Cardiopulmonary exercise testing before and after lung and heart-lung transplantation

Differential control of respiratory frequency and tidal volume during exercise

The lack of a testable model explaining how ventilation is regulated in different exercise conditions has been repeatedly acknowledged in the field of exercise physiology. Yet, this issue contrasts with the abundance of insightful findings produced over the last century and calls for the adoption of new integrative perspectives. In this review, we provide a methodological approach supporting the importance of producing a set of evidence by evaluating different studies together-especially those conducted in 'real' exercise conditions-instead of single studies separately. We show how the collective assessment of findings from three domains and three levels of observation support the development of a simple model of ventilatory control which proves to be effective in different exercise protocols, populations and experimental interventions. The main feature of the model is the differential control of respiratory frequency (f_R) and tidal volume (V_T); f_R is primarily modulated by central command (especially during high-intensity exercise) and muscle afferent feedback (especially during moderate exercise) whereas V_T by metabolic inputs. Furthermore, V_T appears to be fine-tuned based on f_R levels to match alveolar ventilation with metabolic requirements in different intensity domains, and even at a breath-by-breath level. This model reconciles the classical neuro-humoral theory with apparently contrasting findings by leveraging on the emerging control properties of the behavioural (i.e. f_R) and metabolic (i.e. V_T) components of minute ventilation. The integrative approach presented is expected to help in the design and interpretation of future studies on the control of f_R and V_T during exercise.

Orthostatic Hypotension and Concurrent Autonomic Dysfunction: A Novel Complication of Lung Transplantation

Background

Persistent orthostatic hypotension (OH) is a lesser-known complication of lung transplantation (LTx). In this retrospective case series, we describe the clinical manifestations, complications, and treatment of persistent OH in 13 LTx recipients.

Methods

We identified LTx recipients who underwent transplantation between March 1, 2018, and March 31, 2020, with persistent symptomatic OH and retrospectively queried the records for clinical information.

Results

Thirteen patients were included in the analysis, 9 (69%) had underlying pulmonary fibrosis, and 12 (92%) were male. The median age, height, and body mass index at LTx were 68 years, 70 inches, and 27 kg/m², respectively. Six (46%) patients were deceased at the time of chart abstraction with a median (IQR) posttransplant survival of 12.6 months (6, 21); the 7 remaining living patients were a median of 19.6 months (18, 32) posttransplant. Signs and symptoms of OH developed a median of 60 (7, 75) days after transplant. Patients were treated with pharmacological agents and underwent extensive physical therapy. Most patients required inpatient rehabilitation (n = 10, 77%), and patients commonly developed comorbid conditions including weight loss, renal insufficiency with eGFR <50 (n = 13, 100%), gastroparesis (n = 7, 54%), and tachycardia-bradycardia syndrome (n = 2, 15%). Falls were common (n = 10, 77%). The incidence of OH in LTx recipients at our center during the study period was 5.6% (13/234).

Conclusions

Persistent OH is a lesser-known complication of LTx that impacts posttransplant rehabilitation and may lead to comorbidities and shortened survival. In addition, most LTx recipients with OH at our center were tall, thin men with underlying pulmonary fibrosis, which may offer an opportunity to instate pretransplant OH screening of at-risk patients.

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.

Addressing the changing rehabilitation needs of patients undergoing thoracic surgery

The rehabilitation needs of individuals undergoing thoracic surgery are changing, especially as surgical management is increasingly being offered to patients who are at risk of developing functional limitations during and after hospital discharge. In the past rehabilitative management of these patients was frequently limited to specific respiratory physiotherapy interventions in the immediate postoperative setting with the aim to prevent postoperative pulmonary complications. In the past two decades, this focus has shifted toward pulmonary rehabilitation interventions that aim to improve functional status of individuals, both in the pre- and (longer-term) postoperative period. While there is increased interest in (p)rehabilitation interventions the majority of thoracic surgery patients are however currently on their own with respect to progression of their exercise and physical activity regimens after they have been discharged from hospital. There are also no formal guidelines supporting the referral of these patients to outpatient rehabilitation programs. The current evidence regarding rehabilitation interventions initiated before, during, and after the hospitalization period will be briefly reviewed with special focus on patients undergoing surgery for lung cancer treatment and patients undergoing lung transplantation. More research will be necessary in the coming years to modify or change clinical rehabilitation practice beyond the acute admission phase in patients undergoing thoracic surgery. Tele rehabilitation or web-based activity counseling programs might also be interesting emerging alternatives in the (long-term) postoperative rehabilitative treatment of these patients.

