Coronary Angioplasty Catheter Research Articles

Detrimental Effects of Sterilization Types on Single-Use Coronary Angioplasty Catheters for Reuse: An Electron Microscopic Study.

Reuse of medical devices poses risks concerning technical issues and patient safety. In this study, we aimed to examine the structural changes in catheters that occur due to the reuse with the aid of electron microscopy. The effects of hydrogen peroxide (HP) and ethylene oxide (EO) sterilization on four percutaneous transluminal coronary angioplasty (PTCA) catheters and control PTCA catheters were examined by scanning electron microscope (SEM). Each catheter sample was divided into four parts during the SEM examination, and a total of 20 pieces were examined. Catheters were reprocessed through every regular sterilization step and used solely for the study, not in patients. Statistical evaluations of histological scoring made on images obtained from scanning electron microscopic images were made using the GraphPad Prism 8 program. Electron microscopical examination showed that HP sterilization caused more robust and deeper lines compared to EO. These distortions increased directly with the increase in the reprocessing cycle. In EO, no significant damage was detected within five cycles in contrast to HP; however, the harmful effects of EO were seen over five cycles. Unprocessed samples had no damage. Outer and inner deterioration was significantly higher in the EO>5 group and HP>5 group than in the control group. However, the bacterial contamination score in the EO>5 group was higher than the control group. Our findings showed that HP and EO sterilizations caused some deterioration in the inner and outer surfaces of PTCA catheter samples. We recommend reprocessing using EO, the least damaging method, when necessary, and paying attention not to exceed five cycles when necessary.

Numerical Methodology to Evaluate Trackability and Pushability of PTCA Balloon Catheter.

During percutaneous coronary intervention (PCI), the ability to navigate a catheter without causing injury to the vessel and damage to the device is crucial outcome of the procedure. This study aimed to develop a numerical model to analyse the percutaneous transluminal coronary angioplasty (PTCA) catheter navigation in coronary vessels. Trackability and pushability are two major parameters used to characterize the navigation of PTCA balloon catheters, and they are influenced by vessel tortuosity, contact interactions and catheter design. In the current study, finite element analysis model is presented to evaluate trackability and pushability considering two different vessel geometries. Impact of contact interactions among catheter, guidewire, and vessel were studied to validate the numerical model with in vitro test data. Further, a parametric study was conducted to understand the influence of distal shaft, and proximal shaft outer diameter. Obtained results suggest that contact interaction and co-efficient of friction between guidewire and catheter are critical parameters to obtain numerical results comparable to experimental data. Results from the parametric study predicted strong positive correlation of distal shaft diameter on pushability, and weak correlation on trackability force. Furthermore, parametric variation in proximal shaft diameter has strong positive correlation on trackability force and strong negative correlation on pushability. Numerical methodology presented in this study is a preliminary attempt to simulate the behavior of PTCA balloon catheter navigation. This methodology will be helpful in the design and optimization of PTCA balloon catheter and similar devices with improved deliverability.

TCTAP A-042 Assessment of the Crossability and Re-Crossability of Coronary Balloon Catheters; An Experimental Study

Among the devices used for PCI, balloon catheter for percutaneous transluminal coronary angioplasty (“balloon catheter”) is the most frequently used device. In addition, since balloon catheter may be used multiple times, it is required not only to have crossability for an initial lesion, but

