CONGESTIVE HEART FAILURE, Issue 2 2010
Scott Harris DO
Background LVAD therapy is an established treatment modality for patients with advanced heart failure. Pulsatile LVADs have limitations in design precluding their use for extended support. Continuous-flow rotary LVADs represent an innovative design with potential for small size and greater reliability by simplification of the pumping mechanism. Methods In a prospective multicenter study, 281 patients urgently listed (United Network for Organ Sharing status 1A or 1B) for heart transplant underwent implant of a continuous-flow LVAD. Survival and transplant rates were assessed at 18 months. Patients were assessed for adverse events throughout the study and for quality of life, functional status, and organ function for 6 months. Results Of 281 patients, 222 (79%) underwent transplant or LVAD removal for cardiac recovery or had ongoing LVAD support at 18-month follow-up. Actuarial survival on support was 72% (95% confidence interval, 65%,79%) at 18 months. At 6 months, there were significant improvements in functional status and 6-minute walk test results (from 0% to 83% of patients in New York Heart Association functional class I or II and from 13% to 89% of patients completing a 6-minute walk test) and in quality of life (mean values improved 41% with Minnesota Living With Heart Failure and 75% with Kansas City Cardiomyopathy questionnaires). Major adverse events included bleeding, stroke, right heart failure, and percutaneous lead infection. Pump thrombosis occurred in 4 patients. Conclusions A continuous-flow LVAD provides effective hemodynamic support for at least 18 months in patients awaiting transplant, with improved functional status and quality of life. [source]

To Explant or Not to Explant: An Invasive and Noninvasive Monitoring Protocol to Determine the Need of Continued Ventricular Assist Device Support

CONGESTIVE HEART FAILURE, Issue 2 2009
Satoru Osaki MD
Predictors of myocardial recovery after ventricular assist device (VAD) implantation are not well defined. The authors report their current VAD weaning protocol. Between 2003 and 2006, 38 patients received VAD implants. The authors performed 5 tests in 4 patients in whom echocardiography findings suggested myocardial recovery after implant. The protocol consists of assessing symptoms, electrocardiographic findings, hemodynamics, and cardiac function at baseline and as VAD support is weaned. As a result, 3 patients passed the weaning protocol and were explanted. There has been no recurrence of heart failure 667, 752, and 1007 days after explant, respectively. One patient failed the protocol after 151 days of support because of low cardiac index during the protocol. This patient was transplanted. This current experience of VAD weaning protocol is a novel tool to identify candidates for successful VAD explantation. [source]

Spontaneous Echocardiographic Contrast in the Ascending Aorta Mimicking the Appearance of Aortic Dissection in a Patient with a Left Ventricular Assist Device

ECHOCARDIOGRAPHY, Issue 2 2004
Dermot G. Nicolson M.B.B.Ch.
We describe a patient with a previously implanted Jarvik 2000 left ventricular assist device (LVAD), who presented with bacteraemia and with features suspected for aortic dissection at the CT scan. However, transesophageal echocardiography showed competition in the ascending aorta between the retrograde pump flow and the anterograde transaortic output, which mimicked true aortic dissection and could be resolved by lowering the pump speed. As patients with LVAD are increasing in number, clinicians should be aware of this possible effect. (ECHOCARDIOGRAPHY, Volume 21, February 2004) [source]

The Use of the Impella® LP 2.5 Percutaneous Microaxial Ventricular Assist Device as Hemodynamic Support During High-Risk Abdominal Surgery

JOURNAL OF CARDIAC SURGERY, Issue 2 2010
Rony Atoui M.D.
In cases when these patients require mechanical circulatory support while undergoing emergent or elective operations, perioparative monitoring becomes of paramount importance.,(J Card Surg 2010;25:238-240) [source]

Fungemia Associated with Left Ventricular Assist Device Support

JOURNAL OF CARDIAC SURGERY, Issue 6 2009
M.P.H., Natasha G. Bagdasarian M.D.
While relatively uncommon, fungal infections present a serious concern given a high association with adverse events including death. We sought to further characterize the epidemiology of fungemias during LVAD support. Methods: Retrospective review of 292 patients receiving LVAD support from October 1996 to April 2009 at the University of Michigan Health System was done. Results: Seven cases of LVAD-associated fungemia were observed during the study period (0.1 infections/1000 days of device support). Five patients had infection with Candida species and two with Aspergillus species. The two patients with Aspergillus infection presented with disseminated disease, quickly dying of multiorgan failure, and sepsis. All five patients with Candida infections were successfully treated with systemic antifungal therapy along with transplantation in four of five patients. The fifth patient is receiving mechanical support as destination therapy. He remains on long-term suppression with high-dose fluconazole. Conclusions: Fungal infections appear to be a rare but serious complication of LVAD support. Future studies should aim to improve our understanding of risk factors for fungal infection during mechanical support, especially disseminated Aspergillus. Short-term perioperative antifungal prophylaxis with fluconazole appears to be an effective and reasonable approach to prevention. [source]

