Effects of rivaroxaban on intimal hyperplasia and smooth muscle cell proliferation at the carotid artery anastomosis site in rabbits

Objective: This study aimed to assess the effect of new generation oral, direct factor Xa inhibitor rivaroxaban on intimal hyperplasia and smooth muscle cell proliferation at the carotid artery anastomosis site of rabbits.
Methods: In total, 14 New Zealand male rabbits weighing 3–3.5 kg were randomized into two groups. Group A (7 rabbits) served as the control group and received no medication. Rivaroxaban was perorally administered to group B (7 rabbits) mg/kg/day for 28 days. Following anesthesia induction, carotid arteries were dissected through a right neck incision. following heparinization at 100 IU/kg, vertical full thickness arteriotomy was performed, then was repaired continuously with 8-0 polypropylene. At day 28, all rabbits were sacrificed and the anastomosed carotid artery segments were analyzed using light microcopy. Hematoxylin–eosin and Masson’s trichrome stained images were analyzed using a digital image analysis program, and lumen diameter, lumen area, intimal and medial thickness, and media areas were measured and results were compared.
Results: In the serial sections, the average lumen diameter of group B was higher than that of group A (p=0.001). The lumen areas of group B were also higher than those of group A (p=0.004). The intimal thickness of group B was lower than that of group A (p=0.001). When the section series were evaluated for media thickness, the thickness of group B was lesser than that of group A; the difference was statistically significant (p=0.002).
Conclusion: This study may imply a potential midterm benefit of rivaroxaban following arterial anastomosis by reducing intimal proliferation and restenosis.