TEVAR+KNICKERBOCKER Eliminates Retrograde False Lumen Perfusion and Reduces Aneurysm Size in Chronic Type B Aortic Dissection
Woodrow J Farrington, William D Jordan, Yazan M Duwayri, Andy Dong, James M Chang, William Brent Keeling, Bradley Leshnower
Emory University, Atlanta, GA
INTRODUCTION: Thoracic endovascular aortic repair (TEVAR) is a well-accepted alternative to open surgery for patients with descending/thoracoabdominal aortic aneurysms secondary to chronic type B aortic dissection (CTBAD). However, the efficacy of TEVAR for CTBAD is limited by persistent retrograde thoracic false lumen perfusion. To achieve a distal seal and eliminate retrograde false lumen perfusion with TEVAR, the technique of balloon septal fenestration (Knickerbocker) has been described. This study examines the safety and efficacy of TEVAR+ Knickerbocker for CTBAD.
METHODS: A retrospective analysis of a U.S. academic aortic database identified 48 patients from 2012-2022 who underwent TEVAR for chronic TBAD. Of this cohort, 29 patients underwent Knickerbocker as an adjunct to TEVAR. Patients with an aortic diameter > 43 mm at the level of the celiac artery were excluded from this study. All patients underwent TEVAR from the left subclavian artery to the celiac artery. Balloon septal fenestration was performed over a 5 cm length of aorta at a location 3-5 cm proximal to the celiac artery following stent graft deployment. Patient demographics and outcomes were analyzed, and aortic centerline analysis of pre-and postoperative computed tomography scans using a Tera Recon Aquarius iNtuition three-dimensional workstation was performed to measure true and false lumen and overall aortic diameters, and the status of false lumen thrombosis.
RESULTS: The mean age was 59±9 years and 14% were female. Fifteen (52%) patients had residual CTBAD following Type A and the remaining 14 (48%) patients were “De Novo” TBAD. No patients received a CSF drain placement. The mean number of stent grafts was 2, and the length of stent graft coverage was 277+43 mm. There was no intraoperative mortality but 2 in-hospital deaths secondary to retrograde type A dissection and aneurysm rupture. There was no incidence of stroke, paraplegia, or renal failure. The mean length of imaging follow-up was 25±21 months. Proximal to the Knickerbocker segment, retrograde false lumen perfusion was eliminated in 100% of patients, resulting in complete false lumen thrombosis in 22 (81%) patients. Persistent false lumen flow secondary to intercostal arteries resulting in partial false lumen thrombosis were present in 5 (19%) patients. TEVAR+Knickerbocker resulted in a decrease in maximum thoracic aortic diameter (Pre 62+10mm vs Post 58±10 mm, p=0.04), and significant expansion of the true lumen (p<0.05) at all levels of the descending thoracic aorta (Table).
CONCLUSIONS:Knickerbocker as an adjunct to TEVAR is a safe and effective approach for select patients with CTBAD. In this early analysis, the addition of balloon septal fenestration produced a distal aortic seal, eliminated retrograde thoracic false lumen perfusion, decreased thoracic aortic diameters and promoted positive aortic remodeling. Longer-term follow-up is necessary to determine the durability of this technique. 
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