Pneumatic pulsatile ventricular assist device as a bridge to heart transplantation in pediatric patients

Despite the remarkable advances with the use of ventricular assist devices (VAD) in adults, pneumatic pulsatile support in children is still limited. We report on our experience in the pediatric population. A retrospective review of 17 consecutive children offered mechanical support with Berlin Heart as a bridge to heart transplant from February 2002 to April 2010 was conducted. The median patient age was 3.9 years (75 days to 13.3 years). The median patient weight was 14.1 kg (2.9–43 kg). Before VAD implantation, all children were managed by multiple intravenous inotropes and mechanical ventilation (14) or extracorporeal membrane oxygenation (3). All patients had right ventricular dysfunction. Nine patients required biventricular mechanical support (BVAD), but in all other cases a single left ventricular assist device proved sufficient (47%). The median duration of VAD support was 47 days (1–168 days). The median pre‐VAD pulmonary vascular resistance index (Rpi) was 5.7 WU/m² (3.5 to 14.4 WU/m²). Eleven patients (65%) were successfully bridged to heart transplantation after a median duration of mechanical support of 68 days (6–168 days). Six deaths occurred (35%), three for neurological complications, one for sepsis, and two others for device malfunctioning. Since 2007, the survival rate of our patients has increased from 43% to 80%, and the need for BVAD has decreased from 86% to 30%. In two patients with Rpi >10 WU/m², unresponsive to pulmonary vasodilatator therapy, Rpi dropped to 2.2 and 2 WU/m² after 40 and 23 days of BVAD support, respectively. Seven patients (41%) required at least one pump change. Of 11 patients undergoing heart transplant, four developed an extremely elevated (>60%) panel reactive antibody by enzyme‐linked immunosorbent assay, confirmed by Luminex. All of them experienced at least one acute episode of rejection in the first month after heart transplant, needing plasmapheresis. The survival rate after heart transplantation was 100% with a median follow‐up of 25.4 months (6 days to 7.7 years). Mechanical support in children with end‐stage heart failure is an effective strategy as a bridge to heart transplantation with a reasonable morbidity and mortality. BVAD support may offer an additional means to reverse extremely elevated pulmonary vascular resistance.     

Successful bridge to transplant using the Berlin Heart left ventricular assist device in a 3-month-old infant

The EXCOR Berlin Heart (Berlin Heart, Berlin, Germany) was successfully used as a pediatric left ventricular assist device as a bridge to cardiac transplantation. The pneumatically driven paracorporeal device successfully supported a 7 kg patient for 53 days until a suitable heart was obtained for transplantation.     

Implantation of a Berlin Heart ventricular assist device

Until recently the only mode of mechanical circulatory support available in North America for use as bridge to cardiac transplantation in small children was extra-corporeal membrane oxygenation. However, since 2005 the Berlin Heart pediatric ventricular assist device has been increasingly widely used for both biventricular and left ventricular support. The device is available in a wide range of sizes, allowing its use in children as small as 5 kg and as large as 60 kg. It has been applied in end-stage heart failure of both structural/congenital and myopathic etiology (including myocarditis). In the article the technique for implantation of the device will be described, with focus on certain details that facilitate safe implantation and subsequent explantation, whether in the setting of a heart transplant operation or in the setting of recovery of native heart function.     

Use of extracorporeal life support as a bridge to pediatric cardiac transplantation.

