Heart and lung transplantation in children

Left Atrial Strain Correlates with Elevated Filling Pressures in Pediatric Heart Transplantation Recipients

BACKGROUND

Noninvasive assessment of diastolic function in pediatric heart transplantation (PHTx) patients is important for monitoring of rejection, cardiac allograft vasculopathy, and nonspecific graft failure. We hypothesized that left atrial strain (LAS) would correlate with pulmonary capillary wedge pressure (PCWP) and that cutoff values to identify elevated left ventricular (LV) filling pressure could be derived for clinical practice and future testing.

METHODS

This was a secondary analysis of a prospectively collected cohort of PHTx patients undergoing same-day cardiac catheterization with biopsy and transthoracic echo. There were 70 patients with 85 clinical encounters. Traditional mitral inflow Doppler, LAS, LV diastolic strain and strain rate, and ratios for mitral E to LV diastolic strain and strain rate were assessed. Correlation with PCWP was performed, and receiver operator characteristic curves were generated for an elevated mean PCWP, acute rejection, and cardiac allograft vasculopathy.

RESULTS

Decreased LAS during the atrial reservoir phase (Ɛres) correlated with higher invasively measured PCWP (r = -0.40, P < .001). An Ɛres cutoff of 14.5% had good discriminatory ability for an elevated PCWP (sensitivity 75%, specificity 82%), and Ɛres > 22.0% had 100% negative predictive value; Ɛres was superior to other measures of diastolic function. Subanalyses for recent acute rejection (n = 9) showed good discriminatory ability for Ɛres of 14.5% (sensitivity 89%, specificity 74%).

CONCLUSIONS

LAS correlates with invasively measured PCWP and can identify elevated pressures better than traditional and other advanced diastolic function parameters. Use of LAS in PHTx patients may aid in noninvasive monitoring for rejection and nonspecific graft dysfunction.

Risks and Epidemiology of Infections After Lung or Heart–Lung Transplantation

Nowadays, lung transplantation is an established treatment option of end-stage pulmonary parenchymal and vascular disease. Post-transplant infections are a significant contributor to overall morbidity and mortality in the lung transplant recipient that, in turn, are higher than in other solid organ transplant recipients. This is likely due to several specific factors such as the constant exposure to the outside environment and the colonized native airway, and the disruption of usual mechanisms of defense including the cough reflex, bronchial circulation, and lymphatic drainage. This chapter will review the common infections that develop in the lung or heart–lung transplant recipient, including the general risk factors for infection in this population, and specific features of prophylaxis and treatment for the most frequent bacterial, viral, and fungal infections. The effects of infection on lung transplant rejection will also be discussed.

Impact of congenital heart disease on outcomes of pediatric heart-lung transplantation

HLT is reserved for children with cardiopulmonary disease not amendable to alternative therapies. Children with CHD with or without ES may be considered for HLT. Outcomes of HLT in this population are not well described. To test the hypothesis that CHD without ES is associated with worse graft survival and identify factors associated with poor outcome, a retrospective analysis of the UNOS database was performed. One hundred and seventy-eight pediatric HLTs were performed between 1987 and 2011. CHD was the diagnosis in 65 patients, of which 34 had CHD without ES. Patients with CHD without ES had decreased patient survival (median 1.31 yr) compared with CHD with ES (4.80 yr, p = 0.05). On multivariable analysis, the following were associated with graft failure: CHD without ES (adjusted HR 1.69, 95% CI 1.09-2.62), younger age (1.04, 1.01-1.08), pretransplant mechanical ventilation (1.75, 1.01-3.06), pretransplant ECMO (3.07, 1.32-7.12), pretransplant PRAs (1.53, 1.06-2.20), and transplant era (1.85, 1.16-2.94). In children with CHD who require HLT, underlying physiology influences outcomes. Those without ES have a worse prognosis. The diagnosis of CHD without ES and preoperative factors may inform decisions in a complex patient population.

