Predictive Utility of the 6-Minute Walk Distance on Survival in Patients Awaiting Lung Transplantation

Using Remote Technology to Engage Patients with Interstitial Lung Diseases in a Home Exercise Program: A Pilot Study

INTRODUCTION

The access and compliance of patients with interstitial lung diseases (ILDs) to exercise programs (EPs) remain challenges.

OBJECTIVES

We assessed the dropout rate, intervention completion, compliance with data acquisition and submission, safety, and satisfaction of a home EP delivered via video conference (EPVC group) or self-directed (EPSD group) to patients with ILD. Pre- and post-intervention changes in patient outcomes (dyspnea, fatigue, exercise capacity, lung function, and quality of life) were secondarily explored.

MATERIAL AND METHODS

Groups performed an eight-week virtual EP three times/week. Video conferences were led by a registered respiratory therapist, whereas self-directed exercises were completed following a pre-recorded video. Participants submitted spirometry, heart rate, and SpO2 results weekly to the research team.

RESULTS

Fourteen patients with ILD were equally assigned to the EPVC and EPSD groups, but three from the EPSD group dropped out after the initial assessment (dropout rate of 42.8% in the EPSD group). Eleven patients (mean age of 67 ± 12 years) completed 96.5% of sessions. Compliance with data acquisition and submission was optimal (≥97.6% in both groups), and no adverse events were reported. Changes in overall fatigue severity were significantly different between groups (p = 0.014, Cohen's r = 0.64).

CONCLUSIONS

The results suggest that a structured virtual EP delivered via video conference or pre-recorded video can be feasible, safe, and acceptable for patients with ILD.

Reproducibility of the 6-minute walk test in lung transplant recipients

PURPOSE

There is reason to believe that the favorable measurement properties of the 6‑minute walk test (6MWT) reported for retest reliability and its capability to detect a true change in healthy individuals or persons with chronic respiratory disease may not apply to lung transplant recipients (LuTXr). We therefore investigated retest reliability of the 6MWT and, in addition, made an attempt to explore whether the 6MWT was sensitive enough to detect important changes that occur with postacute rehabilitation in LuTXr after first time LuTX.

METHODS

Immediately before postacute rehabilitation, 50 LuTXr completed 6MWT testing twice, separated by 1-2 workdays (retest reliability), and were reassessed after completion of rehabilitation 2 months later (sensitivity to changes). Body function measures and health-related quality of life (HRQoL) assessments were collected at baseline.

RESULTS

Baseline retest 6‑minute walk distance (6MWD) and the age-related predicted walking distance (6MWD%pred) scores significantly increased before postacute rehabilitation. The intraclass coefficient of correlation ICC of the 6MWD was 0.93 (95% confidence interval, CI: 0.88-0.96) and its smallest real difference (SRD) 79 m (95% CI: 52;107). Receiver operating curve analyses revealed the rehabilitation associated changes in 6MWD/6MWD%pred to exceed the SRD/SRD% values in a highly accurate way.

CONCLUSION

The 6MWT overall represents a reliable functional performance tool in LuTXr that is sensitive to detect changes in physical performance as a result of medical postacute rehabilitation.

A qualitative exploration of people living with idiopathic pulmonary fibrosis experience of a virtual pulmonary rehabilitation programme

Background

Pulmonary rehabilitation (PR) is recommended in the treatment of people with idiopathic pulmonary fibrosis (IPF). Little is known about the experiences of people with IPF of PR. Due to Covid-19 there has been a rapid shift of PR services to remote/virtual delivery.

Objective

To explore people living with IPFs experience of a virtual PR (VPR) programme.

Methods

All patients with a diagnosis of IPF in a stable phase of the disease were invited to participate in virtual PR: a 10 week exercise programme delivered twice-weekly for one hour. One-to-one semi- structured interviews were conducted within one week following the programme. All interviews were recorded, transcribed and analysed using Braun and Clarke thematic analysis by two independent assessors.

Results

N=13 participants took part in the semi-structured interviews, mean (standard deviation (SD)) age 69.5(10.4) years; 7M:6F. Mean (SD) FEV₁ 2.6(0.3)L, FVC 2.9(0.4)L. Four key themes were identified: 1) The impact of VPR on health and outlook, (2) The reality of VPR, (3) Being active after VPR and (4) Living with IPF during the COVID-19 Pandemic. Participants reported high levels of enjoyment and engagement with the programme regardless of the health benefits experienced. Most participants expressed a desire for a longer programme. Participants expressed different levels of maintenance with exercise since finishing the programme, specific motivators and strategies for maintenance included lung transplant, the maintenance of benefits from the programme and social support. COVID-19 and the restrictions imposed had some negative impacts on some participants lives, engaging with PR helped overcome some of these.

