Type A Dissection at Subthreshold Dimensions in Loeys-Dietz Syndrome: When Guideline-Directed Surveillance Is Not Enough.

BACKGROUND: Loeys-Dietz syndrome (LDS) is a heritable connective tissue disorder associated with aggressive aortic disease. CASE SUMMARY: A 45-year-old woman with a family history of aortic dissection and a TGFB2 variant associated with LDS underwent surveillance demonstrating an aortic root diameter of 3.7 to 4.0 cm. Five months later, she developed an acute Stanford type A aortic dissection requiring emergent Bentall aortic root and hemiarch replacement. Her postoperative course was complicated by graft-adjacent infection, giant graft-adjacent pseudoaneurysms requiring redo aortic root replacement with Cabrol coronary reconstruction, and inferior ST-segment elevation myocardial infarction caused by thrombotic occlusion of the right coronary graft. DISCUSSION: This case illustrates catastrophic vascular progression despite guideline-directed surveillance and highlights the challenges of long-term management after aortic root reconstruction. TAKE-HOME MESSAGES: Patients with LDS may experience life-threatening aortic complications despite subthreshold aortic dimensions. Improved individualized risk stratification beyond maximal aortic diameter is needed to optimize prophylactic intervention.