Pediatric Ventricular Assist Devices

Abstract

In the past 2 decades, pediatric mechanical circulatory support (MCS) strategies have improved. Focus on ventricular assist devices (VAD) is an important topic for pediatric heart failure patients and single ventricle palliation. Application of VADs continues to evolve, including implanting compact adult continuous-flow devices to larger children (HeartMate 3) along with the recent discontinuation of the HeartWare. The Berlin Heart ExCOR has received improved outcomes with adjustments to anticoagulation. Syncardia Total Artificial Heart has also released a smaller version which has been implanted in adolescents. Advanced cross-sectional imaging can now be used for pre-operative planning of device placement. Finally, special consideration is required for usage of these devices in a failing Fontan circulation (univentricular physiology) with some lab studies and small cases highlighting the unique challenges. The potential options for VAD as a bridge to transplant, destination therapy, or recovery continue to expand the crucial role of MCS in congenital heart disease. Smaller patient size, limited availability of organs for heart transplant, and longer survival of pediatric congenital patients continues to make innovation in MCS necessary.

1. Introduction

For patients with severe end-stage heart failure, there are limited therapeutic options past medical goal-directed therapy. The surgical options for treatment of pediatric congenital patients who require mechanical circulatory support (MCS) is gradually increasing with many opportunities for ongoing research, clinical studies, and device innovation. This chapter will focus specifically on ventricular assist devices (VAD) in a pediatric population. Subtopics will include research within the past few decades, size and availability of pediatric devices, anticoagulation, and special anatomic considerations in congenital heart disease (CHD).

2. Sizing and device selection

One of the biggest challenges in utilizing MCS devices in young children is the limited availability of products for a range of patients that are not yet adult-sized. There are several ways to combat this in order to find the optimal available device. One is to identify the currently available range of devices for use in pediatrics. With technological advances in imaging, pre-operative digital modeling can help with preoperative planning. And, lastly, there are currently trials for more products that will hopefully become available for use in children to increase the availability of MCS devices.

2.1 Preoperative advanced imaging and three-dimensional printing

One of the advantages of utilization advanced imaging and customizable technology in congenital heart disease patients is the ability to adapt to variable anatomy. Surgical aspects of implanting a device may benefit from newer technologies such as preoperative computed tomography (CT) or three-dimensional (3D) printing. A few examples include cannula placement and device location in adults with congenital heart disease and heart failure.

Recent usage of this technology over the past two decades requires specific resources including excellent dataset image acquisition, image processing software, a variety of printing materials, and a 3D printer [1]. In Ref. [1], usage in various adult cardiac and congenital heart patients is explored demonstrating interest with multiple clinically useful applications including patient/family education, training, and operative planning. Some interesting case examples include VAD implantation in a failing systemic right ventricle or after Fontan palliation [2]. In Ref. [3], multiple 3D printed models are shown including color cardiac models and a whole-chest with sternum/ribs along with other soft tissue to simulate the ideal location of a VAD device for a congenital heart patient. The future of 3D printing and MCS offers a unique ability to personalize each patient’s anatomy. Although an exciting new tool, the barriers to increased adoption of this technology include cost, inability to print certain valve structures, access to software, image datasets acquisition expertise, printing materials that closely replicate living tissue, personnel, and 3D printers [1, 2].

In terms of precise preoperative management and placement of VADs, the ability to acquire and measure using CT imaging offers an advantage, especially when assessing children who may be borderline candidates due to smaller thoracic cavity size. Some anthropometric measures include chest cavity dimensions (i.e. internal transverse diameter at different levels, etc.). Patients as young as 8 years-old have been described as receiving implantation, with others from 9 to 11 years of age undergoing preoperative CT imaging and successful implantation. One of the major obstacles to placing a sparse selection of VAD device sizes is compromising the position of the pump after closing the chest. Due to patient size variability, CT imaging offers an objective measure to determine feasibility and evaluate technical implantation preoperatively [4].

