Centrifugal Ventricular Assist Device Research Articles

Numerical Optimization of the Hydraulic and Hemolytic Performance of a Centrifugal Ventricular Assist Device Based on Impeller Flow Passage and Outlet Geometry

As technology continues to advance and modern lifestyles become increasingly mechanized, the prevalence of heart disease is steadily growing. On the other hand, donor hearts ready for transplantation are limited worldwide. Therefore, blood pumps are a suitable alternative to help the patient during the waiting period and even until the end of life. Blood pumps must meet biological requirements, including adequate output pressure and flow rate, within an acceptable margin of safety in the event of blood damage. Reduction of pump size, blood exposure time, and blood damage such as hemolysis have been mentioned as important challenges in the design of blood pumps. Statistics show that 30% of the patients who use a left ventricular blood pump need a right ventricular blood pump due to right ventricular failure. The purpose of this research is to determine the effect of the geometrical shape of the impellers (flow passage) and the thrust tube geometry of the volute chamber on the pump’s hydraulic performance, the amount of axial and radial forces, and the amount of blood damage. So, for this study, six blades and two types of geometry for the volute chamber thrust tube were designed. This pump has been simulated using computational fluid dynamics used the Ansys CFX 17. Finally, the appropriate pump has been selected for low hemolysis index (HI). The HI calculated using the Lagrangian method is 0.00279 in the pump with a flow rate of 5 L per minute and 1100 rpm.

Ventricular assist devices as bridge to heart transplantation: minimally invasive approach with axial pumps vs sternotomy approach with centrifugal pumps: short term results

Abstract Introduction Microaxial flow ventricular assist devices (VADs) with hybrid approach could provide an advantage over centrifugal flow VADs with surgical implantation via median sternotomy as bridge to heart transplantation. Purpose We aimed to compare short-term results in intensive cardiac care unit between both groups. Methods Single-center retrospective registry comparing patients supported with microaxial flow VADs with hybrid approach (Impella 5.0 or 5.5) and surgical centrifugal flow VADs (biventricular or left univentricular CentriMag) as bridge to heart transplantation. Results Including 12 patients (January 2020-March 2022), 7 patients in hybrid approach group (2 patients with Impella 5.0-16,7% and 5 patients with Impella 5.5-41,7%) and 5 pacientes in sternotomy approach group (33.3% biventricular support and 8.3% left ventricular support). In first 48 hours after VAD implantation, worsening of renal function was greater in sternotomy approach group (Cr 2.23±0.88, 1.07±0.58;p=0.021) and there was a trend toward lower hemoglobin values (7.72±0.19, 8.9±1.35;p =0.059), with no differences in other analyzed variables (Table). A trend toward earlier respiratory weaning was observed in hybrid approach group (median 12 vs 48 hours,p=0.067). Sternotomy approach group required more frequent use of continuous renal replacement therapy (60% vs 0%,p=0.045). There were statistically non-significant differences in need for blood products or surgical reinterventions, although percentage of red blood cells transfused in first 48 hours after VAD implantation were lower in hybrid approach group than sternotomy approach group (median 4 (1.5-8) versus 8(2.5-13.5) in sternotomy approach group, p=0.309). The most common complication in sternotomy approach group was tamponade (80%- 4 patients versus 0 patients in hybrid approach) and in hybrid approach group access-related infections (28.57%, 2 patients). Ten patients received a transplant, one died for non-cardiovascular cause, and another underwent the implantation of long term VAD as bridge to transplantation. There were no differences in time from assistance implantation to heart transplantation. The most common complication after heart transplantation was primary graft failure in both groups (40%,2 patients) with no differences in mortality. Conclusions Microxial flow VADs with hybrid approach provide adequate support, with less need for continuous renal replacement therapy and shorter duration of mechanical ventilation after VAD implantation to admission in intensive cardiac care unit, a trend towards lower rates of reintervention due to bleeding was observed. The advantages of minimally invasive approach could increase its use as bridge to heart transplantation compared to VADs with sternotomy approach although small sample size may negatively influence the failure to reach statistical significance, and more studies are necessary to validate our preliminary experience.Variables analyzed 48 hours of admission

Development and validation of a mathematical model for evaluating shear-induced damage of von Willebrand factor