Conclusion

Despite the progressive nature of IPF, all participants expressed high levels of enjoyment with the programme. Future research should explore strategies for maintenance post PR and the optimum duration of PR for people with IPF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02221-6.

Relationship of Exercise Capacity, Physical Function, and Frailty Measures With Clinical Outcomes and Healthcare Utilization in Lung Transplantation: A Scoping Review

Measures of exercise capacity, frailty, and physical function are commonly used in lung transplant candidates and recipients to evaluate their physical limitations and the effects of exercise training and to select candidates for transplantation. It is unclear how these measures are related to clinical outcomes and healthcare utilization before and after lung transplantation. The purpose of this scoping review was to describe how measures of exercise capacity, physical function, and frailty are related to pre- and posttransplant outcomes.

Statistical Evaluation of Absolute Change versus Responder Analysis in Clinical Trials

In clinical trials, the primary analysis is often either a test of absolute/relative change in a measured outcome or a corresponding responder analysis. Though each of these tests may be reasonable, determining which test is most suitable for a particular research study is still an open question. These tests may require different sample sizes, define different clinically meaningful differences, and most importantly, lead to different study conclusions. This paper aims to compare a typical non-inferiority test using absolute change as the study endpoint to the corresponding responder analysis in terms of sample size requirements, statistical power, and hypothesis testing results. From numerical analysis, using absolute change as an endpoint generally requires a larger sample size; therefore, when the sample size is the same, the responder analysis has higher power. The cut-off value and non-inferiority margin are critical which can meaningfully impact whether the two types of endpoints yield conflicting conclusions. Specifically, an extreme cut-off value is more likely to cause different conclusions. However, this impact decreases as population variance increases. One important reason for conflicting conclusions is that the population distribution is not normal. To eliminate conflicting results, researchers should pay attention to the population distribution and cut-off value selection.

Clinical Improvement and Effectiveness of Exercise-Based Pulmonary Rehabilitation in Patients With Idiopathic Pulmonary Fibrosis: A BRIEF ANALYTICAL REVIEW

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease associated with high mortality rates and poor clinical condition. Exercise-based pulmonary rehabilitation (EBPR) has been demonstrated to be effective in improving 6-min walk distance (6MWD), although the clinical improvement and effectiveness are less characterized. The current review examined the existing evidence of EBPR among patients with IPF and aimed to analyze the effect of EBPR on clinical improvement and effectiveness.

METHODS

A systematic databases search (MEDLINE/PubMed, EMBASE, and the Cochrane Library) was conducted for available publications as of January 2020. Randomized controlled trials (RCTs) and meta-analyses of RCTs examining the effect of EBPR in patients with IPF were reviewed. Mean difference for RCTs and weighted mean difference for meta-analyses between the EBPR arm and the usual-care arm in 6MWD were compared with the established minimal clinically important difference (MCID) of 30 m. Clinical improvement following EBPR was determined when mean difference and weighted mean difference were equal or exceeding the MCID. Effectiveness of EBPR was assessed using the number needed to treat (NNT) analysis.

RESULTS

Five independent RCTs (including 21-61 patients/study) and five meta-analyses (including two to five studies with 62-169 patients/meta-analysis) were included. The mean difference of 6MWD ranged from 16-81 m in RCTs. Three of five RCTs demonstrated an average improvement that meets or exceeds the MCID. Two RCTs showed favorable improvement in 6MWD but did not reach the MCID. The weighted mean difference of 6MWD ranged from 27-49 m in the meta-analyses. Four of five meta-analyses showed an average improvement that meets or exceeds the MCID. One early meta-analysis of only two RCTs showed significant improvement, although did not reach the MCID. The NNT in three RCTs and four meta-analyses that met clinical improvement in 6MWD was one.

CONCLUSIONS

This review provides novel evidence with respect to clinical improvement and high effectiveness of EBPR among patients with IPF. The results suggest that, on average, the majority of patients would be expected to clinically improve by completing the EBPR program. The findings further support the prescription of EBPR as clinically effective therapy and implementation as standard of care for patients with IPF. Future studies examining clinical improvement and effectiveness utilizing additional outcomes with the MCID are warranted.