Explantation of INCOR Left Ventricular Assist Device After Myocardial Recovery

JOURNAL OF CARDIAC SURGERY, Issue 6 2008
Ph.D., Takeshi Komoda M.D.
We describe improved surgical techniques for INCOR LVAD explantation. Methods: The outcome of INCOR LVAD implantation at our center and the operative techniques of device explantation were studied. The patients weaned from the device were followed up. Results: Out of 121 patients supported by the device, five (4.1 %) were weaned from the device, whereas 34 patients (28.1 %) underwent heart transplantation. In explantation surgery, the inflow cannula was removed (one case) or remained in the left ventricle after occlusion with an inflow cannula plug, with transection of the inflow cannula at its curve (two cases) or without transection (two cases). When the inflow cannula was occluded without the support of cardiopulmonary bypass (two cases), operative time (180 min and 210 min) was shorter than that with other explantation procedures. After mean follow-up of 2.4 years (range two months,four years) after device explantation, all five patients are alive, have not required heart transplantation and are in New York Heart Association class I (one case) or class II (four cases). After weaning from the device, no cerebrovascular complication was observed in any of the five patients. Conclusions: There is a possibility of weaning after INCOR implantation and surgical techniques for the removal of the INCOR LVAD should be further developed. [source]

Experience with over 1000 Implanted Ventricular Assist Devices

JOURNAL OF CARDIAC SURGERY, Issue 3 2008
Evgenij V. Potapov M.D.
We present our experience since 1987. Subjects and Methods: Between July 1987 and December 2006, 1026 VADs were implanted in 970 patients. Most of them were men (81.9%). The indications were: cardiomyopathy (n = 708), postcardiotomy heart failure (n = 173), acute myocardial infarction (n = 36), acute graft failure (n = 45), a VAD problem (n = 6), and others (n = 2). Mean age was 46.1 (range 3 days to 78) years. In 50.5% of the patients the VAD implanted was left ventricular, in 47.9% biventricular, and in 1.5% right ventricular. There were 14 different types of VAD. A total artificial heart was implanted in 14 patients. Results: Survival analysis showed higher early mortality (p < 0.05) in the postcardiotomy group (50.9%) than in patients with preoperative profound cardiogenic shock (31.1%) and patients with preoperative end-stage heart failure without severe shock (28.9%). A total of 270 patients were successfully bridged to heart transplantation (HTx). There were no significant differences in long-term survival after HTx among patients with and without previous VAD. In 76 patients the device could be explanted after myocardial recovery. In 72 patients the aim of implantation was permanent support. During the study period 114 patients were discharged home. Currently, 54 patients are on a device. Conclusions: VAD implantation may lead to recovery from secondary organ failure. Patients should be considered for VAD implantation before profound, possibly irreversible, cardiogenic shock occurs. In patients with postcardiotomy heart failure, a more efficient algorithm should be developed to improve survival. With increased experience, more VAD patients can participate in out-patient programs. [source]

Ventricular Flutter Induced During Electrophysiologic Studies in Patients with Old Myocardial Infarction:

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2003
Clinical, Electrophysiologic Predictors, Prognostic Significance
Introduction: Induction of ventricular flutter during electrophysiologic (EP) studies (similar to that of ventricular fibrillation [VF]) often is viewed as a nonspecific response with limited prognostic significance. However, data supporting this dogma originate from patients without previously documented ventricular tachyarrhythmias. We examined the significance of ventricular flutter in patients with and without spontaneous ventricular arrhythmias. Methods and Results: We conducted a cohort study of all patients with myocardial infarction (MI) undergoing EP studies at our institution. Of 344 consecutive patients, 181 had previously documented spontaneous sustained ventricular arrhythmias, 61 had suspected ventricular arrhythmias, and 102 had neither. Ventricular flutter was induced in 65 (19%) of the patients. Left ventricular ejection fraction was highest among patients with inducible VF (35 ± 13), lowest for patients with inducible sustained monomorphic ventricular tachycardia (SMVT; 27 ± 9), and intermediate for patients with inducible ventricular flutter (30 ± 10). Similarly, the coupling intervals needed to induce the arrhythmia were shortest for VF (200 ± 28 msec), intermediate for ventricular flutter (209 ± 27 msec), and longest for SMVT (230 ± 35 msec). During 5 ± 8 years of follow-up, the risk for ventricular tachycardia/VF was high for patients with SMVT and ventricular flutter and low for patients with inducible VF and noninducible patients (46%, 34%, 17%, and 14%, P < 0.005). Conclusion: Patients with inducible ventricular flutter appear to be "intermediate" between patients with inducible VF and patients with SMVT in terms of clinical and electrophysiologic correlates. However, the prognostic value of inducible ventricular flutter is comparable to that of SMVT. (J Cardiovasc Electrophysiol, Vol. 14, pp. 913-919, September 2003) [source]

