Composite grafts and implantable medical devices include a polymeric layer and a non-porous silicone coating that includes a two-part dispersion of silicone material in an organic solvent. The polymeric layer has a first surface and a second surface, where the first surface and the second surface are positioned on opposite sides of the polymeric layer, and where the first surface is the blood-contacting surface and the second surface is the tissue-contacting surface. The non-porous silicone coating includes a two-part dispersion of silicone material in an organic solvent. The silicone coating is disposed on at least the first surface of the polymeric layer such that the at least first surface or a portion thereof has a substantially reduced permeability or is entirely impermeable. The coating does not substantially increase the thickness of the medical device and reduces the surface friction of the medical device while making the graft layer impermeable to fluids. Methods of making the implantable medical device and methods of repairing or treating a defective vessel in an individual, including treating AAA and thoracic aneurysm, are also provided.
