Lobar lung transplantation from deceased donors: a valid option for small-sized patients with cystic fibrosis

Lobar size reduction in lung transplantation: A propensity score study

OBJECTIVE

For small-sized recipients of lung transplantation, the time span for organ reception from standard donors is generally longer than for normal-sized patients. Despite its underuse, lobar reduction may be a concrete option for these patients. This study aims to assess early and long-term outcomes associated with lobar reduction in lung transplantation.

METHODS

A retrospective study was performed on 608 consecutive lung transplantations at 2 centers between January 2005 and August 2019 (559 standard lung transplantations [standard transplantation] and 49 with lobar reduction [lung transplantation group]). A propensity-score weighting approach was used to account for potential confounding related to patients' nonrandom allocation to the 2 intervention groups. The effects of the intervention on postoperative outcomes were assessed with a weighted regression approach.

RESULTS

The propensity score was estimated on 571 patients (522 in standard transplantation group and 49 in lung transplantation group). In terms of early outcomes, the lung transplantation group showed a higher percentage of severe primary graft dysfunction at 0 hours and reported longer intensive care unit stay than the standard transplantation group. No other differences in terms of morbidity, mortality, mechanical ventilation time, hospital stay, and anastomotic complications were observed. Although the lung transplantation group showed worse long-term pulmonary function, the 2 populations had comparable survival outcomes.

CONCLUSIONS

The use of lobar reduction showed early and long-term results comparable to those after standard lung transplantation. Although a higher rate of early severe primary graft dysfunction and slightly reduced respiratory function were detected in the lobar group, these did not affect patients' morbidity and survival.

Does lobar or size-reduced lung transplantation offer satisfactory early and late outcomes?

A best evidence topic was constructed according to a structured protocol. The question addressed was whether size-reduced or lobar lung transplantation (LLTx) offers the same benefit as classic lung transplantation (LTx). Of the 147 papers found using the reported search, 9 were selected to provide the best evidence. Details of the studies regarding authors, date, journal, country of publication, study type, group studied, relevant outcomes and results are given. All studies reported survival rates of LLTx and most compared it with classical LTx. No statistical differences were reported in medium term and long term. Two of the studies reported a higher incidence of postoperative complications, such as the need for cardiopulmonary bypass, reperfusion oedema or primary graft dysfunction, and longer intubation or intensive care unit stay times. Although the largest study showed a significantly worse 1-year survival in LLTx, a sub-analysis considering patients successfully discharged showed similar outcomes at 1, 3 and 5 years when compared with classic LTx patients. We conclude that LLTx is a valid therapeutic option for recipients with significant donor size mismatch, offering similar outcomes as classical LTx in the medium term and long term.

Efficacy of three-dimensional computed tomography volumetry for recipients in downsizing oversized grafts in brain-dead donor lung transplantation

Objective

Brain-dead donor lung transplantation frequently requires reduction in the size of oversized lung grafts for patients with a small chest cavity. We focused on the role of three-dimensional computed tomography (3D-CT) volumetry for recipients on downsizing oversized lung grafts.

Methods

We performed 53 brain-dead donor bilateral lung transplantations, including 15 lobar lung transplants (Lobar group) and 38 standard lung transplants with full-sized grafts (Full group), between December 2010 and December 2018. Recipient chest volume before transplantation was measured using 3D-CT volumetry, and donor lung volume was evaluated by predicted total lung capacity. Post-transplant outcomes and pulmonary function were retrospectively compared between the groups.

Results

The ratio of the recipient chest volume to the donor lung volume was significantly lower in the Lobar group (0.42 ± 0.15) than in the Full group (0.77 ± 0.30, P < 0.01). The calculated size matching between the donor and recipient after downsizing the grafts was significantly correlated to the ratio of the recipient chest volume to the donor lung volume (Spearman r = 0.69; P < 0.01). Early post-transplant outcomes did not significantly differ between the groups. Although the Full group showed slightly better pulmonary function after transplantation, the 1-, 3-, and 5-year overall survival rates were similar to the Lobar group (100%, 93%, and 81% in the Lobar group vs. 92%, 78%, and 70% in the Full group; P = 0.50).

Conclusions

Brain-dead donor lobar lung transplantation showed favorable post-transplant outcomes. The assessment of recipient chest cavity volume using 3D-CT volumetry may help surgeons precisely downsize oversized lung grafts prior to transplantation.

Current and novel therapeutic strategies for the management of cystic fibrosis

Introduction: Cystic fibrosis (CF), is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and affects thousands of people throughout the world. Lung disease is the leading cause of death in CF patients. Despite the advances in treatments, the management of CF mainly targets symptoms. Recent CFTR modulators however target common mutations in patients, alleviating symptoms of CF. Unfortunately, there is still no approved treatments for patients with rare mutations to date.Areas covered: This paper reviews current treatments of CF that mitigate symptoms and target genetic defects. The use of gene and drug delivery systems such as viral or non-viral vectors and nano-compounds to enhance CFTR expression and the activity of antimicrobials against chronic pulmonary infections respectively, will also be discussed.Expert opinion: Nano-compounds tackle biological barriers to drug delivery and revitalize antimicrobials, anti-inflammatory drugs and even genes delivery to CF patients. Gene therapy and gene editing are of particular interest because they have the potential to directly target genetic defects. Nanoparticles should be formulated to more specifically target epithelial cells, and biofilms. Finally, the development of more potent gene vectors to increase the duration of gene expression and reduce inflammation is a promising strategy to eventually cure CF.

