Pediatric living donor lobar lung transplantation

Lung transplantation in children

Lung transplantation is a well-established treatment for children facing advanced lung disease and pulmonary vascular disorders. However, organ shortage remains highest in children. For fitting the small chest of children, transplantation of downsized adult lungs, lobes, or even segments were successfully established. The worldwide median survival after pediatric lung transplantation is currently 5.7 years, while under consideration of age, underlying disease, and peri- and posttransplant center experience, median survival of more than 10 years is reported. Timing of referral for transplantation, ischemia-reperfusion injury, primary graft dysfunction, and acute and chronic rejection after transplantation remain the main challenges.

Living-donor lobar lung transplantation

Living-donor lobar lung transplantation (LDLLT) is indicated for critically ill patients who would not survive the waiting period in the case of severe brain-dead donor shortage. It is essential to confirm that potential donors are willing to donate without applying psychological pressure from others. In standard LDLLT, the right and left lower lobes donated by 2 healthy donors are implanted into the recipient under cardiopulmonary support. LDLLT can be applied to various lung diseases including restrictive, obstructive, infectious, and vascular lung diseases in both adult and pediatric patients if size matching is acceptable. Functional size matching by measuring donor pulmonary function and anatomical size matching by 3-dimensional computed tomography volumetry are very useful. When 2 donors with ideal size matching are not available, various transplant procedures, such as single lobe, segmental, recipient lobe-sparing, and inverted lobar transplants are valuable options. There seems to be immunological advantages in LDLLT as compared to cadaveric lung transplantation (CLT). Unilateral chronic allograft dysfunction is a unique manifestation after bilateral LDLLT, which may contribute to better prognosis. The growth of adult lung graft implanted into growing pediatric recipients is suggested by radiologic evaluation. Although only 2 lobes are implanted, postoperative pulmonary function is equivalent between LDLLT and CLT. The long-term outcome after LDLLT is similar to or better than that after CLT. The author has performed 164 LDLLTs resulting in 71.6% survival rate at 10 years. All living-donors returned to their previous life styles. Because of possible serious morbidity in donors, LDLLT should be applied only for critically ill patients.

Paediatric lung transplantation: the impact of age on the survival

OBJECTIVES

We herein review the outcomes of paediatric lung transplantation (LTx) and analyse subgroups divided by age.

METHODS

We retrospectively reviewed 43 consecutive paediatric LTx recipients (< 18 years old: cadaveric LTx [n = 9], living-donor lobar LTx [n = 34]). We also analysed subgroups of patients 1-6 years old (n = 10) and 7-17 years old (n = 33).

RESULTS

The 1-, 5- and 10-year overall survival (OS) rates in paediatric recipients were 93%, 82% and 67%, respectively. The 1-, 5- and 10-year graft dysfunction (GD)-free survival rates in paediatric recipients were 85%, 59% and 31%, respectively. The 1- and 5-year OS in the 1- to 6-year-old vs. 7- to 17-year-old groups were 70% vs. 100% and 48% vs. 93%, respectively (p < 0.0001). The 1- and 5-year GD-free survival rates in the 1- to 6-year-old vs. 7- to 17-year-old groups were 60% vs. 93% and 24% vs. 69%, respectively (p = 0.024). The 1- to 6-year-old group showed higher rates of non-standard LTx (p = 0.0001), interstitial pneumonia (p = 0.004) and ventilator dependency (p = 0.007) than the 7- to 17-year-old group.

CONCLUSION

Paediatric recipients under 7 years old seemed to have a higher risk of mortality and GD than those 7 years old and older.