2.2 Available implantable devices

Currently, out of over 200 annual pediatric device implantations worldwide, there are only a few types of devices that are available for use in pediatric patients [5]. Another additive factor includes an increase in heart failure hospitalizations in the pediatric population requiring increased usage of these devices, specifically for CHD [5, 6]. There are two broad categories of VAD implantable devices: continuous-flow and pulsatile. The majority of devices being implanted since 2014 are continuous-flow due to the miniaturization and availability of these adult intracorporeal devices to be placed into adolescents [7]. One of the devices which was available for implantation was recently recalled due to thrombosis risk: Heartware (Medtronic, MN, US) [4]. In a 2019 published article [8], the database of the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), reviewed recent outcomes for children with VADs. There were 108 CHD patients over about 5-year span and these were compared to non-CHD patients; CHD patients tended to be younger and smaller (average age 5.7 years with BSA 0.8 m^2) [8]. This study found that CHD was associated with an increased mortality and decreased transplant rates; however, the subgroup who received implantable devices at high volume centers had higher survival rates [8]. There is a consistent trend with increased numbers of children being implanted with these devices within the last decade [5]. Although limited, clinical trials are on-going to make smaller and improved devices for use in pediatrics.

2.2.1 Berlin Heart EXCOR

A pulsatile, paracorporeal ventricular assist device currently approved for pediatric use is the Berlin Heart EXCOR (Berlin Heart, Inc., The Woodlands, TX, US) [9]. Since the first implantation in 1990s, this device offers multiple pump sizes ranging from 10 to 80 mL stroke volume to be assigned based on the patient’s body surface area (BSA) [10]. In Ref. [10], comparison of 80 patients divided into three groups with an optimally sized pump matching stroke volume to BSA, it appeared that thrombotic events were more frequent statistically significantly in children who had a larger pump placed in comparison to BSA. Also, in a much smaller patient (i.e. <3 kg), the smallest pump (10 mL) may need to be run at a rate that is much lower than the optimal heart rate resulting in lower flow and potentially a risk for thrombosis [9]. One potential solution is to insert an assist device on the right and left ventricular in order to maintain a high enough output [9]. There are studies showing some decrease in survival with biventricular support; however, this may be due to the advanced stages of heart failure, which may be alleviated with earlier implementation of univentricular support [10]. Also, patients less than 5 kg were disproportionately at risk for death, possibly due to size mismatch of the device compared to intrinsic native cardiac output in small infants [9]. There are good results for ultimate transplantation or even recovery; however, there is also noted a high incidence of bleeding and thrombosis. Reference [10] studied a total of 80 children who underwent Berlin Heart implantation. They found that 25 children died (mortality rate of 31.6%); 49% of patients were successfully transplanted and 19% of devices explanted. BSA, young age, or having biventricular support did not appear to be associated with increased mortality – potentially attributable to increased experience. Other technical aspects such as site of cannulation or coated cannulas may also lead to improved results [10]. Another limitation of this device is training of hospital personnel and requirements of staying inpatient for device monitoring.

2.2.2 HeartMate 3

The HeartMate 2 and HeartMate 3 (Abbott, Abbott Park, IL, US) are two devices that are implantable compact continuous-flow VADs designed for use in adults that is being implanted in children [9]. However, the HeartMate 2 is no longer the preferred device in this age group. Some older studies, such as reference [9], authors describe their experience at their institution of developing education and support so that there is comfort and experience in implanting HeartMate 2 devices and allowing pediatric patients to be discharged home and managed as an outpatient. This was a significant improvement from the paracorporeal or centrifugal devices requiring management in the hospital. The MOMENTUM 3 trial released the results for usage of the HeartMate 3 which can provide flows between 2.5 L/min and 10 L/min and alternating rotor speeds every other second [9].

The recall of the other lower profile device, discussed in the subsequent section, has made implementation of HeartMate 3 as the ideal device for smaller patients, with an outer diameter of 50 mm [4]. In [11] the early experience described by the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) published in 2020, 35 patients from 2017 to 2019 at multiple centers had a HeartMate 3 implanted in pediatric and adult patients with congenital heart disease. There were patients as small as 19 kg who were successfully implanted and supported (median age = 15.7) – establishing this device as a feasible option for adolescents [11]. Currently, the consensus for appropriate device usage is for older children or young adults weighing greater than 30 kg, although there is no minimum weight restriction [5]. Research is on-going regarding utilization of preoperative advanced imaging to virtually plan implantation.

2.2.3 HeartWare HVAD

The HeartWare HVAD (HeartWare, Inc., Framingham, MA, US) is another implantable compact continuous-flow VAD that was designed for adults and was being implanted in older children [9]. As in Ref. [9], as of recently, there were excitement and documented case reports describing successful implantation of this compact option even in a child as small as 13 kg and as young as 4 years old for over 600 days. There were published studies from a multicenter study describing the implantation in small children. They described a 33% rate of pump thrombosis yet at this single center, Burki et al. describe no pump thrombosis out of 19 patients [9]. However, this device was discontinued after the rates of thrombosis were very high. Unfortunately, it is no longer an option. Without this device as an option, it is difficult to know what the smaller threshold would have been to avoid patient-device size mistmatch between very small children and adult-designed VADs [9].

