Biventricular Assist Research Articles

(78) - Comparison of Total Artificial Heart and Biventricular Assist Device Support as Bridge-to-Transplantation

Outcomes and durability of current continuous flow left ventricular assist devices (LVADs) have improved significantly compared to previous pump technology. However, right heart dysfunction remains a problem despite the improved outcomes with CF LVADs. Surgical options for bridge to transplantation (BTT) in patients with biventricular failure are total artificial heart (TAH) or biventricular support (BVAD). This study examines the differences in outcomes in post-transplantation survival in patients with TAH or BVAD as BTT.

Minimally Invasive Implantation of Biventricular Assist Devices

As minimally invasive left ventricular assist device implantation is being advocated and more widely performed, bailout strategies for postoperative right ventricular failure (RVF) become necessary. We describe our surgical technique for additional right ventricular assist device implantation through a third mini-thoracotomy incision. This new technique allows avoidance of sternotomy even if RVF occurs.

Modeling And Control Of An Extracorporeal Heart Assist Device

Heart assist devices provide mechanical circulatory support for patients with end-stage heart failure. Extracorporeal heart assist devices are applied to adult and pediatric patients in the case of uni- and biventricular assistance. Modern driving units provide more mobility what is an immense benefit to the quality of life of the patients. The treated heart assist device in this article is the EXCOR system (Berlin Heart GmbH, Germany). This device is pneumatically operated by a piston drive. Pump assistance for the native heart of the patient should be provided by an automatic control system. This could be achieved by the control of the piston movement and the enclosed air mass in the pneumatic system. The model based design of a control system for the extracorporeal assist device is described in this paper.

Con: The Total Artificial Heart—Is It an Appropriate Replacement to Existing Biventricular Assist Devices?

Con: The Total Artificial Heart—Is It an Appropriate Replacement to Existing Biventricular Assist Devices?

Device Optimization Using Pulse Wave Analysis Techniques

Device Optimization Using Pulse Wave Analysis Techniques

Isolated Permanent Right Ventricular Assistance Using the HVAD Continuous-Flow Pump

Acute isolated right ventricular (RV) failure from myocardial infarction is a rare scenario. To date, there are no assist devices developed or approved for permanent isolated right heart support. We report on the successful implantation of a HeartWare HVAD as an isolated RV assist in a patient who suffered extended RV myocardial infarction after iatrogenic dissection of the right coronary artery. No manipulations of the system were required to adapt the assist device to the pulmonary circulation.

Complication Profile of the Berlin Heart EXCOR Biventricular Support in Children

In chronic cardiomyopathy, mechanical circulatory support (MCS) plays an increasingly important role for children as the shortage of suitable donor hearts increases waiting time on the transplant list. We report our experience with the paracorporal Berlin Heart EXCOR System (Berlin Heart AG, Berlin, Germany) used as a biventricuclar assist device (BVAD). Nine patients with a BVAD EXCOR system were treated between 2006 and 2012; out of these patients, four were less than 18 years old (6, 14, 14, and 17 years old). Their diagnoses were postcardotomy failure (n = 1), dilatative cardiomyopathy (n = 2), and terminal heart failure (n = 1). Overall survival, waiting time for heart transplantation (HTx) and complication profile for the BVAD were analyzed retrospectively. Thirty days' mortality was 25% (n = 1). One child died after 84 days on support due to cerebral bleeding. Mean support time was 218.75 days (4, 84, 262, and 525 days). Pump chamber exchange was necessary three times due to pump chamber thrombosis (n = 2) and partial pump chamber membrane rupture (n = 1). Complications included: sepsis (n = 1), drive line infection requiring intravenous antibiotics (n = 2), and recurrent epistaxis (n = 3). Two children were successfully transplanted after 262/525 days on BVAD; they are currently at home (follow-up: 1.9 and 2.3 years). The EXCOR is a life-saving MCS system suitable for long-term paracorporeal biventricular assistance.

