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Stratakos E, Antonini L, Poletti G, Berti F, Tzafriri AR, Petrini L, Pennati G. Investigating Balloon-Vessel Contact Pressure Patterns in Angioplasty: In Silico Insights for Drug-Coated Balloons. Ann Biomed Eng 2023; 51:2908-2922. [PMID: 37751027 PMCID: PMC10632265 DOI: 10.1007/s10439-023-03359-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 09/02/2023] [Indexed: 09/27/2023]
Abstract
Drug-Coated Balloons have shown promising results as a minimally invasive approach to treat stenotic arteries, but recent animal studies have revealed limited, non-uniform coating transfer onto the arterial lumen. In vitro data suggested that local coating transfer tracks the local Contact Pressure (CP) between the balloon and the endothelium. Therefore, this work aimed to investigate in silico how different interventional and device parameters may affect the spatial distribution of CP during the inflation of an angioplasty balloon within idealized vessels that resemble healthy femoral arteries in size and compliance. An angioplasty balloon computational model was developed, considering longitudinal non-uniform wall thickness, due to its forming process, and the folding procedure of the balloon. To identify the conditions leading to non-uniform CP, sensitivity finite element analyses were performed comparing different values for balloon working length, longitudinally varying wall thickness, friction coefficient on the balloon-vessel interface, vessel wall stiffness and thickness, and balloon-to-vessel diameter ratio. Findings indicate a significant irregularity of contact between the balloon and the vessel, mainly affected by the balloon's unfolding and longitudinal thickness variation. Mirroring published data on coating transfer distribution in animal studies, the interfacial CP distribution was maximal at the middle of the balloon treatment site, while exhibiting a circumferential pattern of linear peaks as a consequence of the particular balloon-vessel interaction during unfolding. A high ratio of balloon-to-vessel diameter, higher vessel stiffness, and thickness was found to increase significantly the amplitude and spatial distribution of the CP, while a higher friction coefficient at the balloon-to-vessel interface further exacerbated the non-uniformity of CP. Evaluation of balloon design effects revealed that the thicker tapered part caused CP reduction in the areas that interacted with the extremities of the balloon, whereas total length only weakly impacted the CP. Taken together, this study offers a deeper understanding of the factors influencing the irregularity of balloon-tissue contact, a key step toward uniformity in drug-coating transfer and potential clinical effectiveness.
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Affiliation(s)
- Efstathios Stratakos
- Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Luca Antonini
- Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Gianluca Poletti
- Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | - Francesca Berti
- Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | | | - Lorenza Petrini
- Department of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy.
| | - Giancarlo Pennati
- Laboratory of Biological Structure Mechanics, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
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Amstutz C, Behr J, Krebs S, Haeberlin A, Vogel R, Zurbuchen A, Burger J. Design of percutaneous transluminal coronary angioplasty balloon catheters. Biomed Eng Online 2023; 22:94. [PMID: 37742021 PMCID: PMC10517552 DOI: 10.1186/s12938-023-01155-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/15/2023] [Indexed: 09/25/2023] Open
Abstract
BACKGROUND Eight commercially available percutaneous transluminal coronary angioplasty (PTCA), including semi-compliant and non-compliant balloons, have been assessed in detail on their tip, balloon, shaft, RX-Port, and hypotube design. Important performance characteristics such as tip deformation, balloon elongation, and deflation rate have been quantified. METHODS Five catheters of each model were evaluated during various tests. The robustness of the tips was evaluated through compression, measuring any occurrence of damage. The longitudinal growth of the balloons was recorded during inflation up to Rated Burst Pressure (RBP). The forces required to move the catheter forward and retract it into the guide catheter were measured in a simulated use test setup. The deflation behavior was studied by measuring extracted contrast media over time. Furthermore, balloon compliance and catheter dimensions were investigated. RESULTS The outer dimensions of the catheter were found to be smallest at the hypotube (0.59-0.69 mm) and highest at the balloon, respectively, the crossing profile (0.9-1.2 mm). The tip diameter increased after compression by 1.7-22%. Cross-sections of the folded balloons revealed a tri- and two-fold, respectively. The measured balloon elongation ranged from 0.6 to 2.0 mm. After the inflation of the balloon, an increase in friction between the guide wire and the catheter was observed on four catheters. A maximum increase of 0.12 N to 1.07 N was found. Cross-sections of the RX-Port revealed a semicircular-shaped inflation lumen and a circular guide wire lumen. The measured deflation rate ranged from 0.004 to 0.013 µL/s, resulting in an estimated balloon deflation time of 10.2-28.1 s. CONCLUSION This study provides valuable insights into the design characteristics of RX PTCA balloon catheters, which can contribute to facilitating the development of improved catheter designs and enhancing clinical outcomes. Distinctions between SC and NC catheters, such as balloon performance and dimensions, are evident. It is important to note that no single catheter excels in all aspects, as each possesses unique strengths. Therefore, it is essential to consider individual intervention requirements when selecting a catheter. The research also identifies specific catheter weaknesses, such as reduced wall thickness, fringes at the tip, and reduced performance characteristics.