Living-related lung transplantation

Living-donor lobar lung transplantation (LDLLT) was developed to deal with the severe shortage of brain dead door for patients who would not survive the long waiting period. In standard LDLLT, right and left lower lobes removed from two healthy donors are implanted into a recipient after right and left pneumonectomies using cardiopulmonary bypass (CPB). The number of LDLLT has decreased in the USA due to the recent change in allocation system for cadaveric donor lungs. For the past several years, most of the reports on LDLLT have been from Japan, where the average waiting time for a cadaveric lung is exceeding 800 days. LDLLT has been performed both for adult and pediatric patients suffering from various end-stage lung diseases including restrictive, obstructive, vascular and infectious lung diseases. Since only two lobes are implanted, size matching is a very important issue. Functional size matching by measuring donor pulmonary function and anatomical size matching by three-dimensional computed tomography (3D-CT) volumetry are very useful. For oversize graft, we have employed several techniques, including single lobe transplantation, delayed chest closure, downsizing the graft, and middle lobe transplantation. In cases of undersize mismatch, native upper lobe sparing transplant or right-left inverted transplant was performed. The 5-, 10- and 15-year survivals were 80.8%, 72.6% and 61.7%, respectively. There was no difference in survival between standard LDLLT and non-standard LDLLT such as single, sparing and inverted transplant. All donors have been discharged without any restrictions. LDLLT is a viable option for very ill patients who would not survive a long waiting time for cadaveric lungs. We have successfully developed various surgical techniques to overcome size mismatching with favorable outcome.

Moving Back to the Future: Use of Organ Care System Lung for Lobectomy Before Lobar Lung Transplantation

BACKGROUND Lung transplantation remains the gold standard treatment for patients with end-stage lung disease. Lobar lung transplantation allows for transplantation of size-mismatch donor lungs in small recipients; however, donor lung volume reduction represents a challenging surgical technique. In this paper we present our initial experience with bilateral lobectomy in donor lungs before lobar lung transplantation using normothermic perfusion on the Organ Care System (OCS) Lung. MATERIAL AND METHODS Specifics of the surgical technique for donor lung instrumentation on the OCS, lobar dissection on the OCS, and right and left donor lobectomies are presented in detail. RESULTS Potential advantages of the use of the OCS for lobectomy for lobar lung transplantation are described in this section. Donor lung volume reduction utilizing OCS appeared to be easier and safer compared to the conventional cold storage technique, due to continuous perfusion of the lungs with blood and well-distended vessels that offer the feel of live lobectomy. Moreover, the OCS represents a platform for donor organ assessment and optimization of its function before transplantation. CONCLUSIONS Donor lung volume reduction was safe and feasible utilizing the OCS, which could be a useful tool for volume reduction in cases of size mismatch. Further research is needed to evaluate early and long-term results after lobar lung transplantation using the OCS in clinical studies.

A consensus document for the selection of lung transplant candidates: 2014--an update from the Pulmonary Transplantation Council of the International Society for Heart and Lung Transplantation

The appropriate selection of lung transplant recipients is an important determinant of outcomes. This consensus document is an update of the recipient selection guidelines published in 2006. The Pulmonary Council of the International Society for Heart and Lung Transplantation (ISHLT) organized a Writing Committee of international experts to provide consensus opinion regarding the appropriate timing of referral and listing of candidates for lung transplantation. A comprehensive search of the medical literature was conducted with the assistance of a medical librarian. Writing Committee members were assigned specific topics to research and discuss. The Chairs of the Writing Committee were responsible for evaluating the completeness of the literature search, providing editorial support for the manuscript, and organizing group discussions regarding its content. The consensus document makes specific recommendations regarding the timing of referral and of listing for lung transplantation. These recommendations include discussions not present in previous ISHLT guidelines, including lung allocation scores, bridging to transplant with mechanical circulatory and ventilator support, and expanded indications for lung transplantation. In the absence of high-grade evidence to support decision making, these consensus guidelines remain part of a continuum of expert opinion based on available studies and personal experience. Some positions are immutable. Although transplant is rightly a treatment of last resort for end-stage lung disease, early referral allows proper evaluation and thorough patient education. Subsequent waiting list activation implies a tacit agreement that transplant offers a significant individual survival advantage. It is both the challenge and the responsibility of the transplant community globally to ensure organ allocation maximizes the potential benefits of a scarce resource, thereby achieving that advantage.