Investigation of dose to patients in conventional cardiac intervention

Objective To investigate patient doses undergoing routine interventional cardiology procedures in China. Methods A retrospective analysis was performed on 238 adult patients who achieved one of interventional procedures including coronary angiography (CAG), percutaneous coronary angioplasty (PTCA) and radiofrequency catheter ablation (RF). According to intervention operations, all cases were divided into three groups: CAG (77), PTCA (95) and RF (66). Data of four special metrics, peak skin dose (PSD), dose-area product (DAP), cumulative dose (CD), and fluoroscopy time (FT), these parameters were measured and collected for these procedures. Frequencies of high-dose cases (PSD>2 Gy and PSD>3 Gy) were specifically recorded. Third quartile of DAP distribution was used to establish dose reference level (DRL) and then DRL values in this study were compared with ones reported in literatures. Wallis Kruskal rank-sum test was used to compare radiation dose of patients undergoing different intervention procedures. The total correlation among CD, DAP and PSD was analyzed by Spearman method. Results For patients undergoing CAG,PTCA and RF procedure, the median PSDs were 0.24, 1.05 and 0.62 Gy, respectively.The median DAPs were 34.99, 94.53 and 36.33 Gy·cm2, respectively.The median CDs were 0.39, 1.27 and 0.36 Gy, respectively.The median FTs were 4.50, 15.31 and 13.40 min, respectively. The difference among procedures was statistically significant (χ2=105.083, 92.032, 115.509, 100.883, respectively, P 2 Gy, including 14 patients undergoing PTCA and 8 patients undergoing RF. There were 1.6% (22/238) patients with PSD>3 Gy, including 1 patients undergoing PTCA and 3 patients undergoing RF. The DRL for PTCA in this study is 133 Gy·cm2 and higher than that in literatures. The DRL for CAG in this study is 46 Gy·cm2 and slight lower than that in literatures. The DRL for RF in this study is 49 Gy·cm2. Conclusion Data from this study are in the range of most reported values for CAG and RF procedure, while higher than that obtained in some literatures for PTCA. Key words: Heart; Radiology, interventional; Radiation dose; Comparative study

Off-pump bilateral internal thoracic artery grafting.

We read with interest the article by Dr. Lytle on bilateral internal thoracic artery (BITA) grafting (1). We congratulate him for an excellent review on the subject. We would like to take this opportunity to humbly express our opinion regarding off-pump use of BITA grafting. Our limited experience contradicts his opinion that off-pump CABG (OPCAB) may have negatively influenced the use of BITA and sequential ITA grafting (1). We have reported a simple technique to use BITA with aortic no touch (2) that can be performed off-pump by surgeons even with limited OPCAB experience. Sequential grafting using LITA-RITA y graft technique off-pump has been in practice for a while. Intra-myocardial blood vessels had been successfully grafted during OPCAB (3). We feel that in the absence of the stress of increasing clamp or bypass time, a perfect anastomosis can be performed even in severely diseased arteries. Moreover, the absence of cardiopulmonary bypass-induced inflammatory response may have a favorable impact on the vulnerability of deep mediastinal infection after BITA use. OPCAB is associated with less use of blood and blood product which is known to reduce immunity. We would argue that immunity may be better preserved after OPCAB because of the absence of inflammatory response and less use of blood and blood product. In addition to routine use of skeletonised ITA, these factors may explain the very low incidence of major infection in our OPCAB patients with BITA grafting. Stroke after CABG is probably the major drawback in all the recent trials comparing CABG with percutanous coronary intervention (PCI). Even with the improvement in technology, it would be difficult to reduce the incidence of stroke to less than 2% after on-pump CABG. Even OPCAB (where aortic side clamp had been used) can be complicated by postoperative incidence of stroke. Stroke after CABG is probably the worst complication. OPCAB with aortic-no-touch can reduce the incidence of stroke to the minimum (4). OPCAB with aortic-no-touch which has the lowest incidence of stroke compares favorably with PCI. We have successfully adopted OPCAB use of BITA grafting in more than 90% of unselected consecutive cases of isolated CABG (5). It is well known that coronary artery disease in the Asian population has a very aggressive pattern affecting the younger generation. Moreover, while PCI is preferred for younger patients with low syntax score, our surgical patients have become more complex with higher syntax scores. By using OPCAB with aortic-no-touch and BITA grafting, we have been able to provide an alternative to PCI which has not only better graft patency rates, and provides complete revascularization but also the incidence stroke is comparable or lower than PCI (even passing coronary angioplasty catheters through diseased aorta can produce stroke). Our limited experience has proved that BITA grafting can be successfully used during OPCAB (5). I congratulate Dr. Lytle for highlighting the superiority of BITA grafting in improving long-term patient outcomes. It will require a change in mindset toward BITA grafting to successfully provide a better alternative to PCI in patients with coronary artery disease.

Skin temperature in lower hind limb subjected to distal vein arterialization in rats.

