Original PCB technologies displayed a heterogeneous deposition of crystalline paclitaxel-iopromide inside the balloon folds, whereas second-generation PCBs consisted of more homogeneous, circumferential coatings.
Paclitaxel tissue uptake was assessed in 20 iliofemoral arteries of a domestic swine. Vascular healing response was assessed in the familial hypercholesterolemic model of iliofemoral in-stent restenosis. Three weeks after bare-metal stent implantation, vascular segments were randomly revascularized with first-generation PCBs (n?= 6), second-generation PCBs (n?= 6), or plain balloon angioplasty (PBA) (n?= 6). At?28 days, angiographic and histological evaluation was performed in all treated segments.
One-hour paclitaxel tissue uptake was 42 % higher in the second-generation PCBs (p?= 0.03) and resulted in more homogeneous segment-to-segment distribution compared with first-generation PCBs. Both angiography (percentage of diameter stenosis: second-generation 11.5 ¡À 11 % vs. first-generation 21.9 ¡À 11 % vs. PBA 46.5 ¡À 10 % ; p < 0.01) and histology (percentage of area stenosis: second-generation 50.5 ¡À 7 % vs. first-generation 54.8 ¡À 18 % vs. PBA 78.2 ¡À 9 % ; p < 0.01) showed a decrease in neointimal proliferation in both PCB groups. Histological variance of the percentage of area stenosis was lower in second-generation compared with first-generation PCBs (51.7 vs. 328.3; p?=?0.05). The presence of peristrut fibrin deposits (0.5 vs. 2.4; p < 0.01) and medial smooth muscle cell loss (0 vs. 1.7; p < 0.01) were lower in the second-generation compared with first-generation PCBs.
In the experimental setting, second-generation PCB showed a comparable efficacy profile and more favorable vascular healing response when compared to first-generation PCB. The clinical implications of these findings require further investigation.