Long-term effects on vascular healing of bare metal stents delivered via paclitaxel-coated balloons in the porcine model of restenosis

Background Clinical trials have consistently demonstrated benefits of Paclitaxel-coated balloons (PCB) in particular clinical situations such as in-stent restenosis and peripheral vascular interventions. However, the long-term vascular effects of bare metal stents (BMS) delivered via PCB (PCB+BMS) are still unknown. The aim of this study was to assess the long-term effects of PCB+BMS on vascular healing and neointimal formation (NF). Methods A total of 208 stents: 56 BMS crimped on PCB, 50 BMS crimped on uncoated balloons (UCB+BMS), 52 Taxus and 50 Cypher stents were implanted in normal coronary arteries of 104 pigs using 1.2:1.0 stent-to-artery ratio. Follow-up occurred at 3, 7, 28, 90, and 180 days. Vascular effects were assessed based on angiographic and histological analysis. Endothelialization was evaluated using an anti von-Willebrand Factor stain. Results At 28 days, delivery of a BMS using a PCB led to a significant reduction in NF compared to the UCB+BMS and the Taxus stent (P < 0.01). Between 28 and 180 days, the progression of NF tended to be lower in the PCB+BMS compared to all DES groups. At 90 days, the PCB+BMS (2.56 ± 0.43) and the Taxus stents (2.60 ± 0.59) had a trend toward higher inflammatory scores compared to the UCB+BMS group (1.85 ± 1.13, P = 0.09). By 180 days, inflammation and NF had completely normalized between the groups. Expression of peristrut vWF was comparable among all tested groups at 28 days. Conclusion The long-term pattern of vascular healing occurring following PCB+BMS deployment appears to be comparable to what has been reported with DES technologies.