Donor-recipient size matching and survival after lung transplantation. A cohort study

RATIONALE

The association between a high predicted total lung capacity (pTLC) ratio (equal to pTLC(donor)/pTLC(recipient)), suggestive of an oversized allograft, with improved survival after lung transplantation (LTx) remains controversial.

OBJECTIVES

To characterize donor-recipient lung size matching based on the pTLC ratio and to investigate the relationship of the pTLC ratio with post-LTx survival.

METHODS

All subjects in the Scientific Registry of Transplant Recipients, who underwent first-time LTx in the lung allocation score-based system between May 4, 2005 and March 31, 2012, were studied, and the pTLC ratio was calculated on the basis of sex, height, and age. Risk of death after LTx was analyzed using Cox proportional hazards models.

MEASUREMENTS AND MAIN RESULTS

The pTLC ratio was available for 10,289 of the 10,318 study subjects (99.7%). The mean pTLC ratio was 1.015 ± 0.175 (interquartile range, 0.918-1.119). Univariate analysis showed that the pTLC ratio was strongly associated with death in the first LTx year (P < 0.0001). With the pTLC ratio entered as a spline there was a nonlinear association with declining risk of death with higher pTLC ratio from 0.5 to about 1.3, where an inflection occurred with rising risk at higher values. Accounting for the pTLC ratio, recipient and donor sex were not independently associated with death after LTx. A change of pTLC ratio from 0.918 to 1.119 (the interquartile range) was associated with similar point estimates of reduced risk of death at 1 year in univariate (hazard ratio, 0.78) and comprehensive risk-adjusted multivariate models (hazard ratio, 0.86).

CONCLUSIONS

The pTLC ratio is an independent predictor of death in the first year after LTx and explains the association of sex with survival after LTx. Incorporating the pTLC ratio in the lung allocation mechanism could improve outcomes after LTx.

An oversized allograft is associated with improved survival after lung transplantation for idiopathic pulmonary arterial hypertension

BACKGROUND

Idiopathic pulmonary arterial hypertension (IPAH) is associated with high short-term mortality after bilateral lung transplantation (BLT). Previous studies have suggested that oversized allografts are associated with improved outcomes and that this association was strongest within the first year after transplant. We hypothesized that oversizing the allograft is associated with improved survival after BLT for IPAH.

METHODS

All adults in the United Network of Organ Sharing lung transplant registry who underwent first-time BLT for IPAH between October 1989 and April 2010 were studied. Lung size mismatch was assessed by calculating the predicted total lung capacity (pTLC) ratio of the donor to the recipient. The cohort was divided evenly into "undersized" (pTLC ratio less than the median pTLC ratio) and "oversized" (pTLC ratio exceeding the median pTLC ratio). Risk of death after BLT was analyzed using Kaplan-Meier survival and Cox proportional hazards models.

RESULTS

The mean pTLC ratio was 0.93 ± 0.10 in the 302 undersized patients compared with 1.24 ± 0.14 in the 302 oversized patients. Cohorts had comparable baseline characteristics. Median survival was 831 days longer in the oversized cohort (2,166 vs. 1,335 days, p = 0.006). In a multivariate model controlling for sex mismatch, recipient factors, acuity, donor factors, and transplant factors, oversizing was associated with decreased hazard for death at 5 years (hazard ratio, 0.73; 95% CI 0.56-0.96, p = 0.02).

CONCLUSION

Oversizing the allograft is associated with improved survival after BLT for IPAH. In the setting of donor organ shortages and waiting list mortality, it is not practical to intentionally oversize the allograft. However, the pTLC ratio could provide further refinement in the peri-transplant risk assessment.

Cadaveric lobar lung transplantation: technical aspects

BACKGROUND

The use of lobar transplantation and other size reduction techniques has allowed larger donor lungs to be utilized for smaller recipients who tend to have longer waiting times for transplantation. However, despite these advantages, the techniques have not been widely adopted. We outline the surgical and sizing issues associated with this technique.

