The lead investigator behind new research from a center in Louisiana outlines how his new study—believed to be the largest single-institution analysis of symptomatic carotid web yet reported—shows that carotid duplex is “inadequate” for diagnosis, and medical management is “unacceptable.” The results, he reveals, leave potential clues to possible genetic risk factors.
The appropriate modality used for diagnosis, treatment method and characterization of symptomatic carotid web could be key to tackling a condition that has been shown to result in high rates of recurrent stroke when managed with medical therapy alone, according to a new study carried out by Clayton Brinster, MD, and colleagues at Ochsner Health in New Orleans.
Because there is no bulky athereosclerotic lesion in the carotid bulb in the case of the shelf-like projection redolent of carotid web, the staff surgeon tells Vascular Specialist, this pathology “is often overlooked as an etiology of acute anterior circulation stroke.”
Brinster recently presented data from a rare 52-patient series from his institution at the 2023 annual meeting (Jan. 18–21) of the Southern Association for Vascular Surgery (SAVS) in Rio Grande, Puerto Rico, that led him to conclude that medical management is “no longer an option” to treat carotid web.
Over the six-year study period (2016–2022), the Ochsner researchers identified an average age of 49 years among their cohort of patients—71% of them women, two-thirds African American, and more than a third African-American women under the age of 50. Some 90% presented with stroke, Brinster told SAVS 2023. None were initially diagnosed using carotid duplex, he said. “Definitive treatment consisted of carotid endarterectomy and carotid artery stenting.”
Brinster’s subsequent conclusions were bold. “To our knowledge, this is the largest single-institution analysis of symptomatic carotid web yet reported,” he said. “Our series demonstrates that carotid duplex is inadequate for diagnosis, and that medical
management is unacceptable for symptomatic carotid web. Recurrent stroke occurred in all patients managed early in our experience with medical therapy alone. We have since adopted an aggressive interventional approach in cases of symptomatic carotid web, with no postoperative stroke reported over an average follow-up of 26 months.”
The findings offer key insights, Brinster reflects in an interview with Vascular Specialist after the SAVS meeting. For one, when confronted with a patient who has minimal carotid stenosis, especially a younger patient, “and especially a younger African-American woman under 50 years old, which comprised one third of our series—astronomical when you think about it—this pathology must be ruled out,” Brinster explains. “And the most efficient way to rule that out in a stroke patient is with a high-powered CTA, particularly examining the sagittal projections, That is really where carotid web is most readily identified. It is very easy to miss in the axial and the coronal projections in the scan.”
Second, carotid web demands its own characterization, Brinster says. In the literature, the condition has traditionally been referred to as a form of carotid fibromuscular dysplasia (FMD), he notes.
“In addition to medical management being totally unacceptable for symptomatic carotid web, carotid web needs to be thought of as an independent pathology from traditional carotid FMD,” Brinster relates. “Traditional carotid FMD occurs distally in the internal carotid artery—anatomically in a different region. It appears radiographically totally differently than web. Web appears as a shelf-like projection in the carotid bulb, whereas FMD has a very classical string-of-beads appearance in the more distal carotid. Third, the pathologic specimens of carotid web are completely different than pathologic and histologic examination of traditional FMD.”
The concerning point, Brinster says, “is that referring to carotid web as simply a form of carotid FMD—which has a well-established treatment paradigm that includes medical management and balloon dilation—I think confuses practitioners.”
This may lead to either undertreatment, or mistreatment, and recurrent stroke in these patients, he argues. “It would be totally inappropriate to balloon angioplasty these lesions,” Brinster adds, with the risk of recurrent stroke “astronomical.”
Meanwhile, that younger African-American female portion of the cohort is set to form the basis of at least one dimension of further digging. Thus far, Brinster says the group have only performed a pathologic evaluation on the cases they have analyzed. But, he continues, “what we really need to do is a fresh tissue analysis, and a genetic analysis of the tissue,” he reveals. “If this is based on sex and race, then it most certainly must have a genetic component. The larger French registry [of carotid web cases], called Caroweb, has alluded to a genetic basis, from Central and West African descent, through the Caribbean.” The historical migration patterns of the American South, particularly through the port of New Orleans, “is no coincidence” in the context of the findings contained in the series presented by the Ochsner group, Brinster points out. He now hopes to join forces with the physicians behind the Caroweb registry, first by creating and leading a national consortium in the U.S.
“The more people who know about it and the more people involved, the more strokes we can prevent,” Brinster says. “I can’t tell you how many people came up to me at the Southern meeting, and said, ‘I have seen this once or twice before and I didn’t know what to do. Now, I will.’ There is a lot more work to be done for these patients.”
There are hurdles to be crossed, but a potential roadmap appears to be forming. And that could involve a screening dimension.“If we try to prove some sort of genetic disposition, that could lead to more effective screening,” Brinster says. “It may be worth screening family members of those with carotid web to rule out the pathology.” Still, carotid web is a “very tricky thing to screen for without a family member who has been diagnosed, and because ultrasound is not as reliable as CAT scans, and CAT scanning, of course, is expensive and you need contrast,” he adds.
Ultimately, an opportunity beckons, Brinster says. “We have an opportunity with the size of the series, and the fact it was presented at the Southern [annual meeting], to change the way people manage carotid web—and hopefully avoid recurrent strokes in a vulnerable population.”