A Novel Retrievable Drug Delivery Stentgraft To Enhance Paclitaxel Delivery For Restenosis

Introduction: Half of vascular interventions will fail in under 5 years due to restenosis. While drug coated balloons (DCB) are used to minimize restenosis, there are several disadvantages: 1) Limitations of the amount of drug that can be adhered to a balloon, 2) Significant drug is washed off the balloon by the circulation and 3) There are limits on the time of balloon inflation due to ischemia concerns. We developed a dumbbell shaped, retrievable drug delivery stentgraft (RDDS) that isolates a segment of artery with an outer chamber ( OC ) (Fig 1A). The center lumen of the stent maintains distal perfusion to allow longer drug exposure and this stent is removed after use. Methods: A RDDS stentgraft was fashioned from laser cut nitinol scaffold, covered in polymer and an infusion cannula was installed (Fig B). In a porcine model, bilateral common iliac arteries were dilated by plain balloon angioplasty to simulate endovascular intervention. Next a commercial DCB with paclitaxel (PXL) was used to treat one iliac, while an RDDS infused a similar dose of PXL to treat the contralateral iliac. Vessels and serum had PXL quantitation by liquid chromatography-mass spectrophotometry. Results: Angiographically, the RDDS maintained distal flow while the OC isolated the arterial wall for PXL delivery (Fig C, D). Blood samples distal to the treated areas demonstrated lower concentrations of PXL during treatment with the RDDS compared to DCB (10.50 ± 0.77 vs. 2310.07 ± 471.69 ng/mL, p < 0.0001). There was equivalent drug delivery to target vessel wall between the two approaches (33.85 ± 8.78 vs. 41.45 ± 12.51 ng/mg, p = 0.251, RDDS vs. DCB). Conclusions: The RDDS angiographically isolated a segment of artery, while maintaining distal perfusion. Moreover, compared to a DCB, the RDDS was able to prevent loss of drug to the circulation and effectively deliver paclitaxel to the vessel wall. This this study concludes that chambered retrievable stentgrafts may have a role in locoregional drug delivery.