Aneurysmal expansion of the visceral patch after thoracoabdominal aortic replacement: An argument for limiting patch size?

Introduction: Thoracoabdominal aortic replacement requires visceral vessel revascularization and is usually performed with Crawford's inclusion technique or a large Carrel patch. This segment of retained native aorta may be prone to recurrent aneurysmal disease. We reviewed our experience with patients in whom aneurysmal expansion of the visceral patch was detected. Methods: The records of 107 patients undergoing thoracoabdominal aortic replacement operations performed or followed up at the Johns Hopkins Hospital between 1992 and 2000 were reviewed. All patients had visceral patches created for type II, III, or IV aneurysms. Visceral patches were considered aneurysmal if the maximal diameter of the aortic prosthesis and patch was 4.0 cm or more. Results: Patch aneurysmal expansion (mean, 5.4 cm) was detected in eight patients (7.5%). All three women had connective tissue disorders (mean age, 36 years), and all five men had atherosclerotic disease (mean age, 73 years). Five patients were symptom free with their aneurysms detected by surveillance computed tomography scans; two patients had back pain prompting computed tomography scans; and one patient presented with an emergency patch rupture. Aneurysmal patches were successfully revised in three patients. Two patients died in the operating room, and three patch aneurysms (<5 cm) are still being observed. The mean time to the detection of aneurysmal expansion was 6.5 years after the original operation. Therapy consisted of replacement of a segment of the thoracoabdominal aortic graft and refashioning a smaller patch, including only the visceral artery orifices with separate attachment of the left and possibly right renal artery. Conclusions Although Crawford's inclusion method of visceral patch construction is generally durable, patients undergoing thoracoabdominal aortic replacement require yearly surveillance for the detection of aneurysmal expansion of the visceral patch. We recommend limiting visceral patch size at the original operation by routinely excluding the orifice of the left renal artery. Patients at high risk for recurrent aneurysmal expansion, such as those with connective tissue disorders, will benefit from creating small visceral patches and possibly implanting both renal arteries separately during the original operation.