Exercise training for lung transplant candidates and recipients: a systematic review

Exercise intolerance and impaired quality of life (QoL) are characteristic of lung transplant candidates and recipients. This review investigated the effects of exercise training on exercise capacity, QoL and clinical outcomes in pre- and post-operative lung transplant patients.

A systematic literature search of PubMed, Nursing and Allied Health, Cochrane (CENTRAL), Scopus and CINAHL databases was conducted from inception until February, 2020. The inclusion criteria were assessment of the impact of exercise training before or after lung transplantation on exercise capacity, QoL or clinical outcomes.

21 studies met the inclusion criteria, comprising 1488 lung transplant candidates and 1108 recipients. Studies consisted of five RCTs, two quasi-experimental and 14 single-arm cohort or pilot studies. Exercise training improved or at least maintained exercise capacity and QoL before and after lung transplantation. The impact on clinical outcomes was less clear but suggested a survival benefit. The quality of evidence ranged from fair to excellent.

Exercise training appears to be beneficial for patients before and after lung transplantation; however, the evidence for direct causation is limited by the lack of controlled trials. Well-designed RCTs are needed, as well as further research into the effect of exercise training on important post-transplant clinical outcomes, such as time to discharge, rejection, infection, survival and re-hospitalisation.

Both inpatient and outpatient exercise training appears beneficial for improving exercise capacity and quality of life in lung transplant candidates and recipients. Further research investigating the effect on post-surgery clinical outcomes is required.https://bit.ly/2XD6J6S

Changes in 6-minute walking distance in lung transplant candidates while participating in a home-based pre-habilitation program-A retrospective chart review

Home-based exercise programs may offer a less costly alternative to providing exercise pre-transplant to a large number of patients. We describe the changes in 6-minute walk distance (6MWD) in lung transplant candidates who participated in a home-based exercise program and their relationship to post-transplant outcomes. Retrospectively, we investigated 159 individuals while awaiting transplantation who performed the surgery between 2011 and 2015. Primary outcome was 6MWD at time of assessment for transplant, last test prior to transplant and one-month post-transplant. 6MWD decreased by 28 ± 93.9 m between the time of assessment and the last 6MWD prior to transplantation (P < .001). Forty-one patients (25.8%) increased their 6MWD (mean + 85.8 ± 42.8 m); 72 patients (45.3%) decreased their 6MWD (mean -109.8 ± 71.2 m); and 46 patients (28.9%) had no change in 6MWD (-1.5 ± 15.7 m). There was a moderate correlation (r = .528; P < .001) between the last 6MWD prior to transplant and 6MWD post-transplant. Change in 6MWD prior to transplant weakly correlated with length of time on mechanical ventilation (r = -.185; P = .034). When adjusted for covariates, change in 6MWD prior to transplant was not associated with length of time on mechanical ventilation, total hospital LOS, or intensive care unit LOS. The majority of the patients were able to either increase or maintain their 6MWD while participating in a home-based pre-habilitation program during the waiting list period. Prospective research is needed to evaluate the effects of home-based pre-habilitation program for lung candidates.

Indications for lung transplant referral and listing

Lung transplantation is a valuable therapeutic option for many patients with severe lung disease who have exhausted other medical or surgical therapies. However, since lungs are not a manufacturable organ like artificial heart valves or left ventricular assist devices, and since they are a limited resource compared to number of patients requiring the organs, the Department of Health and Human Services set the Final Rule of organ allocation in 1998. This led to development and implementation of Lung Allocation Score (LAS) in 2005. The score broadly divides lung diseases into 4 diagnostic criteria with a coefficient factor given to each category. The score is based on the prognostic factors of each patient to determine the risk of mortality without a transplant combined with the probability of patient survival post-transplant. Most of the guidelines for "Indications for referral and listing in lung transplant" is based on consensus opinion as there is limited amount of robust data and trials about this topic. The International Society for Heart and Lung Transplant (ISHLT) has published three editions for candidate selection and listing. In this article, we have attempted to highlight the guidelines and incorporated other disease specific prognostic factors that are not captured in the LAS. Ultimately, there are other factors like geographic location, height, blood group, preformed antibodies, transplant center experience, past wait times and transplant rate, availability of organs, etc., which also play a role especially when considering listing a patient for lung transplant. We also highlighted a representative disease in each category and most criteria for that disease will apply to other diseases in that category. Finally, this article does not delve into the history and reasoning behind each guideline but is meant to provide a general overview of indications and contraindications applicable in the field of adult lung transplantation.

