Thoratec Ventricular Assist Device Research Articles

Use of Ventricular Assist Devices in Patients with Mitral Valve Prostheses

Use of ventricular assist devices (VADs) in patients with prosthetic valves may carry an increased risk of thromboembolism; however, clinical information is lacking. The aim of this study was to report our experience of the use of VADs in patients with prosthetic mitral valves. A retrospective analysis of 747 VAD patients from January 1995 to May 2010 was performed. Thirteen patients with a prosthetic mitral valve (average age 56 ± 10 years of age, nine mechanical valve, four biological valve) were identified. Indications for VAD implantation were as a bridge to transplant in 11 patients and destination therapy in two patients. At the time of VAD implant, no intervention to the prosthetic mitral valve was performed. Eight patients received a HeartMate I (Thoratec Corporation, Pleasanton, CA, USA), three patients received a HeartMate II (Thoratec Corporation), and two patients received a Thoratec VAD (Thoratec Corporation). Among nine mechanical valve patients, six patients were anticoagulated with warfarin, and one patient with heparin, while two patients did not receive anticoagulation due to bleeding. Ten patients were successfully transplanted at an average of 123 days post-VAD implant, one died after 48 days from multiorgan failure, and two remained on VAD support. No clinical thromboembolic events were observed. No intracardiac thrombus was detected by echocardiogram or on the pathology of the explanted hearts. Five patients had experienced a bleeding event (postoperative mediastinal bleeds, gastrointestinal bleedings, retroperitoneal hematoma, and subconjuctival bleeding). In patients with mitral valve prostheses who require VAD support, leaving the prosthesis intact does not increase the incidence of adverse events.

Extracoporeal Membrane Oxygenation Hybrid With Thoratec Ventricular-Assist Devices as Double Bridge to Heart Transplantation

Ventricular-assist devices (VADs) have benefitted patients with end-stage heart failure as a bridge to heart transplantation (HTx). Herein, we describe our experience with HTx in the presence of extracorporeal membrane oxygenation (ECMO) together with the Thoratec VAD (Thoratec Corp, Pleasanton, California). From May 1996 to June 2009, mechanical circulatory support with the Thoratec VAD was provided in 20 patients. Before implantation of the VAD, circulation in 17 patients was maintained using ECMO. Although 350 patients underwent HTx during that period, only 13 patients (65%) received suitable donor organs for orthotopic HTx. The 20 patients ranged in age from 10 to 80 years; 3 were female, and 17 were male; and 17 (85%) required ECMO before VAD implantation. In 11 of 17 patients (65%), the VAD was implanted as a double bridge to HTx. The demand for mechanical circulatory support in patients with acute hemodynamic collapse has led to major improvements in clinically available systems such as ECMO as a double bridge to VAD implantation. We use ECMO as a rescue procedure in patients with acute hemodynamic deterioration. However, during ECMO support, left ventricular afterload increases. If prolonged support is necessary, a VAD may be required. We observed that 65% of patients who received support from an ECMO hybridized with the Thoratec VAD could wait for a suitable donor for HTx. We recommend use of ECMO for short-term support (<1 week) and the Thoratec VAD for medium- or long-term support as a bridge to HTx.

360: In Vivo Assessment of Thrombogenicity of the Penn State Pediatric Ventricular Assist Device

Penn State has recently completed the design and feasibility testing of a pulsatile pediatric Ventricular Assist Device (VAD) under the 5 year NHLBI contract program “Pediatric Circulatory Support”. The Infant VAD is a pneumatically-actuated pulsatile pump with a 14 ml stroke volume, based on the adult Thoratec (Pierce-Donachy) VAD. The Pediatric VAD may provide left, right, or biventricular support for long term bridge-to-transplant or weaning applications. The primary design objective has been to minimize thromboembolic risk; thrombogenicity has been assessed in 30 day chronic animal studies.

