Use Of Ventricular Assist Devices Research Articles

Long-Term Outcomes after the Use of Left Ventricular Assist Devices

Long-Term Outcomes after the Use of Left Ventricular Assist Devices

Extracorporeal Lung Assist in the Treatment of Respiratory Failure During Mechanical Circulatory Support

THE EMERGENCY USE of implantable ventricular-assist devices (VADs) in patients with cardiogenic shock or cardiopulmonary arrest is associated with poor survival rates.1 Some centers therefore prefer a mechanical double-bridge strategy using primarily femorofemoral venoarterial extracorporeal membrane oxygenation (ECMO) for emergency, short-term mechanical circulatory support.2,3 In addition to its less invasive and more rapid implantation, ECMO support allows a recovery period from shock-associated multiorgan injury and gives time for patient evaluation (eg, exclusion of ischemic brain injury).

Does Total Implantability Reduce Infection With the Use of a Left Ventricular Assist Device? The LionHeart Experience in Europe

Infection is the leading cause of death for left ventricular assist device (LVAD) patients with end-stage heart failure. Decreased infection may be possible with fully implantable LVADs such as the LionHeart, which lacks percutaneous conduits (PCs), a common source of device-related infection (DRI). This sub-study reports infections with the LionHeart and compares these results with historic data from the REMATCH trial, bridge to recovery (BTR) and bridge-to-transplantation (BTT) studies. Twenty-three patients were implanted with the LionHeart LVAD and followed until death or heart transplant during a non-randomized, multicenter, European trial from October 1999 to April 2004. The nature and incidence of infection were analyzed and adjudicated to definitions similar to, or the same as, the REMATCH definitions. The combined number of implant days was 7,980, with a mean of 347 days (median 112, range 17 to 1,259 days). Survival at 1 year was 39%, with 2-year survival at 22%. Seventy-four percent of patients developed one or more infections, with 30% developing sepsis, and 35% developing pump-pocket infections (PSIs). No patients developed pump-housing or inflow- or outflow-tract infections (PI). For comparison, the prevalence rates of sepsis, PSI and PI in REMATCH were 51%, 35% and 19%, respectively. The patients in the European LionHeart Clinical Utility Baseline Study (CUBS) trial had less sepsis and less overall DRI compared with the REMATCH LVAD group. Therefore, the fully implanted device may cause less infection than PC devices during destination therapy (DT). Although lower for DT, these rates are still higher than for some BTT experiences. Areas for future improvement include miniaturization of controller/battery components to reduce wound complications related to pocket size, and installation of more modern lithium-ion batteries to decrease the need for re-operations due to battery end-of-life.

Successful Use of the Toyobo Left Ventricular Assist Device in a 16-kg Girl Awaiting Cardiac Transplantation

In Japan, no mechanical circulatory support is available for children. We report a case of terminal stage cardiac failure in a 16-kg girl who was implanted with an adult-sized Toyobo-NCVC left ventricular assist device (Toyobo-National Cardiovascular Center, Osaka, Japan) in our unit. She successfully underwent heart transplantation in the United States 5 months later.

Infections associated with ventricular assist devices: epidemiology and effect on prognosis after transplantation

Ventricular assist devices (VADs) can be used as a bridge to orthotopic heart transplantation (OHT) in people with severe congestive heart failure. Although they can be inserted for an indefinite time period (unlike balloon pumps), they do carry a substantial risk of infection. We studied the epidemiology, microbiology, and consequences of infection in patients with VADs who ultimately had cardiac transplantation. Records of VAD-supported patients at our institution between January 1995 and January 2005 were identified by ICD-9 code. Infection was classified as driveline infection, pocket infection, mediastinitis, or VAD endocarditis in increasing severity of illness. Of 73 patients identified by ICD-9 code, 60 had charts available for review. Of these 60, 72% had a VAD infection: 13 had VAD endocarditis; 3, mediastinitis; 25, pocket infection; and 29, driveline infection. The only association of infection (43 patients, 72%) and demography or underlying disease was that of endocarditis with older age (median age 59 vs. 53 years; P=0.02) and diabetes mellitus (13 patients, 30%; risk ratio 3.4; P=0.01). The duration of VAD support was longer in infected patients (median 125 days) vs. uninfected ones (25 days). Median survival measured from the time of VAD placement (although also true from the time of transplantation) was shorter in patients with VAD endocarditis (120 days) and pocket infection (350 days) vs. no infection (>2400 days) with a significant P=0.017 for endocarditis. Four patients had infections after transplantation that were caused by the same organism as their VAD infection. The predominant pathogens in VAD infection were Staphylococcus and Enterococcus spp. VAD use as a bridge to cardiac transplantation is associated with a large number of device-related infections. Patients with infected VADs, on average, wait longer for transplantation than patients with uninfected VADs, and patients with VAD endocarditis have a shorter survival than patients with no VAD infection or simple driveline infection.