Vascular surgery for distal vein arterialization (DVA) has been adopted clinically as a strategy for saving arteriosclerotic lower limbs from amputation. To gain more detailed information on DVA, the present study investigated the procedure in hind limbs of rats under isoflurane anesthesia. Since successful DVA requires destruction of venous valves, a coronary angioplasty catheter guidewire was used to destroy valves either solely in the femoral vein or in both femoral and popliteal veins. The femoral artery was then anastomosed to the femoral vein with sutures under binocular microsopic control. Changes in the distribution of skin blood flow in the hind limbs were studied with a thermal camera. Skin temperature increased in the thigh and knee after femoral venous valve destruction, but hyperthermia was observed in the distal leg and foot only when the valves in the popliteal vein were also disrupted. These results showed that increased arterial blood flow could be established by DVA surgery in both the proximal and distal regions of the hind limbs.

Post-marketing surveillance in the published medical and grey literature for percutaneous transluminal coronary angioplasty catheters: a systematic review

BackgroundPost-marketing surveillance (PMS) may identify rare serious incidents or adverse events due to the long-term use of a medical device, which was not captured in the pre-market process. Percutaneous transluminal coronary angioplasty (PTCA) is a non-surgical procedure that uses a balloon-tipped catheter to enlarge a narrowed artery. In 2011, 1,942 adverse event reports related to the use of PTCA catheters were submitted to the FDA by the manufacturers, an increase from the 883 reported in 2008. The primary research objective is to conduct a systematic review of the published and grey literature published between 2007 and 2012 for the frequency of incidents, adverse events and malfunctions associated with the use of PTCA catheters in patients with coronary artery disease (CAD). Grey literature has not been commercially published.MethodsWe searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials and PubMed for medical literature on PMS for PTCA catheters in patients with CAD published between January 2007 and July 2012. We also searched the grey literature.ResultsThis review included 11 studies. The in-hospital adverse events reported were individual cases of myocardial infarction and hematoma. In studies of patients with coronary perforation, more patients with balloon angioplasty were identified compared with patients who required stenting.ConclusionsOur systematic review illustrates that the volume and quality of PMS studies associated with the use of PTCA catheters in patients with CAD are low in the published and grey literature, and may not be useful sources of information for decisions on safety. In most studies, the objectives were not to monitor the long-term safety of the use of PTCA catheters in clinical practice. Future studies can explore the strengths and limitations of PMS databases administered by regulatory authorities.

Survey of the interventional cardiology procedures in Italy

Interventional cardiology procedures are increasing because they offer many advantages to patients compared with other techniques: therefore the Italian National Institution for Insurance against Accidents at Work decided to start a survey for monitoring the state-of-the-art regarding the professionals involved in those procedures. The survey covered six cardiology and medical physics Italian departments. Each centre was asked to record 10 examinations for five types of procedures: coronary angiography (CA), electrophysiology studies (ES), pacemaker implantation (PI), percutaneous transluminal coronary angioplasty (PTCA) and radiofrequency catheter ablation (RA). For each examination all the centres were requested to fill in a questionnaire containing information regarding the operator performing the examination, the patient and the procedure. A total of 290 examinations were recorded: 103 CA, 14 ES, 68 PI, 79 PTCA and 26 RA. As occupational doses are strongly related to patient doses, both patients and operators radiation dose data are reported. Ratios of maximum to minimum mean patient doses across the hospitals surveyed were 2.0, 3.9, 7.0, 1.8 and 1.4 for CA, ES, PI, PTCA and RA, respectively. The calculated rounded mean dose-area product values across all participating hospitals were comparable with other values reported in the literature. In general, specific radiation protection tools were used by all operators performing different procedures in all hospitals. A major issue in this survey was the absence of information about correlation between staff and patient doses in a single procedure: future studies could be more aimed to prospective goals where occupational exposures per procedure are monitored specifically.

Coronary Artery Bypass as Adequate Treatment for Entrapped Coronary Angioplasty Catheter

A 47-year-old man presenting with stable angina pectoris was admitted for elective coronary angioplasty. After balloon angioplasty and uneventful deployment of the stent in the right coronary artery, the angioplasty catheter became entrapped between the stent and the wall of the right coronary artery. During attempts at percutaneous retrieval of the retained catheter, it was inadvertently broken and became embedded near the stent. The patient was stable during the procedure with no electrocardiographic changes. He underwent emergency triple coronary artery bypass, leaving the piece of catheter in situ. He had an uneventful postoperative recovery. After six months, he was angina-free with no electrocardiographic changes.