Australian Experience with VAD as a Bridge to Paediatric Cardiac Transplantation

The Royal Children's Hospital, Melbourne is the National Paediatric Heart Transplant Centre of Australia. A variety of ventricular assist devices (VADs) have been used effectively as a bridge to heart transplantation in adult patients, however, the experience in the paediatric population is limited. We present our initial experience using the Thoratec and Medos VAD systems as a bridge to heart transplantation in the designated centre for paediatric cardiac transplantation in Australia. The medical records of all patients supported with a Thoratec or Medos VAD at the RCH from July 2005 to July 2007 were retrospectively reviewed. Seven patients between 5 and 16 years of age were supported with the Thoratec or Medos VAD during the period of study. All of the patients were supported with a left sided ventricular assist device (LVAD). The length of time supported ranged from 6 to 230 days, with a median of 22 days. Co-morbidities included surgical re-exploration for bleeding, cannula site wound infections and thromboembolic events. Two patients died before a donor heart became available. From our limited experience, the use of a VAD as a bridge to heart transplantation is a feasible option for children with end stage cardiac failure.

First Clinical Application of the DuraHeart Centrifugal Ventricular Assist Device for a Japanese Patient

The DuraHeart ventricular assist device (VAD) is a third-generation implantable centrifugal pump with a magnetically levitated impeller. Since February 2007, the device has been clinically applied with excellent results as a bridge to heart transplantation in Europe. As of this writing, however, the device has yet to be approved by the Ministry of Health, Labour and Welfare for clinical use in Japan. We herein report the first clinical application of this device for a Japanese patient. A 31-year-old man with dilated cardiomyopathy was transferred to the Heart and Diabetes Center NRW (HDZ-NRW) in Bad Oeynhausen, Germany, where he was to await heart transplantation. The transfer was safely completed under management with low-dose dopamine. His condition gradually deteriorated at HDZ-NRW, and the DuraHeart left ventricular assist device was implanted for the left ventricle at 7 weeks after admission. Shortly thereafter, however, on POD 7, a Thoratec VAD had to be inserted on the right side due to refractory right heart failure. The right ventricular assist device could be explanted after a 3-month assist, and the patient is now waiting for heart transplantation at home in Germany.

Anaesthesia for non-cardiac surgery in a patient with Beckerʼs muscular dystrophy supported with a left ventricular assist device

The Section and Board of Anaesthesiology of the European Union of Medical Specialists aims (EUMS/UEMS) at harmonization of training of anaesthesiologists and at improvement of patient care throughout Europe. Pain medicine is considered to be an area of expertise in anaesthesiology although exclusivity is not claimed. The Section and Board has approved both a core syllabus for pain medicine to be part of the specialist training in anaesthesiology and an additional qualification in pain medicine following the completion of a 5 yr basic specialty training in anaesthesiology. These proposals were prepared by the Working Party on Pain Medicine of the Section and Board. It considers a multidisciplinary approach to pain to contribute to quality in care and has taken the initiative to set up a Multidisciplinary Joint Committee on Pain Medicine within the EUMS/UEMS, for which these guidelines define the area of expertise of anaesthesiology.

Introduction of the Thoratec Ventricular Assist Device into a Paediatric Tertiary Hospital

Introduction of the Thoratec Ventricular Assist Device into a Paediatric Tertiary Hospital

Extracorporeal Membrane Oxygenation Hybrid With Various Ventricular Assist Devices as Double Bridge to Heart Transplantation

Ventricular assist devices (VAD) have benefitted patients with end-stage heart failure as a bridge to heart transplantation (HTx). We present our experience with HTx after an extracorporeal membrane oxygenation (ECMO) hybrid with various ventricular assist devices (VAD). From May 1996 to December 2003, mechanical circulatory support with a Biopump VAD was performed in eight patients, HeartMate left VAD in eight patients, and Thoratec VAD in eight patients. Before VAD implantation, 19 patients maintained their circulation with ECMO. Half of the 24 patients were implanted with VAD to await a suitable donor for HTx. We observed that half of the patients supported by ECMO hybrid with various VAD awaited a suitable donor for HTx. In our experience, we recommend the application of ECMO for short-term support within 1 week and the Biopump VAD, Thoractec VAD, or HeartMate VAD for medium-term or long-term support as a bridge to HTx.

Management of a Patient With Right Ventricular Drainage Cannula Obstruction After Biventricular Assist Device Implantation

VENTRICULAR ASSIST DEVICES (VADs) are increasingly used for treatment of end-stage heart failure.1-3 The Thoratec VAD (Thoratec Corp, Pleasanton, CA) is designed to support the pulmonary and/or systemic circulation when the patient’s heart is unable to maintain adequate perfusion with conventional therapy, often as a bridge to transplantation. An interesting complication of right ventricular cannulation and the related anesthetic management are described.

