Relying on duplex ultrasound to evaluate suspected left renal vein (LRV) compression may lead to underdiagnosis and delayed treatment of nutcracker syndrome, according to new data presented at the 2026 annual meeting of the American Venous Forum (AVF) in Denver, Colorado (Feb. 28-March 4).
Khanjan Nagarsheth, MD, associate professor of surgery at the University of Maryland and first author on the study, said that while intravascular ultrasound is more precise for LRV compression screening, duplex ultrasound is the primary tool because it’s a less invasive procedure. “Ultrasound is not radiating; it has no contrast,” he said. “A lot of these patients are quite young, so it’s usually safer. But the gold standard has been to use intravascular ultrasound and invasive venography as the preferred method to determine the amount of compression and whether or not it’s significant.”
The study retrospectively analyzed 43 patients who underwent both duplex ultrasound and intravascular ultrasound for suspected LRV compression. Findings showed the correlation between duplex ultrasound and intravascular ultrasound measurements were moderate if a standardized duplex ultrasound protocol was used. However, compared to intravascular ultrasound, duplex ultrasound consistently underestimated the amount of compression by about 17%.
Nagarsheth said that the findings suggest clinicians should be cautious when relying on duplex ultrasound alone. “This gives more evidence to say that intravascular ultrasound should be the gold standard,” he said. “Duplex ultrasound is just not as accurate for these patients, especially if they’re borderline in terms of compression. The takeaway is that even though we want to avoid the radiation and we want to avoid the invasive procedure, it’s still better than what we have that’s not invasive.”
Although the data reinforce intravascular ultrasound as the most accurate screening method, Nagarsheth said they also highlight the need for continued improvements in noninvasive imaging. “We’ve been doing intravascular ultrasound for 20 years,” he said. “Technology has advanced. There are better MRI techniques. In the peripheral artery space, we use MRI without contrast with specialized protocols that identify significant stenosis and occlusions in small tibial vessels. If we extrapolate that for renal vein compression, we’re going to be able to have a higher diagnostic accuracy with no radiation, no contrast administration and very little risk to these patients.”