METHODS

A retrospective review of 23 consecutive patients who received lung transplantation with anatomic lobar reduction was performed, focusing on surgical technique and outcomes.

RESULTS

All 23 patients received an anatomic lobar reduction of between 1 and 3 lobes. Survival analysis showed no difference between the lobar reduction cohort and the other historically comparable lung transplant patients from our institution (p=0.115). Percent predicted forced vital capacity and forced expiratory volume in 1 second at 3 months correlated with transplanted donor to recipient total lung capacity ratio, confirming the importance of correct sizing.

CONCLUSIONS

Anatomic lobar reduction in lung transplantation is a safe and effective means of transplanting pediatric and small adult recipients, and urgently listed patients.

Parameters of donor-recipient size mismatch and survival after bilateral lung transplantation

BACKGROUND

The purpose of this study was to investigate the relationship between donor-recipient height, gender and predicted estimates of total lung capacity (pTLC) mismatches and post-transplant survival.

METHODS

The lung transplant databases at three programs were reviewed. The pTLC ratios (donor pTLC/recipient pTLC) and height ratios (donor height/recipient height) were calculated retrospectively. Patients were grouped according to pTLC ratio ≤1.0 or >1.0 and height ratio ≤1.0 or >1.0, and according to gender (mis-)matching. A time-to-event analysis was performed for risk of death after transplantation conditional on 30-day survival using Kaplan-Meier survival and Cox proportional hazard models.

RESULTS

There were 211 adult bilateral lung transplant recipients who qualified for the analysis. Mean follow-up was comparable for all cohorts (range 2.21 to 3.85 years). In the univariate Cox proportional hazard models, a pTLC ratio >1.0 (HR 0.43, p = 0.002) and a height ratio >1.0 (HR 0.61, p = 0.03) were associated with better survival, and a female-donor-to-male-recipient gender mismatch (F-to-M) was associated with worse survival (HR 2.35, p = 0.01). In the multivariate Cox proportional hazard model accounting for F-to-M gender mismatch and height ratio >1.0, a pTLC ratio >1.0 remained associated with survival (HR 0.38, p = 0.015). However, accounting for a pTLC ratio >1.0, a height ratio of >1.0 and F-to-M mismatch were not associated with survival.

CONCLUSIONS

A pTLC ratio >1.0 is associated with improved survival after bilateral lung transplantation. The pTLC ratio might better reflect allograft-thorax mismatch than the height ratio, as it also accounts for effects of gender on lung and thoracic volumes.

Solid organ transplants following hematopoietic stem cell transplant in children

SOT may be indicated for a select group of pediatric patients who experience permanent organ failure following HSCT. However, there is limited information available about outcomes. We identified eight children at our center who received an SOT following an HSCT. Patients were six months to 18 yr at HSCT. Diseases for which children underwent HSCT included thalassemia, Wiskott-Aldrich syndrome, Shwachman-Diamond/bone marrow failure, sickle cell disease (SCD), erythropoietic porphyria (EP), ALL, chronic granulomatous disease, and neuroblastoma. Time from HSCT to SOT was 13 days to seven yr (median, 27 months. Lung SOT was performed for two patients with BO, kidney transplants for three patients, and liver transplants for three patients (VOD, chronic GVHD). Seven patients are alive with functioning allografts 6-180 months from SOT. Advances in organ procurement, operative technique, immunosuppressant therapy, and infection control may allow SOT for a select group of patients post-HSCT. However, scarcity of donor organs available in a timely fashion continues to be a limiting factor. Children who have undergone HSCT and develop single organ failure should be considered for an SOT if there is a high likelihood of cure of the primary disease.

Cystic fibrosis and the thoracic surgeon

Indications for thoracic surgery in patients with cystic fibrosis (CF) are principally represented by pleural diseases including pneumothorax, pleural effusion, and empyema and by parenchymal lung diseases including bronchiectasis, hemoptysis, and pulmonary abscess. Moreover, lung transplantation has proved a viable therapeutic option for progressive respiratory failure due to end-stage CF. Main surgical experiences in this setting are reviewed and discussed.

