Impact of ventricular assist device implantation on the nutritional status of children awaiting heart transplantation

Nutritional status and cannula infections in pediatric patients on ventricular assist device support

BACKGROUND

Ventricular assist devices (VADs) are used to bridge pediatric patients to heart transplantation. Paracorporeal VADs require the placement of cannulas, which can create an environment for infections. We examined cannula infections in pediatric VAD patients and the role of nutritional status.

METHODS

This retrospective study (2005-2021) included patients <20 years old on VAD support using Berlin Heart EXCOR® cannulas. Cannula infections were defined by a positive culture and need for antibiotic therapy. Malnutrition was defined using the American Society of Parenteral and Enteral Nutrition guidelines as well as the Michigan MTool.

RESULTS

There were 76 patients with a median age at implant of 0.9 years (IQR 0.4, 3.6), 50% male, with 73.7% having non-congenital heart disease. More than one-quarter (26.3%) of patients developed a cannula infection. Higher pre-implant weight (OR = 1.93, p = 0.05), creatinine (OR = 1.02, p = 0.044), and pre-albumin (OR = 15.79, p = 0.025), as well as duration of VAD support (OR = 1.01; p = 0.003) were associated with increased odds of developing a cannula infection. There was no difference in the malnutrition parameters between those with and without an infection.

CONCLUSIONS

Further exploration in a larger cohort is needed to see whether these associations remain and if the incorporation of objective measures of nutritional status at the time of infection are predictive.

Malnutrition, sarcopenia, and frailty assessment in pediatric transplantation

Nutrition assessment can be challenging in children with end-stage organ disease and in those requiring an organ transplant. The effect of poor nutrition status can exert long-lasting effects on children with end-stage organ disease requiring transplantation. Malnutrition, sarcopenia, and frailty are conditions that require provision of optimal nutrition to prevent or support the treatment of these conditions. Unfortunately, the literature on the assessment of malnutrition, sarcopenia, and frailty in pediatric end-stage organ disease is scarce, thus leading to confusion on how to effectively identify them. Recently, the addition of a variety of validated nutrition and functional assessment techniques has assisted with appropriate assessment of these conditions. The objective of this narrative review is to provide an overview of the current literature for pediatric assessment of malnutrition, sarcopenia, and frailty in the setting of solid organ transplantation and provide practicing nutrition clinicians a solid foundation for learning how to effectively assess these conditions with the current literature available.

Supplemental nutrition, feeding disorders, and renourishment in pediatric heart failure through transplantation

BACKGROUND

Tube feeds are used commonly in children listed for heart transplant; however, rates of renourishment and development of feeding disorders are not sufficiently characterized.

METHODS

Retrospective review of pediatric heart transplant recipients from January 1, 2014, to January 3, 2021. Demographics, anthropometric, and nutritional data were collected from heart transplant listing through 3 years post-transplant. Renourishment rates, presence of a feeding disorder, and need for a gastric feeding tube were analyzed. Multivariable analysis was conducted to identify risks for poor nutritional outcomes.

RESULTS

Of 104 patients, 35 (34%) and 36 (35%) were malnourished at heart transplant listing and transplant, respectively, persisting in 21/91 (23%) 1 year postheart transplant. Forty (38%) received tube feeds at listing, 42 (40%) at heart transplant, and 18/90 (20%) 1 year post-transplant. Rates of feeding disorders fell from 23% at transplantation to 10% 1 year post-transplant. Feeding disorders were associated with younger age at heart transplant (p < .001) and congenital heart disease (p = .03). Forty-six percent of infants required a gastric feeding tube. Renourishment occurred in 20% during listing and was associated with ventricular assist device support (p = .03) and noncalorically dense feeds (p = .03). Malnutrition at transplant was associated with inferior post-transplant survival (6/36 (17%) vs. 2/68 (3%); p = .02).

CONCLUSIONS

Malnourishment requiring tube feeds is common in pediatric heart transplant candidates; however, most patients who eventually survive to transplant remain malnourished at time of transplantation and 1 year later. While some children develop feeding disorders, they generally resolve by 1 year post-transplant.