An official American Thoracic Society clinical practice guideline: classification, evaluation, and management of childhood interstitial lung disease in infancy

BACKGROUND

There is growing recognition and understanding of the entities that cause interstitial lung disease (ILD) in infants. These entities are distinct from those that cause ILD in older children and adults.

METHODS

A multidisciplinary panel was convened to develop evidence-based guidelines on the classification, diagnosis, and management of ILD in children, focusing on neonates and infants under 2 years of age. Recommendations were formulated using a systematic approach. Outcomes considered important included the accuracy of the diagnostic evaluation, complications of delayed or incorrect diagnosis, psychosocial complications affecting the patient's or family's quality of life, and death.

RESULTS

No controlled clinical trials were identified. Therefore, observational evidence and clinical experience informed judgments. These guidelines: (1) describe the clinical characteristics of neonates and infants (<2 yr of age) with diffuse lung disease (DLD); (2) list the common causes of DLD that should be eliminated during the evaluation of neonates and infants with DLD; (3) recommend methods for further clinical investigation of the remaining infants, who are regarded as having "childhood ILD syndrome"; (4) describe a new pathologic classification scheme of DLD in infants; (5) outline supportive and continuing care; and (6) suggest areas for future research.

CONCLUSIONS

After common causes of DLD are excluded, neonates and infants with childhood ILD syndrome should be evaluated by a knowledgeable subspecialist. The evaluation may include echocardiography, controlled ventilation high-resolution computed tomography, infant pulmonary function testing, bronchoscopy with bronchoalveolar lavage, genetic testing, and/or lung biopsy. Preventive care, family education, and support are essential.

Update on viral infections in lung transplantation

PURPOSE OF REVIEW

Lung transplantation is an established therapeutic option for patients with severe respiratory insufficiency. Graft dysfunction or rejection depends on the orchestrated prevention of infection(s) and the level of immune suppression. More recent reports underlined the role and pathogenicity of cytomegalovirus (CMV) infection in lung transplant recipients and the double-edged sword of maintaining antiviral immune responses versus guided immune suppression to avoid graft rejection. We present data concerning the nature of the cellular response to Epstein-Barr virus (EBV) and CMV, the subsequent use of cellular therapy in antiviral treatment modalities and discuss the role of H1N1 infection and other viral infections in lung transplantation recipients.

RECENT FINDINGS

Patients after lung transplantation showed a similar susceptibility to H1N1 infections as compared to the local, healthy community. After initial recovery and oseltamivir treatment, lung transplantation patients developed bronchiolitis obliterans syndrome. The genetic background of lung transplant recipients, defined by polymorphism in immune molecules, contributes to increased risk of CMV disease; CMV induces local pro-inflammatory chemokines (CXCL10). Anti-CMV prophylaxis does not impact on anti-CMV-directed cellular immune responses, defined by IFNγ and TNFα production. Asymptomatic EBV carriers showed higher numbers of EBV-reactive T cells. High EBV load carriers showed T cells with immune-exhaustion markers and decreased IFNγ production. Anti-CMV-directed cellular therapy may aid to better manage CMV-associated complications after lung transplantation.

SUMMARY

Pharmacological immune suppression, the genetic makeup of the patient as well as concurrent viral infections impact on the successful outcome of lung transplantation and call for more detailed immune-guided diagnostics and therapy.

ECMO after prolonged cardiopulmonary resuscitation as a successful bridge to immediate cardiac retransplant in a 6-year-old girl

Heart failure, life-threatening arrhythmias, and sudden cardiac death are common complications in patients with advanced chronic cardiac allograft rejection--the major limiting factor of long-term survival after heart transplant. In patients with sustained cardiorespiratory arrest refractory to cardiopulmonary resuscitation extracorporeal membrane oxygenation therapy is a therapeutic option. We report the case of a 6-year-old girl with severe chronic allograft vasculopathy who was successfully bridged to cardiac retransplant through extracorporeal membrane oxygenation therapy after prolonged cardiopulmonary resuscitation. Our case demonstrates extracorporeal membrane oxygenation as a rescuing therapeutic option in high-risk, bridge-to-transplant patients, with cardiac arrest. Even after prolonged cardiopulmonary resuscitation, there were no neurologic events, and our patient recovered without any neurologic damage.