PurposeTo develop a mathematical model for predicting shear-induced von Willebrand factor (vWF) function modification which can be used to guide ventricular assist devices (VADs) design, and evaluate the damage of high molecular weight multimers (HMWM)-vWF in VAD patients for reducing clinical complications. MethodsMathematical models were constructed based on three morphological variations (globular vWF, unfolded vWF and degraded vWF) of vWF under shear stress conditions, in which parameters were obtained from previous studies or fitted by experimental data. Different clinical support modes (pediatric vs. adult mode), different VAD operating states (pulsation vs. constant mode) and different clinical VADs (HeartMate II, HeartWare and CentriMag) were utilized to analyze shear-induced damage of HMWM-vWF based on our vWF model. The accuracy and feasibility of the models were evaluated using various experimental and clinical cases, and the biomechanical mechanisms of HMWM-vWF degradation induced by VADs were further explained. ResultsThe mathematical model developed in this study predicted VAD-induced HMWM-vWF degradation with high accuracy (correlation with experimental data r2 > 0.99). The numerical results showed that VAD in the pediatric mode resulted in more HMWM-vWF degradation per unit time and per unit flow rate than in the adult mode. However, the total degradation of HMWM-vWF is less in the pediatric mode than in the adult mode because the pediatric mode has fewer times of blood circulation than the adult mode in the same amount of time. The ratio of HMWM-vWF degradation was lower in the pulsation mode than in the constant mode. This is due to the increased flushing of VADs in the pulsation mode, which avoids prolonged stagnation of blood in high shear regions. This study also found that the design feature, rotor size and volume of the VADs, and the superimposed regions of high shear stress and long residence time inside VADs affect the degradation of HMWM-vWF. The axial flow VADs (HeartMate II) showed higher degradation of HMWM-vWF compared to centrifugal VADs (HeartWare and CentriMag). Compared to fully magnetically suspended VADs (CentriMag), hydrodynamic suspended VADs (HeartWare) produced extremely high degradation of HWMW-vWF in its narrow hydrodynamic clearance. Finally, the study used a mathematical model of HMWM-vWF degradation to interpret the clinical statistics from a biomechanical perspective and found that minimizing the rotating speed of VADs within reasonable limits helps to reduce HWMW-vWF degradation. All predicted conclusions are supported by the experimental and clinical data. ConclusionThis study provides a validated mathematical model to assess the shear-induced degradation of HMWM-vWF, which can help to evaluate the damage of HMWM-vWF in patients implanted with VADs for reducing clinical complications, and to guide the optimization of VADs for improving hemocompatibility.

Hemodynamic investigation and in vitro evaluation of a novel mixed-flow blood pump.

Ventricular assist devices (VADs) are considered an effective treatment for patients with advanced heart failure, while complications associated with blood damage remain a burden. Structure design innovation has the potential to reduce hemolysis and improve hemocompatibility. In this research, a novel mixed-flow blood pump that integrates structural features of the axial and centrifugal VADs was proposed. The pump consists of an inducer, a mixed impeller supported by two ceramic pivot bearings, and a volute. The flow field and laminar viscous shear stress were analyzed by the in silico simulation. The hydraulic and hemolytic performance were evaluated in vitro by using a 3D printed pump. The flow field distribution showed that streamlines in the connection area were smoothly transitioned through structural integration and no irregular flow occurred in the entire flow channel. The axial blades work as a fluid accelerator (generating 18.56% of the energy), and the centrifugal blades provide the main pressure head. The proportion of fluid inside the pump exposed to low laminar viscous shear stress (<50Pa) and high laminar viscous shear stress (>150Pa) was 99.02% and 0.03%, respectively. The in vitro hemolysis test results showed that the NIH (Normalized Index of Hemolysis) value of the mixed pump is 0.0079±0.0039g/100L (n=6). It can be concluded that the mixed flow structure is effective at improving hydraulic performance, eliminating flow disturbance, and minimizing shear stresses. This novel pump design is expected to provide a new direction for the development of next-generation VADs.

