REUSE OF SINGLE-USE DEVICES FOR INTERVENTIONAL CARDIOLOGY: A HCTA APPROACH F. Tessarolo*, M.Fedel*, P. Ferrari**, I. Caola***, G.M. Guarrera***, C. Favaretti***, C. Migliaresi*, and G. Nollo** * Dept. of Materials Engineering and Industrial Technologies, University of Trento, Trento, Italy ** Dept. of Physics, University of Trento, Trento, Italy *** Azienda Provinciale per i Servizi Sanitari, Trento, Italy
[email protected] Abstract: Health Care Technology Assessment on the re-use of disposable devices for interventional cardiology is presented. Devices functionality, material properties and surfaces modifications, are considered as well as microbiological aspects. Results are reported for electrophysiology and angioplasty cardiac single-use catheters. Italian juridical regulation is compared to the European framework. Economic implications of a reprocessing policy are analysed to evaluate the real saving, market and environmental issues. Surfaces and functionality require one-by-one device testing and appropriate methods for verifying catheters efficiency and safeness. Legal requirements suggest the need for a new CE mark apposition. Introduction According to the International Agency for Health Technology Assessment (INAHTA), Health Care Technology Assessment (HCTA) “is a multidisciplinary field of policy analysis. It studies the medical, social, ethical, and economic implications of development, diffusion, and use of health technology” [1]. HCTA is generally carried out on technologies and health applications including their technical characteristics, effectiveness in improving patient’s health, cost effectiveness, and legal and ethical considerations connected to the utilisation of a given technology, and possible alternatives. Modern medicine makes a large use of minimally invasive technology based on disposable devices. The utilisation of single-use percutaneous catheters is a common practice in interventional cardiology, but the increasing of cardiac interventions and the consequent economic load on health system, demand for assessing the possibility to reuse these devices. The need for costs reduction drove many countries, as Canada and USA, to adopt a reprocessing policy [2-5]. At present there are no sufficient European studies on re-use feasibility, nor studies on validation of devices reprocessing [6]. Considering that disposable device reprocessing represents the introduction of a new health technology, a HCTA approach is required, where stringent criteria of effectiveness, safety and suitability must be satisfied [7].
Available literature underlines the need to determine first the correct sterilisation techniques and the relevant quality control and subsequently clear guidelines for defining the organisation procedures and the allocation of responsibilities in the use of reprocessed materials [8]. A HCTA approach would be addressed to health policy stakeholder with macro, meso and micro levels repercussions [9]. The sophisticated techniques applied in this work (microscopic, functional, and microbiological characterizations) supply qualities and safety devices parameters. These information, in addition to the legal, bioethical, and economic issues raised by the use of reprocessed medical devices, are important information at macro level for defining the applicability of the procedure thus warranting safeness and clarifying on responsibility. The meso level decision-maker can obtain information about economic aspect, foreseeing the saving for budgeting. The physicians will be better informed on the quality and safety of the devices. The study aimed to define the fundamental steps required for a complete assessment of a reprocessing procedure on interventional cardiac catheters according to an HCTA approach. Materials and methods Disposable devices for interventional cardiology make use of ablation and diagnostic cardiac catheters for electrophysiology (EP) and percutaneous transluminal coronary angioplasty (PTCA) for haemodynamics procedures (Fig. 1). A total amount of 72 devices were analysed (40 EP and 32 PTCA). This work followed HCTA methodologies, which provide for a priority-setting definition [10]. The process applied to reprocessing issue, underlined the need for safety, ethical, legal, economical, and ecological aspects, focusing on: • Chemical-physical characterization and functionality testing of reprocessed devices compared to new catheters. • Microbiological device analysis and bacterial identification.