BACKGROUND: Extracorporeal life support (ECLS) has been used for post-cardiotomy rescue, but its use as a bridge to heart transplantation (OHT) in patients with post-surgical or end-stage ventricular failure remains controversial. METHODS: Records were reviewed for patients receiving ECLS for ventricular failure from January 1991 to August 2001. Patients listed for OHT were analyzed separately. Listing for OHT requirements were improbable myocardial recovery, absence of contraindications (central nervous system damage, high pulmonary resistance, ongoing infection, etc.), and parental consent. Outcome variables included patient demographics, diagnosis, days from ECLS initiation to United Network for Organ Sharing (UNOS) listing (latency), list time, renal function, and survival to discharge. RESULTS: Of 145 patients with ventricular failure who received ECLS, 21 pediatric patients were UNOS listed. Of 124 non-listed patients, 57 (46%) survived to discharge. All but 3 survivors were separated from ECLS in 相似文献   

Techniques for optimization of pulsatile ventricular assist device support

For some time now researchers have argued the efficacy of pulsatile versus nonpulsatile hemodynamic support. Pulsatile systems, while providing a more physiological pumping source, are burdened with a multiparametric output function that can greatly affect the utility of such ventricular assist device (VAD) support. A simplified approach to the optimization of the pulsatile VADs' output function has been developed. This approach yields device outputs of approximately 5.5 L/min at physiologic pressures while demonstrating clinically acceptable blood chemistry. Obtaining this optimal operating point involves the determination of the VAD system output function for a range of fill-enhancing vacuum settings. A quantitative method for evaluating synchronous versus asynchronous pumping modes as related to coronary perfusion is also demonstrated.     

Left ventricular decompression during peripheral extracorporeal membrane oxygenation support with the use of the novel iVAC pulsatile paracorporeal assist device

Extracorporeal membrane oxygenation (ECMO) has become a widely accepted short-term mechanical circulatory support device in patients with refractory cardiogenic shock. A major drawback of the peripheral venoarterial extracorporeal membrane oxygenation is that in patients with profoundly reduced left ventricular contractility associated with high left-heart filling pressure, there is always concern for venting the failing ventricle. We describe a minimally invasive technique for decompressing the left ventricle in this setting using a novel pulsatile paracorporeal assist device, the iVAC 3L (PulseCath, Groningen, The Netherlands). It is implanted through the right axillary artery and provides hemodynamic support while directly off-loading the left ventricle.     

The Pierce-Donachy ventricular assist device as a bridge to cardiac transplantation

The Pierce-Donachy ventricular assist device (VAD) was used as an attempted bridge to orthotopic cardiac transplantation in 12 patients aged 13 to 55 years. Ischemic (4 patients), dilated (4 patients), acute viral (1 patient), postpartum (1 patient), and hypertrophic cardiomyopathy (1 patient), along with a failed transplant (1 patient), were the causative factors of end-stage cardiomyopathy in these patients. All patients were candidates for orthotopic cardiac transplantation but sustained refractory cardiogenic shock (cardiac index less than 2 L/min/m2). Left VADs were placed in all patients; 7 also required right VADs. Four patients died of hemorrhagic complications less than 24 hours after VAD insertion. Ventricular assist device stabilization was successful in 8 patients and support ranged from eight hours to 64 days. Seven patients successfully underwent orthotopic cardiac transplantation. One died postoperatively of hemorrhagic complications, 6 were discharged from the hospital, and 1 patient died at 3 months of cytomegalovirus infection. Five patients are long-term survivors. The Pierce-Donachy VAD is an effective means for supporting critically ill patients with end-stage cardiomyopathy and cardiogenic shock before orthotopic cardiac transplantation. Death is related to hemorrhagic, rather than infectious or thromboembolic, complications. Patients successfully stabilized with the VAD can undergo orthotopic cardiac transplantation with acceptable mortality and morbidity rates.     

Heart transplant and left ventricular assist device costs.