Nutrition for critically ill children with congenital heart disease

Children with congenital heart disease often require admission to the cardiac intensive care unit at some point in their lives, either after elective surgical or catheter-based procedures or during times of acute critical illness. Meeting both the macronutrient and micronutrient needs of children in the cardiac intensive care unit requires complex decision-making when considering gastrointestinal perfusion, vasoactive support, and fluid balance goals. Although nutrition guidelines exist for critically ill children, these cannot always be extrapolated to children with congenital heart disease. Children with congenital heart disease may also suffer unique circumstances, such as chylothoraces, heart failure, and the need for mechanical circulatory support, which greatly impact nutrition delivery. Guidelines for neonates and children with heart disease continue to be developed. We provide a synthesized narrative review of current literature and considerations for nutrition evaluation and management of critically ill children with congenital heart disease.

Incidence and impact of malnutrition in patients with Fontan physiology

BACKGROUND

Single-ventricle patients require a series of surgeries, with the final stage being the Fontan. This form of circulation results in several long-term complications, but the impact and consequences of nutrition status remain unclear. We sought to evaluate the incidence of malnutrition in Fontan patients and the impact on outcomes.

METHODS

This study was a retrospective cohort study of children who underwent Fontan surgery between 1997 and 2018. Clinical, demographic, and nutrition data were collected, including weight, height, body mass index (BMI), and their respective z scores (z score for weight-for-age [WAZ], z score for height-for-age [HAZ], and z score for BMI-for-age [BMIZ]) pre-Fontan, at discharge, 6 months, and 1, 5, and 10 years post-Fontan. Malnutrition status was categorized using the American Society for Parenteral and Enteral Nutrition guidelines and the Michigan MTool. Fontan failure was defined as listing for heart transplant or death.

RESULTS

Of the 69 patients, moderate-severe malnutrition occurred at any time point in 11% (n = 8) by WAZ, 16% (n = 11) by HAZ, and 6% (n = 4) by BMIZ. Moderate-severe malnutrition persisted in 6.5%-12.9% at 10 years post-Fontan. Compared with the pre-Fontan period, there was no change in these parameters over time. There was no statistically significant difference in Fontan failure between degrees of pre-Fontan malnutrition.

CONCLUSION

There is a 6%-16% incidence of moderate-severe malnutrition in Fontan patients. Malnutrition is a condition that remains present in follow-up. There was no association with anthropometric parameters and transplant-free survival. A prospective multi-institutional study is needed to understand the impact of malnutrition on long-term outcomes.

Safety and Feasibility of Exercise Rehabilitation in Children with Ventricular Assist Devices

Children with advanced heart failure may require ventricular assist devices (VAD) while awaiting heart transplantation. Currently, no data exist regarding the safety of exercise rehabilitation (ER) in children on VAD support. The purpose of this study was to determine the safety and feasibility of ER in children on VAD support awaiting heart transplantation. Eligible patients underwent VAD placement between 1998 and 2019; both inpatient and outpatient participants were included. After VAD implantation and when ambulatory, patients were enrolled in ER. Exercise sessions were scheduled three times a week and consisted of aerobic and musculoskeletal conditioning. A total of 29 patients (59% male, mean age 14 ± 3.2 years) were included with a median VAD duration of 120 ± 109 days. Cardiac diagnoses included cardiomyopathy (81%) and congenital heart disease (19%). VAD type included pulsatile (59%) and continuous-flow devices (41%). Eight hundred and sixty-four (85%) ER sessions were successfully completed and began at a mean of 49 days (range 19-108) after VAD implant. No adverse events, including episodes of hypotension, significant complex arrhythmia, or VAD malfunction occurred during exercise testing or ER, and no sessions were discontinued prematurely. Pediatric patients on VAD support can safely participate in ER with relatively high compliance, and sessions can be implemented early after VAD implantation. Given the safety profile, ER in pediatric VAD recipients, which is a modifiable pre-transplant risk factor that may improve functional capacity, warrants further study as a potential modality to improve post-transplant outcomes.

