Effects of nilvadipine, a calcium antagonist, on intimal thickness of vascular grafting in cholesterol-fed rabbits

Abstract

The effects of nilvadipine on intimal thickness in expanded poly-tetrafluoroethylene grafts were examined in 21 rabbits undergoing infrarenal aorta reconstruction. Seven rabbits received commercial rabbit chow (control group), seven, a regular diet supplemented with 1% cholesterol (cholesterol group); and seven, the cholesterol diet with 98.9% pure nilvadipine 1 mg/kg/day (nilvadipine group). Grafts were harvested 3 months after surgery for histologic examination. Intimal thickness at the proximal and distal anastomosis was, respectively, 225±76 and 273±110 m in the control group, 525±236 and 600±250 m in the cholesterol group, and 284±94 and 241±86 m in the nilvadipine group. Intimal thickness in the cholesterol group was significantly greater than in the nilvadipine group (p<0.01). The smooth muscle cell values in the intima at the proximal and distal anastomosis were, respectively, 10.6±3.6 and 12.6±3.2 %Extinction (%E) in the control group, 15.5±4.0 and 16.1±4.5 %E in the cholesterol group, and 9.1±3.1 and 9.6±2.1 %E in the nilvadipine group. The smooth muscle cell value in the intima of the cholesterol group was greater than that of the nilvadipine group (p<0.01). These data suggest that nilvadipine significantly reduces the degree of intimal thickness in expanded polytetrafluoroethylene grafts in cholesterol-fed rabbits, and that this effect is due to inhibition of smooth muscle cell migration and proliferation.