Intraoperative Aortic Dissection during Lung Transplantation in a Patient with Alpha-1 Antitrypsin Deficiency.

Alpha-1 antitrypsin deficiency (AATD) is an inherited disorder affecting the lung, liver, and rarely skin. The most frequent features of AATD consist of chronic lung disorders related to protease-antiprotease imbalance in the respiratory system, to which lung transplantation is frequently indicated. We describe a case of aortic dissection in a 55-year-old male who underwent left single lung transplantation for respiratory failure due to AATD-related emphysema. Extracorporeal membrane oxygenation (ECMO) was indicated during the procedure, and an arterial cannula was placed into the descending aorta and a venous cannula was placed into the right femoral vein. Bronchial and vascular anastomoses were finished without any problems and ECMO was weaned off However, transesophageal echocardiography carried out at the end of the operation showed a dissected descending aorta. Alpha-1 antitrypsin (AAT) is the major serum inhibitor of seine proteinases, which enzymatically destroys collagen and elastin. Degeneration of connective tissues, in particular elastic tissues, is established in AATD, and decreased stiffness of the aorta due to degradation of elastic fibers has also been reported in AATD. In this patient, reduced AAT activity might have boosted the enzymatic destruction of his arterial walls, leading to enhanced vulnerability to aortic dissections.