Inhibition of experimental neointimal hyperplasia by recombinant human thrombomodulin coated ePTFE stent grafts

Angiographic digital images of the left carotid artery. A, Digital subtraction image of the balloon injury site 2 weeks after angioplasty, prior to stent graft deployment. B and C, Unsubstracted images of a 6 × 25 mm ePTFE covered stent graft deployed in the left common carotid artery at the balloon-injured site.

SEM and back scatter electron emission image (BSI). A, SEM of normal ePTFE. B, SEM of rTM molecules bound to ePTFE. C, BSI demonstrates silver tagged rTM molecules (white particles); D, X-ray microanalysis shows the presence of Ag bonded rTM molecules.

Optical density of activated protein C. The functional presence of rTM on the luminal surface of the rTM coated stent graft and the whole rTM coated stent graft was evaluated with activated protein C. The whole structure of rTM-coated stent graft expressed significantly more activated protein C than the luminal surface alone.

Gross photographs of the luminal surface of ePTFE covered stent grafts explanted at 4 weeks. A, The rTM-coated ePTFE stent graft is covered with a smooth, glistening white thin layer with minimal surface deposition. B, The uncoated ePTFE stent graft is covered with an irregular thick yellow-brown layer with scattered blood clots.

Light microscopic images of a representative transverse section of uncoated and rTM-coated ePTFE stent graft 4 weeks after deployment in the left carotid artery. Uncoated ePTFE covered stent graft. A, Proximal. B, Middle. C, Distal. rTM-coated ePTFE covered stent graft. D, Proximal. E, Middle. F, Distal.

Neointima area (A) and intima to media (I/M) ratio (B) of rTM coated and uncoated stent grafts.

Luminal area of the rTM-coated and uncoated ePTFE stent grafts. The mean luminal area of each segment of the rTM-coated stent graft was larger in each segment compared with uncoated stent graft with an overall luminal area difference of 1.176 mm² (P < .05).