FDA has given a breakthrough designation to a stent used in procedures treating acute Type A aortic dissection, Boca Raton, Florida-based startup Ascyrus Medical announced Wednesday.
The rare but serious condition is marked by a tear in the ascending aorta that can lead to potentially fatal rupture and usually requires immediate open-heart surgery. The Ascyrus Medical Dissection Stent is meant to be adjunctive to hemiarch reconstruction and is specifically designed to protect against post-surgery adverse outcomes prompted by anastomotic tears.
U.S. marketing authorization would build on the CE mark the implantable device gained in February and Health Canada approval it won in December, both of which were based on a prospective trial run in Canada and Germany. 

Ascyrus Medical argues the standard surgical replacement of the hemiarch with a synthetic graft does not address all harmful effects of a Type A dissection. The company asserts the procedure can leave patients with an anastomotic tear, which can lead to pressurization of the false lumen, a newly created channel for blood flow.

That pressure can cause collapse of the true lumen and lead to malperfusion, which poses risk for higher mortality, the company notes. It can also instigate gradual aortic growth (also called negative aortic remodeling) in up to three-quarters of patients which can lead to rupture and therefore result in reintervention in close to half of all cases, the company says.

The Ascyrus stent aims to seal the anastomotic tear to reduce risk of those outcomes. The system is also designed to pressurize the true lumen to allow uninhibited blood flow to aortic arch branches and intercostal muscles and reduce risk of stroke and paraplegia.

The breakthrough designation was supported by a monitored type A dissection trial. "The results have shown a significant reduction in mortality and re-interventions along with effective malperfusion management, without any device related adverse events," the company wrote in a press release.

The company lists a five-year, 100-participant registry for the device initiated in March on clinicaltrials.gov.

Type A dissections differ from Type B, which are found in the descending aorta and are less common than Type A. Cook Medical said in February it received premarket approval for its Zenith Dissection Endovascular System consisting of a proximal stent graft component and a distal bare stent component meant to treat the Type B variety. Procedures with the system allow for insertion of the device near the hips, rather than requiring a large incision near the chest. 

FDA does not disclose individual breakthrough designations, given to products in development that may provide better treatment for, or diagnosis of, life-threatening or irreversibly debilitating diseases or conditions. But the agency recently told MedTech Dive 186 designations had been given as of Aug. 1.

The primary incentive for winning the designation is the opportunity to work more closely with FDA on accelerated product review. Additionally, CMS earlier this month finalized an add-on payment system that would allow for coverage of approved breakthrough devices without manufacturers meeting the substantial clinical improvement standard.