Cost-effectiveness of Ventricular Assist Device Use in the United Kingdom: Results From the Evaluation of Ventricular Assist Device Programme in the UK (EVAD-UK)

The UK Department of Health funds ventricular assist device (VAD) implantation as a bridge to transplantation (BTT) at three centers. The cost-effectiveness of this program has not been established. All 70 VAD implants for BTT and a consecutive cohort of 71 inotrope-dependent transplant candidates, between April 2002 and December 2004, were prospectively monitored for survival, transplantation, quality of life and resource use. Costs and quality-adjusted life-years were estimated for these groups, and for a hypothetical scenario in which VAD patients would die within 30 days in the absence of the program. Mean quality-adjusted life-years for a VAD patient was 3.27 at a lifetime cost of 173,841 pounds (316,078 US dollars). The majority of the cost was attributable to the VAD implant (63,830 pounds, 116,056 US dollars) and the initial hospital stay in the ITU and ward (14,500 pounds, 26,364 US dollars). Inotrope-dependent transplant candidates had mean quality-adjusted life-years of 4.99 at a lifetime cost of 130,905 pounds (238,011 US dollars). The worst clinical scenario resulted in a lifetime cost of 14,400 pounds (26,182 US dollars), based on 1 month in the ICU (mean 15 days). These figures were robust to a range of plausible assumptions. A lifetime model based on current UK practice demonstrates that BTT VAD patients had significant quality-adjusted life-years, but treatment was expensive when compared with the worst clinical scenario. If device technology improves, costs are reduced, or referral practice changes, results should be re-assessed.

Successful Salvage of Ventricular-Assist Devices in the Setting of Pump Pocket Infection

Implantable ventricular-assist devices (VADs) have been approved for use both as a bridge to heart transplantation and as a destination therapy. Rising numbers of patients are surviving with these devices for several years. However, infections of these foreign bodies are serious and frequent complications, often requiring removal of the implant, with serious health consequences. Given the increased use of VADs as life-preserving destination therapy, explantation of these devices in the face of infection is impractical. We evaluated and successfully treated 2 patients with VAD pocket infections referred by the cardiac surgery service at our institution using aggressive surgical and pharmacologic therapy, with the goal of preserving the VADs. However, this is still a largely unsolved dilemma requiring further exploration into prevention and treatment since these devastating infections will likely become a more frequent reconstructive challenge.

Left ventricular assist device for pediatric postcardiotomy cardiac failure.

Children with postcardiotomy heart failure who are unresponsive to maximal medical management have limited options for survival. Short-term mechanical circulatory support, such as with extracorporeal membrane oxygenation and ventricular assist devices, has assumed an expanding role in the care of these patients by providing a bridge to recovery. This report describes the use of left ventricular assist devices with centrifugal pumps in five pediatric cases (weight <15 kg) with postcardiotomy heart failure.

