The new surface modification technology may represent the future of flow diverters, say expert.
The latest iteration of the Pipeline flow diverter, known as the Pipeline Flex Embolization Device with Shield Technology, or simply the Pipeline Shield (Medtronic Neurovascular) may offer concrete improvements that could translate to a lower complication rate for patients treated for unruptured intracranial aneurysms, according to early 1-year follow-up data published online September 27, 2018, ahead of print in the Journal of NeuroInterventional Surgery.
The Pipeline Shield is an updated version of the Pipeline Flex device that has been modified to include a surface phosphorylcholine biocompatible polymer. “The key feature that differentiates the Pipeline Shield from the previous generations is the surface modification making the device more biocompatible, more hydrophilic, and less thrombogenic,” lead author Mario Martínez-Galdámez, MD (Hospital Universitario Fundación Jiménez Diaz, Madrid, Spain), told Neurovascular Exchange in an email.
While early technical success and safety data have been reported previously with the Pipeline Shield, which is not yet available for commercial use in the United States, long-term data are lacking.
The prospective, single-arm, multicenter Pipeline Flex Embolization Device with Shield Technology (PFLEX) study included 50 patients with 50 unruptured intracranial aneurysms. The primary endpoint was a major stroke in the territory supplied by the treated artery, or neurologic death at 1-year postprocedure. Angiographic outcomes were also assessed by an independent radiology laboratory at 6 months and 1 year.
Mean age of the patients was 53 years, and 82% were female. Aneurysm diameter was 8.82 ± 6.15 mm. Of the target aneurysms, three-quarters were small (< 10 mm) and most (94%) were located in the internal carotid artery.
Among the 33 patients with 1-year follow-up data, the complete occlusion rate was 81.8%. No neurologic deaths were reported, nor were there any aneurysm recurrences or retreatments.
“One of the main concerns of using flow-diversion technology for the treatment of intracranial aneurysms [is the risk of] thromboembolic complications,” Martínez-Galdámez said. But the results of this study “were even better than expected, with no major strokes documented during the follow-up.”
Based on these findings, he noted, the Pipeline Shield “has the same efficacy [as] its previous generations, since the porosity has not been modified, and a better clinical outcome [based on comparing] similar preliminary experience with its predecessors.”
Not only is the complication rate with the Pipeline Shield extremely low, Martínez-Galdámez said, angiographic follow-up revealed “a more benign pattern of in-stent stenosis.” Specifically, 1-year angiographic findings in 32 patients revealed only three cases of > 25%-50% in-stent stenosis and only a single case of > 50% in-stent stenosis.
Commenting on the study for Neurovascular Exchange, Alexander L. Coon, MD (Johns Hopkins University School of Medicine, Baltimore, MD), said while these early findings show promise, they require confirmation in large, multicenter trials.
The challenge, he explained, will be to demonstrate superiority with regard to a lower thromboembolic complication rate or the ability to use less antiplatelet therapy. Both of these represent major hurdles, as thousands of patients would be needed to confirm a lower complication rate, and ethical considerations may hamper trials that would examine outcomes using less antiplatelet therapy, he noted.
But the surface-treatment technology on the Pipeline Shield may be the wave of the future, Coon suggested. “Through more experiences like this and multi-institutional registries and reporting, we will get a better understanding of the true benefit of surface-treatment technology on flow diverters. . . . This surface-modification technology is probably the future in the space of flow diversion: to try to find ways to make metals that we need to use for flow-diverting stents less thrombogenic and thereby safer, or allowing us to use less antiplatelet medication.”
Martínez-Galdámez M, Lamin SM, Lagios KG, et al. Treatment of intracranial aneurysms using the Pipeline Flex Embolization Device with Shield Technology: angiographic and safety outcomes at 1-year follow-up. J NeuroIntervent Surg. 2018;Epub ahead of print.
Martínez-Galdámez reports being a consultant and proctor for Medtronic.
Coon reports being a consultant and proctor for Stryker Neurovascular, Medtronic, and MicroVention.