscular dysplasia: Angiography, intravascular ultrasound (with virtual histology), and pressure wire measurements

Abstract

Fibromuscular dysplasia (FMD) of the renal arteries is classically associated with secondary hypertension in younger individuals, which may be treatable and even curable by percutaneous transluminal renal angioplasty. Angiography of these renal arteries often displays "beaded" luminal abnormalities. The angiographic findings, however, may not accurately reflect the severity or precise location of the intraluminal obstruction. We present a case of an older individual with longstanding hypertension and FMD, in whom the use of a coronary pressure wire and intravascular ultrasound enabled precise localization and treatment of the hemodynamically significant stenosis. Virtual histology of FMD in the renal vasculature is also reported.

Fibromuscular Dysplasia: State of the Science and Critical Unanswered Questions

“…Reporting a specific percent stenosis is strongly discouraged, particularly with multifocal FMD, because the severity may appear very mild but still manifest a significant pressure gradient. 58,148 Conversely, the presence of significant beading may not be associated with a hemodynamically significant gradient.…”

“…Some authors suggest that IVUS may improve the diagnostic accuracy of conventional angiography. 58,148 To date, no study has defined the exact role or utility of IVUS in the diagnosis and treatment of renal FMD.…”

“…Through the diagnostic catheter, a 0.014-in pressure wire can be passed through the renal artery lumen to assess the translesional pressure gradient, quantifying the hemodynamic significance of the arteriographic findings. 148 There is growing interest, although few published data, on the use of IVUS in the evaluation of renal artery FMD. Small series have demonstrated abnormalities consistent with FMD in areas with borderline or otherwise normal angiographic appearance.…”

“…58,198 Given the difficulty in ascertaining hemodynamic significance of minor angiographic irregularities or in localizing a culprit lesion within long stretches of stenotic vessel, IVUS may permit more thorough and targeted intervention without repeated exposure to radiation and contrast. 148,199 The ability to detect intraluminal webs missed by angiography may permit PTA of an otherwise normal-appearing vessel. A potential exists for better outcomes with IVUS-directed PTA, and further research is required to determine the utility of this technique in FMD.…”

Focal Renal Arterial Fibromuscular Dysplasia Demonstrated via Intravascular Ultrasound Image

“…Although several reports show the relation of IVUS image with the "string-of-beads" type FMD, there are few reports about focal renal FMD. [8][9][10] Furthermore, most of publications make little mention of the pathological evaluation of the lesions and describe only both the evaluation of the lesion form (size) and how to use the IVUS as a decision maker of interventional strategy.…”