Effect of Chronic Ethanol Ingestion and Gender on Heart Left Ventricular p53 Gene Expression

ALCOHOLISM, Issue 8 2005
Heidi Jänkälä
Background: Although the beneficial effects of mild to moderate ethanol consumption have been implied with respect to heart, alcohol abuse has proven to be a major cause of nonischemic cardiomyopathy in Western society. However, the biochemical and molecular mechanisms, which mediate the pathologic cardiac effects of ethanol, remain largely unknown. The aim of the present study was to explore the effects of chronic ethanol exposure on cardiac apoptosis and expression of some of the genes associated with cardiac remodeling in vivo. Methods: Alcohol-avoiding Alko Non Alcohol rats of both sexes were used. The ethanol-exposed rats (females, n= 6; males, n= 8) were given 12% (v/v) ethanol as the only available fluid from age of three to 24 months of age. The control rats (females, n= 7; males, n= 5) had only water available. At the end of the experiment, free walls of left ventricles of hearts were immediately frozen. Cytosolic DNA fragmentation, reflecting apoptosis, was measured using a commercial quantitative sandwich enzyme-linked immunosorbent assay kit, and mRNA levels were analyzed using a quantitative reverse transcriptase,polymerase chain reaction method. Results: Ethanol treatment for two years increased cardiac left ventricular p53 mRNA levels significantly (p= 0.014) compared with control rats. The gene expression was also dependent on the gender (p= 0.001), so that male rats had higher left ventricular p53 mRNA levels than female rats. However, no significant differences in levels of DNA fragmentation were detected. Conclusions: Chronic ethanol exposure in vivo induces rat cardiac left ventricular p53 gene expression. Expression of p53 is also gender-dependent, males having higher p53 mRNA levels than females. This preliminary finding suggests a role for the p53 gene in ethanol-induced cardiac remodeling. The results might also have some relevance for the known gender-dependent differences in propensity to cardiovascular disease. [source]

Laser Polishing in Medical Engineering

LASER TECHNIK JOURNAL, Issue 2 2010
Laser Polishing of Components for Left Ventricular Assist Devices
Cardiac surgery has made significant progress during the last 50 years. nowadays, almost every congenital or contracted dysfunction of the heart can be treated clinically or at least the etiopathology can be alleviated. During these years, implantable Left Ventricular Assist Devices (LVADs) have proven to be an effective and reliable medical product. In particular, the survival rate of patients with cardiac insufficiency has risen due to these devices. This type of heart-assist device is implanted either to bridge the time until cardiac transplantation or recovery has occurred, or for permanent implantation in the patient's body. Berlin Heart GmbH produces the clinically tested axial pump system INCOR® (Figure 1, above). The INCOR heart-as-sisting pump is a powerful implantable LVAD which has been used in more than 500 clinical applications. The main function of the axial pump is to unload the patient's heart by transporting blood from the left ventricle to the aorta. In order to assure high reliability of the pump's operation, the components used for blood transport have to be highly bio- and hemocompatible. [source]

Antitachycardia Pacing for Spontaneous Rapid Ventricular Tachycardia in Patients with Prophylactic Cardioverter-Defibrillator Therapy