Pediatric heart transplant waiting times in the United States since the 2016 allocation policy change

We describe waiting times for pediatric heart transplant (HT) candidates after the 2016 revision to the US allocation policy. The OPTN database was queried for pediatric HT candidates listed between 7/2016 and 4/2019. Of the 1789 included candidates, 65% underwent HT, 14% died/deteriorated, 8% were removed for improvement, and 13% were still waiting at the end of follow-up. Most candidates were status 1A at HT (81%). Median wait times differ substantially by listing status, blood type, and recipient weight. The likelihood of HT was lower in candidates <25 kg and in those with blood type O; The <25 kg, blood type O subgroup experiences longer wait times and higher wait list mortality. For status 1A candidates, median wait times were 108 days (≤25 kg, blood type O), 80 days (≤25 kg, non-O), 47 days (>25 kg, O), and 24 days (>25 kg, non-O). We found that centers with more selective organ acceptance practices, based on a lower median Pediatric Heart Donor Assessment Tool (PH-DAT) score for completed transplants, experience longer status 1A wait times for their listed patients. These data can be used to counsel families and to select appropriate advanced heart failure therapies to support patients to transplant.

Estimating nutritional needs in paediatric heart failure: beyond the equations

BACKGROUND

Nutrition optimisation is imperative in paediatric patients with heart failure. Energy needs can be assessed using indirect calorimetry.

METHODS

Presented are two cases of children with clinical heart failure who benefited from indirect calorimetry.

RESULTS

Using indirect calorimetry, it was determined both cases were hypermetabolic.

CONCLUSION

These cases demonstrate the impact of heart failure on metabolic rate and growth. Energy requirements were up to two times higher than estimations from predictive equations.

Combining Prognostic Nutritional Index and Brain Natriuretic Peptide as a Predicting Tool for Heart Transplantation

Our study aimed to evaluate the potential of prognostic nutritional index (PNI) and Brain natriuretic peptide (BNP) in predicting the prognosis of heart transplantation (HTx). We retrospectively investigated 489 patients undergoing HTx between 2015 and 2020 in our center. The relationship between preoperative index and prognosis was analyzed respectively, the optimal cut-off values for preoperative PNI and BNP level were evaluated with receiver operating curve analysis. Uni-variate analysis and multivariate analysis were used to compare baseline data (sex, age, diagnosis, etc.) of groups divided by the level of PNI and BNP. Propensity score matching (PSM) was applied to eliminate bias. We calculated the C-index from the prediction efficiency of PNI and BNP. During the period, 489 recipients undergoing HTx in our center were included according to the inclusion criteria; 383 (78.3%) males and 106 (21.7%) females were included in this study, with a median age of 47.57 years old. The ROC curve showed that the optimal cut-off values of each indicator were verified as 49.345 for PNI, and 4397.500 for BNP. The multivariate analyses indicated that PNI (p = 0.047), BNP (p = 0.024), age (p = 0.0023), and waiting time (p = 0.012) were risk factors for all-cause death after HTx. Propensity score matching generated 116 pairs based on PNI level and 126 pairs based on BNP level, and the results showed that OS (overall survival) was significantly correlated with PNI (n = 232, p = 0.0113) and BNP (n = 252, p = 0.0146). Our study implied that higher PNI and lower BNP level had direct correlation with better survival after HTx. Combining PNI and BNP together would be a potential clinical preoperative instrument to predict the survival of patients after HTx, especially in short-term survival.

