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

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.

Feasibility and acceptability of a physical activity behavioural modification tele-coaching intervention in lung transplant recipients

BACKGROUND

Despite improvements in pulmonary function following lung transplantation (LTx), physical activity levels remain significantly lower than the general population. To date, there is little research investigating interventions to improve daily physical activity in LTx recipients. This study assessed the feasibility and acceptability of a novel, 12-weeks physical activity tele-coaching (TC) intervention in LTx recipients.

METHODS

Lung transplant recipients within 2 months of hospital discharge were recruited and randomised (1:1) to TC or usual care (UC). TC consists of a pedometer and smartphone app, allowing transmission of activity data to a platform that provides feedback, activity goals, education, and contact with the researcher as required. Recruitment and retention, occurrence of adverse events, intervention acceptability and usage were used to assess feasibility.

RESULTS

Key criteria for progressing to a larger study were met. Of the 15 patients eligible, 14 were recruited and randomised to TC or UC and 12 completed (67% male; mean ± SD age; 58 ± 7 years; COPD n = 4, ILD n = 6, CF n = 1, PH n = 1): TC (n = 7) and UC (n = 5). TC was well accepted by patients, with 86% indicating that they enjoyed taking part. Usage of the pedometer was excellent, with all patients wearing it for over 90% of days and rating the pedometer and telephone contact as the most vital aspects. There were no adverse events related to the intervention. After 12 weeks, only TC displayed improvements in accelerometry steps/day (by 3475 ± 3422; p = .036) and movement intensity (by 153 ± 166 VMU; p = .019), whereas both TC and UC groups exhibited clinically important changes in physical SF-36 scores (by 11 ± 14 and 7 ± 9 points, respectively).

CONCLUSION

TC appears to be a feasible, safe, and well-accepted intervention in LTx.

Impact of inspiratory muscle strength on exercise capacity after lung transplantation

BACKGROUND AND PURPOSE

Though inspiratory muscle strength is essential for patients with respiratory disease, it is unclear whether the recovery of inspiratory muscle strength contributes to an exemplary achievement of exercise tolerance after lung transplantation (LTx). We aimed to elucidate the inspiratory muscle strength affects the recovery of exercise capacity after LTx.

METHODS

Recipients who underwent LTx between June 2017 and September 2018 were enrolled, and 6-min walking distance (6MWD), quadriceps force, inspiratory muscle strength (maximal inspiratory pressure [MIP]), and spirometry were evaluated at 3, 6, and 12 months after LTx. The relationships between inspiratory muscle strength and changes in physical performance were analyzed.

RESULTS

Nineteen recipients (mean age: 44.8 years, male: 32%) who completed all follow-ups were analyzed. At 3 months after LTx, mean MIP (88.4% predicted) and vital capacity (60.9% predicted), quadriceps force (QF; 2.1 N*m/kg), and 6MWD (504 m) were lower than normal values. After LTx, 6MWD significantly improved up to 12 months. From 3 to 6 months after LTx, changes in MIP were significantly associated with increases in 6MWD by univariate (r = 0.55, p = 0.02) and multivariate (β = 0.59, p = 0.01) regression analyses, whereas changes of QF in place of MIP were significantly associated with the recoveries of 6MWD from 6 to 12 months.

DISCUSSION

Improvements in MIP may impact the recovery of exercise capacity in the early phase after LTx. Factors that determine the improvement in exercise capacity following LTx may vary with postoperative time.

Physical function after lung transplantation for late-onset noninfectious pulmonary complications after allogeneic hematopoietic stem cell transplantation

PURPOSE

Late-onset noninfectious pulmonary complications (LONIPCs) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are fatal, and lung transplantation is the only curative treatment. Although lung transplantation for LONIPCs may confer good survival rates, it is unclear whether or how impaired physical functioning is restored. Thus, this study aimed to investigate the long-term course and associated changes in physical functions after lung transplantation in patients with LONIPCs after allo-HSCT.

METHODS

This prospective cohort study enrolled 15 patients who received lung transplantation for LONIPCs after allo-HSCT between 2012 and 2018. Dyspnea scores, performance status, physical function, and exercise tolerance were assessed before lung transplantation and up to 2 years after transplantation.