Clinical Outcomes in Pediatric Patients Implanted With Thoratec® Ventricular Assist Device

Most mechanical circulatory support devices are designed for adult patients; however, some can be successfully applied to pediatric patients. The rates of complications and patient survival to transplant or native heart recovery after implantation of the Thoratec ventricular assist device (VAD) (Thoratec Corp, Pleasanton, CA) in children and adolescents were determined from the company's voluntary registry. As of January 2005, 209 patients (mean age 14.5 years; range 5 to 18 years) have been supported with the Thoratec VAD. Mean patient weight was 57 kg (range, 17 to 118 kg), and patients had a mean body surface area of 1.6 m2 (range, 0.73 to 2.3 m2). The major etiologies necessitating VAD support included cardiomyopathy (55.0%), acute myocarditis (25.4%), and end-stage congenital heart disease (5.8%). Mean duration of VAD support was 44 days (range, 0 to 434 days). Patient survival to transplantation or native heart recovery was 68.4%. Patients with cardiomyopathy and acute myocarditis had 74.1% and 86.0% survival, respectively, with only 27.3% survival in patients having congenital heart disease. The overall survival rate in smaller children (body surface area, <1.3 m2) was similar at 51.7%, although the incidence of congenital heart disease was higher.

Pediatric Bridge to Heart Transplantation: Application of the Berlin Heart, Medos and Thoratec Ventricular Assist Devices

Bridge to transplantation (BTT) is an accepted option when a donor heart is not available. Extensive clinical study has been done with BTT in the adult population, but comparatively fewer data are available in the pediatric population with regard to pulsatile devices. Ten pediatric patients are presented, all of whom underwent BTT or recovery with pneumatic paracorporeal systems. The Berlin Heart bi-ventricular assist device (BVAD) was utilized in 1 patient, the Medos VAD in 4 patients (1 left ventricular assist device [LVAD], 3 BVADs) and the Thoratec VAD in 5 patients (3 BVADs, 2 LVADs). The pediatric population consisted of 3 females and 7 males. Mean age of the population was 7.4 years, weight 25 kg and body surface area (BSA) 0.88 m(2). Etiology for heart failure consisted of 4 viral, 3 congenital and 3 idiopathic cardiomyopathies. Before implant, all patients had evidence of progressive cardiac failure despite inotropic support, and 2 patients had been on extracorporeal membrane oxygenation (ECMO). Mean duration on the device was 34.3 days (8 to 107 days). Two patients suffered stroke and recovered without sequelae. Two patients died of ischemic stroke and 1 of sepsis. Seven patients survived (6 transplanted and 1 weaned) for a survival rate of 70% compared with survival for ECMO as BTT, which was 40% to 50%. All survivors had complications related to bleeding, thromboembolic events and infections. The Thoratec VAD can be placed in small patients with large hearts that can accommodate the available cannulas. The Berlin Heart and the Medos VAD have a selection of ventricles with small stroke volumes. All 3 systems can be used successfully in the pediatric population as BTT with better survival than with ECMO.

Thoratec Ventricular Assist Devices in Pediatric Patients: Update on Clinical Results

Particularly in pediatric patients, mechanical circulatory support remains a clinical challenge. We analyzed the Stanford experience with use of the Thoratec ventricular assist device (VAD) in children and adolescents and data from the company's voluntary database. Through January 2005, 209 patients up to 18 years of age have been supported with the Thoratec VAD worldwide. Mean age was 14.5 years (range 5-18 years), mean weight was 57 kg (range 17-118 kg), and mean body surface area was 1.6 m2 (range 0.7-2.3 m2). The majority of patients were supported for cardiomyopathies (55%) and acute myocarditis (25%). A minority (6%) was treated for end-stage congenital heart disease. Average duration of support was 44 days (0-434 days). Overall survival to transplantation or weaning off the device was 68%. Survival rates were higher for patients with cardiomyopathies (74%) and acute myocarditis (86%) compared with patients with congenital heart disease (27%). We performed a subanalysis in small children with a body surface area of less 1.3 m2. This subgroup had a higher incidence of congenital heart disease and a slightly lower survival (52%). Aspects of the particular risks and device management in these small patients are discussed.

