COMPARISON OF VASCULAR WALL CHANGES TO RAPAMYCIN (SIROLIMUS) VERSUS BARE METAL STENTS IN BALLOON INJURED EXTERNAL ILIAC ARTERIES OF RABBIT
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Date
2009
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AAU, Anand
Abstract
Cardiovascular medicine is changing rapidly with the development, testing and introduction of new diagnostic and therapeutic methods. Drug-eluting stents (DES) have been shown to improve outcomes among patients undergoing percutaneous coronary intervention by significantly reducing restenosis rates. The long-term incremental risks, benefits and costs of DESs have not yet been optimally evaluated in a broad spectrum of patient and lesion cohorts and animal models. Twenty- one Sirolimus Eluting Stents (SES) were compared with 21 Bare Metal Stents (BMS; control) by implantation into left and right balloon injured external iliac arteries, respectively of 21 healthy New Zealand White (NZW) rabbits. Under Ketamine-Diazepam-Xylazine anaesthesia and fluoroscopic guidance using 3mm coronary balloon catheter, FlexyRap (SES) and FlexyStar (BMS) stents (3 mm diameter and 13 mm long) were deployed. Stents were successfully deployed at 6 atm balloon dilation pressure in prior balloon injured iliac arteries. No anti-coagulant therapy was given in any animal. There was no vascular occlusion in hind limbs of all stented vessels. Various histopathological parameters were assessed after rabbits were sacrificed at 7, 14 and 21 days (7 rabbits in each group). Each stented vessel was subjected to resin embedding technique and methyl methacrylate sections were obtained using tungsten carbide knife for Haematoxylin-Eosin and Martius, Scarlet, Blue staining. On histological examination, SES showed marked reduction in almost all histological parameters. Morphometric analysis showed that arteries with SES had a larger luminal area (p<0.0001), lower intimal (p<0.001) and medial (p<0.001) thickness and lower intimal index (p<0.003) as opposed to arteries stented with BMS. Luminal Narrowing in SES was zero percent and re-endothelialization was similar in both SES and BMS groups (90.48%). Arteries with SES showed marked reduction in non-occlusive peristrut fibrin deposition (3 out of 21 with SES versus 5 out of 21 with BMS). Thus Sirolimus eluting stent had larger luminal area, lower intimal and medial thickness and less peristrut fibrin deposition as compared to bare metal stent in rabbit transcarotid balloon injured external iliac artery model.
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VETERINARY SURGERY AND RADIOLOGY, COMPARISION