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 7 2006
WOLFRAM GRIMM
Aims: Antitachycardia pacing (ATP) has not routinely been used in patients who received implantable cardioverter defibrillators (ICDs) for primary prevention of sudden death. This study investigated the efficacy of empirical ATP to terminate rapid ventricular tachycardia (VT) in heart failure patients with prophylactic ICD therapy. Methods and Results: Ninety-three patients with a mean left ventricular ejection fraction of 22 ± 7% (range: 9,35%) due to nonischemic or ischemic cardiomyopathy received prophylactic ICDs with empiric ATP. At least 2 ATP sequences with 6-pulse burst pacing trains at 81% of VT cycle length (CL) were programmed in one or two VT zones for CL below 335 ± 23 ms and above 253 ± 18 ms. Ventricular flutter and fibrillation (VF) with CL below 253 ± 18 ms were treated in a separate VF zone with ICD shocks without preceding ATP attempts. During 38 ± 27 months follow-up, 339 spontaneous ventricular tachyarrhythmias occurred in 36 of 93 study patients (39%). A total of 232 VT episodes, mean CL 293 ± 22 ms, triggered ATP in 25 of 36 patients with ICD interventions (69%). ATP terminated 199 of 232 VT episodes (86%) with a mean CL of 294 ± 23 ms in 23 of 25 patients (88%) who received ATP therapy. ATP failed to terminate or accelerated 33 of 232 VT episodes (14%) with a mean CL of 287 ± 19 ms in 12 of 25 patients (48%) who received ATP therapy. Conclusions: Painfree termination of rapid VT with empirical ATP is common in heart failure patients with prophylactic ICD therapy. The occasional inability of empiric ATP to terminate rapid VT in almost 50% of patients who receive ATP for rapid VT warrants restrictive ICD programming with regard to the number of ATP attempts in order to avoid syncope before VT termination occurs. [source]

Ventricular shunts and the prevalence of sensitization and clinically relevant allergy to latex in patients with spina bifida

PEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 2 2000
Dietke Buck
Patients with spina bifida represent the highest-risk group for developing hypersensitivity to latex. Recognized risk factors for these patients are repeated surgery and an atopic disposition. Our aim was to study the influence of a ventricular shunt as an independent risk factor. One hundred and sixty-one patients with spina bifida (median age 10 years) were investigated for the presence of a shunting device and the number, type and date of previous surgical interventions. Additionally, skin-prick tests and provocation tests were performed in order to classify sensitized and symptomatic latex-allergic individuals. Eighty-eight patients (54.7%) were sensitized; 55 (34.2%) were provocation-positive. Patients with a shunt system had undergone a significantly higher number of surgical procedures (p < 0.0001) and showed significantly higher levels of immunoglobulin E (IgE)-antibodies to latex (p < 0.0001) than patients without a shunting device. The total number of operations correlated significantly with the level of IgE-antibodies to latex in serum (p < 0.0001), whereas the number of shunt operations in patients with a ventricular shunt did not significantly correlate with the degree of sensitization. In conclusion, patients with spina bifida who have a ventricular shunt are at particularly high risk because they undergo a significantly higher number of operations than patients without a ventricular shunt. However, the ventricular shunt does not seem to be an independent risk factor. Furthermore, this study emphasizes that individuals at high risk, such as patients with spina bifida, should be handled latex-free from the very beginning of life. [source]

Outline of the International Organization for Standardization Standard for Circulatory Support Devices (ISO 14708-5)

ARTIFICIAL ORGANS, Issue 9 2010
Kou Imachi
Abstract The rapid progress of artificial heart and circulatory support devices enables us to apply them to severe heart failure patients. Many types of circulatory support devices have been developed in the United States, Europe, and Japan. This situation urged the establishment of an International Organization for Standardization (ISO) Standard for the circulatory support devices. A new work, "Cardiac Ventricular Assist Devices," was proposed to the ISO/TC150/SC6 (TC150: Technical Committee of Implants for Surgery, SC6: Sub-committee of Active Implants) in 2000, and the work was finalized for publication at a 2009 meeting of the ISO/TC150 in Kyoto. In this article, the authors would like to introduce the ISO system and the outline of the ISO Standard for Circulatory Support Devices. [source]

Japanese Guidance for Ventricular Assist Devices/Total Artificial Hearts

ARTIFICIAL ORGANS, Issue 9 2010
Takashi Yamane
Abstract To facilitate research and development (R&D) and to expedite the review processes of medical devices, the Ministry of Health, Labor and Welfare (MHLW) and the Ministry of Economy, Trade and Industry (METI) founded a joint committee to establish guidance for newly emerging technology. From 2005 to 2007, two working groups held discussions on ventricular assist devices and total artificial hearts, including out-of-hospital programs, based on previous guidance documents and standards. Based on this discussion, the METI published the R&D Guidelines for innovative artificial hearts in 2007, and in 2008 the MHLW published a Notification by Director regarding the evaluation criteria for emerging technology. [source]