CLINICAL DECISION SUPPORT SYSTEM FOR OPTIMAL VAD WEANING

Ventricular Assist Devices (VADs) have demonstrated their therapeutic role in cardiac rehabilitation. However, due to the complexities of caring for these patients and the relatively limited clinical experience, identifying candidates for weaning remains challenging. This study proposes the use of a Clinical Decision Support System (CDSS) to both aid in the identification of VAD weaning candidates, and as a tool for predicting patient outcome. Based upon the UPMC VAD weaning experience, three CDSS models were developed: an expert model, a data model, and an expert/data hybrid model. The decision structures of the expert model were elicited from an 11 member, multi-disciplinary panel through a series of structured interviews and polls. Pattern recognition through Artificial Neural Networks and Natural Language Processing was used to analyze patient data and acquire the decision structures for the data model; all patients receiving a Thoratec VAD which were considered for weaning between 1996 and 2004 (n=19), regardless of outcome, were included in this study. Decision structures were modeled using Bayesian Belief Networks and their predictive values were assessed. A user interface, based on a pocket-PC, was developed to anticipate the translation of this system to clinical practice. The hybrid model, consisting of a 21-parameter health screening and a 3-tier evaluation of cardiac recovery, was the best predictor of outcome, predicting 90% true weans, 100% true transplants, 0% false weans and 10% false transplants. By objectively combing knowledge from experts and data, this study illustrates how a CDSS can facilitate the decision making processes for identifying VAD weaning candidates and promote responsible and widespread use of VADs for cardiac rehabilitation.

Comparison of infections in the CardioWest TAH, the Novacor Left Ventricular Assist System and the Thoratec Ventricular Assist Device in 137 patients

Comparison of infections in the CardioWest TAH, the Novacor Left Ventricular Assist System and the Thoratec Ventricular Assist Device in 137 patients

Heart transplantation in the patient under ventricular assist complicated with device-related infection

Ventricular assist devices (VAD) have benefited patients with end-stage heart failure as a bridge to heart transplantation (HTx). We present our experience of HTx in the presence of device-related infection (DRI) including driveline exit site with pocket infections. From May 1996 to April 2003, mechanical circulatory support with the HeartMate VAD was performed in eight patients, and with the Thoratec VAD in seven patients. Although 151 patients underwent HTx during that period, only 8 of the 15 patients had suitable donors and underwent orthotopic HTx. Six of the eight patients developed DRI. Their ages ranged from 18 to 59 years (mean = 36 ± 14 years). The duration of VAD support ranged from 8 to 287 days (mean = 125 ± 117 days). The general condition and cardiac function improved gradually under VAD support. At the time of HTx, all six male patients were suffering from DRI. The causative microorganisms were Acinetobacter baumannii ( n = 3) methicillin-resistant Staphylococcus aureus ( n = 2), and Enterococcus faecium ( n = 1). All patients underwent successful HTx, and were discharged in good condition. It is concluded that under the coverage of appropriate antibiotics, HTx can be successfully performed for the patients for VAD support with DRI. It is important to prevent the spread of infection during HTx. Adequate debridement and drainage of the infected materials prevents postoperative wound infections.

Biostability of Thoralon Left Ventricular Assist Device Blood Pumping Sacs After Long-Term Clinical Use

The purpose of this paper is to investigate the biostability of Thoralon polyurethane blood pumping sacs that have been used for up to 14 months in the Thoratec ventricular assist device (VAD) in human subjects. Thoralon is a proprietary polyetherurethaneurea (PEUU) blended with siloxane based surface modifying additive (SMA). Samples of Thoralon blood sacs that were used in Thoratec LVAD pumps for 53, 171, 336, and 434 days were taken from three distinct regions identified as high flex, medium flex, and low flex for physicochemical analysis. Explanted samples exhibited a slight but not significant increase in physical properties. The molecular weight of the blood sacs had also increased significantly in all blood sacs regardless of duration of use. SEM images did not indicate any cracking, pitting, or surface erosion; however, in a small area of the high flex region of the 336 day sac some biofilm was seen. The Attenuated Total Reflectance Fourier Transform Infra Red Spectroscopy (ATR-FTIR) analysis showed no significant reduction of surface ether content. The surface chemistry analyzed using Electron Spectroscopy for Chemical Analysis (ESCA) also indicated no significant change compared with control. These results confirm the biostability of Thoralon for long-term clinical applications in the Thoratec VAD.