Heart transplantation in children with markedly elevated pulmonary vascular resistance: impact of right ventricular failure on outcome

BACKGROUND

Pulmonary hypertension causes increased morbidity and mortality in adults after heart transplantation. The effect of markedly elevated pulmonary vascular resistance (PVR) on post-transplant outcomes in children has not been well described.

METHODS

Outcomes were compared in a retrospective study between 58 children with an elevated PVR index (PVRI) ≥ 6 U/m(2) and 205 children with a PVRI < 6 U/m(2). Patients who did and did not respond to acute vasodilator testing and patients who underwent transplant before (pre-1995) and after (post-1995) the availability of inhaled nitric oxide (iNO) were compared.

RESULTS

The pre-transplant diagnoses, and cardiopulmonary bypass and donor ischemic times were similar between the high and low PVRI groups. High PVRI patients were older at transplant (12 ± 6.2 vs 8 ± 7.1 years, p = 0.002). The post-transplant inotrope score was higher in the high PVRI group (12 ± 12 vs 2 ± 2, p = 0.0001) and 1-year survival was worse (76% vs 81%, p = 0.03). The PVRI fell to < 6 U/m(2) with acute vasodilator testing in 21 of 49 (42%) high PVRI patients. RV failure occurred in 4 (19%) of the responders and in 14 (50%) of the non-responders (p = 0.037). One responder (5%) and 4 non-responders (14%) died of RV failure. In the period after 1995, the year iNO became clinically available, the select group of high PVRI patients who received iNO preemptively had a lower incidence of post-transplant RV failure than the group that did not receive preemptive iNO (13% vs 54%, p = 0.04).

CONCLUSIONS

Pre-transplant vasodilator testing identified patients at higher risk for RV failure. Patients who did not respond to vasodilator testing had an increased incidence of RV failure and death from RV failure. Preemptive use of iNO was associated with a decreased incidence of RV failure.

Caries-, Candida- and Candida antigen/antibody frequency in children after heart transplantation and children with congenital heart disease

The aim of this study was to determine the incidence of oral/intestinal Candida colonization and Candida-antigen/antibody in immunosuppressed children after HTx (group III, n = 31), in children with CHD (group II, n = 24) and in children with healthy hearts (comparison group, group I, n = 23) aged 2-16 yr according to their dental status between 2004 and 2007. Candida species in saliva, dental plaque, carious lesions and stool were detected with Sabouraud-/CHROMagar and Auxacolor system. Candida-specific-antigen/antibody assays were used for serological diagnosis. Dental status was determined on the basis of the DMF/dmf(T/t)-index. We found significant group differences in fecal Candida colonization (p = 0.027). In relation to dental status, oral Candida colonization increased within group III from 28.5% [DMF/dmf(T/t) = 0] to 66.7% [DMF/dmf(T/t) > or = 1] up to 100.0% [D/d(T/t) > or = 1], similar in groups I and II. Candida-mannan-antigen was determined to be positive in 16.1% (HTx), 5.5% (CHD) and 13.0% (comparison group). We show correlation between oral Candida colonization and (carious) dental status. We assume that high oral Candida and their descending/resorption through the gastrointestinal tract may lead to serologic Candida accumulation or rather candidiasis. Therefore, healthy oral cavity (especially before/after HTx) is an important precondition to prevent Candida infections.