Coronary vein angioplasty to facilitate implantation of left ventricular lead

Stenosis in the coronary veins can cause the failure of left ventricular (LV) lead implantation, which is the cornerstone of cardiac resynchronization therapy (CRT). There are several cases in which LV pacing could be possible after successful elimination of coronary vein stenosis by coronary vein angioplasty. The study was conducted to investigate the efficacy of coronary vein angioplasty with an aim to a facilitate implantation of LV lead. Transvenous LV leads were implanted in 118 consecutive patients from November 2001 to January 2009. Retrospective analysis performed by the CRT system showed that 3 of 118 patients (2.54%) needed coronary vein angioplasty to facilitate the lead placement. Each target vein was successfully dilated by using coronary balloon angioplasty catheters of 2.5 mm (2 patients) and 3.0 mm (1 patient). Then the LV leads could be inserted and there were no complications. Coronary vein angioplasty is an effective and safe technique to make transvenous LV pacing lead insertion a possibility in case of target vein stenoses.

How firms set prices for medical materials: A multi-country study

This study presents a comparison of medical material prices, discusses why differences exist, and examines methods for comparing prices. Market prices for drug-eluting stents (DES), non-drug-eluting stents (non-DES), and percutaneous transluminal coronary angioplasty (PTCA) catheters were collected from five countries: the United States, Japan, Korea, Turkey, and Thailand. To compare prices, three adjustment methods were used: currency exchange rates, purchasing power parity (PPP), and gross domestic product (GDP) per capita. The ratios of medical material prices compared with those in the United States were higher in Japan (from 1.4 for DES to 5.0 for PTCA catheters) and Korea (from 1.2 for DES to 4.0 for PTCA catheters), and lower in Turkey (from 0.8 for non-DES to 1.4 for DES) and Thailand (from 0.5 for non-DES to 1.3 for PTCA catheters). The PPP-adjusted ratios changed slightly for Japan, Korea, and Turkey. When the prices were adjusted by GDP per capita, the ratios were much higher. Comparing prices using currency exchange rates or PPP is applicable only between countries with stable economic relations; adjustment by GDP per capita reflects the actual burden. Further study is needed to fully elucidate the factors influencing the global medical material market.

Reprocessing single-use cardiac catheters for interventional cardiology. A cost-minimization model for estimating potential saving at departmental scale and national level

Background: The utilization of single-use percutaneous catheters (SUDs) is a common practice in interventional cardiology, but the increasing of cardiac interventions and the consequent economic load demand for assessing SUDs’ reuse. The study aimed at estimating the potential saving for Italian cardiology departments in the hypothesis that reprocessing and reuse of SUD is performed by guaranteeing safety and efficiency of the reconditioned device as high as the new marketed one. Methods: A cost-minimization model was applied from the perspective of the health national service. Input parameters for the model were settled by reviewing published data on technical, hygiene and functional properties of reprocessed electrophysiology (EP) and percutaneous transluminal coronary angioplasty (PTCA) catheters. Potential saving at department level was calculated as percentage of the actual expenditure for purchasing single-use devices. Two-ways sensitivity analysis was conducted on main cost drivers. Finally, saving at national level was estimated. Results: The revision of technical and safety data showed the feasibility of reprocessing and reuse of EP and PTCA catheters under determined constrains. Potential savings of 39%, and 12% were calculated at department level for EP and PTCA catheters, respectively. Sensitivity analysis showed saving was dependent primarily on departmental workload. Major variations in saving occurred in the range between one and 200 catheters per year. The cut-off between benefit and charges was also related to regeneration rate and maximum number of uses. The estimate of potential saving at national level ranged in the interval from €19.85M to €24.24M. Conclusions:When safety and efficiency is assured by certified reuse processing, substantial saving could be achieved both at departmental and national level contributing to optimize budget allocation for the healthcare system.

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.