Cardiopulmonary Rehabilitation Improves Respiratory Muscle Function and Functional Capacity in Children with Congenital Heart Disease. A Prospective Cohort Study

Critical surgical and medical advances have shifted the focus of congenital heart disease (CHD) patients from survival to achievement of a greater health-related quality of life (HRQoL). HRQoL is influenced, amongst other factors, by aerobic capacity and respiratory muscle strength, both of which are reduced in CHD patients. This study evaluates the influence of a cardiopulmonary rehabilitation program (CPRP) on respiratory muscle strength and functional capacity. Fifteen CHD patients, ages 12 to 16, with reduced aerobic capacity in cardiopulmonary exercise testing (CPET) were enrolled in a CPRP involving strength and aerobic training for three months. Measurements for comparison were obtained at the start, end, and six months after the CPRP. A significant improvement of inspiratory muscle strength was evidenced (maximum inspiratory pressure 21 cm H₂O, 23%, p < 0.01). The six-minute walking test showed a statistically and clinically significant rise in walked distance (48 m, p < 0.01) and a reduction in muscle fatigue (1.7 out of 10 points, p = 0.017). These results suggest CPRP could potentially improve respiratory muscle function and functional capacity, with lasting results, in children with congenital heart disease, but additional clinical trials must be conducted to confirm this finding.

Evolution of Functional Exercise Capacity in Lung Transplant Patients With and Without Bronchiolitis Obliterans Syndrome: A Longitudinal Case-Control Study

INTRODUCTION

Bronchiolitis Obliterans Syndrome (BOS) is a debilitating disease with limited treatment options that threatens both the quality of life and long-term survival of lung transplant (LTx) recipients. This retrospective longitudinal case-control study was performed to compare the long-term functional evolution of LTx recipients with and without BOS.

METHODS

Twenty-four LTx recipients with BOS (BOS=Cases) and 24 without BOS (NON-BOS=Controls) were selected and individually matched according to age, gender, diagnosis and LTx characteristics. Measurements of 6-minute walking distance (6MWD), symptoms of dyspnea (BORG CR-10 scale), and comprehensive pulmonary function testing were performed before LTx and at annual follow-up assessments after LTx.

RESULTS

Peak FEV₁ after LTx was similar in both groups [FEV₁ (% predicted) 101±25 vs. 101±31, p=0.96] and BOS diagnosis in cases was established 3.6±2.5 years after LTx. At the final follow-up assessment (6.5±3.2 years after LTx) FEV₁ (% predicted) was 86±34 in NON-BOS vs. 44±17 in BOS (p<0.001). Evolution of 6MWD was different between groups (group by time interaction: p=0.002). Borg dyspnea scores were also significantly different between groups at the final evaluation (NON-BOS 3.3±1.7 vs. BOS 5.0±2.2; p=0.024).

CONCLUSIONS

We observed gradual reductions in functional exercise capacity and increasing symptoms of dyspnea in patients who developed BOS after LTx. As such, prospective studies seem warranted to explore whether rehabilitative interventions might be useful to improve symptoms and slow down deterioration of exercise capacity in these patients from the onset of BOS.

Replicability of Physical Exercise Interventions in Lung Transplant Recipients; A Systematic Review

Introduction: This systematic review aimed to assess the replicability of physical exercise interventions in lung transplantation patients. For replicability we focused on (1) the description of training principles, (2) the description of FITT components and adherence to the interventions, (3) the amount of detailed information given on the physical exercise intervention, and (4) reporting the methodological quality of the included works.

Methods: Relevant databases (Medline-Ovid, EMBASE, CINAHL, PsychInfo, Cochrane Library) were searched. Author dyads selected and systematically analyzed the included studies independent from each other. A purpose developed checklist was used to assess the details of the exercise interventions and their methodological quality.

Results: From the seven included manuscripts, three described resistance training, one endurance, and three combined training approaches. All manuscripts reported specificity and initial values, six manuscripts mention progression and overload. The exercise principle reversibility was reported once and diminishing returns was not reported at all. All studies reported the type of exercise, three studies reported intensity and one study reported time for training. Not any study completely reported frequency or described adherence to the intervention. Lack of detailed reporting was identified as the cause for murky description of the interventions. The highest score for intervention description was 5 of possible 12 items.

Conclusions: Replicability of many exercise interventions in LTX is not warranted due too poor descriptions of important items related to training. In particular there were insufficiently detailed reporting of training principles and FITT components in programs developed for LTX. Future interventions that aim to train LTX patients should spent effort in writing reports in which the intervention is detailed to such an extent that full replicability in clinical settings can be guaranteed.

