495 STANFORD TYPE-A ACUTE AORTIC DISSECTION: A LIFE-THREATENING EMERGENCY
Authors: Pietro Spissu Paolo Marco , Pittau Roberta , Angius Simone , Raffo Alessandro , Massidda Elisabetta , Atzeri Valentina , Falchi Susanna , Dessalvi Christian Cadeddu , Cirio Emiliano Maria , Manconi Manlio 
Published: December 2022

Abstract
Stanford type A acute aortic dissection is a life-threatening cardiological emergency which occurs when an intimal tear in the ascending aorta creates a false lumen within the media refilled by pulsatile blood flow. Some investigators report the immediate mortality to be as high as 40%. Both congenital and acquired conditions can be the cause of an instability of the aortic wall that can lead to dissection. Diagnosis, which requires a high level of suspicion, is usually made with aortic angio-CT.
The case we present involves a 62-years old man with a history of hypertension, parossistic atrial fibrillation and familiarity for type B aortic dissection. He called 911 complaining of sudden onset dorsal pain that then irradiated anteriorly to the chest and upwardly to the neck, associated with profuse sweating. An EKG performed at patient's home showed ST elevation in V1 meaningful of right ventricle infarction. Arrived at the Emergency Ward of our hospital arterial pressure was 80/50 mmHg with an HR of 44 bpm. Rapidly, because of the suspect of aortic dissection, an angio-TC was performed showing a type A aortic dissection starting from Valsalva sinuses and extending till common right iliac artery and external left iliac artery including left subclavian artery ostium. The left renal artery originated from false lumen, but patient had a so-called horseshoe kidney.
For this reason, the patient was transferred immediately to the cardiac surgery room with indication for Bentall procedure (aortic valve plus ascending aorta replacement with home-made valved Dacron tubular prosthesis), aortic arch repair with supra-aortic vessels debranching and reimplantation and saphenous graft on right coronary artery. During surgery was evident that intimal tear was located immediately after left common carotid artery and right coronary sinus was involved in the dissection thus explaining why right ventricle free wall was visibly hypokinetic. Surgery went without complication and patient entered ICU with circulation supported by a low dose of epinephrine and norepinephrine; respiratory weaning took place in day 1 post-operation. The following days patient developed circumferential pericardial effusion which needed percutaneous subxiphoid drainage despite not being hemodynamically relevant. Echocardiography before discharge showed aortic valve prosthesis and ascending aorta prosthesis well positioned, bi-ventricular normal dimensions and function and organized residual pericardial effusion with fibrin strands.
Stanford type A is the most common type of aortic dissection and requires immediate surgical treatment. The Bentall procedure is considered the gold standard for patients needing ascending aorta plus aortic valve replacement.
Even though mortality rates remain high for Stanford type A acute aortic dissection, this case shows how is possible to survive from such a life-threatening condition if a prompt and correct diagnosis is made and thanks to flawless surgical operation.