La tecnica del "frozen elephant trunk" nel trattamento delle lesioni complesse dell'aorta toracica

The treatment of patients with extensive disease of the thoracic aorta represents a formidable challenge for the cardiovascular surgeon. The beginning of thoracic aortic endovascular aortic arch repair has promoted the development of different hybrid approaches as the frozen elephant trunk (FET) strategy, which includes classic arch replacement and antegrade stenting of the descending thoracic aorta. It represents an interesting approach for patients with extensive disease of the thoracic aorta, and its application has significantly increased over recent years. Our indications for this technique include degenerative aneurysms of the aortic arch and acute and chronic aortic dissections. For many years, the conventional surgical approach for the treatment of complex lesions of the thoracic aorta considered the two-stage elephant trunk technique. However, it is still associated with high mortality and morbidity with only half of the patients who underwent the second stage of the operation. These shortcomings can be attenuated by the FET technique which allows to replace in one stage-approach all the thoracic aorta. Anyway, the main problem of the FET remains the paraplegia. Key points during this surgery are represented by an accurate preoperative assessment of the aortic anatomy by angiography computed tomography scan, the employment of reliable methods of organ protection and of effective surgical techniques and strategies. Antegrade selective cerebral perfusion represents a fundamental tool for cerebral protection. In type A chronic aortic dissection utilizing FET technique, it is possible to use the stent-graft as landing-zone for secondary endovascular extension in order to cover the re-entry tears at the distal descending thoracic aorta. Despite the satisfactory short- and mid-term results, longer-term studies are needed to show the benefits of the FET technique versus other types of management.