Pathophysiology and Predictors of Bronchial Complications After Lung Transplantation

Bronchial Stenosis After Lung Transplantation From cDCD Donors Using Simultaneous Abdominal Normothermic Regional Perfusion: A Single-center Experience

BACKGROUND

Controlled donation after circulatory death (cDCD) has increased the number of lung donors significantly. The use of abdominal normothermic regional perfusion (A-NRP) during organ procurement is a common practice in some centers due to its benefits on abdominal grafts. This study aimed to assess whether the use of A-NRP in cDCD increases the frequency of bronchial stenosis in lung transplant (LT) recipients.

METHODS

A single-center, retrospective study including all LTs was performed between January 1, 2015, and August 30, 2022. Airway stenosis was defined as a stricture that leads to clinical/functional worsening requiring the use of invasive monitoring and therapeutic procedures.

RESULTS

A total of 308 LT recipients were included in the study. Seventy-six LT recipients (24.7%) received lungs from cDCD donors using A-NRP during organ procurement. Forty-seven LT recipients (15.3%) developed airway stenosis, with no differences between lung recipients with grafts from cDCD (17.2%) and donation after brain death donors (13.3%; P  = 0.278). A total of 48.9% of recipients showed signs of acute airway ischemia on control bronchoscopy at 2 to 3 wk posttransplant. Acute ischemia was an independent risk factor for airway stenosis development (odds ratio = 2.523 [1.311-4.855], P  = 0.006). The median number of bronchoscopies per patient was 5 (2-9), and 25% of patients needed >8 dilatations. Twenty-three patients underwent endobronchial stenting (50.0%) and each patient needed a median of 1 (1-2) stent.

CONCLUSIONS

Incidence of airway stenosis is not increased in LT recipients with grafts obtained from cDCD donors using A-NRP.

Use of Octopus™ Tissue Stabilizer for Minimal Manipulation Approach of Bronchial Anastomosis in Lung Transplant

Bronchial anastomotic complications are a cause of grave concern for surgeons that perform lung transplantations. There are several risk factors that may lead to this complication, being inadequate surgical technique one of them, specifically regarding adequate exposure and manipulation of the bronchial stump and anastomosis. Here we report the use of Octopus™ Tissue Stabilizer as a mean to allow for a better exposure of the stump and facilitate a "no-touch" approach towards anastomosis. Systematic application of devices that facilitate the employment of the correct surgical techniques can have an effect in reducing the incidence of bronchial anastomotic complications.

Airway Complications after Lung Transplantation-A Contemporary Series of 400 Bronchial Anastomoses from a Single Center

(1) Objective: To determine whether recent advances in lung transplantation (LT) have reduced the incidence and changed the risk factors for airway complications (AC). (2) Methods: Retrospective analysis of patients receiving a lung transplant between January 2007 and January 2019. An AC was defined as a bronchoscopic abnormality in the airway, either requiring or not requiring an endoscopic or surgical intervention. Both univariable and multivariable analyses were performed to identify risk factors for AC. (3) Results: 285 lung transplants (170 single and 115 bilateral lung transplants) were analysed, comprising 400 anastomoses at risk. A total of 50 anastomoses resulted in AC (12%). There were 14 anastomotic and 11 non-anastomotic stenoses, 4 dehiscences, and 3 malacias. Independent predictors for AC were: gender male (OR: 4.18; p = 0.002), cardiac comorbidities (OR: 2.74; p = 0.009), prolonged postoperative mechanical ventilation (OR: 2.5; p = 0.02), P_aO₂/F_iO₂ < 300 mmHg at 24 h post-LT (OR: 2.48; p = 0.01), graft infection (OR: 2.16; p = 0.05), and post-LT isolation of Aspergillus spp. (OR: 2.63; p = 0.03). (4) Conclusions: In spite of advances in lung transplantation practice, the risk factors, incidence, and lethality of AC after LT remains unchanged. Graft dysfunction, an infected environment, and the need of prolonged mechanical ventilation remain an Achilles heel for AC.

Hyperbaric oxygen therapy to prevent central airway stenosis after lung transplantation

BACKGROUND

Central airway stenosis (CAS) is a severe airway complication after lung transplantation associated with bronchial ischemia and necrosis. We sought to determine whether hyperbaric oxygen therapy (HBOT), an established treatment for tissue ischemia, attenuates post-transplant bronchial injury.

METHODS

We performed a randomized, controlled trial comparing usual care with HBOT (2 atm absolute for 2 hours × 20 sessions) in subjects with extensive airway necrosis 4 weeks after transplantation. Endobronchial biopsies were collected at 4, 7, and 10 weeks after transplantation for a quantitative polymerase chain reaction. Coprimary outcomes were incidence of airway stenting and acute cellular rejection (ACR) at 1 year.

RESULTS

The trial was stopped after enrolling 20 subjects (n = 10 per group) after a pre-planned interim analysis showed no difference between usual care and HBOT groups in stenting (both 40%), ACR (70% and 40%, respectively), or CAS (40% and 60%, respectively). Time to first stent placement (median [interquartile range]) was significantly shorter in the HBOT group (150 [73-150] vs 186 [167-206] days, p < 0.05). HIF gene expression was significantly increased in donor tissues at 4, 7, and 10 weeks after transplantation but was not altered by HBOT. Subjects who developed CAS or required stenting had significantly higher HMOX1 and VEGFA expression at 4 weeks (both p < 0.05). Subjects who developed ACR had significant FLT1, TIE2, and KDR expression at 4 weeks (all p < 0.05).

CONCLUSIONS

Incidence of CAS is high after severe, established airway necrosis after transplantation. HBOT does not reduce CAS severity or stenting. Elevated HMOX1 and VEGFA expressions appear to associate with airway complications.

A Simplified Continuous Two-stitch Suture for Bronchial Anastomosis of Left Single Lung Transplant in Dogs

Large animal models are essential to pre-clinical trials of pulmonary transplantation and bronchial anastomosis poses a great technical challenge to the procedure. Presented here is a simplified continuous two-stitch suture technique into bronchial anastomosis during the course of left single lung transplantation in canine. Animals were divided into three groups with each group having 6 animals. Left single lung transplantation in canine was performed to assess the feasibility of using this technique for bronchial anastomosis. In the control groups, all anastomoses were done by using traditional technique. Allograft functions and hemodynamic parameters were monitored during a 3-h reperfusion period. Quality of bronchial healing and airway complications were assessed by bronchoscopic surveillance after transplantation. We successfully completed left lung transplantation in 18 dogs, and all the dogs survived the procedures. The new technique substantially simplified the procedures for bronchial anastomosis and greatly reduced the time for bronchial anastomosis (P<<0.01) and the ischemic time of the grafts (P<0.05) compared to the control group. The continuous two-stitch suture attenuated the tissue injury to allografts and led to better blood gas exchange function as compared to the control group (P<0.05). Good bronchial healing (Grade I) was observed in all the groups. A canine left single lung transplantation model is feasible by using the novel suture technique, and the new technique is as safe as the traditional method. The technique is easy to learn, particularly for less experienced operators. Simpler and time-saving, the technique has great potential to be widely employed in clinical lung transplantation.