RESULTS

Two years after lung transplantation, the dyspnea scores and performance status improved, but did not recover completely. Physical function was assessed using the knee extensor strength (KES) and 6-min walk test (6MWT); the results were poor until 3 months after transplantation but improved over 2 years. The 6MWT distance showed improvement to a nearly healthy level (562.7 m). Recovery of exercise tolerance was associated with recovery in % vital capacity (%VC; r=0.5) and KES (r=0.4) from 3 months to 2 years after lung transplantation. Furthermore, a flat thorax, which is a characteristic of patients with LONIPCs, affected the %VC at 2 years after transplantation (r=0.8).

CONCLUSION

Lung transplantation for LONIPCs may restore impaired physical function. A multifaceted rehabilitation program should be considered, especially to improve muscle weakness and pulmonary function.

Is it Possible to Use the Timed Performance Tests in Lung Transplantation Candidates to Determine the Exercise Capacity?

OBJECTIVES

Lung transplantation (LTx) candidates have severe exercise intolerance. This makes it difficult for them to complete the field tests used to determine the exercise capacity of patients. Therefore, there is a need for alternative tests that require less effort. We aimed to investigate the use of short-timed performance tests instead of 6-minute walk test (6MWT) in the determination of exercise capacity in LTx.

MATERIALS AND METHODS

A total of 63 LTx candidates were included in the study. Ten-meter walking speed test (10MWT), 5-times sit-to-stand test (5XSST), 6MWT were performed at one-hour intervals within the same day, and by the same physiotherapist in all patients. Maximal inspiratory (MIP) and expiratory pressure (MEP), peripheral muscle strengths, pulmonary function tests, and body mass index (BMI) were recorded for each patient.

RESULTS

The subjects' baseline mean 6-minute walking distance (6MWD) was 336m, 5XSST time was 11.59 sec, and 10MWT time was 8.45sec. There was a negative and moderate correlation between 6MWD and 10MWT (p<0.001, r=0.449). Similarly there was a negative but weak correlation between 6MWD and 5XSST (p=0.001, r=0.397). In addition, there was a strong relationship between 5XSST and 10MWT (p<0.001, r=0.767).

CONCLUSION

This study showed that 6MWT and short-timed performance tests were correlated in terms of exercise capacity assessment. In contrast, there was a strong relationship between 6MWT and 10MWT according to 6MWT and 5XSST. The timed performance tests may be alternative tests to determine exercise capacity in LTx candidates.

Prehabilitation: how to prepare our patients for elective major abdominal surgeries?

Surgical approach is the main form of treatment for several diseases of the abdominal cavity. However, surgical procedure itself is a stressor that may lead to adverse effects unrelated to the treatment goal. Prehabilitation has emerged as a multifactorial preoperative health conditioning program, which promotes improvement in functional capacity and postoperative evolution. The present study reviews literature using MEDLINE, Ovid, Google Scholar, and Cochrane databases in order to determine the concept of prehabilitation program and the indications and means of patient selection for it, as well as to suggest ways to implement this program in cases of major abdominal surgeries.

Association between early pulmonary complications after abdominal surgery and preoperative physical capacity

Objective: To investigate whether early postoperative pulmonary complications after abdominal surgery are associated with a lower performance in preoperative six-minute walk test.Methods: A cross-sectional cohort study of 50 participants who underwent elective abdominal surgery and performed the six-minute walk test within 48 hours prior to surgery were conducted. Postoperative pulmonary complications up to the seventh postoperative day were obtained from medical records.Results: Overall, 25 participants developed postoperative pulmonary complications. The mean (standard deviation) preoperative walked distances of the participants with and without postoperative pulmonary complications were, respectively, 444.8 (81.3) meters and 498.3 (63.7) meters (p = .013). The incidence of postoperative pulmonary complications was greater in the participants with walked distance < 400 meters. The multivariable logistic regression model revealed a significant association between postoperative pulmonary complications and preoperative walked distance (Odds ratio = 0.978, p = .010) in participants who underwent intestinal, stomach, or bile tract resection. Conclusions: This study found a high incidence of postoperative pulmonary complications in abdominal surgery participants and an association between lower preoperative physical capacity and the risk of postoperative pulmonary complications in participants who underwent intestinal, stomach, and biliary tract resection.