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.

The World Transplant Games: an incentive to improve physical fitness and habitual activity in pediatric solid organ transplant recipients

This prospective, interventional study examined the impact of training for the WTG on levels of health-related physical fitness and habitual activity in a cohort of pediatric SOT recipients. Physical fitness (FitnessGram(®) ) and habitual activity (HAES) measures were performed on participants (n = 19) in the WTG and compared to non-participant controls (n = 14) prior to and following the WTG. Pre-WTG exercise training was provided to participants. Participants demonstrated a statistically significant improvement in their habitual weekday (6.1 ± 1.7 to 8.5 ± 1.9 h; p = 0.002) and weekend (6.3 ± 2.6 to 8.4 ± 2.5 h; p = 0.01) activity over the training period, while controls improved weekday activity only (6.3 ± 2.0 to 8.3 ± 2.1 h; p = 0.05. Weekend activity: 7.7 ± 2.7 to 8.3 ± 2.3 h; p = 0.68). Participants demonstrated a non-statistical improvement in select physical fitness parameters; however, a greater number of participants achieved healthy criterion standards for cardiovascular fitness (2 vs. 1), abdominal strength (5 vs. 3), and upper body strength (7 vs. 3) following training and participating in the WTG. The WTG can provide a positive incentive for greater levels of physical activity and promote improvements in physical fitness levels. Further study is needed to examine long-term impact on lifestyle changes and health outcomes.

Solid organ transplant recipients: clinical considerations in the application of exercise

Over 100 000 solid organ transplants are performed worldwide each year and this has a significant impact on physical function and quality of life. However, the capacity for exercise in solid-organ recipients is reduced. Regular physical activity improves most of the indices of fitness in these patients but, with few exceptions, they do not reach the values seen in healthy controls. The reason for the 40-60% reduction in maximal exercise capacity is not clear; the disease process, need for life long immunosuppression and sedentary lifestyle all contribute. The interaction between exercise and immunosuppressing medication merits research as does the specifics of the exercise prescription for these patients. This paper reviews important features of this rapidly expanding group of patients and suggests clinical considerations in the application of exercise in this population.

Exercise limitation following transplantation

Organ transplantation is one of the medical miracles or the 20th century. It has the capacity to substantially improve exercise performance and quality of life in patients who are severely limited with chronic organ failure. We focus on the most commonly performed solid-organ transplants and describe peak exercise performance following recovery from transplantation. Across all of the common transplants, evaluated significant reduction in VO2peak is seen (typically renal and liver 65%-80% with heart and/or lung 50%-60% of predicted). Those with the lowest VO2peak pretransplant have the lowest VO2peak posttransplant. Overall very few patients have a VO2peak in the normal range. Investigation of the cause of the reduction of VO2peak has identified many factors pre- and posttransplant that may contribute. These include organ-specific factors in the otherwise well-functioning allograft (e.g., chronotropic incompetence in heart transplantation) as well as allograft dysfunction itself (e.g., chronic lung allograft dysfunction). However, looking across all transplants, a pattern emerges. A low muscle mass with qualitative change in large exercising skeletal muscle groups is seen pretransplant. Many factor posttransplant aggravate these changes or prevent them recovering, especially calcineurin antagonist drugs which are key immunosuppressing agents. This results in the reduction of VO2peak despite restoration of near normal function of the initially failing organ system. As such organ transplantation has provided an experiment of nature that has focused our attention on an important confounder of chronic organ failure-skeletal muscle dysfunction.

The influence of clinical course after lung transplantation on rehabilitation success

Pulmonary rehabilitation (PR) is a cornerstone of treatment following lung transplantation (LTx). The aim of this study was to observe the influence of a prolonged postsurgical clinical course on success of a 3-week inpatient PR. LTx recipients were divided according to their clinical course defined by their individual length of stay (LOS) in the transplant center (cohort 1: LOS >; cohort 2: ≤42 days). Peak work rate (PWR), maximum oxygen uptake (VO(2max) ), 6-min walk distance (6-MWD), vital capacity (VC), forced expiratory volume in one second (FEV1), physical activity of daily life (ADL), and health-related quality of life (HRQoL) measured using Short Form 36 questionnaire (SF36) were assessed at beginning and completion of PR. A total of 138 patients were included (LOS >42 days: 30; LOS ≤42 days: 108). At completion, physical functioning (VC, FEV1, PWR, VO(2max) , 6-MWD, ADL), and HRQoL (all SF36 domains) improved in each cohort (P < 0.05). No differences were found in between both cohorts in VC, FEV1, and ADL (n.s.), but in PWR, 6-MWD, and the SF36 domain 'physical functioning' (P < 0.05). A 3-week inpatient PR improves physical functioning despite prolonged hospitalization. HRQoL is close to normal. (ClinicalTrials.gov. identifier: NCT00759538).