Over 5 years, it appeared that the implantation of HVAD was steadily increasing through 2017. Even worldwide, there was reported success in children in achieving goal to transplant – over 200 patients from 2015 to 2016 [12]. Perhaps, this was from the innovation of implantation techniques, and even reports demonstrating improvement with biventricular support. Unfortunately, despite these successes, in 2021, the Heartware HVAD was withdrawn completely from the market. Overall, this was a huge setback for the field, but since this was one of two smaller profile devices that were most commonly used in pediatrics, there is currently a gap in comparison to experience versus now this device being unavailable for implantation. HeartMate 3 devices may be able to address the gap for patients that are greater than 30 kg with an adequate chest cavity size. However, practically, given the prevalence of the Berlin Heart as being the only other device having available device sizes from 15 to 30 kg, the removal of the HVAD from markets leaves yet another gap for smaller children less than 30 kg. This is not an ideal replacement, since the Berlin Heart currently requires an inpatient admission without the ability for patients to be discharged home [5]. The impact of this recent device disappearing from the already limited toolkit of the pediatric cardiac surgeon is estimated to have a significant clinical impact without an immediate solution.

2.2.4 Other devices

The Syncardia Total Artificial Heart (Syncardia, Inc., Tuscon, AZ, US) is an option with size constraints to the pumps: a smaller pump 50 mL for the pediatric population which was made available in 2022 and the pre-existing 70 mL pump which is too large for most pediatric patients [9].

Short-term, centrifugal paracorporeal devices using in smaller children such as the PediMag, RotaFlow, or CentriMag (Abbott, Abbott Park, IL, US) are all important as contemporary options for mechanical circulatory support for inpatients who are critically ill [5]. However, the discussion of the usage of these devices compared to implantable durable devices is beyond the scope of this chapter.

2.3 Device development

Currently, there very few clinical trials with device development geared specifically towards pediatric patients [5]. Unfortunately, progress has been slow and halting. Resources are limited. Reasons studies are lacking and difficulty in making substantial progress with a potentially life-saving device are multifactorial including small consumer numbers, substantial regulatory and administrative burden, and patient variability [9]. One potential solution is to encourage device development for both adults and pediatrics [5]. The MVAD (Heartware, Inc.) is another adult-size continuous-flow compact device undergoing testing with a volume of 20 mL [9]. Despite multiple studies originally being funded, there is only one that is currently on-going specifically for pediatrics [7]. The most well-described, smallest device is the Jarvik Infant 2015 which is a continuous-flow VAD targeted towards children 8 kg to 20 kg; the device length is about equal to a AA-battery [9, 13]. The difficulty in performing research in this specific area has been well-described by the lead investigators at Texas Heart Institute [7, 13]. One of the biggest hurtles in developing this device was addressing hemolysis [9]. Another obstacle is the concern for thrombosis. This comes from the inherent patient-device mismatch from implanting adult devices into pediatric patients [7]. Finally, this long awaited device specifically designed for kids will be ready to enroll patients in the PumpKIN (pumps for kids, infants, and neonates) trial [7, 9, 13]. We eagerly await the results for at least another feasible option in the treatment of young children.

3. Anticoagulation

One of the biggest challenges in children and MCS is achieving the ideal balance between bleeding and anticoagulation to prevent thrombosis. This balance is particularly difficult to achieve in pediatric patients due to alterations in hemostasis during development, pro-inflammatory states, or various genetic syndromes [9]. Pharmocologic regimens and combinations differ with a variety of options including the usage of a heparin infusion, low-molecular-weight-heparin, anti-platelet therapy, direct thrombin inhibitors, or warfarin. In addition to differences in pharmacology, target goals and measurements for monitoring are also variable. In the Berlin EXCOR study evaluating pump size [10], this institution describes measuring anti-Xa levels, international normalized ratio, as well as obtaining thromboelastography and platelet aggregation tests for patients also being treated with acetylsalicyclic acid and dipyridamole (or clopidogrel) to ensure therapeutic effect. Reported thrombosis rates for the Berlin Heart are 20–29%. It is hypothesized that larger pump size, due to limitations of appropriate device size for patient body, may be a risk for thromboembolic events [10]. There is variability in whether studies find that <10 kg body weight is a risk factor for thrombosis. Optimal protocols and regimes have been studied to decrease the risk of thromboembolic events while also keeping rates of bleeding low, especially around the perioperative period.

