RESULTS
During the research period 71 patients were admitted, and fifteen were
excluded due to physical limitations. Thus, 56 patients were evaluated,
of these 38 (63%) were male, mean age 61 ± 9 years, with an average BMI
of 27 ± 5 km/m2, with the most prevalent comorbidity being sedentary
with 19 (63%). The other data are shown in table 1.
The average walking speed in the slow group was 0.6 m/s, while in the
non-slow group it was 1.2 m/s. Twenty patients (40%) were readmitted to
the hospital during the observation period of 6 months. Of those, 14
(70%) were slow walkers, as defined by a gait speed of less than 1.0
m/s, and 6 (30%) were non-slow walkers. The 6 months rate of
readmission was 58% (14/24; 95% CI 49% to 80%) among slow walkers
and 17% (6/36; 95% CI 13% to 46%) among non-slow walkers (p =
0.002).In univariate analysis, gait speed, treated as a continuous
variable, was associated with the primary outcome (HR 0.6; 95%CI 0.2 to
0.9), while age, gender, BMI, MV and CPB time were not (table 2). In the
multivariate model including age, gender, BMI, MV and CPB time, gait
speed remained the only variable associated with readmission
(multivariate HR: 0.5, 95% CI 0.1 to 0.7 p=0.02; table 2).
DISCUSSION
Based on the results of this prospective cohort study, gait speed was
associated with hospital readmission of patients undergoing to coronary
artery bypass grafting. Walking more slowly (<1 m/s) was
associated with hospital readmission, but variables such as age, male
gender, BMI, MV and CPB team were not related to the outcome in six
months.
Previous studies suggest that gait speed is an independent variable for
mortality and hospital readmission in survivors of acute hypercapnic
respiratory failure and heart failure11,12. Being an
extremely simple and feasible test for the application of the practice,
we suggest its adoption by hospital services aiming at reducing hospital
readmissions, thus minimizing costs, improving the survival and quality
of life of these patients.
Afilalo et al. demonstrated that patients with low gait speed in the
preoperative period have a higher rate of morbidity and mortality during
the ICU stay13. They also found that factors such as
female gender and diabetics made up the slow speed group. In our study,
we did not find any difference regarding gender, age or comorbidities,
which may be associated with a smaller sample size in the present study.
This result only reinforces the need to stratify patients with a higher
risk of complications or hospital readmission, and gait speed is a
useful tool.
In this rationale Sawatzky et al.14 found that the
application of a program in the preoperative period can increase gait
speed, with this effect remaining for up to three months after the
procedure. On the other hand, Cerqueira et al.15 did
not demonstrate any impact when applied to neuromuscular electrical
stimulation in the postoperative period.
A possible explanation for reducing gait speed and increasing the risk
of hospital readmission is fragility. It is considered a
multidimensional syndrome resulting from the reduction of physiological
reserves and an increase in physical and functional decline when exposed
to external stressors16. After cardiac surgery,
factors such as cardiopulmonary bypass, surgical incision, pleurotomy
and duration of mechanical ventilation generate pulmonary dysfunction
and decrease in physiological reserves17.
Bed restriction time and contributes to physical and functional
decline18,19. Our group demonstrated that after
myocardial revascularization it generates a decrease in functional
capacity, observed through the six-minute walk test20.
We found that performing inspiratory muscle training helps to minimize
this decline and improve clinical outcomes such as length of hospital
stay20,21.
Lal et al.22 demonstrated that the frailty assessed
using the Edmonton scale is a predictor for the length of hospital stay
and risk of readmission up to twelve months in elderly patients
undergoing cardiac surgery. The combination of frailty assessment with
gait speed will give the therapist fundamental information for the
organization of an intervention protocol.
In Castro et al.23, it was evidenced that the greater
distance covered in the 6MWT was associated with a shorter hospital
stay, as a quick recovery after the surgical procedure allows walking
autonomy that allows the transfer of this patient earlier for
rehabilitation, and consequently reduce hospitalization time. In the
study by Aikawa et al.24, they say that immediate
post-surgical rehabilitation can be a means that enables the more agile
development and recovery of these patients and found in the 6MWT that
there was a significant increase in the distance covered and gait speed
of these patients. Thus, comparing the studies presented, it can be
understood that an early rehabilitation of patients after CABG is linked
to a shorter hospital stay, consequently generating an improvement in
gait speed when evaluated by the 6MWT.
According to Oliveira et al.25, it was evaluated that
the CPB time has minimal influence on the patient’s ability to walk, the
research shows that despite the occurrence of muscle inefficiency,
generating a loss of postoperative strength, it does not interfere in
the gait of patients themselves. Reinforcing with the results of this
study, we analyzed that the CPB time had no correlation with the
patients’ gait, as it statistically had no influence.
Borges et al.26 showed that patients undergoing
cardiac surgery suffer adverse risks during hospitalization in the
postoperative period, where they become more fragile due to some
physiological changes that occur during the intervention, such as: motor
disabilities and physical limitations that can be prolonged, and
consequently, which may lead to future readmissions, the author also
identified a vicious cycle of slow gait after surgery. The results of
this study were similar to ours, in which it showed that patients
undergoing CABG showed a decrease in gait speed due to several
associated and already mentioned factors, and that it may possibly be
associated with the risk of a hospital readmission.
The limitations of this study include the sample calculation, limiting
the extent of its findings, absence of information on pulmonary
function, which may have an influence on the performance of the gait
speed test and the lack of a spirometric test.