Effects of an acute, outpatient physiotherapy exercise program following pediatric heart or lung transplantation

This prospective interventional study investigated the impact of a three-month, ambulatory HA or HB, semi-individualized, PT-prescribed exercise program following pediatric HTx or LTx. SMW distance, strength, and flexibility were assessed at start and completion of the program and one yr after enrollment. Subjects received either an HB or HA exercise program three times per week. The cohort demonstrated clinically and statistically significant improvements in SMW distances at three months (425.7 ± 109.4-500.6 ± 93.6 m, p < 0.001) and at one yr (528.5 ± 66.6 m, p = 0.001), although there was no difference between the two groups at any time. Similar improvements were also observed in strength and flexibility measures. Correlates with higher SMW distance at three months and one yr included older age, male gender, and underlying diagnosis other than CHD. Male gender and diagnosis other than CHD were associated with a slower improvement in the SMW distance. This is the first report of institutionally based, outpatient exercise rehabilitation in the recovery following pediatric thoracic transplantation. We found similar improvements to HB interventions up to one yr after surgery. Further study of the role of exercise rehabilitation and long-term fitness outcomes is needed.

Exercise training after lung transplantation improves participation in daily activity: a randomized controlled trial

The effects of exercise training after lung transplantation have not been studied in a randomized controlled trial so far. We investigated whether 3 months of supervised training, initiated immediately after hospital discharge, improve functional recovery and cardiovascular morbidity of patients up to 1 year after lung transplantation. Patients older than 40 years, who experienced an uncomplicated postoperative period, were eligible for this single blind, parallel group study. Sealed envelopes were used to randomly allocate patients to 3 months of exercise training (n = 21) or a control intervention (n = 19). Minutes of daily walking time (primary outcome), physical fitness, quality of life and cardiovascular morbidity were compared between groups adjusting for baseline assessments in a mixed models analysis. After 1 year daily walking time in the treated patients (n = 18) was 85 ± 27 min and in the control group (n = 16) 54 ± 30 min (adjusted difference 26 min [95%CI 8-45 min, p = 0.006]). Quadriceps force (p = 0.001), 6-minute walking distance (p = 0.002) and self-reported physical functioning (p = 0.039) were significantly higher in the intervention group. Average 24 h ambulatory blood pressures were significantly lower in the treated patients (p ≤ 0.01). Based on these results patients should be strongly encouraged to participate in an exercise training intervention after lung transplantation.

Cardiopulmonary exercise testing in lung transplantation: a review

There has been an increase in lung transplantation in the USA. Lung allocation is guided by the lung allocation score (LAS), which takes into account one measure of exercise capacity, the 6-minute walk test (6MWT). There is a paucity of data regarding the role and value of cardiopulmonary stress test (CPET) in the evaluation of lung transplant recipients while on the transplant waiting list and after lung transplantation. While clearly there is a need for further prospective investigation, the available literature strongly suggests a potential role for CPET in the setting of lung transplant.

Atrial fibrillation after pulmonary transplantation: incidence, impact on mortality, treatment effectiveness, and risk factors

BACKGROUND

Atrial fibrillation (AF) is common after thoracic surgery. Limited data exist concerning the incidence of AF, its impact on mortality, the effectiveness of therapy, and the risk factors of AF after pulmonary transplantation.

METHODS AND RESULTS

We reviewed the medical files of 224 consecutive lung transplant recipients who underwent surgery over a 10-year period at a large Canadian center. We collected patient characteristics, in-hospital treatments, and outcomes. Time-to-event analysis was used to account for in-hospital follow-up and models generated to assess the impact of AF on mortality and independent risk factors of AF after transplantation. Postoperative AF occurred in 65 patients (29%). AF was more likely to occur with complications such as pneumonia, mediastinitis, and bronchial dehiscence and was not an independent risk factor of mortality (hazard ratio=1.56; 95% confidence interval, 0.52-4.63). Pharmacological or electric therapy for rhythm or rate control of AF was administered to 97% of patients. Intravenous amiodarone was used in 46%, electric cardioversion in 28%, and heparin in 26%. Only 1 patient remained in AF at discharge. Age (hazard ratio=1.08 by year; 95% confidence interval, 1.05-1.12), bilateral transplantation (hazard ratio=1.87; 95% confidence interval, 1.03-3.42), and a history of AF before the transplantation (hazard ratio=4.48; 95% confidence interval, 1.05-19.11) were found to be independently associated with an increased incidence of postoperative AF.