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Comparative analysis of legal and ethical issues surrounding the processing and re-use of materials and devices intended for single-use. • Economic cost-benefit analysis for the introduction of a reprocessing policy in disposable interventional cardiology devices. Chemical-physical-functional characterization The reprocessing feasibility was evaluated on devices produced by different manufacturers. All reprocessed devices were collected after a first standard clinical procedure. The study first assessed the chemical-physical properties of about 15 PTCA and 40 EP common-use non-irrigated catheters in order to define standard device features and to individuate critical parts. After a preliminary characterization of shapes and materials, a cleaning-sterilization process was drafted. Detergents, procedures, and sterilization methods were selected according to materials properties and UNI-EN 556 regulation. Material analyses were performed comparing new and reprocessed devices by using both superficial and bulk techniques. Optical microscopy (OM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and gel electrophoresis (GE) gave information about contaminations, residuals, and topography changes. Infra-red spectroscopy (IR), thermal, dynamic, and mechanical tests evaluated bulk modifications. Functionality performances were assessed realizing specific experimental sets-up for quantifying respectively the radiofrequency ablation efficiency in ablation catheters and balloon profile and compliance curve for PTCA catheters. Material properties and functionality were evaluated on devices reprocessed different times (up to 14 cycles) for estimating the maximum number of reuse sustainable in a completely efficient status.
Microbiologic tests Microbiologic tests were conducted on PTCA catheters to determine the possible pathogenic species that could contaminate devices surfaces in clinical procedures. This work was carried out on used catheters for evaluating the microorganism load following UNI EN 1174-2 and 1174-3 regulations. Preliminary tests were conducted using standard ATCC bacterial strains to assess the best elution-filtration procedure for the quantification of very low microbial load. Sterile devices were inoculated with 100 UFC of Enterococcus faecium (ATCC 35667) and successively dried. Inoculated sample were eluted whit physiological solution and different aliquots were inoculated in agar plates for colonies counting. The retrieval efficiency was computed by retrieved titre to initial inoculus ratio. The best-proven method was applied on 12 catheters immediately after the clinical procedure and on 5 catheters after decontamination step to verify the effects of this treatment on bio-burden reduction. All positive samples were analysed for microbial load and biochemical identification of the isolated strains. Ethical, juridical and economic aspects The ethical-juridical aspect of a reuse activity was assessed by a comparative analysis between Italian and other European countries current legislation. The German legal framework and the Medical Devices Act (MedizinprodukteG), implementing the Council Directive 93/42/EEC, were examined as an example of legal regulation for reprocessing. Economic analysis aimed to determine the real cost saving, considering as crucial variables the new device price, the regeneration cost, the average regeneration number and the regeneration tax (percent probability of successful regeneration). Also considered variables were: savings obtained by waste reduction, packaging and labelling costs, and the cost for new device contract assignment. Results and Discussion
Figure 1: Distal portions of an EP (left) and a PTCA (right) catheter. The grid is 1x1mm squared.
Chemical-physical-functional characterization Lack of detailed device technical sheets and specifications, often protected by manufacturer patents, required an accurate device analysis. The investigation for material characterization elicited how different classes of biomedical polymers and metals are used respectively for EP and PTCA devices. According to Italian legislation for blood contacting devices, all used catheters were firstly decontaminated by immersion in a chlorate solution. Design features allowed a rapid and easy cleaning procedure for the EP catheters based on brushing with moistened tissue nontissue gauzes and rinsing solution. The cleaning of PTCA catheters was more challenging, needing the accurate flushing of the guide-wire lumen and the balloon lumen suction for eliminating the iodate contrast medium. Because of the presence of long and narrow lumens in PTCA catheters, a standard ethylene oxide (EO) process was preferred for these devices, while gas plasma (GP) sterilization was suitable for EP catheters.