4. Clinical pathways after device implantation

There are several clinical outcomes for children after VAD implantation. It seems that there are increased hospitalizations for decompensated heart failure and more utilization of VADs. Mechanical circulatory device clinical pathways can include bridge-to-transplant, bridge-to-recovery, or currently alive [6]. If it is unknown whether the patient will be suitable for transplant, bridge-to-decision is also an option, but less likely for a durable device in the era of other temporary MCS options. A subset of patients may also require biventricular assist device placement in both the right and left ventricle. Given the growing number of device implantation in children, it is imperative that we continue to review early and late outcomes, as well as measure the impact of quality of life (QOL) in these complex patients.

4.1 Bridge-to-transplant

Some CHD patients may fail surgical repair or multi-stage surgical palliation and require bridging support prior to heart transplantation. One of the benefits of implanting durable VADs in children awaiting transplant is the improved posttransplant survival and decreased waitlist times compared to using temporary mechanical circulatory support such as ECMO. This includes improved nutrition, function of other organs, and rehab prior to transplant – with reports of increased VAD utilization in this pediatric population. Unfortunately, the number of pediatric heart transplantation donors continues to be static within North America [5].

In the most recent era, reference [14] studied the pediatric VAD implantation across two eras (1999 to 2004 or 2005 to 2012). There have been more pediatric patients listed Status 1A – indicating the highest critical need. However, despite this increase, there has been a significant decrease from 2005 to 2012 of 50% in transplant waitlist mortality compared to the previous era. Risk factors for waitlist mortality included weight < 10 kg, CHD, ECMO, mechanical ventilation, or renal dysfunction. VAD was protective and improved waitlist survival [14].

When analyzing whether racial disparities exist in post-transplant survival after VAD implantation, reference [15] elucidates that disparities still exist. Studies have shown that racial minorities experience inferior outcomes after heart transplant. Black children were most ill with a greater proportion Status 1A. Outcomes at 1-year post-transplant were equivalent, but long-term survival was worse for non-whites. On multivariable analysis, black race independently predicted mortality. This study showed that even though the most ill patients receive VADs, with similar pretransplant and early transplant outcomes, black and Hispanic pediatric patients experienced inferior post-transplant survival after VAD as a bridge-to-transplant.

4.2 Biventricular assist device support

Another portion of CHD patients after placement of left VAD may experience severe right ventricular dysfunction, necessitating a right VAD: biventricular assist device (BiVAD) support. In adults, attempts have been made to identify risk factors and subsequent risk scoring to try and predict which patients may need both ventricles supported [16, 17]. Physiologically, LVAD support may augment worsening RVAD failure through many factors, but predicting the level to which a second device placement is warranted is difficult [18]. In Ref. [18], authors reviewed long-term VAD implantation to try and identify risk factors. Unfortunately, patients requiring temporary right VAD support or BiVAD support were at increased risk of mortality [12, 18]. Also, emergent RVAD implantation was associated with worse outcomes. After multivariate logistic regression indicated that decreased milrinone application was a preoperative risk factor associated with requiring BiVAD instead of sole left VAD support. But, in other terms, patients who received preoperative milrinone had decreased odds of developing right heart dysfunction, which was statistically significant [18]. This paralleled some findings in adults as well [17]. However, none of the many other variables evaluated were correlated with predisposing to BiVAD support. It was also observed that the frequency of BiVAD placement in pediatric patients has been decreasing, possibly from improved implantation techniques [18].