CONCLUSIONS

AF is fairly common after pulmonary transplantation, transient, and relatively benign. It is not independently associated with increased in-hospital mortality. Most patients return to sinus rhythm before discharge. Age, prior AF, and bilateral transplantation increase the risk of postoperative AF.

Availability, characteristics, and barriers of rehabilitation programs in organ transplant populations across Canada

Rehabilitation is receiving increasingly more attention from the medical community in the management of individuals' pre- and post-organ transplantation. A cross-sectional descriptive survey was administered to all known transplant programs across Canada to explore the availability, characteristics, and barriers of rehabilitation programs pre- and post-heart, lung, kidney, and liver transplantation. Of the 58 programs surveyed, 35 agreed to participate (nine heart, six lung, 13 kidney, seven liver), and six refused for a response rate of 71%. Twelve transplant programs that offered rehabilitation were identified (six heart, five lung, one liver). All rehabilitation programs identified included aerobic exercises, strength training, and education and involved a multidisciplinary team. The Six Minute Walk Test and the Medical Outcomes Short Form-36 questionnaire were the most commonly used outcome measures. In kidney and liver transplant programs, over 50% of respondents from these programs cited lack of funding, shortage of health care personnel, and a low volume of patients in a centralized region as barriers to providing rehabilitation programs. Rehabilitation can play an integral role in pre- and post-transplantation management, and barriers to access and provision of rehabilitation for organ transplant populations should be examined further.

Lung transplantation and lung volume reduction surgery

Since the publication of the last edition of the Handbook of Physiology, lung transplantation has become widely available, via specialized centers, for a variety of end-stage lung diseases. Lung volume reduction surgery, a procedure for emphysema first conceptualized in the 1950s, electrified the pulmonary medicine community when it was rediscovered in the 1990s. In parallel with their technical and clinical refinement, extensive investigation has explored the unique physiology of these procedures. In the case of lung transplantation, relevant issues include the discrepant mechanical function of the donor lungs and recipient thorax, the effects of surgical denervation, acute and chronic rejection, respiratory, chest wall, and limb muscle function, and response to exercise. For lung volume reduction surgery, there have been new insights into the counterintuitive observation that lung function in severe emphysema can be improved by resecting the most diseased portions of the lungs. For both procedures, insights from physiology have fed back to clinicians to refine patient selection and to scientists to design clinical trials. This section will first provide an overview of the clinical aspects of these procedures, including patient selection, surgical techniques, complications, and outcomes. It then reviews the extensive data on lung and muscle function following transplantation and its complications. Finally, it reviews the insights from the last 15 years on the mechanisms whereby removal of lung from an emphysema patient can improve the function of the lung left behind.

Exercise training after lung transplantation: a systematic review

BACKGROUND

Lung transplant recipients experience persistent impairments in exercise capacity and skeletal muscle function despite a vast improvement in lung function after transplantation. Exercise training may be beneficial in improving exercise capacity in lung transplant recipients. A systematic review was undertaken to examine the evidence for exercise training on functional outcomes in lung transplant recipients.

METHODS

Studies were identified by searching electronic databases and scanning reference lists. Only randomized controlled trials, controlled trials, and prospective cohorts were included in the review. Seven studies met the inclusion criteria. Study quality was assessed using the Physiotherapy Evidence Database, Jadad, and Downs scales.

RESULTS

The overall quality of studies was fair to moderate in assessing the effect of exercise training on maximal and functional exercise capacity, skeletal muscle function, and lumbar bone mineral density. Every study reported significant improvements in these outcomes. Some studies lacked randomization and/or a control group, so it was not possible to separate the effects of training with the natural recovery process after lung transplantation.

CONCLUSION

Some evidence was found to support that a period of structured exercise training could improve maximal and functional exercise capacity, skeletal muscle strength, and lumbar bone mineral density in lung transplant recipients. Further studies are needed to determine the potential for exercise training to optimize these functional outcomes and to develop optimal guidelines for exercise prescription in the lung transplant population.