Physical-Chemical studies on reprocessed surfaces and bulks evaluated modifications on different constituents and correlated alterations with number of reprocessing cycles. OM on EP catheter underlined the presence of micro-scratches on the polyurethane shaft surface (Fig. 2). This modification was probably due to the use of tissue-non-tissue gauzes in cleaning process. AFM documented a physical-chemical etching effect on polymers, due to plasma sterilization, and an increase of nano-roughness vs. number of reprocessing cycles. Shaft hydrolytic stability appears to be weakly compromised by the etching effect of the GP sterilization process. Plasma treatment caused scissoring effects on the polymer long chains and might form oligomers and instable compounds. The reprocessing procedure did not seem to influence the functionality of EP catheters. Ablation patterns obtained from the same catheters, before and after reprocessing, were compared in a specific experimental set-up. No appreciable differences were revealed for ablation efficiency, electrodes conductivity, or thermometric sensor precision and accuracy. SEM analysis on PTCA catheters did not evidence a remarkable presence of particulate or deep scratches on surfaces and no traces of adsorbed proteins were revealed by GE. Some residuals of iodate contrast medium in the inner balloon underlined the need of an efficient cleaning of balloon lumens for avoiding crystallization and loss of functionality. IR analysis did not show chemical changes up to five consecutive sterilization cycles, suggesting that EO did not modify polymeric surface characteristics. Essential functional properties for PTCA catheters as crossing profile, balloon compliance (ratio between diameter value and inflating pressure) and bursting pressure have been analysed.
Compliance curves resulting from functional tests documented the tendency of both new and reprocessed devices to lose elasticity, once reached the nominal pressure. Balloons diameter increases with consecutive inflations but stabilizes after 2-3 dilations (Fig. 3). In case of reprocessing it should be sufficient to introduce a new calibration curve, with new nominal diameter values for every single devices. Microbiologic tests Microbiology assessment on used but untreated PTCA devices revealed a very low contamination (minor than 6UFC per device) in six of the 12 catheters examined. The following species were isolated: Staphylococcus haemolyticus, Staphylococcus warneri, Staphylococcus hominis hominis, Staphylococcus capitis capitis, Staphylococcus auricolaris, Staphylococcus aureus, Corynebacterium jeikeium, and Corynebacterium species. The same approach, applied to used and cleaned devices, aimed to evaluate the effect of the decontamination-cleaning procedure on the bioburden. Four out of five catheters were positive with a contamination of 2, 2, 11, 109UFC respectively. The most diffused pathogens were Staphylococcus species. All negative samples were successively inoculated with low microbial load of Enterococcus faecalis (ATCC 35667) and incubated at 37°C for a week. The regular growth confirmed the absence of any inhibitor released by catheter materials. The whole analysis confirmed that cleaning and decontamination steps might generate bacterial contamination with pathogen dissemination in formerly sterile device surfaces. Considering that device cleaning is necessary for obtaining an acceptable bioburden reduction, including haematic constituents removal, it is mandatory to control this process and optimize chemicals, mechanical methods, time legs, and device expositions to nonprotected environments. This analysis represents the first approach to microbiological aspect that should be completed by sterility validation, endotoxin and pyrogen tests.
0.040 0.038
Compliance (mm/atm)
0.036 0.034 0.032 0.030 0.028 0.026 0.024 0.022 0.020
Figure 2: OM images on polyurethane shaft of an EP catheter with different reprocessing cycles. New (a), reprocessed 1 (b), 4 (c), 8 (d) times. Changes in microroughness were probably related to cleaning procedure and occurred in most samples.
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Number of inflation cycles
Figure 3: Compliance versus number of inflation cycles for a typical PTCA catheter balloon.
