Validity and reproducibility of practical performance-based tests to estimate aerobic capacity in patients scheduled for elective colorectal surgery

The primary treatment for colorectal cancer is surgical resection of the tumor.
Undergoing major surgery is like running a marathon, and requires an optimal
physical fitness of patients in order to cope with the surgical stress and
hospitalization. Preoperative aerobic capacity, measured during cardiopulmonary
exercise testing, has been found to have a consistent positive relation with
postoperative outcome in elective major intra-abdominal surgery (e.g. less
morbidity, shorter length of hospital stay, and lower mortality). Hence,
cardiopulmonary exercise testing can be used to identify patients with an
increased risk for postoperative morbidity, an increased length of stay and/or
an increased mortality risk. Preoperative exercise training of high-risk
patients to improve their aerobic capacity (prehabilitation) is beneficial for
preventing peri- and/or postoperative complications, reducing
morbidity/mortality, and facilitating a swift return to an adequate performance
of activities of daily living. However, performing cardiopulmonary exercise
testing - requiring respiratory gas analysis measurements - is sometimes not
feasible due to the expense, the need for special equipment, and the required
trained staff. Therefore, the use of practical and inexpensive alternative
performance-based aerobic capacity tests might increase the incorporation of
objectively measured exercise capacity to estimate aerobic capacity for
preoperative risk strati*cation. The steep ramp test and 3-minute step test
might be useful, non-sophisticated, alternative performance-based tests, to
estimate aerobic capacity as measured during cardiopulmonary exercise testing.
This has not yet been investigated in patients opting for elective major
intra-abdominal surgery, while accurate assessment of aerobic capacity in
patients opting for major intra-abdominal surgery is crucial for identifying
high-risk patients with a low aerobic capacity, as these patients might benefit
from prehabilitation to decrease postoperative health- and functioning-related
problems. Easy-to-perform performance-based aerobic capacity tests (steep ramp
test and 3-minute step test) might thus be cost-efficient alternatives for more
expensive and complicated laboratory aerobic capacity tests (cardiopulmonary
exercise testing). These alternative tests are readily implementable in
clinical oncology practice and can be invaluable for preoperative screening to
guide individual patient management for the purpose of improving postoperative
outcomes and prognosis.

We aim to determine the validity of the steep ramp test as practical
performance-based aerobic capacity test in patients undergoing elective
colorectal resection by correlating the tests* scores with the ventilatory
anaerobic threshold and oxygen uptake at peak exercise attained during maximal
cardiopulmonary exercise testing on a cycle ergometer as gold standard test.

Cross-sectional study design. All patients will preoperatively perform the
steep ramp test as part of usual care (regular hospital visit), whereafter only
study participants will perform cardiopulmonary exercise testing in the context
of the study (no extra study visit).

There will be no direct benefits for patients participating in this study.
Patients gain insight in their physical fitness and as part of usual care will
receive preoperative advice after the last study procedure about the importance
of preoperative physical fitness and physical activity in relation to the risk
for morbidity and recovery of physical functioning postoperatively. Moreover,
in an extension of their regular care visit (preoperative assessment of
physical fitness) of one hour at maximum, participants help to optimize
perioperative care for future patients. Risks associated with participation are
considered negligible. Exercise testing will be performed under controlled
conditions and under the guidance of specifically trained employees and under
supervision of a sport physician. All non-usual care measurements are
non-invasive. Nevertheless, we realize that participation might be a burden for
every patient.