Single Center Experience with the Heartmate 3 Continuous-Flow Ventricular Assist Device in Pediatric Patients

Purpose The HeartMate 3 ventricular assist device (VAD) is a newer centrifugal continuous-flow VAD used for bridge-to-transplant and destination therapy in adults. However, there is limited experience regarding its use in children and adolescents. Methods We examined the outcomes of pediatric patients undergoing HeartMate 3 implantation at our institution between January 2016 and September 2020. Indications were bridge-to-transplant and bridge-to-recovery. All patients were in INTERMACS 2 profile at the time of surgery. In the early postoperative period bivalirudin was used as a bridge to warfarin therapy in all patients. Results Seven HeartMate 3 were implanted in five patients, with a median age of 14.5 (9.0-16.5) years, median weight of 48 (40.0-75.0) kg, and median body surface area (BSA) of 1.43 (1.36-1.92) m 2. Of the cohort, all patients but one weighed Conclusion Use of the HeartMate 3 in children and adolescents was associated with no mortality. All patients were successfully implanted and supported, some for several months, indicating that this device is appropriate for older children and adolescents. The HeartMate 3 device in a RVAD configuration was able to provide satisfactory hemodynamic support. The anticoagulation protocol with bivalirudin to warfarin transition proved excellent virtually eliminating bleeding and thromboembolic events.

Early Clinical Experience of a Novel Mobile Driving Unit for Pediatric VAD Support

Purpose Recently, a novel mobile driving unit (MDU) of the only approved pediatric ventricular assist device (VAD) system for both short- and long-term support of children of all sizes and ages received market approval. The MDU was specifically developed to improve mobility and autonomy of children supported with this paracorporeal (pc) VAD. This case series collects initial information with the aim to assess the first clinical experience. Methods A retrospective case series gathered anonymized patient health data of pediatric patients supported with MDU. The usability was assessed by means of a patient standardized questionnaire (numerical scale, 1= worst to 5= best). Results From February 2020 until September 2020, eight children (3 females) have been supported with a pc VAD in combination with the MDU. The median age was 1.4 years (range 0.5 - 7.5), median body surface area 0.4 m2 (0.3 - 0.9). Primary diagnosis was cardiomyopathy (CM) in 7 patients (5 dilated and 2 restrictive CM), and congenital heart disease in one child. Five patients (62.5%) received a pc VAD as left-sided and two patients as biventricular support (BVAD, 25%). One had a secondary right-sided pc VAD in combination with an implantable left-sided centrifugal VAD. The distribution of pc pump chambers by size was 10 ml pump: 2 patients (25%), 15 ml pump: 4 subjects (50%) and 30 ml pump: 2 children (25%), plus 15 ml pumps in both pc BVAD patients. The mean time of VAD support was 406 ± 241 days, with 148 ± 76 days on MDU. At the end of the observational period, 5 patients (62.5%) were still on system, 2 (25%) were transplanted and 1 died (12.5%) for causes not related to the driving unit. The survey found increased mobility (score 4.2/5), enlarged activity radius (5/5) and reduced noise nuisance (4.5/5) with MDU in comparison to the stationary unit. There were no complaints in MDU handling reported and the easiness to use was rated (4.5/5). In addition the parents reported a significant less heat generation by the MDU. The safety profile of MDU showed five adverse events: one fatal case (12.5%), one respiratory failure (12.5%), both not device-related, and two pump malfunctions (25%). One patient (12.5%) underwent pump replacement due to fibrin debris. Conclusion The case series suggests that the novel MDU is safe and effective for VAD support in the pediatric population. It is likely that MDU will increase the quality of life in this cohort.

Fifteen years of the first Brazilian Centrifugal Ventricular Assist Device for long term Mechanically Assisted Circulatory Support

More than simply being a review paper and telling the story of the development of a ventricular assist device, this paper aims to critically review changes in technical nomenclature and scientific positioning, taxonomy and its applications, therapeutic indications and the results of its application in patients. After 15 years of the first Brazilian Centrifugal Ventricular Assist Device, many things have changed for the better. Mechanically Assisted Circulatory Support is a therapy consolidated as a safe and effective alternative for the treatment of congestive heart failure, as well as heart transplantation and other drug therapies. It is still seen as science fiction in several countries or media, but that is a cruel reality in our post-truth and fake news times. In reality, it should receive more funding resources especially in developing countries and emerging economies with strong hospital industry of the cardiovascular field that may have surprising results with all the technology already established.

High-speed visualization of ingested, ejected, adherent, and disintegrated thrombus in contemporary ventricular assist devices.

