WP3 - Experimental activities [Months: 3-48]

NKUA Description of Work and Role ofSpecific Beneficiaries/Partner Organisations: The experimental activities of DECODE will be undertaken jointly by the partners UM, POLIMI, NKUA, CBSET, BRFAA, BSL, while NKUA will be the lead beneficiary. WP3 includes the following tasks:

 

Task 3.1 In vitro testing (UM, POLIMI, NKUA, CBSET, BRFAA, BSL, M3-48). This task includes a series of subactivities as follows: (i) Review on specific drug properties and available coating process based on DCB requirements. (ii) Development of analytical methods to characterize drug/material candidates. (iii) Solubility and stability studies with different solvents and co-solvents for drug/material candidates. (iv) Processing screening. (v) Prototypes of drug / material evaluation. (vi) Drug delivery system optimisation. This step will propose improved drug / material candidates through the feedback of the previous steps in order to further meet DCB requirements. Through material and processing modifications improved functionality will be proposed. Moreover, the mechanical interactions between the balloon and the arterial wall at different spatial scales (device, materials, coating microstructures) will be assessed using various experimental techniques. First, the coating mechanical stability in DCB systems will be investigated at micro- and nano-scale by means of small scale mechanical loading (uniaxal, biaxial, bulge loading) with simultaneous microscopy analyses (optical and confocal laser). Smaller scale study through AFM will also be performed with the purpose to characterize the coating itself (thickness distribution, homogeneity and nano-scale mechanical stability). Then, microscale mechanical characterization of the vascular tissue (animal peripheral arteries) will be performed with specific reference to the damage mechanisms occurring in the vascular tissues subjected to the mechanical contact with the DCB. Finally, supplementary in vitro experiments will be planned to further support the aims of the in silico study as described in Task 4.2 and Task 4.3. Lead partner: UM. Associated deliverable: D3.1

 

Task 3.2 Animal Study (NKUA, BRFAA, CBSET, BSL, M3-48): The aim of this task is to study the influence of lesion composition and stiffness on the transfer and distribution of the drug coating during the deployment of DCBs onto porcine superior femoral arteries (SFA). Model stiff atherosclerotic arteries will be created via deployment of bare metal stents in one SFA per swine and survived for one month before bilateral DCB deployment ((one balloon per artery at the recommended inflation time and balloon to artery ratio). After one month of survival stented SFA are known to develop substantial restenosis and are therefore an accepted model for instent restenosis (ISR) and its treatment by atherectomy devices or additional drug eluting stents. In the current study, presented arteries will provide an animal model of DCB treatment of ISR, and owing to stent stiffness model stiffness of mineralized arteries. BSL will provide the bare metal stents and two formulations of DCB as dictated by the in vitro experiments. Both SFA per pig will be imaged by OCT and/or by colour Doppler ultrasonography (Duplex sonography – DUS) and bilateral angiography prior to DCB deployment so as to provide imaging data for vessel geometry reconstruction to the computational model developed in WP4. A total of 32 DCB will be deployed 16 animals (16 naïve SFA and 16 stented SFA). 8 animals will be studied by NKUA and BRFAA in collaboration and 8 animals by CBSET, with both sites using the same inlife procedures and devices, but different post necropsy evaluations of coating distribution and arterial morphology. Moreover, NKUA/BRFAA will also deploy 8 stents in deep femoral arteries – these arteries will not receive DCB treatments and will instead undergo mechanical testing to define the effects of stenting on stiffness and provide input for the computational models developed in WP4. Both institutions adhere to the highest technical and ethical standard and will adhere to these throughout the studies. Animals will be euthanized 1 hour post treatment and the iliac arteries perfused with physiological solution without pressure to maximize coating preservation in the tissue and minimize blood clot presence. Treated arterial segments, including proximal and distal excess tissue (~20 mm), will be removed intact so as not to affect transferred coating.

​Lead partner: NKUA. Associated deliverables: D3.2, D3.3