Management Options to Treat Gastrointestinal Bleeding in Patients Supported on Rotary Left Ventricular Assist Devices: A Single-Center Experience

ARTIFICIAL ORGANS, Issue 9 2010
Helen M. Hayes
Abstract Gastrointestinal (GI) bleeding in ventricular assist devices (VADs) has been reported with rotary devices. The pathophysiological mechanisms and treatments are in evolution. We performed a retrospective review of GI bleeding episodes for all VADs implanted at our institution. Five male patients experienced GI bleeding,age 63.6 ± 3.64 years. VAD type VentrAssist n = 1, Jarvik 2000 n = 2, and HeartWare n = 2. All patients were anticoagulated as per protocol with antiplatelet agents (aspirin and/or clopidogrel bisulfate [Plavix] and warfarin (therapeutic international normalized ratio 2.0,3.5). There was no prior history of gastric bleeding in this group. Ten episodes of bleeding requiring blood transfusion occurred in five patients. Some patients had multiple episodes (1 × 5, 1 × 2, 3 × 1). The events occurred at varying times post-VAD implantation (days 14, 21, 26, 107, 152, 189, 476, 582, 669, and 839). Octreotide (a long-acting somatostatin analogue that reduces splanchnic arterial and portal blood flow) was administered subcutaneously or intravenously. Three patients received infusions of adrenaline at 1 µg/min to enhance pulsatility. Anticoagulation was interrupted during bleeding episodes but successfully introduced post bleeding event. GI bleeding is a significant complication of VAD therapy. In this article, we discuss diagnosis and management options. [source]

Atrial Versus Ventricular Cannulation for a Rotary Ventricular Assist Device

ARTIFICIAL ORGANS, Issue 9 2010
Daniel Timms
Abstract The ventricular assist device inflow cannulation site is the primary interface between the device and the patient. Connecting these cannulae to either atria or ventricles induces major changes in flow dynamics; however, there are little data available on precise quantification of these changes. The objective of this investigation was to quantify the difference in ventricular/vascular hemodynamics during a range of left heart failure conditions with either atrial (AC) or ventricular (VC) inflow cannulation in a mock circulation loop with a rotary left VAD. Ventricular ejection fraction (EF), stroke work, and pump flow rates were found to be consistently lower with AC compared with VC over all simulated heart failure conditions. Adequate ventricular ejection remained with AC under low levels of mechanical support; however, the reduced EF in cases of severe heart failure may increase the risk of thromboembolic events. AC is therefore more suitable for class III, bridge to recovery patients, while VC is appropriate for class IV, bridge to transplant/destination patients. [source]

Patient Satisfaction With the External Equipment of Implantable Left Ventricular Assist Devices

ARTIFICIAL ORGANS, Issue 9 2010
Anna L. Meyer
Abstract Patient satisfaction with left ventricular assist device (LVAD) external equipment has not yet been reported. We aimed to evaluate the quality of two different systems based on patients' perspective and its interrelationship with quality of life. Differential assessment of the HeartMate II axial flow pump (n = 17; Thoratec, Pleasanton, CA, USA) and the HVAD centrifugal pump (n = 10; HeartWare, Inc., Miramar, FL, USA) was obtained from 27 outpatients by a questionnaire 2 months to 2.9 years after device implantation. In addition, a health-related quality of life questionnaire (Short Form-36 [SF-36]) was completed. Overall patients' satisfaction was high. Severe limitations were attributed to the loudness of the power base unit in HeartMate II patients (P = 0.00), and HVAD patients were dissatisfied by the length of the driveline (P = 0.02). Between HVAD and HeartMate II patients, no significant differences in the quality of life (assessed by SF-36) were reported. While the overall satisfaction of outpatients on LVAD support was high, differences between the systems were found. Patients' perspectives may have an important impact on future modification of external components. Ultimately, this may also contribute to an improvement in the quality of life of chronic LVAD patients. [source]

Left Ventricle Afterload Impedance Control by an Axial Flow Ventricular Assist Device: A Potential Tool for Ventricular Recovery