Pediatric lung transplantation

Lung transplantation is an accepted therapy for selected pediatric patients with severe end-stage vascular or parenchymal lung disease. Collaboration between the patients' primary care physicians, the lung transplant team, patients, and patients' families is essential. The challenges of this treatment include the limited availability of suitable donor organs, the toxicity of immunosuppressive medications needed to prevent rejection, the prevention and treatment of obliterative bronchiolitis, and maximizing growth, development, and quality of life of the recipients. This article describes the current status of pediatric lung transplantation, indications for listing, evaluation of recipient and donor, updates on the operative procedure,graft dysfunction, and the risk factors, outcomes, and future directions.

Computed tomography measurement of lung volume in preoperative assessment for living donor lung transplantation: volume calculation using 3D surface rendering in the determination of size compatibility

The objective of this study was to describe the use of CT volume quantification assessment of candidates for LLDLT. Six pediatric candidates for LDLLT and their donors were investigated with helical chest CT, as part of the preoperative assessment. The CT images were analyzed as per routine and additional post-processing with CT volume quantification (CT densitovolumetry) was performed to assess volume matching between the lower lobes of the donors and respective lungs of the receptors. CT images were segmented by density and region of interest, using post-processing software. Size matching was also assessed using the FVC formula. Compatible volumes were found in three cases. The other three cases were considered incompatible. All three recipients with compatible sizes survived the procedure and are alive and well. One patient with incompatible size was submitted to the procedure and died because of complications attributed to the incompatible volumes. One patient with incompatible size has subsequently grown and new measurements are to be taken to check the current volumes. Different donors are being sought for the remaining patient whose lung volumes were considered too big for the prospective transplant donor lobes. Under FVC formula criteria, all cases were considered compatible. CT volume quantification is an easy to perform, non-invasive technique that uses CT images for the preassessment of candidates for LDLLT, to compare the volume of the lower lobes from the donors with volume of each lung in the prospective recipients. Size matching based on CT densitovolumetry and FVC may differ.

Management of the pediatric organ donor to optimize lung donation

Lung transplantation in childhood is a highly specialized clinical practice confined to a few centers around the world. Organ availability remains an important limiting factor in extending the application of this procedure to more infants, children and adolescents. The lungs are the organ most vulnerable to injury, infection and dysfunction among transplantable organs in the brain dead deceased donor. In this manuscript, we review the pathophysiology of the most common and important disease states that affect the lungs in potential donors. Furthermore, we herein provide recommendations for optimal management of the pediatric organ donor with an emphasis on strategies to improve the opportunity for the lungs to be placed in candidates on the transplant list.

Pediatric lung transplantation: perspectives for the pathologist

Lung transplantation offers life-saving and life-extending treatment for children and adolescents with congenital and acquired forms of pulmonary and pulmonary vascular disease, for whom medical therapy is ineffective or insufficient for sustained response. This review summarizes the pathology related to lung transplantation for the practicing pediatric pathologist and also highlights aspects of lung transplantation unique to the pediatric population. Clinical issues related to availability of organs, candidate eligibility, surgical technique, and postoperative monitoring are discussed. Pathologic evaluation of routine surveillance transbronchial biopsies requires attention to acute cellular rejection, opportunistic infection, and other forms of acute and resolving lung injury. These findings are correlated in some cases with endobronchial biopsies and bronchoalveolar lavage as adjunctive tools in surveillance. Open or thoracoscopic biopsies also have diagnostic utility in cases with acute or chronic graft deterioration of uncertain etiology. Future challenges in pediatric lung transplantation are similar to those in the adult population, with continued efforts focused on prolonging graft survival, prevention of bronchiolitis obliterans syndrome due to chronic cellular rejection, and evaluation of humoral rejection.