Biocompatibility of ventricular assist devices (VADs) has been steadily improving, yet the rate of neurological events remains unacceptably high. Recent speculation for elevated stroke rates centers on ingestion of thrombi originating upstream of the pump, such as in the ventricle or left atrial appendage. These thrombi may be ejected by the VAD or become deposited within the blood flow pathway, presenting serious complications to the patient. This study was performed to visualize and quantify the degree of disruption, adherence, and disintegration of thrombi that are ingested by the three most implanted VADs: the HeartMate II, HeartMate 3, and HVAD. Clot analogs of varying microstructure compositions (red, white) and sizes (0.5, 1, 2cm3 ) were synthesized in vitro based on clinical explant data. These were introduced individually into an in vitro flow loop with a transparent replica of the HMII, HM3, and HVAD operated at nominal steady flow (2.3-4.0L/min). High-speed videography (up to 10000fps) revealed the ingestion, disruption, ejection, and adherence of thrombus fragments. Thromboemboli of varying compositions and sizes were observed mechanically attaching to components in all 3 VAD models. In some instances, ingested thrombi physically obstructed portions of the blood flow path; 18% (3 of 17 total) of red thrombi adhered to the inflow straightener of the transparent HMII. In the HVAD model, fewer than 4% of clots were adherent or trapped within the pump, irrespective of microstructure or initial volume. In comparison, 100% (4 of 4 total) of 1-cm3 white (fibrin) clots became lodged within the transparent HM3 while, in contrast, less than 5% of macerated red clots (3 of 63 total) of the same volume were adherent inside the pump. A significant proportion of ingested thrombi were macerated into infinitesimal fragments; 84% and 74% of 2-cm3 red thrombi in the HVAD and HM3 models, respectively, were found to have disintegrated upon ingestion. However, large emboli were also discharged from both centrifugal VADs; these fragments, ranging from 0.01 to 0.29 cm3 regardless of microstructure and original volume, may be capable of occluding an intracranial vessel. Therefore, ingested thrombus may explain, in part, elevated stroke rates in contemporary blood pumps in the absence of adherent pump thrombosis.

The HeartMate 6

The need for biventricular support poses significant challenges for patients who require a mechanical bridge to transplantation. Recent improvements in ventricular assist device (VAD) technology has made possible the use of two centrifugal flow VADs as a total artificial heart (TAH) replacement. The HeartMate 3 (HM3; [Full MagLev, Abbott Laboratories, Chicago, Illinois]) was recently approved as a destination therapy; this VAD has a number of unique advantages that allow for its off-label use for biventricular support. Here, we describe the use of two HM3s as a TAH in a patient as a bridge to transplant.

Early experience with the HeartMate 3 continuous-flow ventricular assist device in pediatric patients and patients with congenital heart disease: A multicenter registry analysis

The HeartMate 3 ventricular assist device (VAD) is a newer centrifugal continuous-flow VAD used for bridge-to-transplant and destination therapy in adults. However, there is limited experience regarding its use in children and adults with complex congenital heart disease (CHD). The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) is a multicenter learning network comprised of pediatric hospitals implanting VADs in children and adults with complex CHD. We examined the outcomes of patients undergoing HeartMate 3 implantation at an ACTION center between December 2017 and September 2019. The HeartMate 3 was implanted in 35 patients at 9 ACTION centers, with a median age of 15.7 (8.8-47.3) years, median weight of 65.7 (19.1-114.1) kg, and median body surface area (BSA) of 1.74 (0.78-2.36) m2. Of the cohort, 14 patients (40%) weighed <60 kg. Diagnoses included dilated cardiomyopathy (63%), dilated cardiomyopathy in neuromuscular disease (20%), and CHD (17%). Of those with CHD, most had a Fontan circulation. With a median 78 days of follow-up, there was 1 death on device (97% survival); 20 out of 35 (57%) underwent transplantation with no post-transplantation mortality. There were no episodes of stroke or pump thrombosis. Use of the HeartMate 3 in ACTION centers was associated with a low incidence of mortality and adverse events. Patients as small as 19 kg (BSA 0.78 m2) were successfully implanted and supported, indicating that this device may be appropriate for older children and small adults.