Transplantation immunology: solid organ and bone marrow

Development of the field of organ and tissue transplantation has accelerated remarkably since the human MHC was discovered in 1967. Matching of donor and recipient for MHC antigens has been shown to have a significant positive effect on graft acceptance. The roles of the different components of the immune system involved in the tolerance or rejection of grafts and in graft-versus-host disease have been clarified. These components include antibodies, antigen-presenting cells, helper and cytotoxic T-cell subsets, immune cell-surface molecules, signaling mechanisms, and cytokines. The development of pharmacologic and biological agents that interfere with the alloimmune response has had a crucial role in the success of organ transplantation. Combinations of these agents work synergistically, leading to lower doses of immunosuppressive drugs and reduced toxicity. Reports of significant numbers of successful solid-organ transplantations include those of the kidneys, liver, heart, and lung. The use of bone marrow transplantation for hematologic diseases, particularly hematologic malignancies and primary immunodeficiencies, has become the treatment of choice in many of these conditions. Other sources of hematopoietic stem cells are also being used, and diverse immunosuppressive drug regimens of reduced intensity are being proposed to circumvent the mortality associated with the toxicity of these drugs. Gene therapy to correct inherited diseases by means of infusion of gene-modified autologous hematopoietic stem cells has shown efficacy in 2 forms of severe combined immunodeficiency, providing an alternative to allogeneic tissue transplantation.

The impact of EBV load on T-cell immunity in pediatric thoracic transplant recipients

BACKGROUND

Immunologic monitoring of pediatric transplant (Tx) recipients, who are at increased risk of Epstein-Barr virus (EBV)-driven posttransplant lymphoproliferative disease, is an important goal in clinical transplantation. Here, we investigated the impact of EBV load on T-cell immunity from pediatric Tx recipients, using clinically applicable tests for improved assessment of T-cell immune competence.

METHODS

Thirty-five asymptomatic pediatric thoracic Tx patients were categorized into three groups according to their EBV load levels as follows: undetectable viral load (UVL), chronic low viral load (LVL) and chronic high viral load (HVL). Global and EBV-specific T-cell immunity were assessed by ATP release using Cylex Immuknow and T Cell Memory assays.

RESULTS

UVL patients exhibited normal ATP release to Concanavalin A (ConA) and phytohemagglutinin (PHA; 190+/-86 ng/mL, 328+/-163 ng/mL) and detectable EBV-specific (37+/-34 ng/mL) ATP responses. LVL patients displayed significantly stronger responses to ConA (373+/-174 ng/mL), PHA (498+/-196 ng/mL) and EBV (152+/-179 ng/mL), when compared with UVL or to HVL patients (ConA 185+/-114 ng/mL, PHA 318+/-173 ng/mL, and EBV 33+/-42 ng/mL). Moreover, HVL patients displayed significant inverse correlation between CD4+ T-cell ATP levels and EBV loads.

CONCLUSIONS

Evaluation of global and EBV-specific T-cell immunity provides a rapid assessment of patients' immune competence. It is still unclear whether selective oversuppressed ATP release by CD4+ T cells reflects HVL patients at risk of posttransplant lymphoproliferative disease. Further longitudinal studies will determine the importance of Immuknow test in identifying asymptomatic HVL patients vulnerable to EBV complications.

Children with chronic organ failure possibly ending in organ transplantation: a survey in an Italian region of 5,000,000 inhabitants

AIM

The Italian Piedmont region sponsored in 2005 a population-based registry to assess the epidemiology of childhood chronic organ failure involving kidneys, liver, heart or lungs.

METHODS

Patients in chronic organ failure who were younger than 18 years were selected, and entered the registry when accomplishing the standard failure criteria for each organ. The cases were reported by the general paediatricians of the region and integrated with the data gathered by the Children University Hospital, a tertiary care centre.

