Background: The current study investigated the effect of verapamil on the d
evelopment of intimal hyperplasia (IH) using a sheep model.
Methods: A gelatin-sealed Dacron patch graft was implanted into the left co
mmon carotid artery in 40 adult Merino sheep. Sheep were then randomly allo
cated to four groups. Group 1 were controls given no treatment (n = 10). Gr
oups 2-4 were treated with intravenous verapamil 0.5 mg/kg per day in two d
ivided doses for different lengths of time. Group 2 (n = 10) received treat
ment for 1 week, group 3 (n = 10) received treatment for 2 weeks and group
4 (n = 10) received treatment for 4 weeks. All sheep were killed at 4 weeks
and the grafted segments of artery were harvested for IH assessment by an
image analysis system.
Results: The IH index from the three groups treated with verapamil was sign
ificantly less than that of the control (group 1, 0.287 +/- 0.077; group 2,
0.205 +/- 0.064, P < 0.05; group 3, 0.193 +/- 0.059, P < 0.01; group 4, 0.
171 +/- 0.036, P < 0.01).
Conclusion: The present study suggests that verapamil inhibits the developm
ent of IH even when treatment is given for only 1 week.