Start with a duplex scan, continue with axial imaging, and then assess with venography and intravascular ultrasound (IVUS). This was the advice of Efthymios (Makis) Avgerinos, MD, speaking on the standard of care that is multimodal imaging in assessing venous disease at the recent European Society for Vascular Surgery 37th annual meeting (Sept. 26–29) in Belfast, Northern Ireland.
The importance of identifying symptoms prior to conducting any imaging was a key message from the talk. Before beginning his run-through of using multimodal imaging, Avgerinos, of Athens Medical Center and the University of Athens in Greece, first advised: “We shouldn’t be talking of venous imaging unless we have a clinical suspicion that something is going on with the pelvic veins, unless [the patient] has back pain or abdominopelvic pain, a swollen leg, or varicose veins in unusual sites like the pubic area or the posterior thigh.”
Avgerinos noted that there are four anatomic levels that should be considered when it comes to identifying pathologic pelvic veins. Based on the most recent Symptoms, varices and pathophysiology (SVP) classification by Mark Meissner, MD, these are: the left renal vein level, the iliac and gonadal vein level, the extra-pubic varicosities, and the lower leg level. “We are looking for reflux, or we are looking for obstruction,” he said.
The presenter noted that there are four imaging modalities available at present—duplex scan, axial imaging, venography, and IVUS.
Duplex scan: “Not an easy-to-do ultrasound”
“Starting from the basics,” Avgerinos said, “the pelvic ultrasound”. This, he advised, will determine the pathophysiology and hemodynamics of pelvic venous disease (PeVD). “We can measure diameters, identify obstructions, identify reflux and the sources of reflux, and we can also identify the varices,” he said, outlining the uses of duplex.
He also shared the “various” criteria available on how to document and establish a diagnosis of PeVD. The most frequently used ones are dilated veins of more than 5mm around the ovary and the uterus; dilated transuterine veins connecting the left and right uterine veins; and disappearance of, altered, or reversed flow with the Valsalva maneuver.
“This is not an easy-to-do ultrasound,” Avgerinos warned. “It requires expertise, dedication and time.” He also urged delegates to “be aware” that “it really matters how the patient is standing”.
The presenter explained: “If you have the patient in the supine position, most of the time you are going to see compression at the common iliac, compression at the left renal vein. If you have the patient in the supine position, you are going to miss reflux of the ovarian vein, you are going to miss reflux of the internal iliac veins, so you should get these patients in the standing position, and, many times, you are going to see the compression disappear, or you may actually uncover a reflux.”
Axial imaging: “We don’t look at images unless the patient has relevant symptoms”
Moving on to axial imaging, Avgerinos explained that this encompasses computed tomography (CT) venograms and magnetic resonance (MR) venograms. While practitioners might be more familiar with the former, the presenter highlighted the radiation hazards associated with this type of imaging, particularly for younger patients and those of childbearing age.
MR venogram, Avgerinos stated, has the benefit of being able to also provide venous flow information, however there is one major downside: “it’s not readily available, not many institutions have it”.
He also warned: “With axial imaging, if you get 100 asymptomatic patients, 25 of them are going to have a left common iliac vein compression and one-third of the patients are going to have a left renal vein compression, so, again, we don’t look at images unless the patient has relevant symptoms.”
Venography: “Not always accurate”
Avgerinos then turned his attention to venography. He informed delegates that a full venographic assessment for PeVD should include the inferior vena cava (IVC), the right and left ovarian veins, the common iliac, and the internal iliac veins. The scope is to identify reflux or obstruction.
In terms of identifying common iliac vein stenosis, the presenter pointed out that this is not something that can often be seen directly. “You need to be familiar with the indirect signs of common iliac vein compression,” he advised.
Sharing the details of some of these “indirect” indicators, Avgerinos highlighted contrast stagnation, ‘pancaking’, the ‘bull’s eye’—which he explained is a white area in the middle of an image that shows compression of an overlying common iliac artery—as well as midline crossing, when there is internal iliac vein reflux, or varicose veins that can be seen down into the proximal thigh by injecting contrast in a refluxing internal iliac vein.
“Venography is not always accurate though,” Avgerinos warned, noting that “it really depends on the rotation that you give in your C-arm to identify the stenosis—you may actually miss it”.
In addition, he stressed that veins have a low flow, multiple curves, and collateral washout, and given that stenosis >50% is “significant” it can be “difficult to visualize with a venogram”.
IVUS: “You’re giving your patient the best shot for a long-term patency”
This is where IVUS technology comes in. Avgerinos noted that, currently, this is the standard of care for the diagnosis of venous obstruction, with two technologies on the market at present: one from Boston Scientific, another from Philips. With IVUS, he said, “you can see every little luminal, wall, and extraluminal detail”.
There are data indicating how many more lesions IVUS can identify against traditional venography, the presenter pointed out, turning the audience’s attention to the Venogram versus IVUS for diagnosis iliac vein obstruction (VIDIO) trial, in which the treatment plan changed in 57 out of 100 cases when IVUS was used.
Avgerinos listed some further benefits of the technology: “You don’t need to use much contrast, you decrease radiation, you have a better sensitivity in your diagnostic testing, you have better and more accurate diameter measurements, you have better visualization of your stent to position it, and to assess its expansion.”
The presenter added: “By using IVUS, you can guarantee that you’re giving your patient the best shot for a long-term patency.” He referenced his work at the University of Pittsburgh, Pennsylvania, of IVUS versus no IVUS, sharing that patency was “significantly higher” for patients in whom IVUS was used because lesions were not missed.
Despite these multiple benefits, Avgerinos did urge caution. “Be careful with IVUS,” he said, “because you may get overdiagnosis.” To this point, he showed a series of images that demonstrated a compressed common iliac vein with a patient in the supine position, compared to a drastically different image with the patient lying on their left side or standing up.
“Treat symptoms, not images”
Closing his presentation, Avgerinos stressed that “imaging for PeVD should always follow relevant symptomatology” and that it is important to identify all communications between the pelvic and the leg veins. In addition, he shared that no single imaging modality is ideal, and easy to perform and interpret. He advised delegates to start with duplex—stressing that this needs competency—continue with axial imaging, and then assess further with a complete venography and IVUS, closing with his key message of “treat symptoms, not images”.
