The Source for Neurovascular News and Education

July 14, 2024


The next-generation device may become part of standard aneurysm care, even when coiling is possible, investigator says.


Pipeline Flex is an improvement on the classic design that translates into fewer complications and better patient outcomes, according to a retrospective, single-center analysis published online January 12, 2018, ahead of print in the Journal of Neurosurgery.

“Since the institution of the second-generation Pipeline system, there has been been a lot of discussion about whether it is better,” lead author Alexander Coon, MD (Johns Hopkins University School of Medicine, Baltimore, MD), told Neurovascular Exchange. “It seems to be easier to deploy, but does this translate to better patient outcomes?”


One of the most significant improvements, said Coon, is the Flex’s reengineered distal constraining apparatus. “Instead of a capture coil screwed on to the end of it, it has winglets, which allow for much easier, more reliable opening of the distal end of the device without the need to torque the delivery wire,” he explained. Meanwhile, the stainless-steel delivery wire was replaced with a hypotube pusher wire. “This allows the braided Pipeline to be compressed more, which allows for more reliable and more consistent opening of the device,” Coon noted, adding that the newer model is also resheathable, “which does give it an added level of safety.”


Coon and colleagues conducted an analysis of a prospective, single-institution database, identifying all 568 patients with anterior circulation aneurysms treated by flow diversion since August 2011. The Pipeline classic (Medtronic) was used from August 2011 to January 2015 in 252 patients. The Pipeline Flex (Medtronic) has been used since February 2015 in 316 patients at the time of this analysis.


The overall average aneurysm size was 6.8 mm. Patients treated with the Flex device had smaller aneurysms (P = 0.006) and were more likely to have undergone previous treatments (P = 0.001). For both groups of patients, aneurysms originated most commonly along the internal carotid artery (89% of those treated with the classic Pipeline and 75% of those treated with the Flex). Using the Flex, however, there were more deployments in the anterior cerebral artery (18%) and middle cerebral artery (7%; P = 0.001).


There was a trend toward higher rates of procedural success with the Flex device. In addition, there was a significantly lower rate of major morbidity or death using Flex.


Outcomes by Pipeline Type



(n = 252)


(n = 316)

P Value

Procedural Success




Morbidity or Death





Multivariate analysis revealed that independent predictors of major complications were in situ thrombosis (OR 4.3, P = 0.006), use of the classic versus the Flex device (OR 3.7, P = 0.008), and device deployment in the anterior cerebral artery or middle cerebral artery as opposed to the internal carotid artery (OR 3.5, P = 0.034).


Coon said the “improved delivery system and low complication rate [indicate Pipeline Flex] is something that is viable to being mainstream in primary use treatment for standard aneurysms, even aneurysms that [can be coiled].”


It was important to conduct the study, but the findings come as no surprise because they reflect users’ clinical experience, Pascal Jabbour, MD (Thomas Jefferson University Hospital, Philadelphia, PA), told NVX. He described the Flex as “much more user-friendly and easier to deploy than the old Pipeline.”


Jabbour, who did not take part in the current research, expects that this demonstrated reduced rate of morbidity and mortality with the Flex means “more interventionalists will be encouraged to use this device to treat aneurysms.”


On Jabbour’s wish list for additional technical improvements is a Pipeline device that does not require use of dual antiplatelet therapy, a characteristic that makes using them tricky in patients with ruptured aneurysms.


For his part, Coon mentioned he would like to see surface treatments and coatings as well as variable strand numbers and consistent porosity. The Pipeline device is 48 strands across all diameters, [but] there are times you will need more strands to get the device to open more widely and times when maybe you don’t need as many strands.”


Both Coon and Jabbour emphasized the importance of operator experience with the Pipeline device when it comes to optimizing outcomes. Jabbour and colleagues have shown with the classic Pipeline how dramatically complication rates diminish with continued use. He added that appropriate patient selection is another crucial component of outcome optimization.





Colby GP, Bender MT, Lin LM, et al. Declining complication rates with flow diversion of anterior circulation aneurysms after introduction of the Pipeline Flex: Analysis of a single-institution series of 568 cases. J Neurosurg. 2018;Epub ahead of print.



  • Coon reports being a consultant and proctor for Stryker Neurovascular, Medtronic, and MicroVention.
  • Jabbour reports being a consultant for Medtronic and MicroVention.