Outcomes of Arterial Bypass With the Human Acellular Vessel for Chronic Limb-Threatening Ischemia Performed Under the FDA Expanded Access Program.

OBJECTIVE: To report outcomes of the human acellular vessel (HAV) implanted for limb salvage through the Food and Drug Administration (FDA) Expanded Access Program for patients with chronic limb-threatening ischemia with no autologous conduit. METHODS: The HAV is a bioengineered vascular conduit designed with human vascular smooth muscle cells. The product is under regulatory study. From April 2019 to November 2021, the HAV was implanted in 14 patients (12 men; mean age, 62±14 years) at 3 US centers. Each case was performed with a single-use investigational new drug Expanded Access Program issued by the FDA. Institutional review board approval was obtained; technical and clinical outcomes were analyzed. RESULTS: A single 6-mm-diameter (40-cm-long) HAV was implanted in 9 patients; 5 patients required 2 HAVs sewn together as a composite. Technical success was 100%. Median follow-up was 12 (range, 1 to 41) months. Primary and secondary patency rates were 72% and 81% at 12 months; assisted primary patency was attained in 4 patients. Amputation-free survival was 93% at 6 months and 77% at 12 months. All patients with a patent HAV experienced clinical improvement with no HAV-related infections or adverse events. There were 4 deaths in the cohort, late mortality unrelated to the HAV. CONCLUSION: The HAV is a safe and effective "off-the-shelf" biologic conduit. This experience from the FDA Expanded Access Program in this population with few alternative limb salvage options will help guide regulatory deliberations for patients with lower extremity ischemia and no autologous bypass conduit options.

Preliminary Experience With the Human Acellular Vessel: A Descriptive Case Series Detailing Early Use of a Bioengineered Blood Vessel for Arterial Repair.

BACKGROUND: An infection-resistant, immediately available conduit for trauma and urgent vascular reconstruction remains a critical need for successful limb salvage. While autologous vein remains the gold standard, vein-limited patients and size mismatch are common issues. The Human Acellular Vessel (HAV) (Humacyte, Inc., Durham, NC) is a bioengineered conduit with off-the-shelf availability and resistance to infection, ideal characteristics for patients with challenging revascularization scenarios. This report describes HAV implantation in patients with complex limb-threatening ischemia and limited conduit options who may have otherwise faced limb loss. METHODS: The Food and Drug Administration (FDA) expanded-access program was used to allow urgent implantation of the HAV for arterial reconstruction. Electronic medical records were reviewed with extraction of relevant data including patient demographics, surgical implantation, patency, infectious complications, and mortality. RESULTS: The HAV was implanted in 8 patients requiring vascular reconstruction. Graft or soft tissue infection was present in 2 patients. One patient with severe penetrating pelvic injury had 4 HAV placed to repair bilateral external iliac artery and vein injuries. There was 1 technical failure due to poor outflow, 2 patients died unrelated to HAV use, and 5 lower extremity bypasses maintained patency at an average of 11.4 months (range: 4-20 months). No HAV infectious complications were identified. CONCLUSIONS: This report is the first United States series describing early outcomes using the HAV under the FDA expanded-access program for urgent vascular reconstruction. The HAV demonstrates resistance to infection, reliable patency, and offers surgeons an immediate option when confronted with complex revascularization scenarios. Assessment of long-term outcomes will be important for future studies.