A 1-Month Physical Therapy-Based Outpatient Program for Adults Awaiting Lung Transplantation: A Retrospective Analysis of Exercise Capacity, Symptoms, and Quality of Life

Purpose

Rehabilitation can improve health outcomes in candidates for lung transplantation. The purpose of this study was to retrospectively evaluate the effect of a one-month physical therapy (PT)-based outpatient program on exercise capacity, symptoms, quality of life and examine predictors of functional outcome changes in adults awaiting lung transplantation.

Methods

Participants (n=141) completed a 23-session exercise and educational program over one month. Outcomes included 6-minute walk distance (6MWD), San Diego Shortness of Breath Questionnaire (SOBQ), Center for Epidemiological Studies-Depression Scale (CESD), and Ferrans and Powers Quality of Life Index Pulmonary Version III (QOL).

Results

Participants were older (median age 63) with restrictive (59%) or obstructive (24%) disease. Moderate-to-large improvements in 6MWD were observed (69 m, p < 0.001, d = 0.72), independent of demographics, symptoms, and QOL. Lower initial 6MWD and lower oxygen utilization were associated with greater 6MWD improvements, with largest gains occurring in initial 6MWD < 305 m. Small-to-moderate improvements were observed on CESD (p < 0.001, d = 0.26) and in overall QOL (p < 0.001, d = 0.27), with a non-significant improvement observed on SOBQ (p = 0.248, d = 0.13).

Conclusions

Completion of a one-month PT-based outpatient rehabilitation program was associated with improved exercise capacity, depressive symptoms and QOL.

8-Foot-Up-and-Go Test is Associated with Hospitalizations and Mortality in Idiopathic Pulmonary Fibrosis: A Prospective Pilot Study

PURPOSE

To assess the prognostic value of the 8-foot-up-and-go test (8-FUGT) in pilot cohort of patients with idiopathic pulmonary fibrosis (IPF).

METHODS

Thirty-four patients with IPF (68 ± 8 years) underwent 8-FUGT at baseline and were followed for up to 40 months. Receiver operating characteristics and age-adjusted Cox hazard ratios (HR) were analyzed for 8-FUGT, hospitalizations, and mortality. Correlation coefficients were determined between 8-FUGT and other exercise tests.

RESULTS

8-FUGT ≥ 6.9 s was found to be associated with hospitalization (sensitivity = 77%, specificity = 76%, p = 0.03) and mortality (sensitivity = 91%, specificity = 70% p = 0.008) in patients with IPF. Categorical models demonstrated that 8-FUGT ≥ 6.9 s was associated with 14.1- (p < 0.001) and 55.4-fold (p = 0.001) increased risks for hospitalization and mortality, respectively. In continuous models, for every 1-s slower performance in the 8-FUGT there were 54% [HR = 1.54, 95% CI (1.11-2.15) p = 0.01] increased risk for hospitalization and 94% [HR = 1.94, 95% CI (1.26-2.99) p = 0.003] increased risk for mortality. 8-FUGT was inversely related to 6-min walk distance (r = - 0.61), peak oxygen consumption (r = - 0.58), and peak work rate (r = - 0.72), all p < 0.001.

CONCLUSIONS

The 8-FUGT was strongly associated with hospitalizations and mortality in patients with IPF, as well as correlated with established prognostic markers. These novel findings suggest a prognostic value of the 8-FUGT for risk stratification, referral to pulmonary rehabilitation, and considering listing for lung transplantation. 8-FUGT is an inexpensive and practical tool that has prospective for implementation in clinical and research settings in IPF. Future prospective studies should evaluate the effect of changes in 8-FUGT on clinical outcomes.

TRIAL REGISTRATION

NCT01499745, Clinicaltrials.gov.

Physical Activity, Sedentary Time, and Associated Factors in Recipients of Solid-Organ Transplantation

BACKGROUND

Short-term survival after solid-organ transplantation has substantially improved, and the focus has shifted to long-term survival, including the role of physical activity (PA). Knowledge about PA and sedentary time in recipients of solid-organ transplantation is limited, and identification of the levels and associated factors is necessary for intervention development.

OBJECTIVE

The objectives of this study were to investigate the level of PA and sedentary time in recipients of solid-organ transplantation and to identify factors associated with these behaviors.

DESIGN

The design consisted of a cross-sectional survey.

