Study suggests feasibility of Baby Trevo for treatment of distal cerebrovascular occlusions

Diogo Haussen and Raul Nogueira

Diogo Haussen and colleagues (Emory University School of Medicine, Atlanta, USA) report that their initial data suggest that treatment of distal cerebrovascular occlusions with the Trevo XP ProVue 3x20mm retriever (“Baby Trevo”, Stryker Neurovascular) is feasible.

In this single-centre initial experience study, Haussen et al performed a retrospective review of their interventional database for consecutive patients who underwent treatment for acute ischaemic stroke with the Baby Trevo device between February and December 2014. The study was recently published in the Journal of NeuroInterventional Surgery.

According to the study authors, the exisitng stent retrievers that are currently FDA-cleared (eg. Trevo Retriever, Stryker Neurovascular and Solitaire stent retriever, Covidien/Medtronic) have been shown to be safer than the older coil retriever mechanical thrombectomy technology, resulting in less vessel perforation and device-related subarachnoid haemorrhage. However, there are concerns about their use in smaller vessels.

The Trevo XP 3×20 is a laser-cut, closed-cell, nitinol stent retriever specifically built to retrieve intracranial clots in patients with acute ischaemic stroke. The 3x20mm diameter device was uniquely designed to target smaller vessels.

The authors explain that, according to the manufacturer, in comparison with a 4mm diameter stent retriever, the Baby Trevo was shown in bench testing to have much larger cell sizes when deployed in small vessels (217% larger cell size in a 2mm vessel and 57% larger cell size in a 3mm vessel); larger cells in smaller vessels maximise clot integration.

Deployment and retrieval safety have also been optimised to allow for more distal use. The distal tip of the Baby Trevo is at least 48% softer then the 4×20 versions of other stent retrievers. The device also has less radial force than larger stent retrievers across all vessel diameters. “These differences should minimise the chances of vessel perforation and endothelial damage in smaller vessels,” they write.

Of 134 patients (mean age 51±20 years, five male treated during the study period, eight underwent treatment with the Baby Trevo for distal occlusions. The device was used for a total of 10 branches: five middle cerebral arteries, three anterior cerebral arteries, and two posterior cerebral arteries occlusions.

Haussen et al report that all patients achieved complete recanalisation of the artery targeted by the Baby Trevo, while “capillary-level reperfusion was noted in six (75%) cases. One pass was performed in seven vessels and two passes in three branches. Vasospasm was frequent, being noted in five (62.5%) of the vessels and fully responded to intra-arterial vasodilator infusion. Follow-up MRI revealed no infarct within the territory vascularised by the artery targeted by the Baby Trevo in four cases, partial infarct in five and complete infarct in one. No vessel perforations dissections or subarachnoid haemorrhage were noted,” they write.

The authors conclude that “Although this device emerges as a promising technology for small and tortuous distal intracranial vessels, larger studies are still necessary to establish its safety profile and clinical benefit.”

Haussen et al further caution that due to the small number of patients, the results should be interpreted with caution as it relates to the relatively high number of parenchymal haemorrhages as compared to other recently published thrombectomy trials.

They told NeuroNews that, to their knowledge, there are not currently any other additional or larger studies of the Baby Trevo device for small and tortuous distal intracranial vessels ongoing.