Impaired cardiac autonomic response in lung transplant patients: A retrospective cohort study

Pulmonary rehabilitation in lung transplant candidates with pulmonary arterial hypertension

BACKGROUND

Pulmonary rehabilitation (PR) guidelines support the efficacy and safety of supervised exercise training in mild-moderate pulmonary arterial hypertension (PAH). However, the exercise training response and safety of PR in PAH lung transplant (LTx) candidates has not been described.

OBJECTIVES

(1) characterize the clinical characteristics and illness trajectory of adult patients with severe PAH listed for LTx and participating in PR; (2) evaluate the change in exercise capacity, aerobic and resistance training volumes; (3) assess PR safety.

METHODS

Single-centre retrospective cohort study of PAH LTx candidates listed January 2014-December 2018 attending a supervised, facility-based outpatient program three times per week. Functional capacity was evaluated using 6-min walk distance (6MWD). Aerobic and muscle training volumes were evaluated with paired comparisons.

RESULTS

40 PAH LTx candidates (age 50 ± 12 years, 73% females, mean pulmonary artery pressure 53 ± 16 mmHg) were included. The median listing duration was 91 [IQR 43-232] days. Sixteen patients (40%) had ≥1 admission pre-transplant. Nine patients (56%) were discharged home and resumed outpatient PR. Baseline 6MWD was 330 ± 119 metres (n = 40) with the final 6MWD pre-LTx increasing by 18 metres 95% CI (-18 to 56), p-value = 0.31, n = 25) over a median duration of 225 [IQR 70-311] days. Modest gains were observed in aerobic and resistance training volumes in PR with no adverse safety events.

CONCLUSION

Despite progressive and severe disease in PAH LTx candidates, patients safely participated in PR and maintained exercise capacity. Given frequent admissions, physiotherapy during hospitalization should focus on preserving functional capacity and facilitating re-integration into outpatient PR post-discharge.

Orthostatic Hypotension and Antihypertensive Treatment in Lung Transplant Recipients: A Cross-Sectional Study

OBJECTIVES

Lung transplant is the ultimate treatment of many end-stage lung diseases. Calcineurin inhibitors, crucial in immunosuppression for lung transplant recipients, are linked to secondary hypertension, necessitating antihypertensive treatment. In addition, lung transplant recipients frequently experience orthostatic hypotension, occasionally stemming from autonomic dysfunction, but also commonly attributed as a negative side effect of antihypertensive treatment. Our study aimed to evaluate the frequency of orthostatic blood pressure irregularities and investigate the involvement of antihypertensive treatment as a potential risk factor in the occurrence among lung transplant recipients.

MATERIALS AND METHODS

Fifty-six consecutive lung transplant recipients, both inpatient and outpatient, at the University Hospital Zurich (Switzerland) were monitored from 1999 to 2013. Transplant recipients underwent a Schellong test (an active standing test). Our evaluation encompassed their initial traits, such as the existence of supine hypertension. We computed the odds ratio for the comparison of the likelihood of experiencing orthostatic hypotension while using a minimum of 1 type of antihypertensive medication versus absence of antihypertensive drugs.

RESULTS

Of the lung transplant recipients, 25% showed a positive Schellong test. Within this group, 64% had supine hypertension, and 29% displayed symptoms of orthostatic hypotension. Among the patients, 71% were using at least 1 type of antihypertensive medication. The odds ratio for showing orthostatic hypotension while taking at least 1 type of antihypertensive drug versus the absence of antihypertensive medications was 1.64 (95% exact CI, 0.39-6.90) with P = .50. This finding remained consistent regardless of age, sex, inpatient or outpatient status, and the duration since transplant.

CONCLUSIONS

Orthostatic blood pressure dysregulation is prevalent among lung transplant recipients, frequently without noticeable symptoms. In our cohort, the use of antihypertensive medications did not elevate the risk of orthostatic hypotension.