ARTIFICIAL ORGANS, Issue 9 2010
Francesco Moscato
Abstract Ventricular assist devices (VADs) are increasingly used for supporting blood circulation in heart failure patients. To protect or even to restore the myocardial function, a defined loading of the ventricle for training would be important. Therefore, a VAD control strategy was developed that provides an explicitly definable loading condition for the failing ventricle. A mathematical model of the cardiovascular system with an axial flow VAD was used to test the control strategy in the presence of a failing left ventricle, slight physical activity, and a recovering scenario. Furthermore, the proposed control strategy was compared to a conventional constant speed mode during hemodynamic changes (reduced venous return and arterial vasoconstriction). The physiological benefit of the control strategy was manifested by a large increase in the ventricular Frank,Starling reserve and by restoration of normal hemodynamics (5.1 L/min cardiac output at a left atrial pressure of 10 mm Hg vs. 4.2 L/min at 21 mm Hg in the unassisted case). The control strategy automatically reduced the pump speed in response to reduced venous return and kept the pump flow independent of the vasoconstriction condition. Most importantly, the ventricular load was kept stable within 1%, compared to a change of 75% for the constant speed. As a key feature, the proposed control strategy provides a defined and adjustable load to the failing ventricle by an automatic regulation of the VAD speed and allows a controlled training of the myocardium. This, in turn, may represent a potential additional tool to increase the number of patients showing recovery. [source]

Evaluation of the Impeller Shroud Performance of an Axial Flow Ventricular Assist Device Using Computational Fluid Dynamics

ARTIFICIAL ORGANS, Issue 9 2010
Boyang Su
Abstract Generally, there are two types of impeller design used in the axial flow blood pumps. For the first type, which can be found in most of the axial flow blood pumps, the magnet is embedded inside the impeller hub or blades. For the second type, the magnet is embedded inside the cylindrical impeller shroud, and this design has not only increased the rotating stability of the impeller but has also avoided the flow interaction between the impeller blade tip and the pump casing. Although the axial flow blood pumps with either impeller design have been studied individually, the comparisons between these two designs have not been conducted in the literature. Therefore, in this study, two axial flow blood pumps with and without impeller shrouds were numerically simulated with computational fluid dynamics and compared with each other in terms of hydraulic and hematologic performances. For the ease of comparison, these two models have the same inner components, which include a three-blade straightener, a two-blade impeller, and a three-blade diffuser. The simulation results showed that the model with impeller shroud had a lower static pressure head with a lower hydraulic efficiency than its counterpart. It was also found that the blood had a high possibility to deposit on the impeller shroud inner surface, which greatly enhanced the possibility of thrombus formation. The blood damage indices in both models were around 1%, which was much lower than the 13.1% of the axial flow blood pump of Yano et al. with the corresponding experimental hemolysis of 0.033 g/100 L. [source]

The Need for a Low-Cost Ventricular Assist Device in India

ARTIFICIAL ORGANS, Issue 9 2010
Ramachandra K. Bhide MD
No abstract is available for this article. [source]

Initial Clinical Experience With the HeartMate II Ventricular Assist System in a Pediatric Institution

ARTIFICIAL ORGANS, Issue 7 2010
William R. Owens
Abstract In many adult cardiac programs, intracorporeal mechanical circulatory support has become a routine treatment for end-stage cardiac failure. For the pediatric population, options are often limited by a small body habitus. Even when an adolescent's weight may suggest adequate space for device implant, most intracorporeal adult devices remain too large for adolescents. The Thoratec HeartMate II (HM II) (approved by the FDA in April of 2008) is a small, noiseless device that is easily operated and monitored. By having an uncomplicated operating system and small percutaneous drive line, the HM II provides an opportunity for these patients to aggressively rehabilitate to become a better transplant candidate and also provides the potential to be discharged home. The two youngest patients ever to utilize the HM II are also the first two cases of using the HM II at a freestanding pediatric hospital. A 12-year-old, 53 kg, girl with dilated cardiomyopathy was supported for 85 days before receiving her heart transplant. The second patient, a 13-year-old, 149 kg, Hispanic male suffering from morbid obesity and dilated cardiomyopathy, was supported for 128 days. The HM II allowed for rehabilitation and nutritional education, resulting in this patient losing 50 kg before heart transplant. Despite both of these patients' size, their thoracic cavities were that of a preadolescent and thus techniques were developed to avoid morbidities like chest wall abrasion and bleeding. Because of differences between adult and pediatric patients and institutions, these cases provided unique challenges. However, as pediatric device therapy is now maturing, pediatric programs such as Texas Children's Hospital have begun to develop strategies for mechanical support that factor in patient's size and need for long-term or temporary support, utilizing the growing number of devices (i.e., Jostra Rotoflow, Tandem Heart PTVA, Thoratec CentriMag, Berlin Heart EXCOR, etc.) that are now available to children. [source]