4.3 Outcomes and quality of life

In the past few decades, outcomes for pediatric VAD implantation continue to improve. Patients can be successfully bridged to transplant in over 20% of patients [19]. Unfortunately, some of the outcomes data are currently outdated due to use in previous studies of devices that are no longer available [9, 12]. In the early experience of HeartMate 3, short-term follow-up of 35 patients demonstrated an early survival of 97%, with only one mortality [11]. Almost 60% were able to achieve transplantation. Early results were encouraging with no stroke or pump thrombosis after an average of 3-months of follow-up. Not evaluating just by device type, the larger registry among the 471 patients enrolled in the Pediatric Interagency Registry for Mechanical Circulatory Support from 2012 until 2017, groups were divided looking at outcomes for biventricular versus single ventricle patients, specifically with CHD, compared with non-CHD pediatric patients [8]. At 6 months, CHD patients had a higher mortality (36.4%) compared to non-CHD VAD patients (12.1%) and almost half transplantation rate of 29% versus 60%. However, this study also included patients with paracorporeal devices as well as implantable continuous devices. Despite looking at multiple variables, CHD seemed to be the highest association of mortality with VAD placement. As experience with implantation and increased number of children receiving these devices, more data from large registries will be able to help predict which patients will achieve the best outcomes from VAD implantation [9].

One of the earliest studies to compare outcomes of Berlin Heart to ECMO for bridge to transplant demonstrated that longer duration of support without significant risk of stroke and suggested improved survival on Berlin versus ECMO: 86% versus 56%. An updated study looking at more children in 47 centers identified about 200 children requiring support between 2007 and 2010, with median duration of support 40 days. The authors concluded that with the dramatic rise in usage, about 75% of patients survived to transplant or recovery. Risk factors associated with mortality included smaller patients, renal/hepatic dysfunction, and use of biventricular support [20].

Another large, single-center summarized the morbidity for patients requiring MCS associated with mortality from 1998 to 2007. In [21], some major complications the authors noted included infection, respiratory failure, major bleeding, hepatic/renal failure, right heart failure, and neurologic injury. They cited major neurologic injury occurring in almost half of the 25 patients. Although survival to transplant was still three-quarters, consistent with other reports, the monitoring of neuro status changes continues to be challenging requiring aggressive evaluation for potential injury with patient sympatoms.

In a prospective study from 2014, VAD questionnaires were administered to parents to assess children’s Pediatric Quality of Life Inventory pre- and post- VAD placement [19]. These scores were compared to healthy children, outpatients with heart failure, and children after heart transplant. Out of 13 patients, 11 were able to receive a heart transplant and one was still alive on VAD support. Patients reported lower physical QOL scores and lower psychosocial scores. In Ref. [22], 82 children from the Pediatric Interagency Registry for Mechanical Circulatory Support completed a self-report quality of life assessment from pre- and post- VAD implantation. QOL scores were lower than normal for physical and psychosocial scores in both groups pre-VAD. However, it appeared that psychosocial scores improved in children post-VAD at 3 and 6 months post-op. Patients seemed to be mostly concerned physically with being unable to resume usual play activities compared to other children. However, this survey suggests that VAD placement may improve children’s psychosocial health after implantation.

5. Special anatomic congenital considerations

Another challenge in utilizing MCS devices in children or adults with congenital heart disease is the incredible amount of variation that occurs either at birth or after multiple palliative operations. We discuss some of these specific examples to highlight the challenges and the limited data available on current usage. Although this appears to be increasing, the practical application of MCS to these challenging patient cases will require more experience and long-term follow-up.

5.1 Single ventricle patients

Single ventricle patients who undergo staged palliation requiring partial or complete cavopulmonary anastomosis present a unique challenge to implementation of MCS. These challenges include technical/anatomic differences in these patients, as well as physiologic. However, this population is also at significant risk for heart failure during the interstages between Stage I (Norwood or Hybrid), Stage II (bidirectional Glenn), and Stage III (Fontan operation). For example, the authors from Kansas City describe a case report supplying MCS in a superior cavopulmonary patient as a bridge to transplant in an infant [23]. In Figure 1 [23], the authors illustrate cannulation in the reconstructed aortic root (Damus-Kaye-Stansel) and systemic ventricle for a failing Glenn patient. They describe the patient’s changes in physiology while maintained on support and prior to successful transplantation after one year. They conclude that successful long-term support is feasible and ECMO in parallel can be instituted as a strategy for short-term pulmonary support [23].

Figure 1.

Ref. [23]. Reprinted with permission from Elsevier under CC-BY-ND-ND license.

