Transluminal Coronary Angioplasty Balloon Catheter Research Articles

Development of a patient-specific model of the human coronary system for percutaneous transluminal coronary angioplasty balloon catheter training and testing

BackgroundTo treat stenosed coronary arteries, percutaneous transluminal coronary angioplasty (PTCA) balloon catheters must combine pushability, trackability, crossability, and rewrap behavior. The existing anatomic track model (ASTM F2394) for catheter testing lacks 3D morphology, vessel tortuosity, and compliance, making evaluating performance characteristics difficult. This study aimed to develop a three-dimensional patient-specific phantom (3DPSP) for device testing and safe training for interventional cardiologists.MethodsA range of silicone materials with different shore hardnesses (00–30–45 A) and wall thicknesses (0.5 mm, 1 mm, 2 mm) were tested to determine compliance for creating coronary vessel phantoms. Compliance was assessed using optical coherence tomography (OCT) and compared to values in the literature. Stenosis was induced using multilayer casting and brushing methods, with gypsum added for calcification. The radial tensile properties of the samples were investigated, and the relationship between Young’s modulus and compliance was determined. Various methods have been introduced to approximate the friction between silicone and real coronary vessel walls. Computerized tomography (CT) scans were used to obtain patient-specific anatomy from the femoral artery to the coronary arteries. Artery lumens were segmented from the CT scans to create dissolvable 3D-printed core models.ResultsA 15A shore hardness silicone yielded an experimental compliance of 12.3–22.4 mm2mmHg·103\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\frac{m{m}^{2}}{mmHg}\\cdot {10}^{3}$$\\end{document} for stenosed tubes and 14.7–57.9 mm2mmHg·103\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\frac{m{m}^{2}}{mmHg}\\cdot {10}^{3}$$\\end{document} for uniform tubes, aligning closely with the literature data (6.28–40.88 mm2mmHg·103\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\frac{m{m}^{2}}{mmHg}\\cdot {10}^{3}$$\\end{document}). The Young’s modulus ranged from 43.2 to 75.5 kPa and 56.6–67.9 kPa for the uniform and calcified materials, respectively. The dependency of the compliance on the wall thickness, Young’s modulus, and inner diameter could be shown. Introducing a lubricant reduced the silicone friction coefficient from 0.52 to 0.13. The 3DPSP was successfully fabricated, and comparative analyses were conducted among eight commercially available catheters.ConclusionThis study presents a novel method for crafting 3DPSPs with realistic mechanical and frictional properties. The proposed approach enables the creation of comprehensive and anatomically precise setups spanning the right femoral artery to the coronary arteries, highlighting the importance of such realistic environments for advancing medical device development and fostering safe training conditions.

Design of percutaneous transluminal coronary angioplasty balloon catheters

BackgroundEight 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.MethodsFive 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.ResultsThe 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.ConclusionThis 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.

Temperature-dependent tensile properties of polyamide 12 for the use in percutaneous transluminal coronary angioplasty balloon catheters

BackgroundPercutaneous 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.ResultsThe 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.ConclusionThe 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.

Drug-eluting balloons: where are we and what are the problems?

The starting point of percutaneous transluminal coronary angioplasty was defined by Andreas Gruntzig in 1977 [1]. He developed the novel technique of revascularization and established a new speciality – interventional cardiology. Since that time, interventionalists have been confronted with the problems of vessel recoil during the procedure and restenosis within the first 6 months of balloon angioplasty. In spite of progress in some indications, in others these challenges have lost nothing of their significance, motivating investigators to pursue their research efforts with a view to finding new strategies for overcoming these difficulties. Stents proved to be a significant advance in reducing the frequency of restenosis by eliminating elastic recoil and negative remodeling at the treatment site [2]. However, neointimal proliferation is not prevented by stenting, and thus in-stent restenosis became a ‘new’ disease, especially in some patient populations such as diabetics or in certain lesions such as bifurcation, long lesions, lesions in small vessels, total occlusions and diffuse disease [3]. The systemic administration of anti-inflammatory, antiproliferative, anticlotting or other agents before or after balloon dilatation was shown to effectively reduce neointimal hyperplasia in animal models. Clinical use in humans, however, failed to result in adequate restenosis prevention [4]. The advent of drug-eluting stents (DESs) marked a decisive advance, enabling direct transfer of drugs to the target site and prolonged exposure of the vessel wall. Sirolimus and paclitaxel were shown to be effective pharmacological inhibitors of neointimal hyperplasia in vitro and in vivo [5,6]. Stents coated with these agents were successfully used in both the coronary arteries [7] and below the knee [8]. By contrast, use of these stents were not found to be superior to bare-metal stents in femoral and popliteal arteries or in patients with severe diffuse disease and long, complicated lesions [9]. The occurrence of late stent thrombosis, caused by incomplete endothelization of the stent struts and an inflammatory response to the polymer matrix, considerably limited the use of DES [10,11]. Coating paclitaxel onto the surface of conventional percutaneous transluminal coronary angioplasty balloon catheters with a new coating technique that provides immediate drug release upon inflation was a new approach to preventing restenosis without having to implant a stent. The drug is transferred to the dilated segment when the balloon is inflated. An effective local drug concentration is achieved with very low systemic exposure. Paclitaxel admixed to a small amount of the hydrophilic x-ray contrast medium iopromide (Ultravist) emerged as a very effective coating matrix from numerous in vitro and in vivo experiments investigating different coating techniques, the adhesion of paclitaxel to the balloon surface while the catheter is advanced to the lesion, and the release of the active agent into the vessel wall during balloon expansion [12,13]. Balloon catheters coated in this way have a paclitaxel dose of 3 μg/mm of balloon surface and are marketed as Paccocath (Bayer Schering Pharma AG, Germany). 1Department of Radiology, Charite – Universitatsmedizin Berlin, Chariteplatz 1, 10117 Berlin, Germany 2Clinic for Internal Medicine III, Cardiology, Angiology and Intensive Care, University Hospital of Saarland, Homburg/Saar, Germany †Author for correspondence: Tel.: +49 304 5053 9076 Fax: +49 304 5052 7993 E-mail: beatrix.schnorr@charite.de