METHODS

Questionnaires on PA level, sedentary time, and potential associated factors were used for recipients of solid-organ transplantation (kidney, liver, lung, and heart [N = 656]). Multiple regression analyses with a variable selection procedure were used.

RESULTS

Fewer than 60% of the recipients fulfilled the PA guideline. Factors significantly associated with a lower level of PA included being a woman, younger age (nonlinear), not actively working or being retired, physical limitations, and low expectations and self-confidence. Factors significantly associated with less sedentary time included exercise self-efficacy and not actively working or being retired. Significantly associated with more sedentary time were a high education level, fear of negative effects, physical limitations, and the motivator "health and physical outcomes." The type of transplantation did not significantly influence either of the outcome measures.

LIMITATIONS

The design did not allow for causal inferences to be made. The studied associated factors were limited to individual and interpersonal factors. Self-reported measures of PA and sedentary time were used.

CONCLUSIONS

In intervention development directed at increasing the level of PA and reducing sedentary time in recipients of solid-organ transplantation, attention should be paid to physical limitations, fear of negative effects, low expectations and self-confidence, health and physical outcomes, and exercise self-efficacy.

Lung transplantation: indications and contraindications

The selection of appropriate recipients for lung transplantation is an evolving discipline. As experience with the procedure has developed over the last decades, the identification of transplant candidates has also changed as transplant centers strive to safely provide the therapy to as many patients possible. The International Society for Heart and Lung Transplantation (ISHLT) has developed three editions of recipient selection guidelines. Published in 1998, 2006, and 2015, these guidelines represented the best information relevant to the appropriate selection of lung transplant candidates. A discussion of areas supported by the most robust scientific data will be undertaken, but in many aspects of recipient selection, there is a paucity of data upon which to rely. Therefore, it is ultimately the prerogative and responsibility of individual centers to determine, after carefully weighing the best evidence available, whether a patient is deemed a suitable candidate at a specific program. All possible indications and contraindications for transplantation will be reviewed with attention also given to the appropriate timing of referral and listing of patients with advanced lung disease to a transplant center.

What is expected in lung function after lung transplantation due to end-stage pulmonary silicosis?

In this study, we aimed to determine the impact of lung transplantation (LTx) on pulmonary function tests (PFTs) and survival among patients with end-stage silicosis. We included patients with end-stage silicosis on the wait list for LTx, between January 1989 and July 2015 (N = 26). Sixteen of these patients received LTx; 10 were eligible, but did not undergo LTx (non-LTx) during the study period. Retrospective information on PFTs (spirometry [volumes and flows], 6-minute walking test [6MWT], and DLCO) was retrieved from patients' medical charts, including baseline information for all patients and follow-up information for the LTx. At baseline, most patients presented with spirometric and 6MWT values that were suggestive of severe disease (FEV₁ /FVC 76.5 ± 29.7; 6MWT 267.4 ± 104.5 m). Significant increases in these values were observed at follow-up in the LTx (P = .036 and .151, respectively). The overall median survival of patients in the LTx and non-LTx was 3.35 years (95% CI: 0.16-14.38) and 0.78 years (95% confidence interval [CI]: 0.12-3.65) (P = 0.002), respectively. For patients with end-stage silicosis, LTx offers significant benefits regarding pulmonary function and survival when compared to non-LTx, and is a reliable tool to help this critical population of patients, whose only treatment option is LTx.

Factors affecting discharge destination following lung transplantation

BACKGROUND

Lung transplant (LT) recipients requiring additional care may be referred to inpatient rehabilitation prior to discharge home. This study seeks to describe discharge destinations following LT, compare the characteristics of patients discharged to different destinations, and identify the predictors of discharge destination.

METHODS

Retrospective study of 243 LT recipients who survived to hospital discharge between 2006 and 2009. LT recipients were compared based on discharge destination on data pertaining to demographics, clinical characteristics, and healthcare utilization.

RESULTS

Of the 243 recipients, 197 (81%) were discharged home, 42 (17%) to inpatient rehabilitation, and 4 (2%) to other medical facilities. Age, pulmonary diagnosis, most recent six-minute walk distance (6 MWD) prior to transplant, pre-transplant mechanical ventilation, priority listing status, pre- and post-transplant intensive care unit length of stay (ICU LOS), post-transplant LOS, total LOS, and participation in pre-transplant rehabilitation were statistically different between patients that were discharged home versus inpatient rehabilitation. Age, most recent 6 MWD prior to transplant, pre-transplant mechanical ventilation, and total LOS were found to be independent predictors of discharge destination.

