Lower extremity revascularization with a stem cell matrix; initial clinical and histologic results
Andrew J. Soo Hoo, MD1, Kendal Endicott, MD2, Arnold Schwartz, MD2, Josh Adams, MD3, Richard Neville, MD1.
1INOVA Fairfax Medical Center, Falls Church, VA, USA, 2George Washington Hospital, Washington, DC, USA, 3Medical University of South Carolina, Charleston, SC, USA.
OBJECTIVES: Failure of lower extremity revascularization (LE) often results from the tissue reparative response leading to myointimal hyperplasia. An extracellular matrix substrate (ECM) derived from porcine small intestinal submucosa has shown promise as a scaffold to foster a stem cell mediated, regenerative remodeling of vascular tissue. We present clinical results with available histologic analysis using this ECM material for LE revascularization.
METHODS: Over a 24-month period, 103 LE vascular reconstructions were performed with an ECM vascular patch (Cormatrix, Roswell, GA). A retrospective analysis of prospectively collected data was performed with institutional IRB approval. Patient demographics included; DM (33%), renal failure (13%), and active tobacco use (31%). Indications for intervention were claudication (39%), rest pain (37%), tissue loss (16%), and graft restenosis (8%). Procedures included ilio-femoral thromboendarterectomy with patch angioplasty (63), profundaplasty (16), distal vein patch bypass (n=13), graft revision (9), and femoral pseudoaneurysm repair (2). Follow-up evaluation involved clinical exam, ABI and duplex ultrasound in all patients with selective CTA and arteriography.
RESULTS: The follow-up interval ranged from one to fifteen months with a mean of 7.5 months. There were no acute episodes of thrombosis or infection with one suture line dehiscence. Late complications included; graft thrombosis (3), anastomotic pseudoaneurysm formation (2), wound dehiscence (5), groin infection (5). There were five unrelated mortalities. Analysis of the ECM reparative response was possible from anastomotic tissue harvested during revision of two thrombosed bypass grafts (4 and 6 months). Histologic analysis demonstrated a neo-intima, macrophages and fibroblasts with endothelial cell migration, a media, vascular smooth muscle with a mild inflammatory response, sparse collagen fibers, prominent elastic fibers, and an outer adventitial layer with inflammatory characteristics but granulation tissue present.
CONCLUSIONS: Initial clinical outcomes for LE revascularization performed with an ECM material demonstrated encouraging acute and chronic results. Histologic analysis demonstrates formation of a neo-intima, media, and adventitia with favorable regenerative characteristics; thereby showing promise to generate favorable vascular healing and potentially minimize the hyperplastic reparative response in select revascularization procedures.
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