Early Gastrointestinal Complications From Ventricular Assist Devices is Increased by Non-Pulsatile Flow

Measurements of organ flow and perfusion during cardiopulmonary bypass suggest that perfusion of the splanchnic bed can be impaired by non-pulsatile flow. We postulated that non-pulsatile flow from centrifugal ventricular assist devices might also compromise splanchnic blood flow and cause bowel ischaemia especially in the period of circulatory instability early post-implant. The aim of the present studies was to compare the incidence of gastrointestinal (GI) complications in patients having a non-pulsatile device with the incidence in those having a pulsatile device. In a pilot study, the initial 12 patients who received the Ventrassist (Ventracor, Sydney, NSW, Australia) centrifugal, non-pulsatile device during the period from June 2003 to September 2005 at the Alfred Hospital, Melbourne were compared with 11 patients who received a Thoratec (Thoratec, Pleasanton, CA, USA), pulsatile, positive displacement device and the incidence was recorded of GI complications requiring an intervention either surgical, endoscopic or by interventional radiology. This was followed by a larger (full) study of a second cohort of similar ventricular assist device (VAD) patients from January 1992 until December 2012 comparing 53 patients having non-pulsatile devices and 110 having pulsatile devices. In the pilot study, the overall incidence of complications in the non-pulsatile group (67%) was almost double that in the pulsatile group (36%) but the difference was not statistically significant (p = 0.15) because of the small number (n = 23) of participants. In the full study, all GI complications with either device occurred within the first 3 weeks post-implant. In the non-pulsatile patients, there was a higher incidence of GI bleeding, 23% vs 4% (p = 0.002), endoscopies, 24% vs 12% (p = 0.049). More patients with a non-pulsatile flow device had delayed absorption of nasogastric feeds than their pulsatile counterparts, 35% vs 7% (p < 0.0001). Patients with a non-pulsatile flow device had a higher overall rate of gastrointestinal complications than patients had with a pulsatile flow device, 56% vs 20% (p < 0.0001). After correcting for the other predictors, the odds of developing a gastrointestinal complication in the pulsatile group was significantly lower (odds ratio 0.07) than in the non-pulsatile device group (p < 0.0001). We conclude that the use of non-pulsatile centrifugal VADs compared with pulsatile positive displacement VADs is associated with a higher incidence of both haemorrhagic and ischaemic complications in the gastro-intestinal system especially in the very early post-implant period. Whether these complications could be reduced in centrifugal devices by increasing their pulsatility is not clear and merits further research.

Use of Ventricular Assist Device Acoustical Signatures to Detect Device Thrombosis

Background Pump thrombosis (PT), the most common cause of failure in ventricular assist devices (VADs), can be mitigated with earlier diagnosis before triggering any clinical events or requiring VAD replacement. Hypothesis Acoustical signatures of VADs can provide substantial information regarding PT. Methods We included 10 patients (6 axial, 4 centrifugal VADs) presenting with pump power elevations and recurrent abnormal hemolysis markers consistent with suspected PT. VAD sounds were recorded multiple times using a digital stethoscope (EKO Core) at baseline or before developing thrombosis (normal baseline), during thrombosis episodes and after treatment with heparin or tissue plasminogen activator (Fig. (a)). The 2 types of pumps were analyzed separately (42 recordings from axial and 30 recordings from centrifugal) using 3 steps: (1) Extracting features (time-frequency, acoustic and nonlinearity features) from each recording; (2) Feature importance ranking using Extreme Gradient Boosting (XGBoost) to evaluate which features were most relevant for distinguishing among different states; (3) Principal Component Analysis (PCA) for dimensionality reduction and 2D visualization (Fig. (b)). Results We found that separation among the different states is achieved using the combination of XGBoost feature importance ranking and PCA (Fig. (c)). The suggested pipeline of analysis can overcome the problems emerging from inter-subject variability. In both pumps, sounds recorded from VADs with PT had different signatures than baseline sounds. Better separation was observed for axial pumps relative to centrifugal pumps, which may be due to the difference in operating speeds (average 9400 vs 2600 rpms, respectively). We observed a slight overlap between the post treatment and baseline episodes, suggesting the possible presence of residual PT that is not identified by hemolysis biomarkers and/or pump powers. Conclusion Applying machine learning algorithms on pump acoustical signals provides substantial information regarding thrombosis states, and potentially allows for sensitive detection of PT assisting hemolysis biomarkers and pump powers.

Use of Two Intracorporeal Ventricular Assist Devices As a Total Artificial Heart.

