Biogenesis and etiology of distal anastomotic intimal hyperplasia.

Distal anastomotic intimal hyperplasia (DAIH) is a viable biologic entity composed of a multi-interlamination of cells and extracellular matrix. Cell transformation and orientation characterize the dynamic process of this 80-130 cell structure. Morphologic similarity exists in the cytoarchitecture of DAIH irrespective of the graft material. Compliance mismatch is not a cause of DAIH, but it enhances the formation. The geometry of the unnatural distal end-to-side anastomosis is predisposed to turbulent flow and DAIH formation. Prevention of DAIH is dependent on pharmacologic suppression of subendothelial smooth muscle proliferation and synthesis of extracellular matrix.