Preclinical evaluation of a paclitaxel-incorporated nanoparticle-coated balloon in rabbit and porcine models.

BACKGROUND: The main drawback of current available drug coated balloons (DCB) is that a certain percentage of the coated drug is lost in the bloodstream during its delivery to the target lesion. We integrated the nanoparticle-mediated drug delivery technology and polydimethylsiloxane (PDMS) as a new excipient to facilitate an efficient drug delivery and uptake by endothelial cells. The present study aimed to evaluate the efficacy of the new DCB. METHOD AND RESULTS: The novel DCB were coated with 5.6mg of paclitaxel-incorporated nanoparticles using PDMS. The efficacy of the new DCB was examined in rabbit iliac stent model (n=12) and in the swine in-stent restenosis model (n=8) by quantitative coronary angiography (QCA) and optical coherence tomography (OCT). At 28days follow-up in the swine in-stent restenosis model, the area stenosis was significantly lower in DCB group as compared with that of the control group in OCT analysis (0.31±0.05 vs 0.49±0.06, p=0.04) though there was no significant differences observed in the rabbit iliac stent model in QCA and OCT analysis. CONCLUSION: The study results indicated that the paclitaxel-incorporated nanoparticle-coated balloon using PDMS has an inhibitory effect for the proliferation of smooth muscle cell in a swine coronary in-stent restenosis model.

Prevention of neointimal formation using miRNA-126-containing nanoparticle-conjugated stents in a rabbit model.

BACKGROUND: Despite recent progress with drug-eluting stents, restenosis and thrombosis after endovascular intervention are still major limitations in the treatment of cardiovascular diseases. These problems are possibly caused by inappropriate inhibition of neointimal formation and retardation of re-endothelialization on the surface of the stents. miR-126 has been shown to have the potential to enhance vascular endothelial cell proliferation. METHODS AND RESULTS: We designed and constructed a 27-nt double strand RNA (dsRNA) conjugated to cholesterol, which has high membrane permeability, and formed mature miR-126 after transfection. For site-specific induction of miR-126, we utilized poly (DL-lactide-co-glycolide) nanoparticles (NPs). miR-126-dsRNA-containing NPs (miR-126 NPs) significantly reduced the protein expression of a previously identified miR-126 target, SPRED1, in human umbilical vascular endothelial cells (HUVECs), and miR-126 NPs enhanced the proliferation and migration of HUVECs. On the other hand, miR-126 NPs reduced the proliferation and migration of vascular smooth muscle cells, via the suppression of IRS-1. Finally, we developed a stent system that eluted miR-126. This delivery system exhibited significant inhibition of neointimal formation in a rabbit model of restenosis. CONCLUSIONS: miR-126 NP-conjugated stents significantly inhibited the development of neointimal hyperplasia in rabbits. The present study may indicate the possibility of a novel therapeutic option to prevent restenosis after angioplasty.

One-year outcome of a prospective trial stopping dual antiplatelet therapy at 3 months after everolimus-eluting cobalt-chromium stent implantation: ShortT and OPtimal duration of Dual AntiPlatelet Therapy after everolimus-eluting cobalt-chromium stent (STOPDAPT) trial.

There has been no previous prospective study evaluating dual antiplatelet therapy (DAPT) duration shorter than 6 months after cobalt-chromium everolimus-eluting stent (CoCr-EES) implantation. STOPDAPT trial is a prospective multi-center single-arm study evaluating 3-month DAPT duration after CoCr-EES implantation. The primary endpoint was a composite of cardiovascular death, myocardial infarction (MI), stroke, definite stent thrombosis (ST) and TIMI major/minor bleeding at 1 year. Between September 2012 and October 2013, a total of 1525 patients were enrolled from 58 Japanese centers, with complete 1-year follow-up in 1519 patients (99.6 %). Thienopyridine was discontinued within 4 months in 1444 patients (94.7 %). The event rates beyond 3 months were very low (cardiovascular death: 0.5 %, MI: 0.1 %, ST: 0 %, stroke: 0.7 %, and TIMI major/minor bleeding: 0.8 %). Cumulative 1-year incidence of the primary endpoint was 2.8 % [upper 97.5 % confidence interval (CI) 3.6 %], which was lower than the pre-defined performance goal of 6.6 % (P < 0.0001). Using the CoCr-EES group in the RESET trial as a historical comparison group, where nearly 90 % of patients had continued DAPT at 1 year, cumulative incidence of the primary endpoint tended to be lower in the STOPDAPT than in the RESET (2.8 versus 4.0 %, P = 0.06) and adjusted hazard ratio was 0.64 (95 % CI 0.42-0.95, P = 0.03). The cumulative incidence of definite/probable ST was lower in the STOPDAPT than in the RESET [0 patient (0 %) versus 5 patients (0.3 %), P = 0.03]. In conclusion, stopping DAPT at 3 months in selected patients after CoCr-EES implantation was at least as safe as the prolonged DAPT regimen adopted in the historical control group.

Microcatheter-facilitated reverse wire technique for side branch wiring in bifurcated vessels: an in vitro evaluation.

AIMS: To assess when and how the microcatheter-facilitated reverse wire technique should be applied to cross the guidewire into side branches in coronary bifurcations. METHODS AND RESULTS: Three interventional cardiologists with different levels of experience performed in vitro bench testing using an originally developed coronary bifurcation simulator which had six coronary bifurcations. The bifurcation angles were 90, 105, 120, 135, 150 and 165 degrees (°). Experiment 1 was conducted to assess in what coronary bifurcation the reverse wire technique is required. Antegrade guidewire advancement was conducted with two different guidewires: the spring coil guidewire SION blue and the polymer-jacket hydrophilic guidewire Fielder FC. Experiment 2 was conducted to determine what the optimal guidewire selection and the optimal guidewire shape for the reverse wire technique would be. Assessment of the guidewire crossability into the highly angulated side branch was performed, and then the balloon crossability was assessed. A total of four guidewire types were compared in experiment 2. In experiment 1, guidewire crossing was impossible by conventional antegrade wiring when the bifurcation angle became 150° or more. In experiment 2, guidewire crossing of more than 150° of bifurcation angle was achievable independent of the guidewire types and shape. Balloon deliverability was best when using a polymer-jacket hydrophilic guidewire with a round shape 3 cm from the guidewire tip. CONCLUSIONS: Although the guidewire crossing into the side branch was impossible by conventional antegrade methods when the bifurcation angle became 150° or more, the guidewire crossing into such a highly angulated side branch was easily possible using the reverse wire technique. The optimal guidewire selection for the reverse wire technique is the polymer-jacket hydrophilic guidewire with a round shape 3 cm from the guidewire tip.