Invited commentary

The present study by Sharma and coworkers [1Sharma M.S. Webber S.A. Morell V.O. et al.Ventricular assist device support in children and adolescents as a bridge to heart transplantation.Ann Thorac Surg. 2006; 82: 926-933Abstract Full Text Full Text PDF PubMed Scopus (52) Google Scholar] describes one of the larger single center experiences using ventricular assist devices (VADs) in a pediatric population. Of the 18 patients, 13 were 11 years old or older, while 14 of the patients had a body surface area of 1.4 or greater. Mechanical circulatory support for patients in this age range has more in common with support for adult patients than with support for infants and small children. The development of successful strategies for device bridging to heart transplantation for these smallest children continues to provide the greatest challenge in pediatric mechanical circulatory support. With this in mind, the overall good results reported here reflect what would be expected for a similar young adult patient population, with less pre-existing morbidities than older patients who required VAD support treated at a leading institution in this field. Likewise, the observed morbidities were similar to those reported in the adult literature and occurred with equivalent frequency. One result of particular interest was the finding that elevated panel reactive antibody (PRA) levels in 2 of the patients had no apparent adverse impact on their outcomes. Due to the relative lack of literature regarding the PRA response to VADs in children, further investigation in a larger number of patients may be warranted, perhaps through a multi-institutional approach. Aside from these issues, the present report is of considerable value because it adds to the relatively small number of existing reports that describe the use of VADs in children. Of particular importance, the detailed management points provided here, by a unit with considerable expertise in providing mechanical circulatory support for patients of all ages, should serve as a useful guide for any center that may only rarely encounters pediatric patients who require such support. The evolution of anticoagulation management described here should be especially helpful in this regard. Furthermore, the authors’ description of which of the many available devices may be useful in various clinical settings or for a given patient age should prove valuable for pediatric practitioners who may have less experience with these devices than their adult counterparts. In many ways, mechanical circulatory support for children remains in its earliest stages of development. Continued reporting and analysis of clinical series of pediatric VAD support, particularly for the smallest children, is vital to sustain the needed growth in this field.

Technology Insight: use of ventricular assist devices in children

Mechanical circulatory support systems for the treatment of end-stage heart failure are now available for a wide variety of clinical situations and support times. Extracorporeal membrane oxygenation and centrifugal pump circuits have been most widely used in children, particularly in small infants. These systems are preferred for support after cardiac operations and for use in patients who have concomitant respiratory failure, but are suitable for short-term application only and intensive care is obligatory. True ventricular assist devices (VADs) qualify for long-term application and allow patients full mobilization. These features are important in patients awaiting heart transplantation as well as in those with myocarditis and cardiomyopathy, who might achieve complete cardiac recovery. Pneumatic pulsatile VADs have been available in pediatric sizes since 1992. At our institution, VAD use lasting from several days to 14 months in 70 infants and children with myocarditis and cardiomyopathy has led to a notable rise in survival in the past 5 years. We have been able to discharge 78% of the infants under 1 year old. In this review we present current VAD experience in children in the light of improvements in decision making, device technology, implantation techniques, and in coagulation monitoring and anticoagulation.

Ventricular assist device use for the treatment of acute viral myocarditis

Ventricular assist device use for the treatment of acute viral myocarditis

Relationship Between Renal Function and Left Ventricular Assist Device Use

Poor renal function may affect outcomes after left ventricular assist device (LVAD) placement. Conversely, LVADs may optimize circulation and improve renal function. To assess the relationship between renal function and LVAD use, changes in creatinine clearances (CrCl, in mL/min) were assessed retrospectively in 220 patients who underwent LVAD placement. These patients were also divided into four groups based on CrCl quartiles (< 47, 48-68, 69-95, and > 95) and compared for outcomes post-LVAD placement. Eighty-four patients died on LVAD support. Survival on LVAD was worse for patients with the worst baseline CrCl (42%, 52%, 63%, and 79% for 6 month and 26%, 34%, 47%, and 66% for 12 month survival for quartiles 1-4; both p < 0.01 for trend). Adjusting for other covariates, patients in the lowest CrCl quartile were at a higher risk of dying postimplant (odds ratio 1.95, 95% confidence interval 1.14-3.63). Paired sample analysis showed the following changes in CrCl: preoperative to week 1, 77.0 +/- 46.6 to 92.1 +/- 51.1 (p < 0.01; n = 202), week 1 to 2, 89.4 +/- 49.2 to 95.2 +/- 52.4 (p = 0.01, n = 171), week 2 to 3, 107.5 +/- 58.1 to 113.7 +/- 66.1 (p = 0.16, n = 74), and week 3 to 4, 111.1 +/- 56.6 to 110.5 +/- 56.8 (p = 0.87, n = 60). For the 60 patients with baseline CrCl less than 50, CrCl increased from 36.7 +/- 9.2 to 60.1 +/- 35.5 (p < 0.01; n = 55 pairs) from preimplant to week 1. In 37 of these patients (62%) on intraaortic balloon pump support preimplant, CrCl increased from 38.4 +/- 8.2 to 67.9 +/- 40.3 mL/minute (p < 0.01) during week 1 postimplant. Recovery of renal function to CrCl greater than 50 was associated with a trend towards better 30-day survival (84% vs 66%, p = 0.09). Baseline poor renal function is associated with worse outcomes after LVAD implantation. However, renal function improves substantially and rapidly in post-LVAD survivors and is associated with improved outcomes. These data underscore the importance of careful patient selection for LVAD therapy.

