Time-dependently slow-released multiple-drug eluting external sheath for efficient long-term inhibition of saphenous vein graft failure.

Coronary artery bypass graft surgery (CABG) is an effective therapeutic method for coronary artery disease. Great saphenous vein is the predominant graft due to the accessibility, sufficient length and suitable size matching with coronary artery. However, saphenous vein graft failure (SVGF) always restrict the long-term success of CABG. In this study, a complex external sheath was prepared using multi-channel and coaxial electrospinning techniques. The sheath can slowly release fasudil dihydrochloride (100% at 63 days), everolimus (100% at 84 days) and simvastatin (31.87 ± 1.55% at 20 weeks) to match the time-dependent pathological changes of SVGF through a cocktail pattern. In 16 weeks animal experiments, drug loaded sheath exhibited significantly greater efficacy in inhibiting neointima formation and ensuring graft patency than bare vein graft and empty sheath. Under the joint action of mechanical restriction of the sheath and the synergistic effect of loaded fasudil dihydrochloride and everolimus, the endothelium damage and the proliferation/migration of smooth muscle cells, which were thought to be the early cause of graft failure, could be efficiently alleviated. Moreover, the long-term patency could be expected due to the inhibition of atherosclerosis by the sustained released simvastatin.