Evaluation and Management of Dyspnea in Hypermobile Ehlers-Danlos Syndrome and Generalized Hypermobility Spectrum Disorder: Protocol for a Pilot and Feasibility Randomized Controlled Trial

BACKGROUND

Dyspnea is a prevalent symptom in individuals with hypermobile Ehlers-Danlos Syndrome (hEDS) and generalized hypermobility spectrum disorder (G-HSD), yet its contributors have not been identified. One known contributor to dyspnea is respiratory muscle weakness. The feasibility and effectiveness of inspiratory muscle training (IMT) in combination with standard-of-care rehabilitation (aerobic, resistance, neuromuscular stabilization, and balance and proprioception exercises) in improving respiratory muscle strength and patient-reported outcomes in patients with hEDS or G-HSD have not been evaluated.

OBJECTIVE

This study aims to evaluate dyspnea, respiratory muscle strength, and patient-reported outcome measures (PROMs) in hEDS or G-HSD compared with healthy controls and to assess the feasibility of a randomized controlled trial of IMT and standard-of-care rehabilitation for improving respiratory muscle strength, exercise capacity, and PROMs compared with standard-of-care rehabilitation in hEDS and G-HSD.

METHODS

The study will include 34 participants with hEDS or G-HSD and 17 healthy, age- and sex-matched controls to compare respiratory muscle structure and function and PROMs. After baseline assessments, participants with hEDS or G-HSD will be randomized into the intervention group and provided IMT combined with Ehlers-Danlos Syndrome standard-of-care rehabilitation or into the usual care group, and provided only standard-of-care rehabilitation for 8 weeks. The intervention group will be prescribed IMT in their home environment using the POWERbreathe K5 IMT device (POWERbreathe International Ltd). IMT will comprise 2 daily sessions of 30 breaths for 5 days per week, with IMT progressing from 20% to 60% of the baseline maximal inspiratory pressure (MIP) over an 8-week period. Feasibility will be assessed through rates of recruitment, attrition, adherence, adverse events, and participant satisfaction. The primary pilot outcome is MIP change over an 8-week period in hEDS or G-HSD. Secondary outcomes will include the evaluation of dyspnea using Medical Research Council Scale and 18-point qualitative dyspnea descriptors; diaphragmatic thickening fraction using ultrasound; respiratory muscle endurance; pulmonary function; prefrontal cortical activity using functional near-infrared spectroscopy; aerobic capacity during cardiopulmonary exercise testing; quality of life using Short Form-36; and scores from the Depression, Anxiety, and Stress scale-21. These measures will also be performed once in healthy controls to compare normative values. Multivariable regression will be used to assess the contributors to dyspnea. Paired 2-tailed t tests will be used to assess the changes in MIP and secondary measures after 8 weeks of IMT.

RESULTS

Study recruitment began in August 2021 and, with several disruptions owing to COVID-19, is expected to be completed by December 2023.

CONCLUSIONS

This study will provide a better understanding of the factors associated with dyspnea and the feasibility and effectiveness of IMT combined with standard-of-care rehabilitation. IMT may be a novel therapeutic strategy for improving respiratory muscle function and patient-reported outcomes in individuals with hEDS or G-HSD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04972565; https://clinicaltrials.gov/ct2/show/NCT04972565.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/44832.

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.

Methods

We considered studies of any design that included performance-based tests of exercise capacity, physical function, and frailty in adult lung transplant candidates or recipients. Outcomes of interest were clinical outcomes (eg, mortality, quality of life) and healthcare utilization.

Results

Seventy-two articles met the inclusion criteria. The 6-min walk test (6MWT) was shown to be related to mortality on the waiting list with different distance values as cutoffs points. There were inconsistent results regarding the relationship of the 6MWT with other clinical outcomes. Few studies have examined the relationship between the cardiopulmonary exercise test or the short physical performance battery and clinical outcomes, although some studies have shown relationship with survival posttransplant and quality of life. Few studies examined the relationship between the tests of interest and healthcare utilization' and the results were inconsistent.

Conclusions

Except for the relationship between the 6MWT and mortality on the waiting list, there is limited evidence regarding the relationship of performance-based measures of exercise capacity, frailty, and physical function with clinical outcomes or healthcare utilization.

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.