Ethical, juridical and economic aspects European legal framework lacks of a harmonizing transposition of the European Council directive 93/42 for the reprocessing activity. For instance the Italian acknowledge of the European legislation 93/42, doesn’t provide at all, unlike the German model, to consider the reprocessed medical device as not in need of CE marking. Hence, it is evident the need for unified regulations and standards with European countries harmonized conformation. Besides some consideration about possible improvement in device safeness and reliability related to a one-by-one control, the driving reason that forces for reusing disposable devices is economic saving. Economic saving increases with number of used devices, but amortization of fixed costs may be unfavorable for limited number of clinical interventions. The average number of regenerations and the regeneration tax are basic variables for saving computation. Higher are the two variables and larger is the economic benefit. Finally, risk assessment of the reprocessing policy may be potentially followed by economic implications. Conclusions The articulate and complex approach for assessing the reuse feasibility kept in consideration safety, economic, legal, ethical, and technical issues and any correlation and implications among these aspects. The assessment elicited some important considerations in these fields. • Single-use cardiac catheters reprocessing may induce surface and bulk modifications. • Maximum number of reprocessing cycles depends on specific devices features, use conditions, and reprocessing protocol. • Complete device testing is mandatory on every reprocessing cycle and on every single device. The efficacy of any reprocessing protocol should be carefully verified with safe, fast, reproducible, and regularly updated investigation techniques. Real saving should be carefully assessed, and might be nullified for small amount of clinical procedure. The opportunity to reduce waste quantities, water and energy consumption, but also global consumption of raw materials and primary energy deserves closer attention for both economic and ecological aspects. In conclusion this study does not give a definitive answer to the reuse feasibility, nevertheless it represents, for its multidisciplinary investigations, a valid instrument for health stakeholders who wants to introduce this new technology. Acknowledgements Financial support by SICC-SIX project (Safeness in Interventional Cardiology and Cardiac surgery), Fondo Unico per la Ricerca 2001, Provincia Autonoma di Trento.
References [1] INHATA, Internet site address: http://www.inahta.org/ [2] BATHINA M. N., ET AL., (1998), “Safety and Efficacy of Hydrogen Peroxide Plasma Sterilization for Repeated Use of Electrophysiology Catheters”, J. Am. Coll. Cardiol., 32, pp. 1384-1388 [3] LEROUGE S., TABRIZIAN M., WERTHEIMER M. R., MARCHAND R., AND YAHIA L'H., (2000), “Plasma Based Sterilization: Effect on Surface and Bulk Properties and Hydrolytic Stability of Reprocessed Polyurethane Electrophysiology Catheters”, J. of Biomed. Mat. Res., 52, pp. 774-782 [4] SHAW J. P., EISENBERG M. J., AZOULAY A., NGUYEN N., (1999), “Reuse of Catheters for Percutaneous Transluminal Coronary Angioplasty: Effects on Procedure Time and Clinical Outcomes”, Cathet. Cardiovasc. Intervent., 48, pp. 54-60 [5] MAK K. H., EISENBERG M. J., PLANTE S., STRAUSS B. H., ARHEART K. L., TOPOL E. J., (1996), ”Absence of Increased in-Hospital Complications with Reused Balloon Catheters”. Am. J. Cardiol., 78, pp. 717-719 [6] “Re-use of Devices in Cardiology - Policy Document”, (1998), Europ. Heart J., 19, pp. 16281631 [7] BATTISTA R. N., HODGE M. J., (1999), “The Evolving Paradigm of Health Technology Assessment : Reflections for the Millennium”, Can. Med. Ass. J., 160, pp. 1464-1467 [8] FDA, Enforcement Priorities for Single-Use Devices Reprocessed by Third Parties and Hospital; August, 14, 2000, Internet site address: http://www.fda.gov/cdrh/comp/guidance/1168.pdf [9] JONSSON E., BANTA D., (1999) “Management of Health Technologies: an International View”, Biomed. J., 319, pp. 1293-1295 [10] HENSHALL C., OORTWIJN W., STEVENS A., GRANADOS A., BANTA D., (1997), “Priority-Setting for Health Technology Assessment. Theoretical Considerations and Practical Approaches”, Int. J. Technol. Assess. Health Care; 13, pp. 144-185
Francesco Tessarolo E-mail:
[email protected] Tel +39 0461 881594 Fax +39 0461 881696 Department of Materials Engineering and Industrial Technologies University of Trento Via Mesiano 77, I-38050 TRENTO, Italy
