FMD Peak Systolic Velocity May Lead to Comprehensive Clinical Guidelines

New data from Emory University and University Hospitals have indicated the potential for a comprehensive guideline to help clinicians quantify hemodynamically significant renal artery stenosis in patients with fibromuscular dysplasia (FMD).1

Presented at the 2026 International Fibromuscular Dysplasia (FMD) Think Tank and Symposium in Cleveland, Ohio, by Bryan Wells, MD, a cardiovascular disease specialist at Emory Healthcare, these data highlight a potential path forward for broader implementation of renal duplex ultrasound in this challenging disease, optimizing screening for non-atherosclerotic patients.1

“Typically, you have a patient with hypertension that’s resistant to medications. You think about other sources of secondary hypertension, and so that’s part of the workup,” Wells told HCPLive in an exclusive interview. “For atherosclerosis, there have been studies that have validated this with angiography as well as hemodynamic parameters with invasive angiograms and pressure gradients and so forth, but that data doesn’t exist for fibromuscular dysplasia. We’re trying to avoid invasive procedures whenever possible, and to come up with safe and effective ways to do surveillance for these patients.”

FMD is an idiopathic, segmentary, non-inflammatory, non-atherosclerotic disease affecting all layers of small- and medium-caliber arteries. While the condition primarily affects the renal, carotid, and vertebral arteries, it can potentially affect any artery. FMD’s direct cause is unknown, although clinicians largely attribute it to a mix of genetics, physical factors, and hormones.2

FMD most commonly appears in the kidneys of younger patients with resistant hypertension secondary to fibrodysplastic renal artery stenosis (RAS) and is found in roughly 1% of hypertensive patients. The disease represents the second leading cause of renovascular hypertension, after atherosclerotic disease. FMD-related lesions are most common in the renal arteries – several prior studies have indicated a substantially higher involvement of these vessels compared to carotid arteries.2

Examination of the renal arteries by duplex ultrasound is a difficult process, requiring a skilled ultrasound technologist and several degrees of oversight. The ultrasound typically highlights evidence of arterial stenosis in the affected artery, including an increase in peak systolic velocity in the mid to distal portion of the main renal artery or a delayed systolic upstroke in arterial branches distal to the stenosis.3

In the present datasets, investigators from Emory and University Hospitals combined their respective cohorts of patients with FMD who had had a renal duplex ultrasound followed by invasive angiogram within 6 months. Wells and colleagues compared duplex parameters such as peak systolic and diastolic velocity and renal to aortic ratio, aiming to find correlation with the invasive pressure wire gradient.1

A total of 41 renal arteries from roughly 20 patients were included in the dataset. Wells and colleagues noted a moderate correlation between the highest peak systolic velocity, as scanned by renal duplex ultrasound, and a PD-PA ratio of <0.9. Additionally, the team determined the most effective and sensitive peak systolic velocity to be 300, which typically occurs in the mid to distal renal artery. Cleveland Clinic also conducted a similar study with similar results, with a cutoff peak systolic velocity of 275 cm/second – after consolidating all data, Wells and colleagues found a significant degree of consistency between the 2 studies. The team now plans to build out larger studies based on these pilot examinations, aiming to apply these results and evaluate their reproducibility and clinical value.1

“We need to continue to collect our data at Emory and the other institutions and hopefully start to apply those and get more power in the data as we use this cutoff as an indication for an invasive renal angiogram,” Wells said. “It would be very nice to collaborate with more institutions and collect these data to see if it applies more broadly to this patient population.”

Editors’ Note: Wells reports no relevant disclosures.

References

1. Wells B, Sammak S. Renal Duplex for FMD: Data from Emory and University Hospitals. Presented at the 2026 International Fibromuscular Dysplasia (FMD) Think Tank and Symposium, Cleveland, OH. July 23-24, 2026.

2. Varennes L, Tahon F, Kastler A, et al. Fibromuscular dysplasia: what the radiologist should know: a pictorial review. Insights Imaging. 2015;6(3):295-307. doi:10.1007/s13244-015-0382-4

3. Olin JW, Gornik HL, Bacharach JM, et al. Fibromuscular dysplasia: State of the science and critical unanswered questions. Circulation. 2014;129(9):1048-1078. doi:10.1161/01.cir.0000442577.96802.8c