The Anatomic Spectrum of Malperfusion Syndromes in Aortic Dissection

Purpose: End organ ischemia is one of the most feared complications of aortic dissection, complicating 15-40% of all cases. Malperfusion may variably manifest in nearly all vascular distributions, contributing to dismal perioperative outcomes. In this study, we characterize the anatomic spectrum of branch artery compromise in aortic dissection and describe its management.

Materials and Methods: A total of 599 consecutive patients with 602 cases of aortic dissections, including 450 males (75%) and 149 females (25%) with acute type A (41.0%), chronic Type A (8.5%), acute type B (40.7%) and chronic type B (9.8%) dissections, were referred for evaluation and treatment of branch artery malperfusion between February 1996 and December 2022. Investigation of the aorta true lumen (TL), false lumen (FL), and branch vessels was performed using angiography, intravascular ultrasound and manometry to guide intervention of the obstruction with fenestration, stenting, exclusion of the entry tear by thoracic endovascular aortic repair, or other branch artery intervention including thrombectomy or thrombolysis. Malperfusion was defined as a pressure gradient between the ascending aorta and branch artery ≥15 mm Hg.

Results: Branch artery origins were categorized by their perfusion from the TL, FL, or both, with or without a reentry tear. The mechanism of obstruction (dynamic, static, combined, or complicated by thrombosis, respectively) was characterized in the mesenteric (22%, 9%, 9%, 10%), right (20%, 7%, 3%, 8%) and left renal (7%, 12%, 8%, 9%), right (10%, 10%, 10%, 13%) and left iliofemoral (9%, 10%, 11%, 10%) arterial distributions, and was treated by fenestration, endograft, or bare metal stents. Notably, thrombus in the TL (9%), FL (29%) or both lumina (9%) was found to further compromise branch vessel perfusion. TL thrombus in the mesenteric (5%), right (2%) and left (3%) renal, and right (8%) and left (5%) iliofemoral distributions necessitated meticulous catheter-directed thrombolysis or mechanical thrombectomy in 69 patients (36 type A, 33 type B), before addressing the underlying obstruction, to allow catheter access past precarious thrombus or to prevent catastrophic thromboembolic events from premature flow restoration.

Conclusion: A comprehensive understanding of the anatomic, radiologic, and hemodynamic spectrum of branch vessel compromise after aortic dissection can provide a rational guide for treatment of malperfusion syndromes. TL thrombus formation complicates near 10% of cases and must be treated appropriately before restoring TL flow.