Hybrid Repair Techniques for Complex Aneurysms and Dissections Involving the Aortic Arch and Thoracic Aorta.

ABSTRACT

Aortic aneurysms involving the ascending aorta, aortic arch, and descending thoracic aorta have been a challenging entity to surgically treat for over 60 years. Despite the mortality of the disease, early open surgical procedures also had significant morbidity and mortality. The inherent risk in treating multiple anatomic segments simultaneously led to the innovation of the staged elephant trunk (ET) approach by Borst in 1983. To avoid the thoracotomy and associated complications related to the second stage of the procedure, an endovascular completion paradigm was begun by Volodos in 1991. This theoretical hybrid technique combinined shorter and less elaborate open supra-aortic trunk debranching with less invasive endovascular exclusion and has grown since then in terms of different approaches and case volume. The rise of thoracic endovascular aortic repair (TEVAR) combined with debranching bypass has allowed certain lesions to be treated without a large scale intrathoracic open surgical procedure. The complexity and extensiveness of certain lesions, however, has necessitated a hybrid approach such as the frozen elephant trunk (FET) and the standard ET with second stage TEVAR. The former has been used to treat multifocal degenerative aneurysms, chronic dissections with aneurysm, and acute extensive dissections. After conventional proximal aortic replacement, a stent-graft (SG) is delivered antegrade through the transected arch where it is sutured proximally and then "frozen" distally via endovascular means. The FET has the advantage of avoiding a second stage, but potentially introduces a greater rate of spinal cord ischemia compared to the standard elephant trunk. Improvements on the FET procedure have included the development of more advanced hybrid SG such as the Vascutek® Thoraflex™ Hybrid graft (Vascutek Ltd, Scotland, UK), which consists of a distal en,dograft sealed to a proximal four-branched Vascutek Gelweave™ Vascutek Ltd, Scotland, UK) and incorporated sewing collar. While open surgery continues to be a component of complex aortic arch aneurysms, the development of hybrid devices that can bridge the gap between open and endovascular surgery will continue to flourish.