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Affiliation(s)
- C. Amstutz
- School of Biomedical and Precision Engineering, University of Bern, Güterstrasse 24/26, CH-3008 Bern, Switzerland
| | - J. Behr
- SMD Swiss Medical Devices, Beringen, Switzerland
| | - S. Krebs
- School of Biomedical and Precision Engineering, University of Bern, Güterstrasse 24/26, CH-3008 Bern, Switzerland
| | - A. Haeberlin
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - R. Vogel
- Department of Cardiology, Buergerspital Solothurn, Solothurn, Switzerland
| | - A. Zurbuchen
- School of Biomedical and Precision Engineering, University of Bern, Güterstrasse 24/26, CH-3008 Bern, Switzerland
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - J. Burger
- School of Biomedical and Precision Engineering, University of Bern, Güterstrasse 24/26, CH-3008 Bern, Switzerland
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Li T, Zhang Z, Wang W, Mao A, Chen Y, Xiong Y, Gao F. Simulation and Experimental Investigation of Balloon Folding and Inserting Performance for Angioplasty: A Comparison of Two Materials, Polyamide-12 and Pebax. J Funct Biomater 2023; 14:312. [PMID: 37367276 DOI: 10.3390/jfb14060312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/26/2023] [Accepted: 05/31/2023] [Indexed: 06/28/2023] Open
Abstract
BACKGROUND A balloon dilatation catheter is a vital tool in percutaneous transluminal angioplasty. Various factors, including the material used, influence the ability of different types of balloons to navigate through lesions during delivery. OBJECTIVE Thus far, numerical simulation studies comparing the impacts of different materials on the trackability of balloon catheters has been limited. This project seeks to unveil the underlying patterns more effectively by utilizing a highly realistic balloon-folding simulation method to compare the trackability of balloons made from different materials. METHODS Two materials, nylon-12 and Pebax, were examined for their insertion forces via a bench test and a numerical simulation. The simulation built a model identical to the bench test's groove and simulated the balloon's folding process prior to insertion to better replicate the experimental conditions. RESULTS In the bench test, nylon-12 demonstrated the highest insertion force, peaking at 0.866 N, significantly outstripping the 0.156 N force exhibited by the Pebax balloon. In the simulation, nylon-12 experienced a higher level of stress after folding, while Pebax had demonstrated a higher effective strain and surface energy density. In terms of insertion force, nylon-12 was higher than Pebax in specific areas. CONCLUSION nylon-12 exerts greater pressure on the vessel wall in curved pathways when compared to Pebax. The simulated insertion forces of nylon-12 align with the experimental results. However, when using the same friction coefficient, the difference in insertion forces between the two materials is minimal. The numerical simulation method used in this study can be used for relevant research. This method can assess the performance of balloons made from diverse materials navigating curved paths and can yield more precise and detailed data feedback compared to benchtop experiments.
