Die Behandlung der akuten Typ-A-Dissektion mit dem Ascyrus Medical Dissection Stent bei 57 konsekutiven Patienten

The Stanford type A aortic dissection is a clinical emergency associated with high mortality, requiring prompt diagnosis and surgical intervention. Typically, type A dissections extend from the ascending aorta into the descending aorta, often involving the supra-aortic branches. In such cases, there is a risk of cerebral malperfusion leading to neurological impairments. The surgical gold standard is total aortic arch replacement using a frozen elephant trunk (FET) and the reconstruction of supra-aortic branches or extra-anatomical bypasses. Even with immediate surgery, the postoperative mortality in aortic dissection type A ranges from 17% to 26%.

Recently, the Ascyrus Medical Dissection Stent (AMDS, Artivion, Kennesaw, GA, USA) has been introduced as an alternative hybrid prosthesis for technically simplified aortic arch replacement. The advantage of AMDS lies in potentially reducing cardiopulmonary bypass time and its comparatively simple application. Initial clinical results of this treatment are promising, albeit with relatively small patient numbers.

The AMDS consists of an uncovered nitinol stent frame and a polytetrafluoroethylene (PTFE) cuff for proximal arch anastomosis (in zone 0). The aim of the stent is to stabilize the true aortic lumen and ensure positive aortic remodelling. The AMDS is available in two different forms (straight and conical) and two different cuff sizes (24 mm and 32 mm). Preoperative sizing and determination of prosthesis size and shape are done using contrast-enhanced multiplanar computed tomography (CT). For this two diameter measurements of the aorta are taken: at the level of zone 1 in the aortic arch and zone 4 at the level of the pulmonary bifurcation.

The surgery involves classical ascending replacement with or without root replacement and subsequent arch inspection after achieving hypothermia. If there is no re-entry, prominent aneurysm, or kinking in the aortic arch (caution: contraindication), the AMDS can be deployed in the aortic arch. Subsequently, the stent is secured at four points with individual sutures and then oversewn with an external felt strip. Finally, the reinforced distal aorta is anastomosed with the ascending graft.