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.