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Affiliation(s)
- Tao Li
- College of Mechanical Engineering, Sichuan University, Chengdu 610065, China
| | - Zhuo Zhang
- College of Mechanical Engineering, Sichuan University, Chengdu 610065, China
| | - Wenyuan Wang
- Chengdu Neurotrans Medical Technology Co., Ltd., Chengdu 610065, China
| | - Aijia Mao
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Yu Chen
- Department of Applied Mechanics, Sichuan University, Chengdu 610065, China
| | - Yan Xiong
- College of Mechanical Engineering, Sichuan University, Chengdu 610065, China
| | - Fei Gao
- Chengdu Neurotrans Medical Technology Co., Ltd., Chengdu 610065, China
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Amstutz C, Weisse B, Valet S, Haeberlin A, Burger J, Zurbuchen A. Temperature-dependent tensile properties of polyamide 12 for the use in percutaneous transluminal coronary angioplasty balloon catheters. Biomed Eng Online 2021; 20:110. [PMID: 34702259 PMCID: PMC8549196 DOI: 10.1186/s12938-021-00947-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 10/14/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Percutaneous transluminal coronary angioplasty (PTCA) balloon catheters must withstand high pressures required for the lesion treatment, pushing loads during insertion, and pulling loads during withdrawal. These loads pose a challenge especially for polymeric tubular shafts with small cross sections. In order to enable new design innovations and to better understand the mechanics of current catheter technologies, the tensile properties of polyamide (PA) 12 were investigated. PA 12 dog bone specimens and medical PA 12 tubes were either stored at ambient temperature and humidity or conditioned in water, and subjected to tensile loads at different temperatures. In addition, the effect on the tensile properties of the necking process, a forming process to reduce the wall thickness of the tubes, was determined. RESULTS The tested tubes showed a reduction in both Young's Modulus (- 41.5%) and yield stress (- 29.2%) compared to standardized specimens. Furthermore, an increase in temperature and water absorption softens the material and reduces the mechanical properties like the Young's Modulus and the yield stress. It was found that the material strengthens during the necking process. Likely due to the orientation of the polymers chain molecules in load direction (Rösler et al., 2007), the Young's Modulus of the material could be increased by 43.5%. Furthermore, the absence of a yield point after necking allows for a greater loading capacity of the material without unstable neck growth. Besides the strengthening, the ultimate strain is reduced by 50%. This indicates that the necking process induces plastic deformation. CONCLUSION The investigation showed that the environmental conditions like temperature and humidity can influence mechanical properties. It could also be shown that pre-forming processes such as necking can enhance the mechanical properties, such as the Young's Modulus, while reducing the wall thickness. These findings suggest possible further development of catheters with a small cross section and higher mechanical strength and highlight the importance to account for the targeted operating temperature during the design process.
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Affiliation(s)
- C Amstutz
- Sitem Center for Translational Medicine and Biomechanical Entrepreneurship, University of Bern, Freiburgstrasse 3, 3010, Bern, Switzerland.
| | - B Weisse
- EMPA, Swiss Federal Laboratories for Material Science and Technology: Mechanical Systems Engineering, Duebendorf, Switzerland
| | - S Valet
- EMPA, Swiss Federal Laboratories for Material Science and Technology: Mechanical Systems Engineering, Duebendorf, Switzerland
| | - A Haeberlin
- Sitem Center for Translational Medicine and Biomechanical Entrepreneurship, University of Bern, Freiburgstrasse 3, 3010, Bern, Switzerland.,Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - J Burger
- Sitem Center for Translational Medicine and Biomechanical Entrepreneurship, University of Bern, Freiburgstrasse 3, 3010, Bern, Switzerland
| | - A Zurbuchen
- Sitem Center for Translational Medicine and Biomechanical Entrepreneurship, University of Bern, Freiburgstrasse 3, 3010, Bern, Switzerland.,Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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