BACKGROUND: With the increasing clinical success of left ventricular assist devices (LVADs), physicians need to measure device cost efficacy to determine the societal value of this technology. Today's large clinical volume allows comparison of the costs of this innovation as compared with orthotopic heart transplant (OHT). METHODS: We evaluated hospital cost and reimbursement for patients who were discharged after LVAD implantation and returned to the hospital for OHT. To control for patient-specific variables, LVAD therapy and OHT therapy were compared in the same patient; that is, only those patients who received an LVAD were discharged, and returned for OHT were studied. Length of stay (LOS), re-admissions and outpatient services were analyzed, including their respective total actual hospital cost (TAHC) and net revenue (NR). Time periods analyzed were the same for LVAD and OHT. RESULTS: From the LVAD population at Columbia-Presbyterian Medical Center, 36 patients were discharged following HeartMate vented electric (VE) implantation and re-admitted for OHT between December 1996 and June 2000. Mean pre-LVAD implantation LOS was 21.3 +/- 24.1 days. Post-LVAD LOS was 36.8 +/- 22.2 days vs 18.2 +/- 12.2 days post-OHT (p < 0.001). Mean length of LVAD support was 123.4 +/- 77.7 days. Overall total costs for LVADs exceeded that of OHT, whereas revenue was relatively lower. TAHC post-LVAD averaged $197,957 +/- 77,291, whereas TAHC post-OHT averaged $151,646 +/-53,909 (p = 0.005). NR averaged $144,756 +/- 96,656 post-LVAD vs $178,562 +/- 68,571 post-OHT (p = 0.09). LVAD patients had more re-admissions compared with OHT: 1.2/123 days (+/- 1.7) vs 0.3/123 days (+/- 0.6), respectively (p = 0.005). The average LOS during a re-admission was similar between the 2 groups (LVAD 5.6 days [+/- 10.6] vs OHT 9.6 days [+/- 8.2]; p = 0.18). OHT was associated with a significantly greater number of outpatient services compared with LVAD (9.7 [+/- 6.1] vs 3.0 [+/- 4.7]; p < 0.001). In contrast to OHT, revenues did not match the costs of LVAD therapy. CONCLUSIONS: LVAD implantation is associated with longer LOS and higher cost for initial hospitalization compared with OHT. LVAD patients have higher re-admission rates compared with OHT but similar costs and LOS. OHT is associated with a greater number of outpatient services. Reimbursements for LVAD therapy are relatively low, resulting in significant lost revenue. If LVAD therapy is to become a viable alternative, improvements in both cost-effectiveness and reimbursement will be necessary.     

Successful use of the TandemHeart percutaneous ventricular assist device as a bridge to recovery for acute cellular rejection in a cardiac transplant patient

In this report, we presented a patient who benefited from hemodynamic support with the TandemHeart Percutaneous Ventricular Assist Device (pVAD; Cardiac Assist, Inc) implantation in the setting of early acute graft rejection 2 months after orthotopic heart transplant. The TandemHeart initially had been used for temporary hemodynamic assistance during postcardiotomy heart failure and high-risk coronary interventions. More recently, its use in patients with cardiogenic shock from acute myocardial infarction, fulminant myocarditis, and critical aortic stenosis has been reported. To our knowledge, this is one of the first reported cases in which the TandemHeart pVAD served as a successful device for support during acute cardiac transplant rejection.     

Mechanical bridge with extracorporeal membrane oxygenation and ventricular assist device to heart transplantation

The aim of this study was to evaluate the effect of double bridges with extracorporeal membrane oxygenation (ECMO) and ventricular assist devices (VADs) in clinical heart transplantation. Between May 1994 and October 2000, 134 patients underwent heart transplantation at the National Taiwan University Hospital. Ten patients received ECMO or VAD support as bridges to transplantation. The ages ranged from 3 to 63 years. The indications included cardiac arrest under cardiopulmonary resuscitation in 2 and profound cardiogenic shock refractory to conventional therapy in 8 patients. Usually ECMO was first set up as rescue therapy. If ECMO could not be weaned off after short-term (usually 1 week) support, suitable VADs (HeartMate or Thoratec VAD) were implanted for medium-term or long-term support. Five patients received ECMO support as emergency rescue for 2 to 9 days, and then moved to Thoratec VAD for 8, 49, and 55 days, respectively, or centrifugal VAD for 31 days, or HeartMate VAD for 224 days. They all survived. The survival rate of double bridges with ECMO and VAD was 100%. In postcardiotomy cardiogenic shock, circulatory collapse from acute myocardial infarction or myocarditis, ECMO is the device of choice for short-term support. If heart transplantation is indicated, VADs should replace ECMO for their superiority as a bridge to heart transplantation. Our preliminary data of double bridges with ECMO and VAD revealed good results and were reliable and effective bridges to transplantation.     