Transplantation in Chronic Obstructive Pulmonary Disease

Lung transplantation is a surgical option for patients who fail optimization of medical treatment for the severe symptoms that result from COPD. This review will discuss patient selection, transplant listing, and the surgical technique for transplantation in COPD. Furthermore, it will describe transplant outcomes and its effects on recipient survival, pulmonary function, exercise capacity, respiratory muscle function, and quality of life. The respective roles of transplantation and lung volume reduction surgery as therapies for advanced disease will be outlined.

Physical activity in daily life 1 year after lung transplantation

BACKGROUND

Reduced physical fitness has been reported to occur after lung transplantation. Pre- and post-transplant factors, including an inactive lifestyle, have been proposed as possible causes. However, daily physical activity has not been objectively assessed so far in lung recipients. The purpose of this study was to objectively measure daily physical activity in lung recipients.

METHODS

Twenty-two clinically stable patients with single (n = 7) and bilateral lung grafts (n = 15) underwent measurements of physical activity with activity monitors at least 12 months after surgery. Results were compared with findings from 22 healthy, age- and gender-matched control subjects.

RESULTS

Substantial and statistically significant differences in daily activity were observed. Steps, standing time and moderate-intensity activity of lung recipients were reduced by 42%, 29% and 66%, respectively, relative to controls. Daily sedentary time was increased by 30%. Daily steps correlated with self-reported physical functioning (r = 0.81), 6-minute walk distance (r = 0.68), quadriceps force (r = 0.66) and maximum workload (r = 0.63).

CONCLUSIONS

This study has shown for the first time that daily activity is substantially reduced after lung transplantation and related to measures of physical fitness and health-related quality of life. Future studies need to examine whether physical activity can be modified to improve functional recovery after lung transplantation.

Lung transplantation and lung volume reduction surgery versus transplantation in chronic obstructive pulmonary disease

Lung transplantation and lung volume reduction surgery are surgical options for patients with advanced chronic obstructive pulmonary disease that is refractory to medical treatment. In this review, we discuss the differential indications for each procedure, as well as compare their risks and benefits. We also present an algorithm for selecting the most appropriate procedure for individual patients. Finally, we discuss the feasibility and role of lung transplantation after lung volume reduction surgery in the management of selected patients with chronic obstructive pulmonary disease.

Skeletal muscle force and functional exercise tolerance before and after lung transplantation: a cohort study

We investigated the impact of lung transplantation and outpatient pulmonary rehabilitation after lung transplantation on skeletal muscle function and exercise tolerance. Skeletal muscle force (Quadriceps force, QF), exercise tolerance (six minute walking distance, 6MWD) and lung function were assessed in 36 patients before and after lung transplantation. Seventeen male and 19 female patients (age 57 +/- 4) showed skeletal muscle weakness before the transplantation. A further 32 +/- 21% reduction was seen 1.2 (interquartile range 0.9 to 2.0) months after LTX. The number of days on the intensive care unit was significantly related to the observed deterioration in muscle force after LTX. At this time point 6MWD was comparable to pre-LTX. Rehabilitation started 37 (IQR 29 to 61) days after LTX. 6MWD and QF improved significantly (140 +/- 91 m, and 35 +/- 48%, respectively; p < 0.05) with rehabilitation. QF remained below pre-LTX values. The evolution of the 6MWD with the transplantation and the subsequent rehabilitation was less in female compared to male subjects. We conclude that muscle strength deteriorates after lung transplantation, particularly in patients with long ICU stay. Outpatient pulmonary rehabilitation is feasible after lung transplantation and leads to recovery of skeletal muscle function. In female patients this recovery is significantly less compared to male recipients.

Update in Surgical Therapy for Chronic Obstructive Pulmonary Disease

Bullectomy for giant bullae, lung volume reduction surgery, and lung transplantation are three surgical therapies that may benefit highly selected patients with advanced chronic obstructive pulmonary disease. In this article, each procedure is reviewed, with an emphasis on guidelines for patient selection and clinical outcomes for the practicing pulmonologist. Recent results from the National Emphysema Treatment Trial, updated International Society for Heart and Lung Transplantation Registry data, and revised guidelines for patient selection for lung transplantation are discussed.

Surgical therapies for pulmonary arterial hypertension

Surgical therapies for the treatment of pulmonary arterial hypertension typically are reserved for patients who are deemed to be refractory to medical therapy and have evidence of progressive right-sided heart failure. Atrial septostomy, a primarily palliative procedure, may stave off hemodynamic collapse from right-sided heart failure long enough to permit a more definitive surgical treatment such as lung or combined heart-lung transplantation. This article discusses indications for and results of atrial septostomy and lung and heart-lung transplantation in patients who have pulmonary arterial hypertension.

