Frozen Elephant Trunk
When is this procedure indicated?
Aneurysmal dilatation of the aortic arch with extension distal to the origin of the left subclavian artery at the level of the descending thoracic aorta, the treatment of which is performed at a later time. Aortic dissection.
How is it performed?
Median sternotomy is performed in extracorporeal circulation. Cerebral protection is achieved by selective cerebral perfusion.
Systemic heparinization is performed and a transfemoral guiding catheter is placed in the descending thoracic aorta. Under transesophageal echocardiographic control, the correct localization of the catheter in true lumen is verified in patients with aortic dissection.
Extracorporeal circulation is initiated by cannulation of the axillary artery, ascending aorta, femoral artery, this aortic prosthesis or anonymous trunk for arterial return, and the right atrium or the two hollow veins for venous drainage. Cooling is performed, at a nasopharyngeal temperature of 26°C, circulatory arrest is established, and bilateral anterograde cerebral perfusion is performed by cannulation of the epiaortic vessels. Myocardial protection is achieved by anterograde or retrograde infusion of crystalloid cardioplegic solution. The aortic arch is recentated and the distal aortic stump is prepared. Specifically, in patients with aortic dissection, the false lumen is obliterated by application of 4 U-shaped stitches with pledget. The hybrid prosthesis delivery system is inserted anterograde into descending thoracic aorta on the previously placed guide line. The endoprosthesis is relaxed under direct vision and then anastomosed in its proximal part in Dacron to the previously prepared distal aortic stump.
A short period of reperfusion (10-12 min) of the thoracoabdominal aorta is initiated to verify hemostasis at the site of anastomosis and prepare the epiaortic vessels for subsequent reimplantation ("en bloc" or separate with trifurcated prosthesis) performed in a second short period of circulatory arrest. Circulation is then permanently restarted along with patient warming. Aortic reconstruction is completed by packing the proximal anastomosis.
The postoperative clinical course lasts 20 days on average and includes a period of observation in intensive care until adequate respiratory weaning and hemodynamic stability. Daily clinical and instrumental monitoring. Rehabilitation cycle.
Cardiac and respiratory complications. Aortic dissection of the ascending aorta (type A), sometimes involving the valvular plane and the ostium of the coronary arteries. This event is burdened by a very high risk of death. Bleeding of such entity as to require surgical revision and/or conditioning cardiac tamponade (exitus). Hemomediastinum. Mediastinitis requiring drainage, including surgical drainage, formation of fistulous bronchial and esophageal traps, local and generalized sepsis. These events carry a very high risk of death and require emergency surgical measures. Chylothorax with possible need for prolonged artificial feeding and need for percutaneous or surgical drainage. Renal failure with risk of dialysis, even definitive; peripheral embolization (limbs, viscera); lower and upper limb ischemia with risk of amputation; intestinal ischemia with need for extensive ileal and colic resection, colostomy. Cerebral stroke, both ischemic and hemorrhagic, both of the anterior and posterior circulation with hemiplegia, aphasia, dyslexia, disorders of consciousness, balance disorders, visual disturbances up to blindness, even definitive and able to determine total disability. In case of hemorrhagic stroke need of drainage by craniotomy. Phonation disorders (including recurrent paralysis) and swallowing disorders, even permanent, which can lead to inability to take liquids and solids and the need for prolonged artificial feeding.
Postoperative bleeding, even massive, with need for revision, capable of conditioning hemorrhagic shock and exitus; multi-organ failure with exitus. Infection of prostheses, even after some time. Wound dehiscence/infection with possibility of infection. Ineffective exclusion of the aneurysm/formation of endoleaks with expansion of the same over time and subsequent need for surgery.