Intracardiac echocardiography during interventional procedures.

As non-surgical percutaneous interventions are increasingly considered for many cardiac conditions, high quality near field continuous imaging is warranted, in order to optimize the results, and to prevent and detect complications. Transesophageal echocardiography is the standard imaging technique, however general anesthesia and endotracheal intubation is required during prolonged monitoring of percutaneous interventions. Intracardiac echocardiography is a novel emerging tool that allows a view within the cardiac chambers and the large vessels and can be employed by the interventional cardiologist. In our department, a phased array, multi-frequency, four-way steerable catheter (AcuNaV - Siemens) was used for anatomic and haemodynamic cardiac assessment and for guidance and monitoring during non-coronary percutaneous interventions. In total 135 patients underwent intracardiac echocardiographic investigation, 4 during diagnostic heart catheterization, 6 during percutaneous coronary intervention with the use of a new left ventricular assist device, the Impella Recover LP 2.5 system, 26 during percutaneous transluminal septal myocardial ablation (10 patients were reevaluated with intracardiac echocardiography at 6 months), 50 during interatrial communication closure, 4 during percutaneous left atrial appendage transcatheter occlusion, 7 during percutaneous balloon valvuloplasty, 1 during percutaneous aortic valve replacement and 27 during pulmonary vein ablation. All patients tolerated the procedure very well with no catheter related complications. However, there were two complications, which were due to the guidewire and the sheath, an inferior vena cava dissection and a femoral vein dissection, respectively. Phased array intracardiac imaging is a safe technology, which facilitates non-surgical interventions by providing high quality images. It eliminates the need for general anesthesia and thus increases the patient comfort.

Duration of inotropic support after left ventricular assist device implantation: Risk factors and impact on outcome

Because duration of inotropic support after left ventricular assist device implantation has been recognized as a surrogate for right ventricular dysfunction, we sought to (1) identify its preimplantation risk factors, particularly its association with preimplantation right ventricular dysfunction, and (2) assess its impact on clinical outcomes. Between 1991 and 2002, left ventricular assist devices were implanted in 207 patients, exclusive of those receiving preoperative mechanical circulatory support, which precluded measuring right ventricular stroke work. Duration of inotropic support was analyzed as a continuous variable, truncated by death or transplantation, and in turn as a risk factor for these 2 events. Inotropic support decreased from 100% on the day of implantation to 57%, 33%, and 22% by days 7, 14, and 21. Its duration was strongly associated with lower preimplantation right ventricular stroke work index, older age, and nonischemic cardiomyopathy and was associated (P < .04) with higher mortality before transplantation but not with transition to transplantation. We identified no preimplantation risk factors for right ventricular assist device use because of its relatively infrequent use in this population (18 patients, only 4 of whom survived to transplantation). Duration of inotropic support after left ventricular assist device insertion is strongly correlated with low preimplantation right ventricular stroke work index. In turn, it was associated with reduced survival to transplantation. Thus, right ventricular stroke work measured before implantation might be useful in decision making for biventricular support, destination therapy, or total artificial heart.

Artificial Heart Research and Present Status of Clinical Application in Japan

Japan has a long history of research and development of the artificial heart since Atsumi began studying artificial hearts at the University of Tokyo in 1959. Since that time, the University of Tokyo group has been developing different types of artificial hearts, as well as materials, blood pumps, driving mechanisms, and control methods. Other than the University of Tokyo, there are 12 institutes involved in artificial heart research and development in Japan. As for artificial heart clinical application in Japan, four devices were approved by the government; two are domestic, two are imported. Between 1980 and 2004, 697 cases of clinical application of a ventricular assist device (VAD) have been performed, including in 38 pediatric patients under 18 years. Recently, clinical use of percutaneous cardiopulmonary support has been increasing with 600 to 800 cases being performed every year, including in 40 to 60 patients under age 20 years. Although the requirement for clinical use of pediatric VADs is increasing, there is no device, domestic or imported, currently used in Japan; therefore, there is an urgent need for development of a pediatric VAD.

