Bailout Implantation of a New Single-Branch Stent Graft for the Aortic Arch

Technical tips and clinical experience with the Nexus Endospan arch branch stent-graft

Aortic arch pathologies are commonly treated by open surgery which is still the gold standard. Patients that are unfit for surgery can be effectively treated mini-invasively with novel endovascular endograft specifically designed for the arch. Endovascular technology has remarkably improved in recent years and is a valid alternative option for the treatment of aortic arch. Available endografts on the market include fenestrated and branched (single, double, or triple). Most endograft designed for the aortic arch are custom-made and production time could be limiting. The aim of this study is to report our experience with the only single branch bi-modular off-the shelf device available on the market specifically designed for aortic arch aneurysms and dissections. We perform endovascular treatment of the arch in a multidisciplinary team together with dedicated anesthesiologist team, interventional cardiologists, and cardiac surgeons. Prior to the implantation of the endograft, a debranching procedure must be made to redirect the blood from brachiocephalic trunk (BCT) to the left common carotid artery and left subclavian artery. A through and through system from the right axillary artery to the femoral artery is required to deploy the main module. The ascending module is delivered over an extra stiff guidewire placed in the left ventricle. Molding of the endografts is performed with kissing balloon in rapid pacing. We performed 8 cases. Six of them came to our attention for residual dissection and has already been treated with ascending aorta replacement. Mean aortic diameter was 63 mm. All patients required complete debranching of the supra-aortic vessel and received a right common carotid -left subclavian artery bypass with reimplantation of the left common carotid artery on the graft. Timing of the debranching was a few days before the endovascular procedure in 76% of cases. Technical success of the endovascular intervention occurred in 100% of cases. In 2 cases the target supra-aortic trunk for the deployment of the main module BCT branch was the left subclavian artery with no adverse event related to this variation. No intraoperative adjunctive maneuvers have been registered, left subclavian artery have been embolized during the procedure in 5 cases. No access complications have been reported. We experienced 1 case of major stroke with permanent neurological impairments that lead to worsening of clinical condition and death at 6 months. No cardiological adverse event have been registered. Two cases of type 2 endoleak have been reported and required reintervention with embolization of the LSA. At 1 year follow-up no aorta-related adverse event has been reported. The use of this off-the-shelf device for the treatment of aortic arch pathologies requiring total debranching of the supra-aortic vessels seems to be safe and effective. Preliminary results are promising despite available data are insufficient and further data collection is mandatory.

Total Endovascular Aortic Arch Repair: From Dream to Reality

The gold-standard therapy for the treatment of aortic arch pathologies is conventional open surgery. Recently, total endovascular aortic arch replacement with branched stent-grafts has been introduced into clinical practice with the aim of reducing invasiveness especially in selected high-risk patients. The aim of this review is to describe the two most commonly used branched devices for endovascular arch stent-grafting: Nexus (Endospan, Herzlia, Israle) and RelayBranch (Terumo Aortic, Glasgow, United Kingdom). Nexus is a CE-certified off-the-shelf, single branch, double stent graft system. It consists of two different components: a main module for the aortic arch and the descending aorta with a side-branch for the brachiocephalic artery (BCA), and a curved module for the ascending aorta that lands into the sino-tubular junction and connects to the main module through a side-facing self-protecting sleeve. Nexus may be used in urgent-emergency cases and also in patients with only one suitable supra-aortic target vessel but, on the other hand, it makes cerebral blood flow dependent on one source vessel only. The RelayBranch Thoracic Stent-Graft System is a custom made, double branched endograft with a wide window on its superior portion to accommodate two inner tunnels for BCA and left common carotid artery connection; bilateral cervical accesses are generally used to advance guidewires for catheterization of the inner tunnels in a retrograde fashion. RelayBranch can be customized on every patient’s specific anatomy and provides a double blood source for the brain, but it cannot be used in urgent-emergency conditions. Therefore, in order to optimize outcomes, the choice of the most appropriate device should be made considering pros and cons of each system and patient’s anatomy by an experienced aortic team. In conclusion, total endovascular aortic arch exclusion is a promising reality in selected high-risk patients.

Aortic arch aneurysm repair - Unsteady hemodynamics and perfusion at different heart rates

The aortic arch aneurysm is a complex disease that requires branching of one or more aortic arch vessels and can be fatal if left untreated. In this in vitro study, we examine the effect of the treatment approach on the unsteady hemodynamics and blood perfusion to the upper vessel's in models of an aortic arch aneurysm, and of the three common repair approaches: open-chest surgical repair, chimney, and hybrid approach. A particle image velocimetry method was used to quantify the unsteady hemodynamics in the four models simulated in a mock circulatory loop, to evaluate unsteady hemodynamic parameters and measure perfusion to the brain and the upper body. According to the findings, in terms of perfusion to the brain and upper body, the surgery model has the highest flow rate comparing to the other models in most heart-rate conditions. It also shows oscillatory parameters in the upper vessels which in normal arteries are correlated with a better arterial function. Between the two endovascular procedures, the hybrid model exhibits slightly better hemodynamic characteristics than the chimney model, with lower shear stresses and more oscillatory flow and WSS in the upper vessels. The hybrid model had lower perfusion flow rates to upper vessels during rest conditions (90BPM). However, unlike the other models, perfusion in the hybrid model increased with heart rate, thus at 135 BPM, it results in flow rate to upper vessels similar to that of the chimney model. The results of this study may shed light on future endograft' design and placement techniques.