Successful Abdominal Organ Donation after Brain Death in a Patient with a Biventricular Assist Device: Extending Extended Criteria

Few studies address the potential for donation after brain death (DBD) in the limited population of patients with ongoing mechanical circulatory support (MCS). A case study was conducted reviewing available records of both donor and recipient, and available literature. The donor was a young female with an acute myocardial infarction precipitating emergent off-pump 2-vessel bypass graft complicated by profound cardiogenic shock refractory to inotropes and intra-aortic balloon pump. A heparin drip was started following percutaneous placement of a left ventricular-assist device (TandemHeart?) which improved her hemodynamics to stabilize for transfer. She ultimately required surgical placement of biventricular assist device (CentraMag?) to normalize hemodynamics. Two days post-operatively, she developed a cerebellar hemorrhage and was declared brain dead. Pre-donation blood chemistry showed adequate end-organ function. Both kidneys were placed locally. The liver was rejected for two regional status 1 patients and by all other local centers. We accepted the liver for a patient with polycystic liver disease with a MELD exception score of 20. The recipient is now 4 years post-transplant with excellent graft function. Extending donor criteria to include MCS patients can result in successful transplantation and should be considered in selected circumstances once satisfactory donor end-organ function is established.

Pediatric Mechanical Support with an External Cardiac Compression Device

The PediBooster external cardiac compression device is a minimally invasive, non-blood contacting Biventricular Assist Device (BiVAD) intended for pediatric use. It is being developed as a palliative therapy for acute Postcardiotomy Shock (PCS). The PediBooster extracardiac wrap is pneumatically actuated to circumferentially compress the heart, providing co-pulsation support. Attachment is via a novel hydrogel coating. Early versions of the wrap were tested in vivo using a single ventricle congenital heart disease model with postcardiotomy shock, which proved unstable and demonstrated high peri-operative mortality. The final wrap design was tested in 4 acute studies with piglets (5.1 ± 0.3 kg), where the combination of ASD and PA banding induced acute right ventricular dysfunction. Data collected included routine hemodynamic values, TEE, video of the exposed heart, and cardiac histology. The model proved stable for support durations ranging from 2 to 16 hours. The wrap restricted the heart in 3 of the 4 animals, as evidenced by increased diastolic LVP during support compared to the baseline failure condition. TEE and video data showed good attachment and function of the wrap, particularly during the final 16 hr study. This model of congenital heart disease shows promise for chronic (24-72 hr) studies. Ventricular filling during support may be improved by adjusting wrap dimensions to eliminate end diastolic restriction.

Abstract 9934: Biventricular Assist Device May be Superior to Left Ventricular Assist Device for Crash and Burn Patients

Purpose: Over 15,000 left ventricular assist devices (LVADs; HeartMate I and II) have been implanted world-wide as bridge to transplant or destination in the last decade and appears to be the device of choice. However, the 1 year survival and success to transplant rates are not uniform across the INTERMACS profile spectrum. Current 6 month survival for INTERMACS profile 1 patients undergoing VAD support as bridge to transplant is 60%. We reviewed our more recent experience with both biventricular assist device (BiVAD) and LVAD support to compare the effectiveness and success rates for these two bridging modalities in this critically-ill cohort of patients. Methods: Between Jan 2007 and Mar 2012, we reviewed 56 INTERMACS profile 1 patients. 32 patients who appeared to have adequate right ventricular function received the LVAD (20 HeartMate I and 12 HeartMate II) alone while the remaining 24 patients were supported with a pneumatic BiVAD. Successful bridge to transplant, recovery and ongoing support at 6 months were analyzed among these groups. Results: 21/24 BiVAD patients vs 11/32 LVAD pts (88% vs 34%, p<0.001) were successfully transplanted or explanted due to recovery of cardiac function. Of the LVAD patients, 7/20 HeartMate II patients vs 4/12 HeartMate I patients (35% vs 33%, p=0.93) were successfully transplanted or explanted due to recovery of cardiac function. Multivariate analysis suggested that inotropic support more than 14 days post VAD implantation in LVAD patients was associated with increased mortality. 2/3 BiVAD deaths and 13/21 LVAD deaths were due to progressive shock, hemorrhage or right ventricular failure. 1-year survival post transplant was 18/20 (90%) in the BiVAD group and 11/11 (100%) in the LVAD group. Conclusions: In critically-ill INTERMACS profile 1 transplant candidates, BiVAD support may result in improved outcomes compared to LVAD and could be the device of choice. In these LVAD patients, perceived adequate right ventricular function may be misleading as these are very ill INTERMACS profile 1 patients where subsequent progressive shock, hemorrhage and right ventricular failure are major causes of death.

