Experimental evaluation of pharmacokinetic profile and biological effect of a novel paclitaxel microcrystalline balloon coating in the iliofemoral territory of swine.

BACKGROUND: New paclitaxel coated balloons (PCB) developments have been proposed to maintain therapeutic levels of drug in the tissue while decreasing particle release. In this series of studies, we evaluated the pharmacokinetic profile and biological effects after paclitaxel delivery via novel microcrystalline PCB coating (mcPCB, Pax®, Balton) in porcine iliofemoral arteries. METHODS: Ten domestic swine were enrolled yielding 24 iliofemoral segments for evaluation. In the pharmacokinetic study, nine mcPCBs were dilated for 60 sec and animals sacrificed after 1 hr, 3 and 7 days. Studied segments were harvested and tissue paclitaxel concentration was analyzed utilizing HPLC. In the biological response evaluation, self-expandable stents were implanted followed by post dilation with either mcPCB (n = 10) or POBA (n = 5). After 28 days, angiography was performed, animals were sacrificed and stented segments harvested for histopathological evaluation. RESULTS: The 1-hr, 3 and 7 days vessel paclitaxel concentrations were 152.9 ± 154.5, 36.5 ± 49.5, and 0.9 ± 0.7 ng/mg respectively. In the biological response study, stents in the mcPCB group presented lower angiographic measures of neointimal hyperplasia as expressed by late loss when compared to POBA (-0.43 ± 0.9 vs. 0.23 ± 1.2; P = 0.24) at 28 days. In the histopathological evaluation, percent area of stenosis (%AS) was reduced by 42% in the mcPCB group (P < 0.05). The healing process in mcPCB group was comparable to POBA with regard to fibrin deposition (0.7 vs. 0.7; P = ns), neointimal maturity (1.97 vs. 1.93; P = ns), inflammation score (0.92 vs. 1; P = ns) and endothelialization score (1.77 vs. 1.73; P = ns). The mcPCB group did however display a greater tendency of medial cell loss and mineralization (60% vs. 0; P = 0.08). CONCLUSIONS: Delivery of paclitaxel via a novel mcPCB resulted in low long-term tissue retention of paclitaxel. However, this technological approach displayed reduced neointimal proliferation and favorable healing profile.

Comparable clinical safety and efficacy of biodegradable versus durable polymer paclitaxel eluting stents despite shorter dual antiplatelet therapy: insights from a multicenter, propensity score-matched registry.

BACKGROUND: The biodegradable polymer drug-eluting stents have been proposed as an alternative to durable polymer DES, theoretically improving vessel healing and reducing the need for prolonged double anti platelet therapy (DAPT), however clinical significance of this technology is under debate. Therefore, we sought to compare the clinical outcomes of two Paclitaxel eluting stents (PES) containing different polymer-based eluting matrices. METHODS: In this multicenter registry of 392 consecutive patients who underwent PCI between June 2006 and September 2008, we included patients with stable angina or NSTE-ACS displaying at least one significant lesion (>50% diameter stenosis) in native coronary arteries. RESULTS: Biodegradable polymer PES (BP-PES, LUC Chopin(2) , Balton, Poland) was implanted in 206 patients, whereas durable polymer PES (DP-PES, Taxus, Boston Scientific, USA) was implanted in 186 patients. There were no significant differences in baseline characteristics between groups with the exception of increased diabetes and number of lesions for BP-PES. In risk-unadjusted analysis at 1-year follow-up, there were no significant differences in TLR (BP-PES: 8.4% vs. DP-PES: 6%; P = 0.36), TVR (BP-PES: 11.1% vs. DP-PES: 8.4%; P = 0.36) and incidence of stent thromboses (BP-PES: 2.15% vs. DP-PES: 3.4%; P = 0.42) between groups. There was also no difference in MACCE between groups (17.6% vs. 14.4%, P = 0.49). The mean dual antiplatelet therapy (DAPT) compliance at 1 year was 77% for BP-PES versus 92% for DP-PES (P = 0.03). Kaplan-Meier analysis showed a significantly higher long-term stroke free survival in BP-PES (P = 0.04). After adjustment, this was sustained with an additional tendency toward higher MI free survival for BP-PES (P = 0.059). CONCLUSIONS: In this observational analysis, BP-PES were comparable to DP-PES, with regard to incidence of repeated revascularizations, stent thromboses and MACCE despite earlier DAPT discontinuation.

Tissue uptake, distribution, and healing response after delivery of paclitaxel via second-generation iopromide-based balloon coating: a comparison with the first-generation technology in the iliofemoral porcine model.

OBJECTIVES: This study sought to evaluate vascular drug uptake, distribution and response of second-generation paclitaxel coated balloon (PCB) (Cotavance, MEDRAD Interventional, Indianola, Pennsylvania) and compare it with first-generation technology, containing identical excipient and drug concentration. BACKGROUND: 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. METHODS: 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. RESULTS: 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 ± 11% vs. first-generation 21.9 ± 11% vs. PBA 46.5 ± 10%; p < 0.01) and histology (percentage of area stenosis: second-generation 50.5 ± 7% vs. first-generation 54.8 ± 18% vs. PBA 78.2 ± 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. CONCLUSIONS: 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.