CONCLUSION

Clinical factors can help identify patients more likely to require inpatient rehabilitation. Identification of these factors has the potential to facilitate early discharge planning and optimize continuity of care.

Predicting 6-minute walking distance in recipients of lung transplantation: longitudinal study of 108 patients

BACKGROUND

Exercise capacity, muscle function, and physical activity levels remain reduced in recipients of lung transplantation. Factors associated with this deficiency in functional exercise capacity have not been studied longitudinally.

OBJECTIVE

The study aims were to analyze the longitudinal change in 6-minute walking distance and to identify factors contributing to this change.

DESIGN

This was a longitudinal historical cohort study.

METHODS

Data from patients who received a lung transplantation between March 2003 and March 2013 were analyzed for the change in 6-minute walking distance and contributing factors at screening, discharge, and 6 and 12 months after transplantation. Linear mixed-model and logistic regression analyses were performed with data on characteristics of patients, diagnosis, waiting list time, length of hospital stay, rejection, lung function, and peripheral muscle strength.

RESULTS

Data from 108 recipients were included. Factors predicting 6-minute walking distance were measurement moment, diagnosis, sex, quadriceps muscle and grip strength, forced expiratory volume in 1 second (percentage of predicted), and length of hospital stay. After transplantation, 6-minute walking distance increased considerably. This initial increase was not continued between 6 and 12 months. At 12 months after lung transplantation, 58.3% of recipients did not reach the cutoff point of 82% of the predicted 6-minute walking distance. Logistic regression demonstrated that discharge values for forced expiratory volume in 1 second and quadriceps or grip strength were predictive for reaching this criterion.

LIMITATIONS

Study limitations included lack of knowledge on the course of disease during the waiting list period, type and frequency of physical therapy after transplantation, and number of missing data points.

CONCLUSIONS

Peripheral muscle strength predicted 6-minute walking distance; this finding suggests that quadriceps strength training should be included in physical training to increase functional exercise capacity. Attention should be paid to further increasing 6-minute walking distance between 6 and 12 months after transplantation.

Lung transplantation for cystic fibrosis: results, indications, complications, and controversies

Survival in patients with cystic fibrosis (CF) has improved dramatically over the past 30 to 40 years, with mean survival now approximately 40 years. Nonetheless, progressive respiratory insufficiency remains the major cause of mortality in CF patients, and lung transplantation (LT) is eventually required. Timing of listing for LT is critical, because up to 25 to 41% of CF patients have died while awaiting LT. Globally, approximately 16.4% of lung transplants are performed in adults with CF. Survival rates for LT recipients with CF are superior to other indications, yet LT is associated with substantial morbidity and mortality (∼50% at 5-year survival rates). Myriad complications of LT include allograft failure (acute or chronic), opportunistic infections, and complications of chronic immunosuppressive medications (including malignancy). Determining which patients are candidates for LT is difficult, and survival benefit remains uncertain. In this review, we discuss when LT should be considered, criteria for identifying candidates, contraindications to LT, results post-LT, and specific complications that may be associated with LT. Infectious complications that may complicate CF (particularly Burkholderia cepacia spp., opportunistic fungi, and nontuberculous mycobacteria) are discussed.

An official systematic review of the European Respiratory Society/American Thoracic Society: measurement properties of field walking tests in chronic respiratory disease

This systematic review examined the measurement properties of the 6-min walk test (6MWT), incremental shuttle walk test (ISWT) and endurance shuttle walk test (ESWT) in adults with chronic respiratory disease.

Studies that report the evaluation or use of the 6MWT, ISWT or ESWT were included. We searched electronic databases for studies published between January 2000 and September 2013.

The 6-min walking distance (6MWD) is a reliable measure (intra-class correlation coefficients ranged from 0.82 to 0.99 in seven studies). There is a learning effect, with greater distance walked on the second test (pooled mean improvement of 26 m in 13 studies). Reliability was similar for ISWT and ESWT, with a learning effect also evident for ISWT (pooled mean improvement of 20 m in six studies). The 6MWD correlates more strongly with peak work capacity (r=0.59–0.93) and physical activity (r=0.40–0.85) than with respiratory function (r=0.10–0.59). Methodological factors affecting 6MWD include track length, encouragement, supplemental oxygen and walking aids. Supplemental oxygen also affects ISWT and ESWT performance. Responsiveness was moderate to high for all tests, with greater responsiveness to interventions that included exercise training.