Mechanical circulatory support (MCS) has been introduced as a viable alternative to heart transplantation primarily through the use of intracorporeal ventricular assist devices (VADs) for support of the left ventricle. However, certain clinical scenarios warrant biventricular mechanical support. One strategy for some patients is the excision of both ventricles and the implantation of two VAD pumps as a total artificial heart (TAH). This has recently been made possible by the improvements in device design and the small profile of centrifugal devices. This TAH approach remains experimental with many important challenges such as the device settings to balance the right and left circulation, the orientation of the devices and the outflow graft with their influence on hemolysis and stability, and the outcome of chronic support using such an orientation. This protocol aims to provide a reproducible approach for total artificial heart replacement with two intracorporeal centrifugal VADs in a cow model.

Single-Centre Experience of Durable Bi-Ventricular Support with HeartWare Continuous Flow, Centrifugal Ventricular Assist Devices (HeartWare BiVADs)

Single-Centre Experience of Durable Bi-Ventricular Support with HeartWare Continuous Flow, Centrifugal Ventricular Assist Devices (HeartWare BiVADs)

Novel Modifications of a Ventricular Assist Device for Infants and Children

A continuous-flow "adult" ventricular assist device (VAD) was modified to support infants and children waiting for heart transplantation. A centrifugal VAD, designed to flow at 1.5 to 8 L/min, was used as a bridge to transplantation in pediatric patients. In smaller children and infants, a modified recirculation shunt permitted lower flow ranges. In hypoxic patients, an oxygenator was spliced into the circuit. From 2010 to 2015, the VAD was placed in 13 consecutive patients. Age ranged from 0.9 to 16 years (median, 7 years). Body surface area (BSA) ranged from 0.4 to 2.1 m(2) (median, 0.8 m(2)). Ten patients had a BSA less than 1.0 m(2). Four patients were receiving extracorporeal membrane oxygenation (ECMO) before VAD. Three patients had single-ventricle physiology. Five patients hada recirculation shunt and 3 underwent insertion of an oxygenator. Median time on the VAD was 20 days (range, 2-140 days). In patients with a recirculation shunt, mean patient flow was 1.5 L/min (mean flow/BSA, 2.7 L/min/m(2)), with mean total VAD flow of 3.4 L/min. Twelve patients underwent transplantation, and 1 patient underwent VAD explantation. All patients survived and were discharged at a median of 26 days (range, 17-83 days) after transplantation. Three patients experienced major bleeding events. There were 2 cerebrovascular accidents. VAD mortality dropped from 33% (3 of 9) during 2007 to 2010 to 0% (0 of 13) between 2011 and 2015 (p= 0.05). Wait-list mortality dropped from 10% (5 of 52) to 4% (4 of 91) for these periods (p= 0.29). The centrifugal VAD successfully supported pediatric patients awaiting heart transplantation. The modified recirculation shunt facilitated the successful support of patients in whom optimal flows were substantially lower than those recommended by the manufacturer. The design allows placement of an in-line oxygenator. Compared with pulsatile devices, use of this VAD was associated with a trend toward decreased mortality associated with VAD use.

(236) - Early Results of Biventricular Support with Durable, Intracorporeal Continuous Flow Centrifugal Ventricular Assist Devices: Analysis from INTERMACS

(236) - Early Results of Biventricular Support with Durable, Intracorporeal Continuous Flow Centrifugal Ventricular Assist Devices: Analysis from INTERMACS

(30) - Centrifugal Ventricular Assist Device Flow Rates

The use of ventricular assist devices (VADs) in pediatric heart failure (HF) has increased dramatically in recent years, despite high rates of morbidity and mortality. We reviewed all patients (pts) at our center who were placed on centrifugal continuous flow VADs (CentriMag, PediMag) to assess the relationship of flow rates to complications and outcomes.

Considerations on Afterload Management for Patients with Centrifugal Ventricular Assist Devices

This case report illustrates the challenges in managing patients with centrifugal ventricular assist devices (VADs). As these devices have evolved, their physical properties have changed, impacting patient management. Levitated centrifugal pumps have a non-linear response to afterloads. The device output will decrease significantly in the presence of high systemic vascular resistance. Blood pressure control is integral to the management of patients in the immediate and later postoperative period.

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

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

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.