Long-Term Support with a Bi-Ventricular Assist Device. A Single Center Experience

Long-Term Support with a Bi-Ventricular Assist Device. A Single Center Experience

Long-Term Support with a Bi-Ventricular Assist Device. A Single Center Experience

Long-Term Support with a Bi-Ventricular Assist Device. A Single Center Experience

Cardiac Tamponade From Compression of the Pulmonary Arterial Outflow Graft of a Biventricular Assist Device

A 19-year-old patient with a Thoratec Paracorporeal Biventricular Assist Device implanted 15 weeks previously complained of discomfort in his back and chest area, lightheadedness, and diaphoresis, and was noted to have a blood pressure of 62/26 mm Hg. Device alarms sounded for both the left and right ventricular assist devices indicating that the paracorporeal pumps were not filling normally. An ECG showed sinus tachycardia with low voltage (Figure 1). A portable chest radiograph showed enlargement of the cardiac silhouette, loss of the left hemidiaphragmatic contour, and mild left midlung atelectasis (Figure 2). Transthoracic and transesophageal echocardiography showed a large pericardial hematoma with compression of the right ventricle and diastolic compression of the pulmonary arterial outflow graft (Figure 3 and Movies I and II in the online-only Data Supplement). The aortic outflow graft and the right atrium did not appear to be compressed. Computed tomographic scanning confirmed the extent of the pericardial hematoma and demonstrated a mass effect on the right ventricle (Figure 4). Figure 1. ECG showing sinus tachycardia with low …

Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS)

The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) is a North American national registry for mechanical circulatory support devices (MCSDs) that are used to treat advanced heart failure. Durable MCSDs that have been approved by the US Food and Drug Administration (FDA) are included in this registry; however, MCSDs that remain in FDA trials pending initial approval (ie, investigational device exemption [IDE] trials) and devices intended for short-term use (eg, Abiomed BVS 5000 ventricular assist device [Abiomed, Danvers, MA]) are not included. The purposes of this article are to present a developmental history of INTERMACS, to outline the collaboration of INTERMACS with various constituencies (eg, FDA, National Institutes of Health, Center for Medicare & Medicaid Services, industry, and physicians), to present a summary of information generated to date by INTERMACS, and to describe the future directions of INTERMACS. The concept of using mechanical circulatory assistance for more than a brief time after a cardiac operation dates to the early 1960s with the development of MCSDs that fit the definitions of counterpulsation devices (eg, the intra-aortic balloon pump), ventricular assist devices (VADs), and total artificial hearts.1–5 The development and initial clinical evaluation of these devices were regulated by individual academic medical center review groups that evolved into institutional review boards. The FDA entered this arena in 1976 with the advent of the FDA section for device regulation based on passage of the 1976 Medical Device Amendments.6 By 1991, groups including the Institute of Medicine foresaw the need for a detailed longitudinal database for patients receiving MCSDs, stating in an Institute of Medicine report that “patients should be followed through a registry for the remainder of their lives….”7 The committee further recommended that the National Heart, Lung, and Blood Institute support long-term follow-up studies. Eventually, a …

Passive Control of a Biventricular Assist Device With Compliant Inflow Cannulae

Rotary ventricular assist device (VAD) support of the cardiovascular system is susceptible to suction events due to the limited preload sensitivity of these devices. This may be of particular concern with rotary biventricular support (BiVAD) where the native, flow balancing Starling response is diminished in both ventricles. The reliability of sensor and sensorless-based control systems which aim to control VAD flow based on preload has limitations, and, thus, an alternative solution is desired. This study introduces a compliant inflow cannula (CIC) which could improve the preload sensitivity of a rotary VAD by passively altering VAD flow depending on preload. To evaluate the design, both the CIC and a standard rigid inflow cannula were inserted into a mock circulation loop to enable biventricular heart failure support using configurations of atrial and ventricular inflow, and arterial outflow cannulation. A range of left (LVAD) and right VAD (RVAD) rotational speeds were tested as well as step changes in systemic/pulmonary vascular resistance to alter relative preloads, with resulting flow rates recorded. Simulated suction events were observed, particularly at higher VAD speeds, during support with the rigid inflow cannula, while the CIC prevented suction events under all circumstances. The compliant section passively restricted its internal diameter as preload was reduced, which increased the VAD circuit resistance and thus reduced VAD flow. Therefore, a CIC could potentially be used as a passive control system to prevent suction events in rotary left, right, and biventricular support.