Compact, reliable ventricular assist device as a bridge to recovery or for semipermanent use

OBJECTIVES: The magnetically suspended centrifugal pump has gained attention as an implantable ventricular assist device for long-term use. We report recovery-oriented pump operation and results of a chronic animal experiment. METHODS: In an acute experiment in 8 sheep having microspheres injected to induce heart failure, left ventricular assist was implemented by 2 inflow cannulas, 1 each in the left atrium and left ventricle. The pressure-volume loop of the left ventricle and myocardial oxygen consumption were measured varying the assist rate. The chronic animal experiment used 10 sheep whose native heart was kept intact. Continuous hemodynamic monitoring and periodic blood sampling were conducted. RESULTS: In the acute study, myocardial oxygen consumption decreased proportionally with increasing assist rate in left atrial drainage, but was significantly less at a 100% assist rate in left ventricular drainage. External work in left ventricular drainage did not decrease until a 75% assist rate, suggesting that the left ventricle shape and size were maintained despite decreased myocardial oxygen consumption. In the chronic experiment, the pumping duration was 14 to 248 days. No thrombi or emboli in the pump or any major organ were found in sacrificed sheep after living more than 100 days. Hepatic and renal function were within an almost normal range throughout the experiment. CONCLUSION: Left ventricular blood drainage effectively reduced oxygen consumption, maintaining the shape of the left ventricle. The magnetically suspended centrifugal pump is suitable for recovery of a failing heart or semipermanent use.     

Berlin Heart ventricular assist device in a child with hypoplastic left heart syndrome

We report the implantation of a Berlin Heart ventricular assist device (VAD) in a 4-year-old boy with hypoplastic left heart syndrome previously palliated with Norwood and Glenn operations, who presented with progressive ventricular failure and hypoxemia. Insertion of a 30-mL pneumatic pediatric pump with cannulation of the systemic right ventricle and aorta had a salutary effect on cardiac output, improving oxygen saturations. While awaiting heart transplantation, multiple thromboembolic complications developed and he died, despite therapeutic heparinization and aspirin therapy. Important lessons learned about VAD support in Glenn physiology, anticoagulation, and complications of the Berlin Heart are discussed.     

The use of the Jarvik-7 total artificial heart and the Symbion ventricular assist device as a bridge to transplantation

The proliferation of transplantation programs has not been paralleled by a similar increase in the availability of organ donors. Between 1984 and 1987, 104 orthotopic heart transplantations were performed at Loyola University Medical Center. During the same period, 25 patients died while awaiting a donor organ. To reduce the mortality, we began using the total artificial heart (TAH) and a ventricular assist device (VAD) as a bridge to transplantation in 1988. Of 29 patients who underwent transplantation, 15 patients required a TAH and three patients required a VAD as a bridge. The underlying heart conditions were ischemic cardiomyopathy (11 patients), dilated cardiomyopathy (5 patients), giant cell myocarditis (1 patient), and allograft failure (1 patient). The average duration of mechanical support was 10 days (range, 1 to 35 days). Of the 17 patients who successfully underwent transplantation, 1 patient died at 17 days because of acute rejection of the transplanted heart, and another patient died at 14 days because of a cerebral vascular event. Fifteen patients (83%) were long-term survivors. Nine patients required reoperation for bleeding. While the mechanical device was in place, the activated clotting time was maintained between 170 and 200 seconds with heparin. Dipyridamole was given. We conclude that the TAH and VAD are excellent mechanical bridges to transplantation.