Trends in Body Mass Index and Association With Outcomes in Pediatric Patients on Continuous Flow Ventricular Assist Device Support

Data are limited regarding body mass index (BMI) in pediatric patients supported by ventricular assist devices (VAD) and associated clinical outcomes and complications. We performed a retrospective single-center cohort study including patients aged ≤21 years on durable continuous-flow VAD support for ≥30 days from 2009 to 2020. Patients were classified based on BMI percentile at implant using the US Centers for Disease Control and Prevention criteria: underweight (<5th percentile), healthy weight (5th-<85th percentile, reference group), overweight (85th-<95th percentile), and obese (≥95th percentile). Primary outcomes were hospital mortality and length of stay (LOS) after implant. Secondary outcomes included infectious complications and pump thrombosis. Seventy-two patients (58 HeartWare, 13 HeartMateII, 1 HeartMate3) were included. At implant, the study cohort comprised 13% underweight, 53% healthy weight, 18% overweight, and 17% obese. BMI increased across all categories during support, with 29% gaining BMI categories. No patients with obesity reduced their BMI category. At explant, the study cohort comprised 1% underweight, 54% healthy weight, 22% overweight, and 22% obese. There was no significant difference in hospital mortality, postoperative LOS, or pump thrombosis. Patients who were overweight had more frequent non-VAD infections. Patients with obesity required longer duration on VAD support and were less likely to be transplanted. We concluded that pediatric patients on VAD support who are overweight or have obesity do not improve their BMI and instead have significant increase. Larger studies are needed to assess the impact of abnormal BMI on VAD complications in pediatric patients.

Variation in Cardiac Rehabilitation for Pediatric Ventricular Assist Device Recipients Across North America

Despite increasing utilization of continuous-flow pediatric ventricular assist devices (VAD) in children, data on exercise testing and cardiac rehabilitation (CR) are unknown. We described variation in CR practices and identified barriers to exercise testing and CR. A survey was performed through the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) representing pediatric VAD centers across North America. Descriptive statistics were performed. A multidisciplinary cohort of 52 respondents from 28 pediatric VAD centers responded. Although 38% reported performing exercise testing, most (65%) used 6 minute walk tests rather than formal cycle or treadmill exercise testing. While all respondents refer to physical therapy during the initial inpatient stay for VAD placement, only 52% refer to a CR program. When performed, CR was performed at an ACTION center (84%), a local specialized center (21%), or a home-based CR program (26%). Commonly cited barriers to either CR or exercise testing were inadequate resources, inadequate implementation logistics knowledge, concerns about safety, inability of patients to travel to a CR facility, and concern about utility of exercise testing or CR. Over 90% of centers were interested in implementing a standardized pediatric VAD CR program. Utilization of exercise testing and CR after VAD placement is variable. Despite perceived barriers, most pediatric VAD centers are interested in implementing a standardized CR program for recipients. In response to this interest, we plan to implement a standardized CR protocol to all ACTION pediatric VAD centers in an effort to improve pretransplant waitlist rehabilitation and post-transplant outcomes.

A comprehensive strategy in donor acceptance: Impact on pediatric waitlist and heart transplant outcomes

Significant inter- and intra-center practice variability is present in pediatric donor heart acceptability. This may contribute to variation in the donor refusal rate and may impact waitlist time, morbidity, mortality, and transplant rates. In order to reduce practice variability, our center developed and implemented a comprehensive strategy regarding donor acceptance in September 2017. The aim of this study was to assess the impact of this strategy on waitlist time and outcomes as well as early post-transplant outcomes. We performed a single-center, retrospective analysis of all pediatric (<18 years) patients listed for single-organ heart transplant at our center from September 2015 to September 2018. Patients were divided into those listed before (Group 1) and after implementation of the comprehensive strategy (Group 2). The primary end-point was waitlist time. Secondary end-points included waitlist removal due to death or clinical deterioration, donor refusals per listed patient, early post-transplant outcomes (graft failure, mechanical ventilation time, inotropic support, length of hospital stay) and 1-year post-transplant survival. Of 78 listed patients, 54 were transplanted (29 in Group 1), 9 were removed due to death or clinical deterioration (7 in Group 1) and 15 were removed due to clinical improvement (12 in Group 1). The waitlist time was significantly shorter in Group 2 (17 days, IQR 7-53) vs Group 1 (90 days, IQR 14-162); P = .006. The number of donor refusals was lower in Group 2 (1, IQR 0-2.2) vs Group 1 (4, IQR 2-19); P < .001. The percentage of refused donors with normal function (Left ventricular ejection fraction > 50%) was lower in Group 2 vs Group 1 (53% vs 84%; P < .001). Difference in removal from the waitlist for death or deterioration in Group 2 vs Group 1 (n = 2, 7% vs n = 7, 20%, P = .18) did not reach statistical significance. There was no difference in post-transplant outcomes between groups. The waitlist time and donor refusals significantly decreased after implementation of a comprehensive donor acceptance strategy without impacting transplant outcomes. This analysis supports the need for a comprehensive approach to donor organ acceptance within a pediatric transplant center.