Noninfectious Pulmonary Complications After Lung Transplantation

This article reviews several important noninfectious pulmonary complications that threaten survival, pulmonary function, and quality of life after lung transplantation. Topics reviewed include primary graft dysfunction (PGD), native lung hyperinflation, anastomotic complications, phrenic nerve injury, pleural complications, lung cancer, pulmonary toxicity associated with immunosuppressive medications, and exercise limitation.

Long-term Pulmonary Function After Living-donor Lobar Lung Transplantation in Adults

BACKGROUND

Living-donor lobar lung transplantation was developed as an alternative to cadaveric transplantation. However, whether two pulmonary lobes provide comparable intermediate and long-term pulmonary function to full-sized bilateral cadaveric grafts in adults is unknown.

METHODS

An analysis of the pulmonary functions of 59 bilateral lobar and 43 bilateral cadaveric adult lung transplant recipients who survived more than 3 months after transplantation was performed.

RESULTS

Mean follow-up was 3.8 +/- 2.8 years. In lobar recipients, mean percent predicted forced vital capacity and forced expiratory volume in 1 second improved between 1 and 6 months after transplantation (42.5% +/- 13.4% and 46.9% +/- 14.0% at 1 month versus 63.6% +/- 14.1% and 64.5% +/- 13.7% at 6 months; p < 0.001 and <0.001, respectively). In cadaveric recipients, mean percent predicted forced vital capacity improved after transplantation (54.3% +/- 14.5% at 1 month versus 74.2% +/- 21.3% at 12 months; p < 0.01). As compared with the cadaveric group, mean percent predicted forced vital capacity and forced expiratory volume in 1 second were lower 1 and 3 months after transplantation in the lobar recipients (p = 0.001 at both times); however, by 6 months after transplantation, these values were comparable and remained so throughout the follow-up period. In a subset of lobar and cadaveric recipients, maximal exercise, heart rate, peak oxygen consumption, anaerobic oxygen consumption threshold, and ability to maintain oxygen saturation were also comparable.

CONCLUSIONS

In those adult recipients surviving more than 3 months after transplantation, lobar lung transplantation provides comparable intermediate and long-term pulmonary function and exercise capacity to bilateral cadaveric lung transplantation.

Lungentransplantation

Lung transplantation is an option for patients with endstage pulmonary diseases without contraindications. Recent European studies showed a survival benefit for patients with cystic fibrosis, fibrosis and emphysema after lung transplantation. Early mortality has been reduced recently by surgical improvements. Life expectancy after lung transplantation has improved in recent years but is still lower than in patients with other solid organ transplantations. Quality of life is consistently improved but exercise tolerance keeps reduced in comparison to the normal population. Specific problems described in detail are frequent organ rejections and infections, airway problems and a high incidence of malignant diseases. 5-year survival after lung transplantation is in average 60%.

Effects of upper extremity exercise training on peak aerobic and anaerobic fitness in patients after transplantation

We found that patients with transplants, regardless of transplant type, and sedentary control subjects experience significant increases in aerobic fitness after 10 weeks of Dragon boat training. However, the magnitude of improvement in aerobic fitness depends on the transplant type, with patients having cardiac transplant experiencing greater relative changes in response to training than patients with noncardiac transplant. It also appears that patients with cardiac and noncardiac transplants have an increased reliance on anaerobic energy systems during exercise conditions compared with healthy control subjects.

Clinical research in chronic obstructive pulmonary disease: needs and opportunities

Chronic obstructive pulmonary disease (COPD) is a common condition, and one difficult to manage. Available treatments, other than smoking cessation, are only minimally effective, and the knowledge basis for clinical decision making is limited. To identify areas in which further clinical research may lead to significant improvements in the care of patients with COPD, the National Heart, Lung, and Blood Institute convened a Working Group, entitled "Clinical Research in COPD: Needs and Opportunities," on March 21-22, 2002. This group of experts identified important questions in the field and made the following recommendations: (1) establish a multicenter Clinical Research Network to perform multiple, short-term clinical trials of treatments in patients with moderate-to-severe COPD; (2) create a system for the standardized collection, processing, and distribution of lung tissue specimens and associated clinical and laboratory data; (3) develop standards for the classification and staging of COPD; (4) characterize the development and progression of COPD using measures and biomarkers that relate to current concepts of pathogenesis; and (5) evaluate indications for long-term oxygen therapy for patients with COPD.

