Clemens Aigner, Walter Klepetko
4Lung transplantation
4.1Introduction
The performance of pediatric lung transplantation remains the domain of a few highly specialized centers. Written by the experts Clemens Aigner and Walter Klepetko, and supported by Axel Haverich, this chapter presents a state-of-the-art position.
4.2General considerations
Lung transplantation is an established therapy for virtually all non-malignant end-stage lung diseases. Lung transplantation in children presents some unique challenges that are not directly comparable to adult lung transplantation. This article focuses on the perioperative surgical aspects of the procedure. Differences in the immune system, tolerance mechanisms, psychosocial and long term care are equally important, however, they are beyond the scope of this chapter. The first pediatric lung transplantation was performed in a 16-year-old boy in 1987 in Toronto [1]. Pediatric lung transplantation is a relatively rare procedure with around 120 procedures reported annually to the registry of the International Society for Heart and Lung Transplantation by 45 centers [2]. Even large centers perform only 10–20 procedures per year. Ideally this complex treatment should be performed in dedicated centers of expertise only. Survival after pediatric lung transplantation has improved over recent years mainly due to improvements in candidate selection, immunosuppression and refinements in the surgical technique and perioperative management.
4.3Indications
Children in need of lung transplantation represent a specific spectrum of indications. Almost 80% of the children are older than 11 years at the time of their transplant. In the case of a progressive lung disease on maximal medical therapy with a short life expectancy and a poor quality of life a referral for lung transplantation is indicated.
Cystic fibrosis (CF), pulmonary arterial hypertension, congenital heart disease and surfactant protein B deficiency are the most common indications in infant transplantation with substantial variations in different age groups (Tab. 4.3.1)[3].
Tab. 4.3.1: Common indications for pediatric lung transplatation (ISHLT registry report 2013).
| Age group | Indication | % in age group |
| <1 year | spB Deficiency | 20.4% |
| CHD | 14.8% | |
| iPAH | 13.0% | |
| Fibrosis | 13.0% | |
| 1–5 years | iPAH | 21.8% |
| IPF | 12.6% | |
| Fibrosis (other) | 11.5% | |
| OB | 9.2% | |
| CHD | 8.0% | |
| 6–10 years | CF | 50.5% |
| OB | 10.7% | |
| iPAH | 10.2% | |
| Fibrosis (other) | 7.7% | |
| >11 years | CF | 69.1% |
| iPAH | 7.9% | |
| OB | 4.6% |
The spectrum of indications and ideal timing for referral are outlined in Tab. 4.3.2. In the recent guidelines of the International Society for Heart and Lung Transplantation (ISHLT) specific recommendations for the selection of pediatric recipients are mentioned for the first time [4].
Tab. 4.3.2: Indications and timing for referral.
| Disease | Timing of referral |
| CF | FEV < 30%, rapid decline, increasing frequency of hospitalization and exacerbations, recurrent hemoptysis and/or pneumothorax |
| IPAH | WHO class III/IV, evidence of right heart failure, inadaequate reponse to medical therapy |
| Eisenmenger syndrome | Progressive pulmonary arterial hypertension, impaired exercise tolerance |
| Interstitial lung disease | Histologic evidence amd progressing functional decline |
| Bronchopulmonary dysplasia | Respiraotry failure, progressive pulmonary arterial hypertension |
| Pulmonary vascular disorders | Evidence in histology and right heart catheterization |
| Surfactant dysfunction | Progressive or treatment refractory respiratory failure, progressive pulmonary arterial hypertension |
Pediatric patients requiring mechanical ventilation and extracorporeal life support still represent a high risk group for transplantation, however recent results by a number of experienced centers show very favorable outcomes in this group based on a careful patient selection.
4.4Allocation and size matching
The average waiting time for a suitable donor lung varies significantly in different countries, however, particularly for smaller children longer waiting times can be expected thus referral and listing should be early enough. Allocation algorithms vary substantially between different countries. The lung allocation score (LAS), which has been used in the United States since 2005, was also introduced in some European countries and allocates organs based on an algorithm to calculate waiting list mortality and expected one year survival post-transplant [5, 6]. Children below the age of 12 years automatically receive the highest possible LAS score in the Eurotransplant area. In the United States there is an ongoing discussion about the allocation of lungs of donors aged > 12 years towards recipients < 12 years. Size matching is crucial and frequently limits the organ availability for pediatric recipients. Therefore several strategies have been developed to overcome this aspect of donor organ shortage and to be able to utilize oversized donors. These aspects will be discussed in detail in the chapter on surgical technique. Donor and recipient height, gender, and total lung capacity (TLC) are the most important parameters used for size matching. Depending on the underlying disease the real TLC may differ significantly from the predicted TLC of the recipient, which has to be taken into account accordingly [7].
4.5Surgical technique and lobar transplantation
The technique of pediatric lung transplantation is basically comparable to adult transplantation. While the general principles of the operation are equal in all centers, differences in technical details can be observed. This chapter describes the Vienna technique. Intubation is usually performed with a left-sided double lumen tube to allow unilateral ventilation. In very small children a standard tube with the use of a bronchus blocker is an alternative. The choice, which lung is transplanted first, depends on donor as well as recipient issues. The preoperative recipient V/ Q scan is an important tool in this decision process. Usually the functionally worse side is transplanted first. In case of a quality difference between the donor lungs, e.g. due to traumatic alterations or other minor impairments, the better lung will be transplanted first. The implantation in bilateral procedures is performed in a sequential technique.
Pneumonectomy is performed in standard fashion with stapling of the pulmonary artery and pulmonary veins. The bronchus is prepared centrally and opened with a scalpel. Two polydioxanone stay sutures are placed at the angles between the cartilaginous and the membranous portion. Thereafter the lung is removed from the chest cavity and the vessels are prepared intrapericardially. Meticulous hemostasis has to be performed before beginning with the implantation.
The donor lung is then unpacked and the vessels are prepared and shortened (Fig. 4.5.1). The pulmonary artery has to be carefully inspected for any intraluminal embolism. The bronchus is shortened with not more than one cartilage ring remaining after the separation of the upper lobe bronchus and careful preservation of the peribronchial tissue. This is equally important for the area adjacent to the anastomosis as well as the bronchus intermedius on the right side, which is particularly prone to ischemic alterations. A bacteriological swab is taken and any residual mucus is removed from the bronchial system. Thereafter the implantation is performed with permanent topical cooling of the donor lung with ice slush. The first step is the bronchial anastomosis, which is performed using a double-armed polydioxanone suture, starting at one end of the cartilaginous part, going over the membranous portion in a single running suture technique and then using the same single running suture for the anterior cartilaginous part. In case of a bronchial size mismatch the imbalance is adjusted over the whole circumference. Usually the anastomosis is not covered with any additional tissue. Some centers still use interrupted suture techniques on the cartilagineous part of the bronchus.
