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"Contemporary Questions in Lung Transplantation" Poster Discussion Session: American Thoracic Society May 2016

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Sangeeta Bhorade, MD
Northwestern Memorial Hospital
Chicago, IL, USA

During the American Thoracic Society (ATS) meeting in May, several interesting and relevant topics were discussed in the poster session "Contemporary questions in lung transplantation". The topics were broad - ranging from persistent questions on the benefit of surveillance bronchoscopies in the lung transplant population while others addressed newer issues regarding the adequacy of the lung allocation scoring system and the concept of body composition, frailty and outcomes after lung transplantation. Here are some intriguing musings from this ATS session:

Potential improvements in the Lung Allocation system gained favored responses...

In two separate abstracts, Mooney and colleagues showed that both broader geographic sharing in patients with LAS > 50 and multiple listed lung transplant candidates decreased waitlist mortality suggesting that these may be important alterations to incorporate into the LAS. On the other hand, Nunley et al. showed that small changes in the LAS while listed may actually decrease chances for waitlisted patients to get transplanted.

Health related quality of life (HRQL) is now getting the attention that it has deserved...

While Dilling et al showed that the majority of patients having an improvement in their quality of life, the rigors of post-transplant care may result in worsening depression, anxiety and suicidal ideation, two abstracts from the UCSF group (Singer and Shah and colleagues) showed significant improvements in all lung transplant recipients including those with connective tissue disease.

Much to be gained by understanding Body composition as opposed to BMI...

Several studies are now assessing the importance of body composition compared to BMI to determine effect on outcome. By utilizing dual energy X-ray absorptiometry (DXA) scanning, Ahmad and colleagues were able to measure body fat percentage (BF%). They found that BF% was higher than predicted by BMI calculation and there was an association with BF% and increase length of stay and one year readmissions in COPD patients. Debiane and colleagues evaluated skeletal muscle (SM) and visceral fat (VF) by using SliceOmatic software via chest CT scan. They found that an increased axial VF:SM ratio was associated with a reduced 6MWD up to one year post transplant. Li et al. also measured pectoralis muscle area (PMA) by single axial CT imaging and found that although there was an overall association with BMI, there were several cases where this was not true. Finally, Madahar and colleagues used DXA scan to define lean body mass and sarcopenia was defined as an appendicular skeletal muscle index (ASMI). They found that 90% of lung transplant candidates had abnormal body composition and 25% were simultaneously obese and sarcopenic.

The limitations of PFTs continue to foster studies for diagnostic testing for BOS/CLAD...

Barbosa and colleagues looked at a novel imaging method, Functional Respiratory Imaging, using paired inspiratory- expiratory CT scan and found it to be an excellent technique to measure regional drivers for FEV1 decline. Using this technique could serve as a predictor for BOS. Ventilation heterogeneity as measured by the Multiple Breath Washout using Nitrogen by the Melbourne group showed that 6 month elevations was associated with increased risk of BOS / mortality within 4 years.

To perform or not to perform surveillance bronchoscopies that remains the question...over the past decade.

Two abstracts from Michigan (Haupt et al.) and Cleveland (Inaty et al.) readdressed the question with a lively discussion from the audience. Both groups showed that surveillance bronchoscopies (done within the first three months post-transplant) resulted in positive clinical findings. However, debate remains whether changes in management from these bronchoscopies affect outcome and whether there is a true overall benefit versus risk of surveillance bronchoscopies. The discussion continues...

We were reminded of various post-transplant conditions that may result in poorer outcomes...

These conditions included bronchiectasis (Kennedy et al), early nosocomial adenovirus (Mohamedaly et al) and early rehospitalizations (Courtwright et al) all resulting in higher than expected mortality after transplantation. However, Weigt and colleagues shed some positive light on outcomes showing that lung transplant recipients with weak to moderate range DSA could successfully undergo transplantation.

Refining our understanding of medical management and biological predictors for lung transplantation also seemed to be a recurring theme...

Circulating plasma elastase was found to be strongly associated with BOS development by Milla and colleagues, while Anderson et al. showed that neuron specific enolase is an early marker of delirium in lung transplant recipients with predictive/prognostic utility. Thoracic adipose tissue that was sampled in lung transplant recipients from the Lung Transplant Body Composition study cohort elicited a distinct gene expression profile associated with lung allograft reperfusion suggesting a link between recipient adiposity, PGD and mortality.

Last but not least a potpourri of important topics in lung transplant...

A European study of viral respiratory tract infections in lung transplant recipients showed a significant variability in the management of patients thus emphasizing the importance of prospective trials to guide practice patterns. Lastly, the BODE index, which has been used to prognosticate COPD candidates for lung transplant, was found to have decreased prognostic implications in lung transplant due to low incidence of comorbid conditions contributing to mortality in this population.

And there you have it. Our lung transplant community continues to eagerly study the important conundrums in lung transplantation in an effort to improve outcomes! ■

Disclosure Statement: The author has no conflicts of interest to disclose.

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