The findings of this review demonstrate that the 6MWT, ISWT and ESWT are robust tests of functional exercise capacity in adults with chronic respiratory disease.

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.

A functional assessment of patients two years after lung transplantation in Poland

THE AIM OF THE STUDY

The aim of the study was to assess the long-term results of lung transplantation (LT) in Poland two years after the procedure.

MATERIAL AND METHODS

The study included patients who underwent LT between December 2004 and December 2009 in the Silesian Center for Heart Diseases in Zabrze. Various lung functions (forced vital capacity - FVC; forced expiratory volume in 1 second - FEV1), the quality of life (SF-36 questionnaire), the level of perceived dyspnea (Medical Research Council - MRC; basic dyspnea index - BDI), and the patient's mobility (the 6-minute walking test - 6MWT) were assessed before and approximately 24 months after LT. Among 35 patients who underwent LT, 20 patients were referred to our study (mean age: 46.6 ± 9.03 years).

RESULTS

After LT, a statistically significant increase was observed in the distance achieved in the 6MWT (323.8 vs. 505.8 m), FVC (1.64 vs. 2.88 L), and FEV1 (1.37 vs. 2.09 L). An improvement in perceived dyspnea in MRC and BDI questionnaires was observed in patients with chronic obstructive pulmonary disease (COPD) after LT. The assessment of the quality of life, excluding perceived pain, showed the most significant improvement in the physical cumulative score (PCS; 25 vs. 45 points), especially in patients with idiopathic pulmonary fibrosis.

CONCLUSIONS

Lung transplantation in Poland, in patients who live longer than 2 years after the procedure, significantly improves the mobility, lung function, perceived dyspnea, and the quality of life.

Pulmonary rehabilitation in lung transplant candidates

BACKGROUND

While awaiting lung transplantation, candidates may participate in pulmonary rehabilitation to improve their fitness for surgery. However, pulmonary rehabilitation outcomes have not been systematically evaluated in lung transplant candidates.

METHODS

This investigation was a retrospective cohort study of 345 pre-transplant pulmonary rehabilitation participants who received a lung transplant between January 2004 and June 2009 and had available pre-transplant exercise data. Data extracted included: 6-minute walk tests at standard intervals; exercise training details; health-related quality-of-life (HRQL) measures; and early post-transplant outcomes. Paired t-tests were used to examine changes in the 6MW distance (6MWD), exercise training volume and HRQL during the pre-transplant period. We evaluated the association between pre-transplant 6MWD and transplant hospitalization outcomes.

RESULTS

The final 6MWD prior to transplantation was only 15 m less than the listing 6MWD (n = 200; p = 0.002). Exercise training volumes increased slightly from the start of the pulmonary rehabilitation program until transplant: treadmill, increase 0.69 ml/kg/min (n = 238; p < 0.0001); biceps resistance training, 18 lbs. × reps (n = 286; p < 0.0001); and quadriceps resistance training, 15 lbs. × reps (n = 278; p < 0.0001). HRQL measures declined. A greater final 6MWD prior to transplant correlated with a shorter length of stay in the hospital (n = 207; p = 0.003).

CONCLUSIONS

Exercise capacity and training volumes are well preserved among lung transplant candidates participating in pulmonary rehabilitation, even in the setting of severe, progressive lung disease. Participants with greater exercise capacity prior to transplantation have more favorable early post-transplant outcomes.

Pretransplant six-minute walk test predicts peri- and post-operative outcomes after pediatric lung transplantation

The purpose of the pretransplant assessment in lung transplantation is to determine a patient's need for transplant as well as their potential survival post-procedure. In 2005, the UNOS introduced the LAS, a calculation based on multiple physiologic measures to determine need and likelihood for survival. Measures include NYHA class and the 6-MWT. Some adult studies indicate a positive correlation with 6-MWT and waiting list survival. In pediatric/adolescent patients, there are minimal data regarding the predictive value of physiologic markers in either wait list survival or post-transplant outcome. A retrospective cohort study of 60 consecutive lung transplantations from 1990 to 2008 was performed at a pediatric tertiary care facility. Functional pretransplant assessments were abstracted from the medical record and compared with outcomes after transplantation.

RESULTS

a 6-MWT of >1000 ft (305 m) prior to transplantation correlated with a shorter ICU stay (7 vs. 11 days, p = 0.046) and fewer days of mechanical ventilation (2 vs. 4, p = 0.04). A pretransplant 6-MWT greater than 750 ft (229 m) correlated with shorter overall hospitalization (37 vs. 20 days, p = 0.03). Measuring pretransplant 6-MWT tests for pediatric patients is valuable in predicting peri-operative outcomes after lung transplantation.