Impaired exercise performance after successful liver transplantation

BACKGROUND

Recipients of heart, lung, and kidney transplants have impaired peak exercise performance (peak Vo2 40% to 60% predicted, reduced anaerobic threshold [AT]) without evidence of ventilatory or cardiac limitations. The aim of this study was to determine whether similar exercise impairment occurs in liver transplant recipients.

METHODS

We studied eight healthy liver transplant recipients (age 42+/-9 [SD] years, 6 male, 31+/-13 months posttransplant). Immunosuppression included FK506 or cyclosporine, azathioprine or mycophenolate mofetil, and prednisone. Subjects underwent lung function testing and cardiopulmonary exercise testing on a cycle ergometer.

RESULTS

Peak exercise oxygen consumption (Vo2) was 22+/-8 ml/min/kg (66+/-20% predicted maximum). No subject demonstrated exercise desaturation or ventilatory limitation (peak minute ventilation 55+/-8% predicted maximum voluntary ventilation). Peak heart rate was 87+/-8% of predicted maximum. Early AT was evident (1.2+/-0.34 L/min, 48+/-11% predicted Vo2max).

CONCLUSIONS

Liver transplant recipients exhibit impaired peak exercise performance similar to that observed after other solid organ transplants, possibly as a result of chronic deconditioning or myopathy related to immunosuppressive medications.

Lung transplantation in interstitial lung disease

Interstitial lung disease is a heterogeneous group of illnesses, some of which may progress to a fibrosing stage and cause respiratory failure. For selected candidates, lung transplantation is the ultimate therapeutic option. We review data on lung transplantation for various interstitial lung diseases. We address indications, procedures, and outcomes for patients undergoing transplantation. Unique issues affecting morbidity, mortality, and recurrence of disease are discussed. We review the literature of transplantation for specific interstitial lung diseases and the outcomes of transplantation for interstitial lung diseases. Candidates with idiopathic pulmonary fibrosis experience high mortality on the waiting list, but derive significant survival benefit from lung transplantation. Recurrence is reported for several interstitial lung diseases after lung transplantation. Survival with lung transplantation for interstitial lung diseases is comparable with that attained in recipients with other indications. Lung transplantation is a well-tolerated, effective therapy for respiratory failure in interstitial lung disease.

Lung transplantation at the turn of the century

Lung transplantation has become a viable treatment option for patients with end-stage lung disease. Donor selection and organ allocation must follow specific guidelines. Single, bilateral, and living-donor lobar transplantation have all been performed successfully for a variety of diseases. Complications include reimplantation response and airway complications. Rejection may occur in the hyperacute, acute, or chronic settings and requires judicious management with immunosuppression. Infection and malignancy remain potential complications of the commitment to lifelong systemic immunosuppression. Survival statistics have remained encouraging and continue to improve with experience. Improved exercise tolerance and quality of life have been demonstrated in the years following transplantation. Remaining obstacles include limited donor organ availability, long-term graft function, and patient survival. However, ongoing advances in immune tolerance and standardized training of physicians in the care of transplant patients should carry lung transplant forward in the twenty-first century.

Determinants of the exercise endurance capacity in patients with chronic obstructive pulmonary disease. The power-duration relationship

To characterize the determinants of the power-duration (W-t) relationship in patients with chronic obstructive pulmonary disease (COPD), we evaluated 8 nonhypoxemic patients (FEV(1) = 1.27 +/- 0.26 L) and 10 healthy controls. After an initial maximum-incremental exercise test on cycle ergometer (peak), the subjects underwent four high-intensity constant-load tests to the limit of tolerance (t), each on different days. The W-t relationship was found to be hyperbolic in both groups. Absolute values of both the critical power asymptote (theta(F)) and the curvature constant (W') were lower in patients than in control subjects. However, when expressed as percentage of peak work rate theta(F) was significantly higher in patients compared with control subjects (81.8 +/- 3.3% versus 67.5 +/- 3.7%, respectively, p < 0.01). There were severe reductions in t in the patients that were consistently associated with higher breathlessness scores and V E/MVV ratios. Interestingly, all patients were able to sustain exercise at theta(F) for 20 min despite near-maximum physiological and subjective stresses. We conclude that the reductions of both parameters of the hyperbolic W-t relationship (theta(F) and W') in patients with COPD were due to the ventilatory constraints and their sensory consequences. Importantly, theta(F) separated a "sustainable" from a "nonsustainable" exercise-intensity domain: this parameter consistently occurred closer to peak work rate in patients than the healthy control subjects.