In Vivo Evaluation of Zirconia Ceramic in the DexAide Right Ventricular Assist Device Journal Bearing

ARTIFICIAL ORGANS, Issue 6 2010
Diyar Saeed
Abstract Zirconia is a ceramic with material properties ideal for journal bearing applications. The purpose of this study was to evaluate the use of zirconium oxide (zirconia) as a blood journal bearing material in the DexAide right ventricular assist device. Zirconia ceramic was used instead of titanium to manufacture the DexAide stator housing without changing the stator geometry or the remaining pump hardware components. Pump hydraulic performance, journal bearing reliability, biocompatibility, and motor efficiency data of the zirconia stator were evaluated in six chronic bovine experiments for 14,91 days and compared with data from chronic experiments using the titanium stator. Pump performance data including average in vivo pump flows and speeds using a zirconia stator showed no statistically significant difference to the average values for 16 prior titanium stator in vivo studies, with the exception of a 19% reduction in power consumption. Indices of hemolysis were comparable for both stator types. Results of coagulation assays and platelet aggregation tests for the zirconia stator implants showed no device-induced increase in platelet activation. Postexplant evaluation of the zirconia journal bearing surfaces showed no biologic deposition in any of the implants. In conclusion, zirconia ceramic can be used as a hemocompatible material to improve motor efficiency while maintaining hydraulic performance in a blood journal bearing application. [source]

Computational Fluid Dynamics Analysis of Blade Tip Clearances on Hemodynamic Performance and Blood Damage in a Centrifugal Ventricular Assist Device

ARTIFICIAL ORGANS, Issue 5 2010
Jingchun Wu
Abstract An important challenge facing the design of turbodynamic ventricular assist devices (VADs) intended for long-term support is the optimization of the flow path geometry to maximize hydraulic performance while minimizing shear-stress-induced hemolysis and thrombosis. For unshrouded centrifugal, mixed-flow and axial-flow blood pumps, the complex flow patterns within the blade tip clearance between the lengthwise upper surface of the rotating impeller blades and the stationary pump housing have a dramatic effect on both the hydrodynamic performance and the blood damage production. Detailed computational fluid dynamics (CFD) analyses were performed in this study to investigate such flow behavior in blade tip clearance region for a centrifugal blood pump representing a scaled-up version of a prototype pediatric VAD. Nominal flow conditions were analyzed at a flow rate of 2.5 L/min and rotor speed of 3000 rpm with three blade tip clearances of 50, 100, and 200 µm. CFD simulations predicted a decrease in the averaged tip leakage flow rate and an increase in pump head and axial thrust with decreasing blade tip clearances from 200 to 50 µm. The predicted hemolysis, however, exhibited a unimodal relationship, having a minimum at 100 µm compared to 50 µm and 200 µm. Experimental data corroborate these predictions. Detailed flow patterns observed in this study revealed interesting fluid dynamic features associated with the blade tip clearances, such as the generation and dissipation of tip leakage vortex and its interaction with the primary flow in the blade-blade passages. Quantitative calculations suggested the existence of an optimal blade tip clearance by which hydraulic efficiency can be maximized and hemolysis minimized. [source]

Letter to the Editor Re: First Clinical Application of the DuraHeart Centrifugal Ventricular Assist Device for a Japanese Patient

ARTIFICIAL ORGANS, Issue 4 2010
Muhammad B. Munir MD
No abstract is available for this article. [source]

Use of Cerebral Oximetry for Monitoring Cardiac Output During Off-Pump Implantation of Jarvik 2000 Left Ventricular Assist Device

ARTIFICIAL ORGANS, Issue 3 2010
Helena Argiriadou MD
No abstract is available for this article. [source]

Use of Zirconia Ceramic in the DexAide Right Ventricular Assist Device Journal Bearing

ARTIFICIAL ORGANS, Issue 2 2010
Diyar Saeed
Abstract Our aim was to evaluate the potential use of zirconium oxide (zirconia) as a blood journal bearing material in the DexAide right ventricular assist device. The DexAide titanium stator was replaced by a zirconia stator in several blood pump builds, without changing the remaining pump hardware components. In vitro pump performance and efficiency were evaluated at a predetermined pump speed and flow. Motor power consumption decreased by 20%, and DexAide battery life was extended to over 12 h on two fully charged batteries. The zirconia stator was also successfully evaluated in a severe start/stop test pre- and postexposure of the zirconia to accelerated simulated biologic aging. This study's outcomes indicated the advantages of zirconia as an alternate journal bearing material for the DexAide device. [source]