Exercise testing in pediatric lung transplant candidates with cystic fibrosis

Exercise testing is considered an important prognostic tool for the selection of pediatric lung transplant candidates with end-stage CF lung disease. To better understand the current practice as it pertains to exercise testing, a self-administered questionnaire was distributed to 25 pediatric lung transplant centers within the IPLTC across Australia, Europe, and North America. All centers perform standardized exercise tests. Fifteen centers perform one single-field test (6MWT/12MWT), while seven perform a six-min walk plus an additional test: SWT (N = 1), 3MST (N = 1), and CPET (N = 5). Frequency of testing is markedly different among centers. Two centers conduct exercise testing once, all others at multiple time points. Equipment availability and cost were no limitations, but lack of time (20%) and personnel (16%), and paucity of prognostic evidence (16%) and reference values (12%) were stated. Exercise testing is considered important and extensively used in the evaluation of pediatric lung transplant candidates with CF; methods of exercise test and the frequency of testing vary widely. We propose a prospective multicenter study to evaluate the efficacy of exercise testing and its prognostic value using a standardized protocol.

Lung transplantation in autoimmune diseases

In the last 45 years, lung transplantation has evolved from its status as a rare extreme form of surgical therapy for the treatment of advanced lung diseases to an accepted therapeutic option for select patients. Although pulmonary fibrosis and pulmonary vascular diseases are important indications for lung transplantation, only a small percentage of transplants are performed in patients with collagen vascular diseases. The reasons for this low number are multifactorial. This article reviews issues relevant to all lung transplant candidates and recipients as well as those specific to patients with autoimmune diseases.

Six-minute walk distance predicts mortality in liver transplant candidates

The 6-minute walk distance (6MWD) is a simple test measuring global physical function. It is commonly used to predict mortality in patients with cardiac and pulmonary diseases, but it is also useful in assessing the functional status of patients with a variety of other medical conditions. We sought to determine (1) the characteristics of the 6MWD in patients listed for liver transplantation (LT), (2) the existence of a relationship between the 6MWD and the quality of life, and (3) the relationship between the 6MWD and survival in LT candidates. The 6MWD was prospectively measured in all patients listed for LT. The 6MWD was determined when the listed Model for End-Stage Liver Disease (MELD) score was ≥ 15. Patients were followed until LT, death, removal from the wait list, or the end of the study period. Quality of life was assessed with the Short Form 36 (SF-36). In 121 patients, the mean 6MWD was 369 ± 122 m; it was not related to age, height, weight, body mass index, albumin level, or etiology of liver disease and showed a moderate correlation with the physical component score (PCS) on the SF-36 (r = 0.4) and a moderate inverse correlation with the native MELD score (r = -0.61). In an unadjusted analysis, a high native MELD score, a low 6MWD, and a low PCS were associated with mortality, with only the 6MWD retaining significance after adjustment for covariates. Each 100-m increase in the 6MWD was significantly associated with increased survival (hazard ratio = 0.48, P = 0.0001), with 6MWD < 250 m being associated with an increased risk of death (P = 0.0001). In conclusion, the 6MWD is significantly reduced in patients awaiting LT and is inversely correlated with the native MELD score. A pretransplant 6MWD < 250 m is a risk for death on the wait list.

Physical function in older candidates for renal transplantation: an impaired population

BACKGROUND AND OBJECTIVES

Although physical function is a major determinant of health outcomes and quality of life in older adults, standard tools for its assessment have not been routinely applied to the fastest growing segment of the kidney transplant candidate population, which is at high risk of comorbidity and disability--people over age 60. The objective of this study was to describe the baseline physical function in older adults with renal failure referred for transplantation and compare them with older adults with other significant comorbidity.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

An observational sample comparing physical performance in renal transplant candidates over age 60 (Renal Failure) to older people with diastolic heart failure (Heart Failure), chronic obstructive pulmonary disease (COPD), or at high risk for cardiovascular disease (High CV Risk) was studied.

RESULTS

Older people with Renal Failure were significantly impaired by objective measures of physical function, including lower Short Physical Performance Battery, slower gait speed, and lower grip strength.

CONCLUSIONS

Older people referred for renal transplantation had poorer physical performance than older adults with other common chronic diseases and may be at high risk for disability while awaiting transplantation.