Fulminant Fungal Infection of a Biventricular Assist Device

Fulminant Fungal Infection of a Biventricular Assist Device

761 Two CircuLite Pumps as Bi-Ventricular Assist Device (BVAD) in an Ovine Animal Model

Purpose: The purpose of this study was to investigate the use of two CircuLite micro-pumps for full biventricular assist in sheep. We therefore examined right and left sided hemodynamic parameters over a range of right and left sided pump speeds. Methods and Materials: Five juvenile sheep (mean-weight 43kg) were implanted with CircuLite pumps in the RV and the LV through a median sternotomy. The RVAD outflow graft was anastomosed end-to-side to the pulmonary artery, and the LVAD outflow to the ascending aorta. After surgical implantation of both pumps we induced ventricular fibrillation and hemodynamic changes were measured using nine different levels of RVAD pump speed (from 20-28k rpm at 1k increments) while the speed of the LVAD was set constant at 24k, then at 26k and finally at 28k rpm. Results: Average results from the 5 sheep with LVAD speed fixed at 24K are shown in the Figure. At any given LVAD speed, both RVAD and LVAD flow increased identically as RVAD speed was increased. Results were similar with LVAD set at the higher speeds. At the highest LVAD and RVAD speeds, flow averaged 3.1 0.7 L/min, and pressures in the right atrium, pulmonary artery, left atrium and aorta averaged 2.2 3.7, 24.4 6.5, 22.4 5.5, and 56.6 8.5 mmHg, respectively. Conclusions: Biventricular assist with the two CircuLite pumps is feasible and able to provide full hemodynamic support in sheep. This approach holds promise for providing biventricular partial support in humans and, in particular, for full support in small adults and children.

747 Long-Term Support with a Bi-Ventricular Assist Device – A Single Center Experience

747 Long-Term Support with a Bi-Ventricular Assist Device – A Single Center Experience

Combination Evaluation of Preoperative Risk Indices Predicts Requirement of Biventricular Assist Device

Patients with biventricular assist device (BiVAD) placement have a poor prognosis, but preoperative risk factors for the necessity of BiVAD have not been fully elucidated. Data from 79 patients who received left ventricular assist device (LVAD) between November 2002 and December 2011 were retrospectively reviewed. Overall, 9 patients (11.4%) required BiVAD, and the survival rate of BiVAD patients was significantly lower than that of LVAD patients (P<0.001). Multivariate analysis for BiVAD requirement showed left ventricular diastolic diameter (LVDd) ≤62 mm (odds ratio [OR], 10.97; P=0.009) to be significantly associated with BiVAD requirement. Preoperative central venous pressure (CVP)/pulmonary capillary wedge pressure (PCWP) ratio ≥0.5 (OR, 13.09; P=0.028) was also significantly associated with BiVAD requirement. A new scoring system for predicting BiVAD requirement was created from the combination of CVP/PCWP ratio (≥0.5), body surface area (≤1.4 m(2)), preoperative continuous hemodiafiltration use, B-type natriuretic peptide (≥1,200 pg/ml) and LVDd (≤62 mm), and this had a significantly larger area under the curve (0.909; P=0.003) than right ventricular stroke work index on receiver operating characteristic analysis. A score >20 using the new scoring method indicated significantly high probability of BiVAD requirement (OR, 16.00; P=0.019). The new scoring method, which includes CVP/PCWP ratio, is a novel risk stratification tool for BiVAD therapy.

Unusual Presentation of Cardiac Tamponade after Biventricular Assist Device Implantation: Diastolic Collapse of the Outflow Graft

(Echocardiography 2012;29:E20‐E21)