Myostatin and other musculoskeletal markers in lung transplant recipients

Recipients of lung transplantation (LuTx) may experience impaired muscle function and bone metabolism even after rehabilitation. We investigated the potential use of musculoskeletal markers in identifying the impairment of muscle function and bone function in these patients. Biochemical parameters, bodily functions, and lung function of 37 LuTx recipients were evaluated at the time of their discharge from the hospital stay and about 6 months later. The biomarkers were also assessed in 30 healthy age and gender distribution-matched controls. Compared to controls, the negative muscle regulator myostatin was elevated in LuTx recipients at baseline and follow-up, whereas its opponent follistatin only showed a group-specific difference at follow-up. LuTx recipients had reduced serum levels of sclerostin and increased levels of dickkopf 1 and periostin. Lung function and physical function were improved during follow-up. The change in lung function was correlated with the change in chair-rising time and the 6-min walking test. At follow-up, all musculoskeletal markers of LuTx recipients differed from those of controls, thus reflecting their still reduced lung function and bodily functions. Among the tested biomarkers, myostatin, sclerostin, dickkopf 1, and periostin were useful to detect impaired musculoskeletal function in LuTx recipients. Myostatin may serve as a target of treatment in the future.

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.

Predictors of Long-Term Exercise Capacity in Patients Who Have Had Lung Transplantation

INTRODUCTION

Six-minute walk distance (6MWD) is a widely used surrogate for exercise capacity in patients both pre- and post-lung transplant. Multiple factors have been suggested to influence exercise capacity.

RESEARCH QUESTIONS

This study sought to determine the change in exercise capacity over time and factors that influence long-term exercise capacity.

DESIGN

Data were collected prospectively on lung transplant recipients from 1 center. The 6MWD was measured preoperatively and at the 6- and 12-month clinic visits postoperatively. The Enright equation was used to calculate patients' percentage predicted 6MWD. The change in 6MWD over time was calculated, and multiple factors affecting 6MWD were analyzed, including predictors of 6MWD at 6 and 12 months posttransplant.

RESULTS

Sixty lung transplant recipients were enrolled. Significant improvement in 6MWD was found between pretransplant and hospital discharge and between hospital discharge and 6 months posttransplant. The percentage predicted 6MWD improved significantly from pretransplant to 6 months and to 12 months posttransplant. Factors associated with 6MWD were sex, diagnosis, graft type, and age. Factors predicting long-term exercise capacity included 6MWD at referral, pretransplant, and hospital discharge; pulmonary diagnosis; and type of transplant.

CONCLUSION

The 6MWD provided useful information about patients' exercise capacity during phases of lung transplantation. The percentage predicted for each patient was found to be a more valuable measure than absolute 6MWD. Intensive, individualized training posttransplant is essential to optimize exercise capacity for this population.

Changes in Muscle Strength and Six-Minute Walk Distance Before and After Living Donor Liver Transplantation

BACKGROUND

Impaired exercise capacity and muscle weakness are important characteristics of liver transplantation recipients. Perioperative rehabilitation has been introduced to promote early mobilization of patients and to prevent postoperative pulmonary complications. However, it is unknown how physical status recovers during the hospital stay after a liver transplant. The purpose of this study was to evaluate the changes in clinical indicators that represent the functional exercise capacity and muscle strength before and after living donor liver transplantation (LDLT).

METHODS

We retrospectively reviewed 21 consecutive patients who underwent LDLT with perioperative rehabilitation from April 2014 to December 2015. Twelve patients who were tested for 6-minute walk distance, hand-grip strength, and isometric knee extensor muscle strength before and 4 weeks after LDLT were enrolled.