Retrieval Of A Fractured And Retained Percutaneous Coronary Angioplasty Catheter On Beating Perfused Heart

A fractured and retained percutaneous transluminal coronary angioplasty catheter was successfully removed on a perfused beating heart with concomitant bypass grafting. We believe this is the first report in English literature of such an operation on a beating heart.Broken and retained percutaneous transluminal coronary angioplasty balloon catheter is a rare but serious complication of interventional cardiology. The presence of a calcified proximal lesion hinders withdrawal of the broken catheter. It requires retrieval and emergency coronary bypass grafting to prevent further complications.

Unusual use of a standard percutaneous transluminal coronary angioplasty balloon catheter to the rescue

Radical mastectomy because of a right-sided invasive ductal breast carcinoma was performed in a 72-year-old patient. After the seventh cycle of combined chemo- and immunotherapies (docetaxel, carboplatin, and trastuzumab), her chest X-ray presented the complication of the broken venous …

Surgical removal of entrapped and broken percutaneous transluminal coronary angioplasty balloon catheter

The percutaneous coronary artery angioplasty is routinely being used worldwide for the management of short and discrete coronary artery stenosis. The purpose of this report is to address the potentially lethal complication among the variety of surgical problems in conjunction with this procedure. The case also illustrates the potential pitfalls in the management of CAD. A 60-year-old man had a broken and retained percutaneous transluminal coronary angioplasty (PTCA) balloon catheter entrapped in the left anterior descending artery and portion of it was lying in the ascending aorta. The patient underwent retrieval of this catheter through the standard coronary arteriotomy for coronary anastomosis without aortotomy on cardiopulmonary bypass. It was found that the PTCA balloon catheter was entrapped in the entire LAD and portion of it was lying in the ascending aorta, which could be delivered through the standard coronary arteriotomy for coronary anastomosis, thus avoiding the aortotomy. PTCA balloon catheter entrapped in the entire LAD and portion of it lying in ascending aorta could be delivered through the standard coronary arteriotomy for coronary anastomosis, thus avoiding the aortotomy.

Identification of a potential role for the adventitia in vascular lesion formation after balloon overstretch injury of porcine coronary arteries.

In the present series of experiments, we examined the onset of cell proliferation and growth factor expression after balloon overstretch injury to porcine coronary arteries. Domestic juvenile swine underwent balloon overstretch injury to the left anterior descending and circumflex coronary arteries with standard percutaneous transluminal coronary angioplasty balloon catheters. To identify proliferating cells, 5-bromo-2-deoxyuridine (BrDU) was administered over a period of 24 hours before the animals were killed at either 1, 3, 7, or 14 days after injury. Immunohistochemistry was performed with monoclonal antibodies to BrDU and smooth muscle cell markers. Three days after injury, a large number of proliferating cells were located in the adventitia, with significantly fewer positive cells found in the media and lumen. Seven days after injury, proliferating cells were found primarily in the neointima, extending along the luminal surface. In situ hybridization for PDGF A-chain and beta-receptor mRNAs revealed that the expression of these two genes was closely correlated with the sites of proliferation at each time point. Studies in which BrDU was injected between days 2 and 3 and the animals were killed on day 14 suggested that the proliferating adventitial cells may migrate into the neointima. These data suggest that adventitial myofibroblasts contribute to the process of vascular lesion formation by proliferating, synthesizing growth factors, and possibly migrating into the neointima. Increased synthesis of alpha-smooth muscle actin observed in the adventitial cells after arterial injury may constrict the injured vessel and contribute to the process of arterial remodeling and late lumen loss after angioplasty.