The frozen elephant trunk procedure: indications, outcomes and future directions

The treatment of complex multi-segment disease concomitantly affecting the aortic arch and descending thoracic aorta is technically challenging. Until the 1990s, such extensive pathology was addressed by median sternotomy for aortic arch replacement followed by a traumatic thoraco-abdominal incision for reconstruction of the descending aorta as a single- or two-stage procedure. The advent of the conventional elephant trunk procedure by Borst in 1983 simplified the second-stage of this procedure by eliminating the need for clamping of the descending thoracic aorta. However, graft-related complications and the considerable inter-stage mortality were significant limitations associated with the conventional elephant trunk procedure. The emergence of endovascular technology and availability of dedicated arch prostheses culminated in a major paradigm change with the introduction of the frozen elephant trunk (FET) concept by Kato and colleagues in the mid-1990s. This one-stage procedure permits concurrent total aortic arch replacement with antegrade delivery of a descending aortic stent-graft which itself functions as a proximal landing zone to facilitate prospective endovascular intervention to treat residual or de novo disease in the more distal aorta. The frozen elephant technique has been applied extensively in acute aortic dissection to restore true lumen patency, occlude descending aortic intimal tears and promote false lumen thrombosis, as well as for chronic degenerative arch aneurysms. The Thoraflex Hybrid and E-vita Open are the two most common commercially available hybrid FET prostheses. This review aims to discuss the development, indications, surgical technique, currently available prostheses, clinical outcomes and future directions regarding the FET procedure.