RESULTS

At the preoperative baseline, the 6-minute walk distance significantly correlated with the Model for End-stage Liver Disease score and pulmonary functions (vital capacity, forced vital capacity, and forced expiratory volume in 1 second of predictive values). Comparisons between the preoperative and postoperative values revealed significant decreases in weight, Barthel Index, hand-grip strength, and isometric knee extensor muscle strength. Changes in hand-grip strength and isometric knee extensor muscle strength after LDLT correlated with the preoperative Model for End-stage Liver Disease score.

CONCLUSIONS

Physical functional status had not been fully recovered 4 weeks after LDLT. Further investigation regarding developing a strategy for prevention of muscle atrophy before LDLT and recovery of physical fitness after LDLT would be helpful.

Physical rehabilitation for lung transplant candidates and recipients: An evidence-informed clinical approach

Physical rehabilitation of lung transplant candidates and recipients plays an important in optimizing physical function prior to transplant and facilitating recovery of function post-transplant. As medical and surgical interventions in lung transplantation have evolved over time, there has been a demographic shift of individuals undergoing lung transplantation including older individuals, those with multiple co-morbidites, and candidates with respiratory failure requiring bridging to transplantation. These changes have an impact on the rehabilitation needs of lung transplant candidates and recipients. This review provides a practical approach to rehabilitation based on research and clinical practice at our transplant centre. It focuses on functional assessment and exercise prescription during an uncomplicated and complicated clinical course in the pre-transplant, early and late post-transplant periods. The target audience includes clinicians involved in pre- and post-transplant patient care and rehabilitation researchers.

Perceived Barriers to and Facilitators of Physical Activity in Recipients of Solid Organ Transplantation, a Qualitative Study

Background

Sufficient physical activity is important for solid organ transplant recipients (heart, lung, liver, kidney). However, recipients do not meet the recommended amount or required type of physical activity. The perceived barriers to and facilitators of physical activity in this population are largely unknown.

Methods

Semi-structured in depth interviews were conducted with solid organ transplant recipients in order to explore experienced barriers and facilitators. Qualitative methodology with thematic line-by-line analysis was used for analysis, and derived themes were classified into personal and environmental factors.

Results

The most important indicated barriers were physical limitations, insufficient energy level, fear, and comorbidities. The most frequently mentioned facilitators included motivation, coping, consequences of (in)activity, routine/habit, goals/goal priority, and responsibility for the transplanted organ. Neutral factors acting as a barrier or facilitator were self-efficacy and expertise of personnel. A comparison of barriers and facilitators between transplant recipient groups yielded no overt differences.

Conclusion

Several personal and environmental factors were indicated that should be considered in intervention development to increase physical activity behavior in solid organ transplant recipients.

Rehabilitation in Patients before and after Lung Transplantation

Lung transplantation is an established treatment for patients with end-stage lung disease. It has been observed that despite near-normal lung function, exercise intolerance and reductions in quality of life (QOL) often persist up to years after transplantation. Several modifiable pre- and posttransplant factors are known to contribute to these persisting impairments. Physiological changes associated with severe and chronic lung disease, limb muscle dysfunction, inactivity/deconditioning, and nutritional depletion can affect exercise capacity and physical functioning in candidates for lung transplantation. After transplantation, extended hospital and intensive care unit stay, prolonged sedentary time, persisting inactivity, immunosuppressant medications and episodes of organ rejection may all impact lung recipients' recovery. Available evidence will be reviewed and content will be proposed (both evidence and experience based) for rehabilitation interventions prior to transplantation, during hospitalization after transplantation, and in both the immediate (≤12 months after hospital discharge) and long-term (>12 months after hospital discharge) posttransplant phase. Outpatient rehabilitation programs including supervised exercise training have been shown to be effective in improving limb muscle dysfunction, exercise capacity, and QOL both before and after transplantation if offered appropriately. Unmet research needs included the absence of sufficiently powered randomized controlled trials measuring the effects of rehabilitation interventions on crucial long-term outcomes such as sustained improvements in QOL, participation in daily activity, survival, incidence of morbidities and cost-effectiveness. Remotely monitored (telehealth) home-based exercise or pedometer-based walking interventions might be interesting alternatives to supervised outpatient rehabilitation interventions in the long-term posttransplant phase and warrant further investigation.