RESULTS

In Piedmont (647,727 inhabitants < 18 years), a total of 146 children (217 cases per million of paediatric population) were found to be affected by chronic organ failure (mean age 10 years; range 0-17). The organ failure involved kidneys in 68 subjects (48%), liver in 24 (17%), heart in 21 (15%) and lungs in 28 (20%), and was severe in 32 subjects (6 on transplantation waiting list). The most represented disease leading to chronic renal failure was renal hypodysplasia (79%). Chronic liver failure was mostly caused by biliary atresia (30%), autoimmune hepatitis (25%) and Wilson's disease (21%). Dilated cardiomyopathy (62%) and surgically treated congenital cardiopathy were the two leading causes of chronic heart failure. The most represented disease leading to chronic lung failure was cystic fibrosis (89%).

CONCLUSION

This is the first report of the literature focusing on the epidemiology of chronic organ failure in children encompassing a region of 4,000,000 inhabitants. This clinical condition is rare, but medically and socially very demanding not only in childhood but the life along, as most of these patients will need solid organ transplantation decades later.

Genetic polymorphisms impact the risk of acute rejection in pediatric heart transplantation: a multi-institutional study

OBJECTIVE

The objective of this study was to determine the association between the genetic polymorphisms of proinflammatory and regulatory cytokines and long-term rates of repeat and late acute rejection episodes in pediatric heart transplant (PHTx) recipients.

METHODS

Three hundred twenty-three PHTx recipients: 205 White non-Hispanic, 43 Black non-Hispanic, and 75 Hispanic were analyzed for time to first repeat and late acute rejection episodes by race, age at transplantation, and gene polymorphism (interleukin [IL]-6, -174 G/C, IL-10, -1082 G/A, -819 C/T, 592 C/A; vascular endothelial growth factor (VEGF) -2578 C/A, -460 C/T, +405 C/G; tumor necrosis factor alpha (TNF-alpha)-308 G/A).

RESULTS

Recipient black race and older age at transplant were risk factors for both repeat and late rejections, though black race was more significantly related to late rejection (P=0.006). Individually, TNF-alpha high, IL-6 high, VEGF high, and IL-10 low phenotypes did not impact the risk of repeat or late rejection. However, the combination VEGF high/IL-6 high and IL-10 low was associated with increased estimated risk of late rejection (P=0.0004) and only marginally with repeat rejection (P=0.051). In a multivariate analysis, adjusting for age and race, VEGF high/IL-6 high and IL-10 low still remained an independent risk factor for late acute rejection (RR=1.91, P<0.001).

CONCLUSION

This is the largest multicenter study to document the impact of genetic polymorphism combinations on PHTx recipients' outcome. The high proinflammatory (VEGF high/IL-6 high) and lower regulatory (IL-10 low) cytokine gene polymorphism profile exhibited increased risk for late rejection, irrespective of age and race/ethnicity.

Mortality After Heart-Lung Transplantation Experience in a Reference Center

The 2006 International Society for Heart and Lung Transplantation registry reported that there were differences in mortality after heart-lung transplantation (HLT) depending on the etiology for transplantation. Our objective was to conduct an analysis on mortality after HLT at our center.

MATERIALS AND METHODS

From January 1991 to December 2006, 25 HLT were performed on patients with the following characteristics: mean age of 38 +/- 11 years with 62% males and 4% with previous surgery. The cohort included 17% urgent transplants. The mean ischemia time was 198 +/- 60 minutes. We divided patients into four etiologic groups: congenital heart disease of the Eisenmenger type; primary pulmonary hypertension; chronic obstructive pulmonary disease/emphysema/fibrosis with right ventricular impact; or pulmonary dysfunction with concomitant left ventricular depression. Three patients were excluded from the analysis because they did not fit in any of the groups.

RESULTS

The mean follow-up of the sample was 862 +/- 1290 days. The overall hospital survival as well as that at 1 and 5 years was 59%, 50%, and 37%, respectively. In the Eisemmenger's syndrome cohort no death occurred during hospitalization and survival at 5 years was 50%.

CONCLUSIONS

HLT was a therapeutic option with high mortality. Hospital mortality was high in absolute terms. Congenital heart disease of the Eisenmenger type may be a lower risk group.