Long-Term Outcomes of Cadaveric Lobar Lung Transplantation: An Important Surgical Option

BACKGROUND

Cadaveric lobar lung transplantation (L-LTx) is developed to overcome donor-recipient size mismatch. Controversial short- and long-term outcomes following L-LTx have been reported compared to full-sized lung transplantation (F-LTx). This study reports long-term outcomes after L-LTx.

METHODS

We reviewed patients undergoing lung transplantation (LTx) between 2000 and 2016. The decision to perform L-LTx was made based mainly on donor-recipient height discrepancy and visual assessment of donor lungs. Predicted donor-recipient total lung capacity (TLC) ratio was calculated more recently. Primary outcome was overall survival.

RESULTS

In all, 370 bilateral LTx were performed during the study period, among those 250 (67%) underwent F-LTx and 120 (32%) underwent L-LTx, respectively. One- and 5-year survival rates were 85% vs. 90% and 53% vs. 63% for L-LTx and F-LTx, respectively (p = 0.16). Chronic lung allograft dysfunction (CLAD)-free survival at 5 years was 48% in L-LTx vs. 51% in F-LTx recipients (p = 0.89), respectively. Age, intraoperative extracorporeal membrane oxygenation (ECMO) use, intensive care unit (ICU) stay, and postoperative renal replacement therapy (RRT) were significant prognostic factors for survival using multivariate analysis.

CONCLUSIONS

Overall survival and CLAD-free survival following L-LTx were comparable to F-LTx. Given the ongoing donor organ shortage, cadaveric L-LTx remains as an important resource in LTx.

Surgical Strategy for Lung Transplantation in Adults With Small Chests: Lobar Transplant Versus a Pediatric Donor

BACKGROUND

Adult lung transplant recipients with small chests have traditionally received lungs from pediatric donors, placing an additional strain on the already restricted pediatric donor pool. Performing lobar lung transplantation (LLT) can circumvent issues with donor-recipient size mismatch; however, LLT imparts additional risks. Here, we review our experience using LLT and standard lung transplantation using a pediatric donor (PDLT) for adults with small chests.

METHODS

We retrospectively reviewed consecutive patients with end-stage lung disease and a height of 65 inches or less who underwent LLT (n = 15) or PDLT (n = 15) between 2006 and 2012 at our institution, a high-volume lung transplant center.

RESULTS

Lobar lung transplantation recipients were older (54 ± 10 vs 48 ± 8 years) and had higher pulmonary pressure (57 ± 11 vs 52 ± 27 mmHg) and higher lung allocation scores (70 ± 9 vs 51 ± 8) than PDLT recipients (all P < 0.05). Mean waiting time was 62 days for PDLT and 9 days for LLT. Postoperatively, the incidence of severe primary graft dysfunction and the incidence of acute renal insufficiency were higher, and the mean intensive care unit stay was longer in the LLT group, but the incidence of bronchial anastomotic complications was higher in the PDLT group because of significant size discrepancy in the main bronchus (P < 0.05). Interestingly, long-term functional outcomes and survival rates were similar between the groups.

CONCLUSIONS

Both LLT and PDLT are viable surgical options for adult patients with small chests. Because of the potential impact on posttransplant outcomes, the technical complexity of transplantation, decisions regarding the best surgical approach should be made by experienced surgeons.

Lobar lung transplantation from deceased donors: A systematic review

AIM

To systematically review reports on deceased-donor-lobar lung transplantation (ddLLTx) and uniformly describe size matching using the donor-to-recipient predicted-total lung-capacity (pTLC) ratio.

METHODS

We set out to systematically review reports on ddLLTx and uniformly describe size matching using the donor-to-recipient pTLC ratio and to summarize reported one-year survival data of ddLLTx and conventional-LTx. We searched in PubMed, CINAHL via EBSCO, Cochrane Database of Systematic Reviews via Wiley (CDSR), Database of Abstracts of Reviews of Effects via Wiley (DARE), Cochrane Central Register of Controlled Trials via Wiley (CENTRAL), Scopus (which includes EMBASE abstracts), and Web of Science for original reports on ddLLTx.

RESULTS

Nine observational cohort studies reporting on 301 ddLLTx met our inclusion criteria for systematic review of size matching, and eight for describing one-year-survival. The ddLLTx-group was often characterized by high acuity; however there was heterogeneity in transplant indications and pre-operative characteristics between studies. Data to calculate the pTLC ratio was available for 242 ddLLTx (80%). The mean pTLCratio before lobar resection was 1.25 ± 0.3 and the transplanted pTLCratio after lobar resection was 0.76 ± 0.2. One-year survival in the ddLLTx-group ranged from 50%-100%, compared to 72%-88% in the conventional-LTx group. In the largest study ddLLTx (n = 138) was associated with a lower one-year-survival compared to conventional-LTx (n = 539) (65.1% vs 84.1%, P < 0.001).

CONCLUSION

Further investigations of optimal donor-to-recipient size matching parameters for ddLLTx could improve outcomes of this important surgical option.

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.

The evolving potential for pediatric ex vivo lung perfusion

Despite the rise in the number of adult lung transplantations performed, rates of pediatric lung transplantation remain low. Lung transplantation is an accepted therapy for pediatric end-stage lung disease; however, it is limited by a shortage of donor organs. EVLP has emerged as a platform for assessment and preservation of donor lung function. EVLP has been adopted in adult lung transplantation and has successfully led to increased adult lung transplantations and donor lung utilization. We discuss the future implications of EVLP utilization, specifically, its potential evolving role in overcoming donor shortages in smaller children and adolescents to improve the quality and outcomes of lung transplantation in pediatric patients.