Page 42 - Physical activity in recipients of solid organ transplantation - Edwin J. van Adrichem

Chapter 3
Introduction
Lung transplantation (LTx) as a treatment in end-stage lung disease has become generally
accepted for appropriately selected patients. In total, 673 single and double LTxs were
performed in the Eurotransplant region in 2013 (5.9 LTxs per 106
2013.3
Transplantation leads to a substantial improvement in quality of life
people). 1
4,5
In Australia
and New Zealand, 144 LTxs (6.3/106
people) and 13 LTxs (3.2/106
people), respectively,
were performed in 2012.2
In the United States, a total of 1,923 LTxs were performed in
and an
increase in exercise performance, that is, exercise capacity and muscle function. However,
recipients of LTxs do not achieve normal levels;
physical activity levels 1 year after
transplantation were considerably lower than those in people who were healthy (controls).8
e main factor limiting exercise performance after LTx, as ascertained with
6,7

maximal exercise testing, is the reduced work capacity of the peripheral skeletal muscles.
7,9–
13
It is expected that the physiological processes underlying this reduced capacity will also
be present at submaximal or functional exercise levels in recipients of LTxs. It is not clear,
however, to what extent. Functional exercise capacity is generally tested with 6-minute
walking distance (6MWD).
In patients with chronic obstructive pulmonary disease
(COPD), a strong correlation between 6MWD and quadriceps muscle force was shown.
Unfortunately, little attention has been paid to factors predicting 6MWD after LTx.
14
15
Only a few studies have used longitudinal data to study the relationship between 6MWD
and peripheral muscle force, post-transplantation recovery rate, and other predicting
factors.
7,16–18

sample sizes (8-36 patients),
e generalizability of the results of these studies is restricted because of small
number of measurement moments (2 moments).
7,16–18
a limited follow-up period (4 months),
16
and a limited
7,17,18
Overall, knowledge about the course of submaximal exercise capacity and the
factors limiting this capacity in recipients of LTxs is limited.

erefore, the aims of this
study were to analyze the course of functional exercise capacity by modeling the change in
6MWD longitudinally and to explore factors predicting this change.

is study should
provide insight into intervention targets and the timing of interventions with the goal of
increasing functional exercise capacity in recipients of LTxs.
Method
Study Design
6MWD test and measurements of peripheral muscle force. Patients were retested at
40.
A longitudinal historical cohort analysis was performed with data collected as part of the
routine clinical evaluation (including screening and evaluation after LTx) of recipients of
single and double LTxs between March 2003 and March 2013 at the University Medical
Center Groningen, Groningen, the Netherlands. Pre-LTx screening before placement on
the waiting list consisted of medical, social (intake medical social work, psychological
analysis when indicated), and physical screening (T0 [screening]). During the medical
screening, lung function testing was performed.

e physical screening consisted of a