Ventricular assist devices as a bridge to cardiac transplantation: the Ottawa experience.

This article reports our experience with ventricular assist devices (VADs) as a bridge to cardiac transplantation. From 1991 to 2003, a total of 42 patients received a Thoratec VAD (Thoratec Laboratories Corporation Inc., Pleasanton, CA, U.S.A.) (Group T) and 12 patients received a Novacor VAD (WorldHeart Corporation, Ottawa, Canada) (Group N). Thirty Thoratec patients were transplanted compared to six in the Novacor group. Four more Novacor patients are still supported. Of the transplanted patients, 87% survived to hospital discharge in Group T and 67% in Group N. Infections affected 29% and 50% of Group T patients during support and post-transplantation, respectively, compared to 25% and 0%, respectively, in Group N. Neurologic complications affected 33% of patients in each group during support. Reopening rates for bleeding during support were 45% and 42% in Groups T and N, respectively. There were no significant differences in outcomes between the two groups. Our study demonstrated the effectiveness of VADs in bridging mortally ill cardiac patients to successful heart transplantation.

Morbidity reduction with the thoratec ventricular assist device (TVAD) for CHF using improved management strategies: a 12 year experience

Morbidity reduction with the thoratec ventricular assist device (TVAD) for CHF using improved management strategies: a 12 year experience

Implantation of the Thoratec Ventricular Assist Device

The Thoratec ventricular assist device (VAD) (Thoratec Corporation, Pleasanton, CA) has been extensively used as the standard therapy for bridge-to-transplant and postcardiotomy failure to wean from cardiopulmonary bypass.1 Recent clinical data suggest that myocardial recovery and improved cardiac function occur in some patients over a period of weeks to months of mechanical ventricular support, allowing removal of the VAD.2 Long-term studies of patients with the Thoratec VAD who recovered and were weaned from the device showed that 1- and 5-year survival rates were essentially identical to VAD patients who received a heart transplant.

And hemolysis goes on: ventricular assist device in combination with veno-venous hemofiltration

Background. Ventricular Assist Device (VAD) is an accepted treatment as a bridge to cardiac transplantation, and may be of help in patients as destination therapy for end-stage cardiac failure. The low output state associated with end-stage cardiac failure predisposes patients to renal dysfunction and the need for short-term renal support. The use of cardiopulmonary bypass for VAD insertion, VAD, and hemofiltration expose the blood to mechanical trauma and activated inflammatory cascades that can result in hemolysis. This produces free hemoglobin, a known nephrotoxin; this is a further renal insult. This study assesses the effect of VAD alone and in combination with continuous veno-venous hemofiltration (CVVHF) on hemolysis. Methods and Results. From July 1999 to December 2000, Thoratec VAD was used in 11 patients. Nine (all males) were included in this study as all had laboratory profiles. Hemolysis was quantified by plasma free hemoglobin (PFHb) and hydroxybuterate dehydrogenase (HBD) levels measured daily, defined as PFHb level greater than 40 mg/L and HBD greater than 250 IU/L. Data relate to the following time intervals while the VAD was still in situ: T 1 = 24 hours post-VAD insertion, T 2 = 24 hours post-CVVHF start, T 3 = 48 to 72 hours with the same CVVHF circuit, T 4 = 24 hours post-stopping of CVVHF, and T 5 = CVVHF off for over 48 hours. The mean (SD) PFHb levels were 19.6 (10.9) at T 1, 31.7 (0.6) at T 2, 93.7 (16.4) at T 3 ( p < 0.05), 32.5 (20.9) at T 4, and 14.2 (3.8) at T 5 ( p < 0.05). These changes were paralleled by the mean (SD) HBD levels: T 1 = 1,337 (616), T 2 = 2,025 (509), T 3 = 2,676 (1,170) ( p < 0.05), T 4 1,780 (618), and T 5 = 1,310 (436). Conclusions. Thoratec VAD was associated with a mild degree of hemolysis. This was worsened by concomitant use of CVVHF. The effect was accentuated if the same CVVHF circuit was used for over 48 hours but was reversible within 24 hours of stopping the hemofilter.