Price Disparity of Percutaneous Coronary Intervention Devices in Japan and the United States in 2006

The price disparity between Japan and foreign countries for medical devices is a controversial issue. Price differences existed between Japan and USA for various medical devices in early 2005, so in the present study, a more precise and detailed investigation of the latest market prices of medical devices between Japan and USA was conducted in 2006, focusing on coronary stents and percutaneous transluminal coronary angioplasty (PTCA) catheters, for an evaluation of the efficacy of current Japanese policies. Japanese market prices were obtained from 31 university hospitals, and US market prices were obtained from 1 hospital chain and 2 group-purchasing organizations. The price ratio (Japanese market price/US market price) was determined to be 1.2-1.4 for drug-eluting stents (DES), 1.6-2.4 for non-DES, and 4.1-5.1 for PTCA catheters. Results showed that the price disparity was relatively small for DES, but still significant for non-DES and PTCA catheters. Radical measures must be taken to improve the fundamental causes of price disparity and might include reviewing the implementation of the Japanese Pharmaceutical Affairs Law, abolishing the reimbursement price system for medical devices, and establishing centers of clinical excellence.

Efficacy of Coronary Venoplasty for Left Ventricular Lead Implantation

Optimal target vein selection for the pacing lead results in a better outcome, but left ventricular (LV) variability limits this selection. The aim of the present study was to investigate the efficacy of coronary venoplasty for insertion of a LV lead. Transvenous LV lead placement was attempted in 208 consecutive patients from November 2002 to January 2007, with success in 206 patients (99%). Retrospective analysis of the cardiac resynchronization therapy system implantation showed that 4 of the 206 patients (1.9%) required coronary venoplasty for insertion of the pacing lead implant. Using coronary balloon angioplasty catheters of 2.5 mm (2 patients), 3.0 mm (1 patient) and 4.0 mm (1 patient), each target vein was dilated. Of 4 patients, stenoses in 3 were dilated by balloon angioplasty only. However, focal stenosis of 1 patient was not able to be dilated due to severe stenosis. Therefore, part of the lesion was sharpened by rotational atherectomy and the stenosis was successfully dilated. The LV pacing lead could then be inserted and no complications occurred. Venoplasty for stenosis was effective in allowing deployment of a LV lead into a target vein in some patients. The safety and complications of the procedure remain unclear.

Functional properties and performance of new and reprocessed coronary angioplasty balloon catheters

The need of health costs control has prompted the reuse of devices originally manufactured for single use only. To assess reprocessing feasibility of disposable medical devices, hygienic, technical, and functional aspects must be taken into account in addition to economical, ethical, and legal implications. This study aims to characterize coronary angioplasty catheters and to evaluate performance changes induced by reprocessing. Multiple analysis including crossing profile, slipperiness, compliance, mechanical, and burst pressure tests were performed at different steps of the protocol on 25 catheters reprocessed up to two times. The results highlighted that both use and reprocessing can affect the features of angioplasty catheters. Mechanical stress caused by clinical inflation and thermal-chemical stress undergone by polymers during cleaning and sterilization procedures caused partial modifications of material properties, inducing an overall shrinking effect on balloons. Compliance tests reported a maximum variation of 6.2% from nominal values, showing the conformity of reprocessed devices with manufacturers' original specifications (+/-10%). The burst pressure of reprocessed devices was 80% higher than the rated burst pressure certified by manufacturers, thus reducing concerns of breakage during reuse. A strict dependence on device model in the behavior of catheters was found, especially for balloons crossing profile and slipperiness. Main changes occurred after the first reprocessing cycle, while a second cleaning and sterilization did not introduce further significant alterations. On the whole, the magnitude of modifications introduced up to two reprocessing cycles did not compromise catheters performance.

A simple method for generating a blood pressure-unit activity relationship for central cardiovascular neurons in the rat.

One way to identify central cardiovascular neurons is to consider their barosensitivity, for example by plotting changes in their single unit activity as a function of evoked changes in blood pressure. To simplify the genesis of such pressure-activity relationships, a coronary angioplasty catheter was threaded into the aorta of anaesthetized rats and the balloon inflated to raise the blood pressure mechanically. Here, such a procedure is exemplified for cardiac vagal motoneurons in the medulla oblongata in eight rats. This simplification bypasses potentially problematic surgery and minimizes deterioration of the animal.

