A new-generation, low-permeability flow diverting device for treatment of saccular aneurysms

The development and understanding of intracranial aneurysm based on rabbit model

In modern society, intracranial aneurysms have seriously affected people's life. To better study and treat intracranial aneurysm, animal models are ideal candidates to perform biological research and preclinical endovascular device testing. Rabbit aneurysm model is one of the most commonly used animal models, and the rabbit aneurysms share similarities in histology, morphology, and hemodynamic aspects with human intracranial aneurysms, which is an ideal model for intracranial aneurysm pre-clinical and basic research. In this review, we will summarize the main methods of establishing rabbit aneurysms model and will further discuss the current biological mechanisms of intracranial aneurysms based on rabbit model. Further improvements of rabbit aneurysm model and more deep studies based on this model are needed to provide new insights into studying and clinical treating intracranial aneurysm.

Intravascular optical coherence tomography for the evaluation of arterial bifurcations covered by flow diverters

Background and objective

Due to its high spatial resolution, intravascular optical coherence tomography (OCT) has been used as a valid method for in vivo evaluation of several types of coronary stents at straight lumen and bifurcation sites. We sought to evaluate its effectiveness for flow diverting stents deployed in arterial bifurcation sites involving jailing of a side branch.

Methods

Four large white swine were stented with flow diverting stents covering the right common carotid artery–ascending pharyngeal artery bifurcation. After 12 weeks of follow-up the animals were evaluated by digital subtraction angiography and intravascular OCT and subsequently sacrificed. Neointimal thickness on the parent arteries and the free segments of the stent were measured. The stented arteries were harvested and underwent scanning electron microscopy (SEM) imaging. Ostia surface values were measured with OCT three-dimensional (3D) reconstructions and SEM images.

Results

All endovascular procedures and OCT pullback runs were feasible. Stent apposition was satisfactory on the immediate post-stent OCT reconstructions. At 12-week controls, all stents and jailed branches were patent. Mean neointimal thickness was 0.11±0.04 mm on the free segments of the stent. The mean ostia surface at 12 weeks was 319 750±345 533 μm2 with 3D-OCT reconstructions and 351 198±396 355 μm2 with SEM image-derived calculations. Good correlation was found for ostia surface values between the two techniques; the values did not differ significantly in this preliminary study.

Conclusions

Intravascular OCT appears to be a promising technique for immediate and follow-up assessment of the orifice of arterial branches covered by flow diverting stents.

Initial Experience with p64: A Novel Mechanically Detachable Flow Diverter for the Treatment of Intracranial Saccular Sidewall Aneurysms

BACKGROUND AND PURPOSE

Flow diverters are important tools for the treatment of intracranial aneurysms. We report a retrospective evaluation of the safety and efficacy of p64, a fully resheathable, detachable flow diverter, in the endovascular treatment of intracranial sidewall aneurysms.

MATERIALS AND METHODS

Results of 121 patients with 130 aneurysms (median neck size, 3 mm; median fundus size, 4 mm), treated from April 2012 through October 2014, were analyzed. Aneurysms were unruptured or beyond the acute SAH phase. Thirteen aneurysms were located in the posterior circulation. Twenty-three aneurysms had previous saccular treatment but no previous parent vessel stent placement. In 19 aneurysms, a combination of coiling and flow diversion was performed.

RESULTS

Successful p64 deployment was achieved in 127/130 aneurysms. The average number of p64s used was 1.1 per aneurysm. The rates of transient and permanent morbidity and mortality were 5%, 1.7%, and 0.8%, respectively. Three-month DSA follow-up in 123/130 aneurysms showed complete occlusion in 58.5%. Nine-month DSA follow-up in 93/106 (87.7%) eligible aneurysms showed complete occlusion in 79.6%. Late follow-up (median, 496 days) has already been performed in 35 aneurysms, showing complete occlusion in 30 (85.7%).

CONCLUSIONS

p64 offers an efficacious treatment option for intracranial sidewall aneurysms with a high aneurysm occlusion and an acceptable complication rate. The possibility of repositioning or removing the device was an advantage. The higher attenuation may lead to fewer devices per case and early aneurysm occlusion. Long-term follow-up data are pending.

Medical Textiles as Vascular Implants and Their Success to Mimic Natural Arteries

Vascular implants belong to a specialised class of medical textiles. The basic purpose of a vascular implant (graft and stent) is to act as an artificial conduit or substitute for a diseased artery. However, the long-term healing function depends on its ability to mimic the mechanical and biological behaviour of the artery. This requires a thorough understanding of the structure and function of an artery, which can then be translated into a synthetic structure based on the capabilities of the manufacturing method utilised. Common textile manufacturing techniques, such as weaving, knitting, braiding, and electrospinning, are frequently used to design vascular implants for research and commercial purposes for the past decades. However, the ability to match attributes of a vascular substitute to those of a native artery still remains a challenge. The synthetic implants have been found to cause disturbance in biological, biomechanical, and hemodynamic parameters at the implant site, which has been widely attributed to their structural design. In this work, we reviewed the design aspect of textile vascular implants and compared them to the structure of a natural artery as a basis for assessing the level of success as an implant. The outcome of this work is expected to encourage future design strategies for developing improved long lasting vascular implants.