Intraoperative Aortic Dissection During Aortic Root Replacement in a Loeys–Dietz Syndrome Type III Patient: A Case Report

Abstract Background Intraoperative aortic dissection during cardiac surgery is a rare but critical complication. At present, no strategies have been developed to prevent it. Here, we report a case of intraoperative aortic dissection during aortic root replacement in a patient with Loeys–Dietz syndrome type III. Case presentation A 60-year-old man was admitted to the hospital for Stanford type B acute aortic dissection and given conservative treatment. The patient was found to have aortic root dilatation and severe aortic regurgitation. Therefore, elective Bentall procedure was performed. Postoperative computed tomography revealed new Stanford type A aortic dissection that may have developed during surgery. The patient was given conservative treatment and was successfully discharged to home at postoperative day 34. A genetic test revealed an unreported SMAD3 frameshift mutation (c.742_749dup, p. Gln252ThrfsTer7), and the patient was diagnosed with Loeys–Dietz syndrome type III. Conclusion In patients with connective tissue disorder, aortic manipulations may become the cause of critical complications. Avoiding the use of invasive techniques, such as cannulation and cross-clamping, and implementing treatment strategies such as open distal anastomosis can prevent these complications and may be useful treatment modalities.