Optimizing the Lung Transplant Candidate through Exercise Training Lisa Wickerson BScPT, MSc Canadian Respiratory Conference April 25, 2014
Conflicts of Interest None to declare
Learning Objectives At the end of this session attendees will be able to: Discuss the evidence for exercise training in lung transplant candidates on improving pre and posttransplant outcomes Recognize the specific challenges of pre-habilitation in lung transplant candidates Identify potential training modes to optimize exercise capacity, muscle strength and physical activity in lung transplant candidates
Indications for adult lung transplant CF COPD Alpha1 AT IPAH Bronchiectasis CHD Re-Tx Other ILD ISHLT 2013
Physical limitations pre-transplant Functional exercise capacity 6-minute walk distance 40-55% predicted Wickerson 2013, Walsh 2013, Langer 2012, Maury 2008 Skeletal muscle strength leg strength 50-85% predicted Walsh 2013, Langer 2012, Maury 2008, Reinsma 2006, Van der Woude 2002 Self-reported physical functioning SF-36 physical functioning score 14-22 /100 Langer 2012, Eskander 2011, Stavem 2000 Physical activity 1400-3200 daily steps Wickerson 2013, Langer 2012, Bossenbroek 2009 70% of day sedentary Langer 2012
Exercise capacity (6MWT) Global marker of health status Reflects severity of disease and level of functional impairment 6MWD correlates with VO 2 max in lung transplant candidates (r=0.73) Cahalin 1995 Reflects multiple factors that can limit exercise capacity ventilatory cardiac peripheral (musculoskeletal)
Why is exercise capacity important pre-transplant? Many physical stressors of transplant Major, complex surgery Peri-operative complications Lifelong exposure to corticosteroids and calcineurin inhibitors/ side effects Exercise capacity is a major predictor of health outcomes pre- and post-transplant
6MWD as a predictor of survival Impaired exercise capacity is an important predictor of thoracic surgery outcomes and survival (LVR, lung resection) 6MWD predictive of survival in PAH, IPF, CF, COPD Lung transplant candidates > 6MWD associated with lower risk of death on waiting list (seen across disease categories) Martinu 2008, Tuppin 2005 > 6MWD associated with decreased mortality 30 days posttransplant Martinu 2008 Varied estimates of low 6MWD (< 207-350m) Lederer 2006, Kawut 2005 Lung Allocation Score 6MWD < 45m given high priority
6MWD as a predictor of posttransplant outcomes 6MWD associated with discharge destination Tang 2014 (submitted for publication) Every 100m increment in 6MWD pre-transplant associated with 2.6 day lower median hospital stay post-transplant Li 2013 6MWD >305m pre-transplant correlated with decreased ICU length of stay and fewer MV days and 6MWD >229m correlated with shorter hospital stay in children/ adolescents Yimlamai 2013
What is the evidence for exercise training in lung transplant candidates?
American Thoracic Society Documents An Official American Thoracic Society/European Respiratory Society Statement: Key Concepts and Advances in Pulmonary Rehabilitation Am J Respir Crit Care Med 2013;188:e13-e64. PR increases exercise tolerance & QOL, decrease symptoms Increased support for PR in conditions other than COPD PR commenced during acute or critical illness will decrease the functional decline/ hasten recovery Even severe COPD can often sustain necessary training intensity and duration for skeletal muscle adaptations Increased evidence for the efficacy of a variety of exercise training strategies (interval, resistance, upper limb, NMES)
Early reports on pre-transplant rehabilitation Several abstracts on pre-operative rehabilitation between 1988-1994 small, uncontrolled, variety of interventions and outcome measures Manzetti 1994 n=9 randomized 6 weeks of a health maintenance program (education or exercise + education) 6MWD and QOL improved over time in both groups
Canadian Transplant Rehab Survey Frequency Intensity 2-5 x/week 6 weeks to duration of wait list Oxygen saturation Target HR Borg (dyspnea), RPE 6MWD RM Medical stability, patient tolerance Time Type Progression 60-120 minutes Treadmill, cycle Upper/lower extremity resistance Flexibility Functional exercises (stairs, squats) Target HR, RPE, Borg dyspnea, O 2 sat Individual assessment Pre-transplant rehab mandatory in 80% of centres Trojetto 2011