Growth stunting in single ventricle patients after heart transplantation

BACKGROUND

Malnutrition is common among children with single ventricle (SV) congenital heart disease (CHD). The impact of heart transplantation (HT) on nutritional status in SV patients is understudied. Our aim was to evaluate anthropometric changes in SV patients after HT, compared with those transplanted for cardiomyopathy (CM).

METHODS

We performed a single-center retrospective chart review of SV and CM patients < 18 years who underwent HT from January 01, 2010 to December 05, 2017. Wasting and stunting were defined as z-scores for weight-for-age or height-for-age ≤-2, respectively. Changes in these indices between HT and 3 years post-HT were analyzed.

RESULTS

Of 86 eligible patients, 28 (33%) had SV CHD and 58 (67%) had CM. Data were available at 3 years post-HT for 57 patients. At transplant, wasting was equally present in SV versus CM patients (7/28, 25% vs. 9/58, 16%, P = .22), which remained true at 3 years post-HT (2/16, 13% vs. 3/41, 7%, P = .61). At transplant, stunting was more common in SV than CM patients (17/28, 61% vs. 8/58, 14%, P < .001). At 3 years post-HT, 6 of 16 (38%) SV patients and 3 of 41 (7%) CM patients remained stunted (P = .01). Among all patients, wasting decreased from transplant to end-point (19% vs. 9%, P = .05), but stunting did not (29% vs. 16%, P = .2), such that wasting and stunting were associated at transplant (P < .001) but not at end-point (P = .17).

CONCLUSIONS

Longitudinal growth remains impaired for several years after HT in SV patients, even when weight gain is achieved, suggesting that some factors contributing to growth impairment persist despite resolution of SV physiology.

Pediatric ventricular assist device therapy for advanced heart failure-Hong Kong experience

Ventricular assist devices (VADs) are life-saving options for children with heart failure unresponsive to medical therapy as a bridge to transplantation or cardiac recovery. We present a retrospective review of 13 consecutive children who underwent implantation of VAD between 2001 and 2018 in our center. The median age was 12 years (1-17 years), weight was 45 kg (10-82 kg). Etiologies of heart failure were dilated cardiomyopathy (CMP) (n = 8), myocarditis (n = 2), ischemic CMP (n = 1), restrictive CMP (n = 1) and congenital heart disease (n = 1). Pre-implantation ECMO was used in 5, mechanical ventilation in 4, renal replacement therapy in 2 and IABP in 1. Devices used were: Berlin Heart EXCOR left VAD (LVAD), biventricular VAD (BIVAD) (n = 5, 2), CentriMag LVAD, BIVAD (n = 1, 2), HeartWare (n = 2), HeartMate II (n = 1). Median duration of support was 45 days (3-823 days). Overall survival was 85%. Four patients were successfully bridged to transplantation, 2 died while on a device, 4 remain on support and 3 were weaned from VAD. Late death occurred in 2 transplanted patients. Complications included bleeding requiring reoperation in 1, neurologic events in 3, driveline infections and pericardial effusion in 2 each. In one patient, CentriMag BIVAD provided support for 235 days, which is longest reported duration on such a VAD in the Asia Pacific region. Survival for pediatric patients of all ages is excellent using VADs. Given the severity of illness in these children morbidity and mortality is acceptable. VADs could potentially be used as a long-term bridge to transplantation in view of the donor shortage in the pediatric population.