RS09 - Hyperoxygenation of Visceral Arteries During Open Thoracoabdominal Aortic Aneurysm Repair: A Propensity Matched Pilot Study

Objectives: Open thoracoabdominal aortic aneurysm (TAAA) repair is independently associated with substantial postoperative complications—including operative death, paraplegia, and renal failure—despite advances in organ protection. Established protective strategies during repair include the use of hypothermic circulatory arrest, left heart bypass, dedicated renal perfusion circuits relying on cold crystalloid perfusates, and selective visceral perfusion using nonoxygenated blood of varying temperature. We speculated that providing warm hyperoxygenated blood to visceral arteries would improve early patient outcomes; we share our pilot study of this approach with matched comparison.

Methods: We analyzed 696 contemporary TAAA repairs performed within a single practice from 2010 to 2024, including our piloted approach (2023-2024). We compared repairs using standard visceral perfusion techniques (n=649) to those using a hyperoxygenated blood perfusion circuit (HBPC; n=47). HBPC utilizes either left heart bypass or partial cardiopulmonary bypass with an oxygenator and heat exchanger added to the perfusion circuit (Figure). This method delivers hyperoxygenated blood at an arterial oxygen partial pressure (PaO2) of 500 mmHg and relies on minimal anticoagulation (a targeted activated clotting time of ~250 seconds). A 3:1 propensity score matching was performed to control for age, comorbidities, extent of TAAA repair, and other factors.

Results: Repairs using HBPC had younger patients, with higher rates of genetic disorders and aortic dissection, more frequently underwent extent II TAAA repair, and more commonly received selective visceral perfusion than standard repairs (Table). The standard group was matched 3:1 (n=123) with the hyperoxygenation group (n=44) with few differences between groups afterwards. The hyperoxygenation group had fewer units of platelets (4 [2-7] vs 10 [8-16], P<.001) and cryoprecipitate (3 [2-10] vs 20 [20-30], P<.001) transfused. Patients who received hyperoxygenation had fewer cardiac complications (13% vs 40% [P <.001], including atrial arrhythmia (4% vs 24% [P=.003]); they also trended (P>.05) towards lower rates of operative death (6% vs 10%), persistent paraplegia (0 vs 4%), persistent renal failure (2% vs 12%), respiratory failure necessitating tracheostomy (6% vs 13%), mesenteric ischemia (0 vs 2%) and bleeding leading to reoperation (0 vs 5%).

Conclusions: Providing hyperoxygenated blood during TAAA repair reduced transfusions and resulted in lowered rates of postoperative cardiac complications; pilot data suggests larger studies may find reduced rates of operative mortality, paraplegia, renal failure, respiratory failure, mesenteric ischemia, and bleeding complications. Additional study will be needed to better understand the risks and benefits of the emerging use of HBPCs.