Ductular Cholestasis, an Unusual Form of Intrahepatic Cholestasis, Associated With Cardiogenic Shock and Ventricular Assist Device

ARTIFICIAL ORGANS, Issue 2 2010
Alberto Mohedano-Gómez
Abstract Ventricular assist devices have been shown to be effective in advanced heart failure selected patients. They often have borderline end-organ function, what facilitates organ dysfunction. Liver failure is difficult to manage and leads to increased morbidity and mortality. We report a case of ductular cholestasis, an unusual cholestatic hepatic failure with untractable coagulopathy, developed during the use of a magnetic levitation centrifugal pump, implanted as a bridge to heart transplantation, in a patient with cardiogenic shock (as an end-stage disease of idiopathic dilated cardiomyopathy). We discussed the pathophysiology of this entity and the possible related factors, including the assist device. Preemptive interventions have been advocated as the primary way of treatment. Preoperative optimization of heart function and avoidance of visceral hypoperfusion and sepsis may play a major role. [source]

Management of Deep Wound Complications With Vacuum-Assisted Therapy After Berlin Heart EXCOR Ventricular Assist Device Placement in the Pediatric Population

ARTIFICIAL ORGANS, Issue 11 2009
Peter C. Kouretas
Abstract Wound complications after ventricular assist device (VAD) placement remain a formidable challenge to surgeons. The Berlin Heart EXCOR VAD is a versatile pulsatile system that has been successful in pediatric patients of all ages and sizes. Prevention of device-related complications such as infection, particularly in pediatric patients, remains an essential issue in minimizing patient morbidity and mortality. The introduction of vacuum-assisted wound closure (VAC) therapy and its application in VAD-related wound complications provide an efficient and effective method for wound healing. We report our experience in the management of deep wound complications in two pediatric patients after placement of the Berlin Heart EXCOR VAD. The wound VAC system proved to achieve complete wound healing without any infectious complications. [source]

Animal Model Development for the Penn State Pediatric Ventricular Assist Device

ARTIFICIAL ORGANS, Issue 11 2009
Elizabeth L. Carney
Abstract:, In March 2004, the National Heart, Lung, and Blood Institute awarded five contracts to develop devices providing circulatory support for infants and small children with congenital and acquired cardiac disease. Since 2004, the team at Penn State College of Medicine has developed a pneumatically actuated ventricular assist device (VAD) with mechanical tilting disk valves. To date, hemodynamic performance, thrombogenesis, and hemolysis have been chronically evaluated in 16 animals, including 4 pygmy goats and 12 sheep. Major complications, mainly respiratory failure, have been encountered and resolved by a multi-disciplinary team. Multi-modal analgesia, appropriate antibiotic therapy, and attentive animal care have contributed to successful outcomes. Time after implant has ranged from 0 to 40 days. Most recently, a sheep implanted with Version 3 Infant VAD was electively terminated at 35 days postimplant, with no major adverse events. This report describes a successful in vivo model for evaluating a pediatric VAD. [source]

The PediPump: A Versatile, Implantable Pediatric Ventricular Assist Device,Update IV

ARTIFICIAL ORGANS, Issue 11 2009
Brian W. Duncan
Abstract Cleveland Clinic's PediPump (Cleveland, OH, USA) is a ventricular assist device designed for the support of pediatric patients. The PediPump is a mixed-flow ventricular assist device with a magnetically suspended impeller measuring 10.5 mm in diameter by 64.5 mm in length. Progress and achievements for the PediPump program are considered according to the development project's three primary objectives: Basic engineering: along with size reductions, substantial design improvements have been incorporated in each design iteration including the motor, magnetic bearings, axial touch points, and heat transfer path; Anatomic modeling and device fitting studies: Techniques based on computed tomography and magnetic resonance imaging have been developed to create three-dimensional anatomic-modeling and device-fitting tools to facilitate device implantation and to assist in preoperative planning. For in vivo testing, to date, six acute (6-h duration) and nine chronic (30-day target duration) implantations have been performed in sheep; the implantation of the PediPump appears to be relatively easy with excellent hemodynamic performance and minimal hemolysis during support. Cleveland Clinic's PediPump program supported by the National Heart, Lung and Blood Institute's Pediatric Circulatory Support Program has led to the development of a pediatric ventricular assist device that has satisfactory performance in preclinical evaluation and appears to be ready to support a program of clinical testing. [source]