The Relationship Between Renal Function and Left Ventricular Assist Device Use

The Relationship Between Renal Function and Left Ventricular Assist Device Use

Mechanical Device–Based Methods of Managing and Treating Heart Failure

Despite advances in pharmacological treatments aimed at neurohormonal blockade for heart failure in the setting of left ventricular pump dysfunction, there is still a growing number of patients with advanced symptoms who suffer significant morbidity and mortality. Mechanical stresses and chronic neurohormonal activation conspire to propagate maladaptive ventricular remodeling responsible for the insidious nature of this disease. Recent studies suggest that further pharmacological neurohormonal blockade may not be safe or effective, which has driven development of devices for this patient population. Furthermore, such devices may target fundamental pathophysiological abnormalities that are largely hemodynamic and mechanical in nature that are not addressed by available pharmacological agents. The profound reverse remodeling routinely associated with left ventricular assist device use, reviewed in detail, further validates device-based approaches and should inspire research to find ways to make this recovery more complete and permanent. Accordingly, this review focuses on the multitude of mechanical device-based approaches currently being investigated to manage and treat this population. From devices for monitoring patient status to anticipate congestive heart failure exacerbations and preemptively adjust therapy to devices to support preterminal patients with end-stage disease, it is recognized that these device-based approaches will assume an increasingly important role in treating the growing number of patients with advanced heart failure.

A Decade Experience of Cardiac Retransplantation in Adult Recipients

Cardiac retransplantation is considered to be the best therapeutic option for a failing cardiac allograft. However, poor outcomes with retransplantation have previously been reported, a factor that raises important ethical, logistic and financial issues given the limited organ donor supply. Seven hundred sixty-six adult patients underwent cardiac transplantation for end-stage heart failure at our institution from 1992 to 2002. Of these, 41 (5.4%) were retransplants. Variables examined included recipient and donor demographics, indications for retransplant, comorbidities, cytomegalovirus (CMV) serology status, left ventricular assist device use before transplant, donor ischemic time, rate of early mortality (within 30 days), and post-transplantation survival rate. Indications for cardiac retransplant were transplant-related coronary artery disease in 37, acute rejection in 3, and other causes in 1. The mean interval between transplantation and retransplantation was 5.9 +/- 3.4 years. Baseline characteristics such as recipient age, gender, CMV serology status, and donor age were similar in the primary transplant and retransplant groups. Early mortality after transplantation was comparable between the 2 groups, but post-transplant survival was significantly lower in retransplant patients compared with primary transplants with 1-, 3-, 5-, and 7-year actuarial survival rates of 72.2%, 66.3%, 47.5%, and 40.7% vs. 85.1%, 79.2%, 72.9%, and 66.8%, respectively (p < 0.001). Cardiac retransplantation offers short-term outcomes similar to primary transplantation but lower long-term survival rates. Non-retransplant surgical options should also be considered in these patients. Careful patient selection and risk-assessment is necessary to govern appropriate allocation of limited donor organs.

Early and Midterm Risk of Coronary Allograft Vasculopathy in Patients Bridged to Orthotopic Heart Transplantation with Ventricular Assist Devices

Coronary transplant vasculopathy (CAV) has been associated with both immunologic and nonimmunologic factors. The impact of preoperative ventricular assist device (VAD) support on the development of CAV has not been studied. To examine this, we obtained posttransplant coronary angiograms from a group of patients bridged with VAD and compared them to post transplant coronary angiograms of a non-VAD cohort. Adult patients undergoing orthotopic heart transplant between 1996-2000 were retrospectively studied and divided into VAD and non-VAD patients. Coronary angiograms were retrospectively reviewed and severity of coronary vasculopathy was categorized as trivial, mild, moderate, or severe. Other variables studied included recipient and donor demographics, cytotoxic panel reactive antibodies (PRA) against T-cell targets and flow cytometric crossmatching against donor T lymphocytes. There was no significant difference between groups regarding demographics. However, VAD patients had a sixfold greater chance of having a T-cell PRA >10% at the time of transplant (p < 0.05), and a fourfold greater chance of having a positive cross match when compared to non-VAD patients (p < 0.05). There was no significant difference in the degree of CAV between groups. Normal coronary anatomy was present in 76% of VAD patients and 64% of non-VAD patients (p = 0.37). These results were similar at 2- and 3-year follow-up (76 vs. 74% and 80 vs. 62%, respectively). Preoperative VAD use is associated with increased sensitization; however, these patients develop CAV at the same rate as those not bridged with a VAD.

CLINICAL DECISION SUPPORT SYSTEM FOR OPTIMAL VAD WEANING

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