WEB Embolization: Transradial and Transfemoral Access Are Comparably Safe, Effective

CT Scan Axial View of Brain to Detect Aneurysm

Some centers now use transradial access (TRA) for most neurovascular procedures. In December 2018, the FDA approved the Woven EndoBridge (WEB) for embolization of wide-neck bifurcation intracranial aneurysms, but information about TRA for this device has only been published in a few case series and reports.

Adam A. Dmytriw, MD, MPH, MSc, and Mohammad A. Aziz-Sultan, MD, physicians in the Neuroradiology and Neurointervention Service and Neurosurgery Service at Brigham and Women’s Hospital, and colleagues used data from a large multicenter study to compare TRA with transfemoral access (TFA) for WEB embolization.

They report in the Journal of Neurosurgery that the two approaches were associated with comparable radiologic and clinical outcomes, and procedure and fluoroscopy times were shorter with TRA.


The researchers analyzed data on 682 patients with intracranial aneurysms who were managed with the WEB device at 22 centers in North and South America, Europe and Australia. There were no restrictions based on aneurysm rupture status or location (bifurcation vs. sidewall).

The site of access, use of ultrasound and use of preprocedural antiplatelet drugs were at the discretion of each institution. TRA was used for 18% of aneurysms.

Procedural Characteristics

The primary outcomes of this analysis were:

  • Technical complications—8 (6.6%) in the TRA group vs. 17 (3.0%) in the TFA group (P=0.057); 6 (75%) complications in the TRA group were deployment issues, all successfully addressed with device exchange or stent placement
  • Median procedure time—76 vs. 85 minutes (P=0.007)
  • Fluoroscopy time—24.0 vs. 29.6 minutes (P<0.001)

There was one fatal technical complication in the TFA group, a femoral puncture site hematoma that resulted in fatal hypovolemic shock.

Rates of adjunctive coiling and stent placement were similar in the two groups.

Clinical and Angiographic Outcomes

The WEB Occlusion Scale, a validated angiographic assessment tool, was used to evaluate post-treatment aneurysm occlusion status. The proportion of aneurysms in which immediate adequate occlusion was achieved (complete occlusion or neck remnant) was lower in the TRA group than in the TFA group (44% vs. 60%; P< 0.001). The two groups were comparable with respect to adequate WEB occlusion rates at last follow-up.

The groups were also similar in modified Rankin Scale (mRS) scores at last follow-up and rates of thromboembolic and hemorrhagic complications, need for retreatment and mortality. No patient in the TRA group experienced symptomatic radial artery occlusion after the procedure.

Propensity Score Matching

To control for possible selection bias in the use of TRA versus TFA, a propensity score was developed to match pairs of patients on age, sex, subarachnoid hemorrhage, aneurysm location, bifurcation aneurysm, aneurysm with the incorporated branch, neck width, aspect ratio, dome width and time since last follow-up imaging.

This resulted in 65 matched pairs of patients who also did not differ in terms of immediate adequate WEB occlusion, adequate WEB occlusion at last follow-up, retreatment, mRS scores at last follow-up, rates of thromboembolic and hemorrhagic complications or mortality rate.

In the propensity score–matched subgroup, TRA was still associated with a significantly shorter procedure time (median 72.0 vs. 96.5 minutes; P=0.006) and fluoroscopy time (24.8 vs. 28.2 minutes, P=0.037). Numerically more deployment issues were noted in the TRA group but none resulted in permanent complications.

Caveats for Neurointerventionists

The increased procedure length and radiation exposure in the TFA group may be attributable to the larger surface area traversed, iliofemoral disease and the need for an additional femoral run prior to closure. On the other hand, arch anatomy and bias toward patients who did not require triaxial support may have exaggerated the speed advantage of TRA.

Neurointerventionists should be aware of certain limitations to the use of TRA during WEB deployment. The size of the radial artery requires the use of long sheaths and intermediate catheters with smaller diameters, which provide less support for the entire construct. That may account for the greater number of deployment issues in the TRA group in this study.

In previous studies of TRA in patients undergoing coronary procedures or other neurointerventions, challenges have included radial artery anatomical anomalies and tortuosity, radial artery spasm after a failed attempt, subclavian tortuosity and catheter knots/kinks.

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