Recent studies Design Intervention Findings Gloeckl 2012 RCT n= 60 with COPD 3 week inpatient rehab 5-6x /week Interval training (n=30) (30sec @ 100% Wpeak: 30 sec rest) Continuous (n=30) 60% Wpeak Similar increases in 6MWD (35 vs. 36m) Less dyspnea & unintended breaks (interval) Same total work in both groups Increased peak work rate Florian 2013 Prospective n=58 3x/week (36 sessions) Treadmill - 60% 6MWT speed Weights - 30% 1RM Increased SF36 6MWD increased 72m Jastrezebsk i 2013 Prospective n=22 males 12 weeks Nordic walking with ski poles (supervised & home) 6MWD increased 62m Increased SF36 (SF) Increased FVC Li 2013 Retrospective n=345 Aerobic & resistance 3x/week (47±59 sessions) Average 6 month wait Preserved 6MWD Small increases in exercise training volumes and caloric expenditure
Pre-transplant rehab in critically ill patients
Turner 2011 Case series (n=3) CF patients aged 16,20,24 Urgently developed ICU ambulatory ECMO program for individuals previously denied transplant candidacy from other centres Multidisciplinary team decided best opportunity for posttransplant survival was pre-transplant rehab Avoid femoral venous cannulation Following bed and chair exercise all could walk with assistance within 7 days of ECMO cannulation (up to 215m) All were discharged from ICU and ambulatory < 1 week post-transplant and discharged home on room air, hospital LOS 14-32 days)
What are the specific challenges of pre-habilitation in lung transplant candidates?
The ideal Listed for transplant 6-8 weeks of outpatient pulmonary rehab Transplantation Patient stable & medically optimized Listing 6MW D (m) 0.5 1 1.5 2 months
The reality Listed for transplant Unknown wait time & duration of pulmonary rehab Transplantation? Disease progression Exacerbations, infections Increased oxygen needs Hospitalizations Medication changes, side-effects Mechanical ventilation, bridge to transplant Anxiety, motivation, support
The reality Listing 6MWD (m) 3 6 9 12 months
What are potential training modes to optimize exercise capacity, muscle strength & physical activity in lung transplant candidates?
Intensity Walking Guided by symptoms, O 2 saturation Use percentage of HR max, VO 2 max/peak (measured or estimated) % of walking speed on 6MWT? High vs. moderate vs. low intensity? Endurance vs. interval (intermittent)
Utility of 6MWT in prescribing walking intensity Retrospective study (n=246) found the average training speed on treadmill was 75% on 6MWD speed There was a lower proportion of patients with COPD who could reach 80% of the 6MWD speed No significant difference between proportion achieving 80% 6MWT speed based on use of gait aid, oxygen requirements or need for a rest during the 6MWT (Caramete 2014 submitted for publication)
Intensity: Cycling Symptoms, HR, O 2 saturation CPET 60% Wpeak? 60% Wmax estimated from 6MWD Hill 2008 Various modes: upright, recumbent, Nu-step, arm ergometry, Moto-med
Resistance training Intensity & progression: 30-70% of 1RM or 10RM 1-3 sets, 8-10 reps patient tolerance (increase 0.5kg)
Additional Strategies Optimize oxygen delivery Review oxygen saturation order for exercise Assessment (disease progression vs. acute exacerbation/event) Modified program post exacerbation/ hospitalizations, progression of disease Education Local / home rehab Adjuncts Non-invasive ventilation Helium-hyperoxia Inspiratory muscle training One-legged cycling
Future directions/ questions How to determine physiologic mechanisms by which 6MWD can be maintained or increased pre-tx? How to ensure we are not undertraining? What are appropriate training intensities in the critically ill? Can exercise training improve transplant candidacy in frail individuals? Are we training muscles pre-tx in anticipation of post-tx limitations (immediate drop 15-32% in QT)? Should there be a greater emphasis on resistance training? What are the optimal modes and intensity of exercise prescription? Is the response to exercise training dependent of pre-transplant diagnosis, age or other factors? Does pre-tx exercise training improve clinical outcomes post- Tx (mortality, LOS, discharge destination)? Is exercise training cost-effective?
Thank you! National Organ & Tissue Donor Awareness Week April 20-27, 2014