The Fontan operation is typically the final staged palliation for single ventricle patients that connects the systemic venous return to the pulmonary circulation (total cavopulmonary anastomosis). In Ref. [24], a broad description of the background, physiology, and details of different types of Fontan surgically created circulation can be reviewed for building a knowledge foundation. The failing Fontan is another category of research that elucidates the inherent challenge in these patients of ultimately needing a heart transplant [25]. This patient population can be particularly medically challenging due to manifestations of chronic Fontan circulation including liver dysfunction, valve regurgitation, myocardial dysfunction, collaterals, plastic bronchitis, and protein-losing enteropathy. With the addition of anatomic and physiologic challenges, inserting MCS devices into this population is currently under review. Fontan failure can be multifactorial with cardiovascular factors including ventricular dysfunction [6]. Once failure symptomatology starts, transplant waitlist mortality is high [6]. Several limited options exist for supporting failing Fontan physiology including VAD implantation [6, 26].

Using VADs addresses myocardial failure, but will not reverse cavopulmonary failure. Currently, there are no pumps specifically designed for Fontan cavopulmonary circulation. Implantation of these devices may be anatomically challenging due to prevalent under development of one ventricle – leading patients down a single-ventricle pathway. Despite these challenges, some bench research has supported using of the VAD successfully in failing Fontan circulation. Also, the HeartMate 2 supported a sheep for 2 hours when placed in the cavopulmonary graft. Implantation of the HeartWare HVAD in three Fontan patients for 5 to 9 months were successful bridge to transplant [26]. However, in 2021, the HeartWare device was recalled and not currently available for implantation [5]. One case demonstrated the Berlin Heart provided biventricular support for a failing Fontan circulation [26]. HeartMate 3 implantation in a CHD Fontan patient is usually performed after multiple previous staged palliative operations [6].

One of the physiologic challenges after insertion of VAD into the ventricle is off-loading, but can also concomitantly increase Fontan pressures, which can lead to a worsening clinical situation. It does appear that continuous devices are more beneficial than pulsatile devices given the reliance of the circulation on passive pulmonary flow [26]. Careful consideration is needed of the underlying etiology for a failing Fontan, such as ventricular failure, elevated pulmonary artery pressures, or end-diastolic pressures.

In Ref. [6], the Society of Thoracic Surgeons created a group dedicated to observing the outcomes of Fontan patients supported with VADs from 2012 to 2019 using large mechanical assist device registries (Pedimacs and Intermacs). Retrospectively, they found 55 Fontan patients with a median age of 10 years and 27 kg who underwent VAD implantation. Highlighting the trend of more device implantation and growing experience, the equivalent number of VADs were implanted in the last year of observation compared to the previous 5 years (28 vs. 27; p = 0.01, from 2018 to 2019 and 2012–2017, respectively). In addition, the later era had a higher pre-VAD glomerular filtration rate, perhaps demonstrating earlier implantation. Overwhelmingly (89%) of devices were placed to support the systemic ventricle as left-sided VADs. The overall positive outcome (alive, transplant, or recovery) was demonstrated in 81% at 6 months with median length of support at 3.8 months. Fifty-eight percent of all mortality occurred during the first month. Demonstrating the length of duration VAD support can offer, five patients received support for greater than 1 year. Adverse events such as stroke, pump thrombosis, and bleeding ranged from 4 to 9% (1.4 to 3.3 out of 100 patient-months). Important implantation considerations in Fontan patients includes perioperative care, aortopulmonary collaterals, pulmonary vascular disease, or end organ dysfunction can coexist [6].

5.2 Surgical modifications

Currently, some alternative surgical techniques to implanting devices through a median sternotomy and placing the device intrapericardially are under investigation. A minimally invasive approach using two anterior thoracotomies or hemi-sternotomy are being explored with multiple potential advantages. Because it may be difficult to align the inflow cannula vertically, so that it lies parallel to the interventricular septum, another implantation technique is to divide the left hemidiaphragm to create a pump pocket, as described by reference [9]. Surgical modifications of tunneling the driveline in under-developed abdominal walls of smaller children may decrease an already elevated risk of driveline infections in this population by off-setting the insertion through the rectus abdominis muscle [9]. Resecting papillary muscle that may cause mechanical obstruction, reorienting the direction of the outflow, and padding the pump housing against the chest to try and decrease pain with a buffer are other surgical techniques described when treating smaller congenital heart disease patients [4].

6. Conclusions

With recent device innovations, there are more options than ever before for pediatric congenital heart disease patients. However, special considerations still need to be given to specific congenital anomalies and patients with single ventricles. Risks of anticoagulation with bleeding and thrombosis are also careful considerations. There has been tremendous progress in the realm of MCS for pediatric patients in end-stage heart failure, but more research focusing on device and pharmacologic improvements needs to be done.

Conflict of interest

The author declares no conflict of interest.