Next generation catheters for excimer laser coronary angioplasty.

In response to the need for maximising debulking in complex lesions, three new excimer laser coronary angioplasty catheter designs have been introduced. The eccentric laser catheter features a fibreoptic bundle disposed opposite the guide-wire lumen at the catheter tip and a torque mechanism that allows the user to rotate the fibre bundle toward the lesion mass. Residual lumens 50% larger than the catheter tip diameter have been obtained when multiple passes were made, with each pass performed using a different tip rotation. A recent case series utilising this catheter in restenosed stents resulted in larger lumens and lower 6-month restenosis rates. The optimal spaced (OS) laser catheter features a fibre bundle placed concentrically around the guide-wire lumen. The 61 microm diameter core fibres are spaced at a nominal centre-to-centre distance of 90 microm, resulting in a 40% increase in ablative area as compared to previous concentric catheter designs. In vitro testing and clinical evaluation demonstrated OS catheters routinely achieve an ablated area > or =90% of the catheter tip size. The 0.9 mm catheter features a high-density fibre pack composed of 65 fibres. Peripheral dead space has been minimised to maximise penetration of calcified plaque. When combined with laser parameters of up to 80 mJ/mm2, and 80 Hz pulse repetition rate, the catheter demonstrated improved hard tissue and calcified tissue penetration in vitro. Clinical evaluation in Canada revealed a 94% lesion recanalisation rate in high-grade stenoses with angiographic evidence of calcification, chronic total occlusions, and lesions which have failed balloon angioplasty.

The History of Balloon Valvuloplasty

The birth of therapeutic balloon dilation in the management of cardiovascular disease can be traced to Rashkind who in 1966 developed balloon atrial septostomy for palliation of patients with complete transposition of the great vessels. Actually, Dotter and Judkins anteceded Rashkind by coaxial sequential dilation of iliofemoral atherosclerotic obstruction in 1964. However, it was not until the development by Grüntzig in 1978 of a miniaturized flexible balloon catheter for percutaneous transluminal coronary angioplasty that therapeutic balloon dilation began to be applied to stenotic heart valves. The development of percutaneous balloon valvuloplasty was the natural consequence of the early success of surgical mechanical dilation of stenotic heart valves; first the pulmonic valve, then the mitral valve, and finally the aortic valve. The successful relief of valvular stenosis by percutaneous balloon valvuloplasty is a remarkable example of how the pioneering cardiac surgeons paved the way for interventional cardiologists to take over the treatment of heretofore, surgically managed diseases.

The effects of acute coronary occlusion on noninvasive echocardiographically derived systolic and diastolic myocardial strain rates

Purpose To compare the magnitude and rates of change of peak systolic (ϵ ′ SYS) and diastolic (ϵ ′ DIAS) strain rates, as measured using tissue Doppler echocardiography, to pressure and volumes left-ventricular indices during acute coronary occlusion. Methods Six closed-chest dogs had a combination high-fidelity conductance pressure transducer placed into the left ventricle for determination of end-diastolic and end-systolic pressures (EDP and ESP) and volumes (EDV, ESV, and ejection fraction [EF]). Other indices included the time constant of left-ventricular relaxation (τ), +dP/dt max, −dP/dt max, end-systolic pressure/volume index (ESPV). A coronary angioplasty catheter was positioned into the left-anterior descending coronary artery. During coronary occlusion, strain rates and hemodynamic parameters were recorded continuously for 2 minutes. Results During occlusion, significant decreases in strain rates occurred within 30 seconds. Systolic indices (ESPV and +dP/dt max) changed at rates similar to ϵ ′ SYS (each p = NS). Diastolic indices (τ, EDP, EDV, −dp/dt max) also changed at rates similar to ϵ ′ DIAS (each p = NS). However, EF decreased at a significantly slower rate than did strain rates (p < 0.05). CONCLUSIONS: Peak systolic and diastolic strain rates decrease with acute ischemia similar to corresponding indices of left-ventricular systolic and diastolic function. Strain rates may be used in the noninvasive assessment of ischemic-induced left-ventricular dysfunction.