Wang R; chool of Medicine South China University of Technology, Guangzhou, China.
Huang Z; Jiang Z; Bai B;et al

BMC Anesthesiology. 26(1), 2026 Jul 06. VI 1

BACKGROUND: In the PORT trial (Perioperative Rehabilitation in Patients
Undergoing Elective Cardiac Valve Surgery: A Randomised Controlled Trial),
a short-term multidomain perioperative rehabilitation programme was
associated with a reduced incidence of postoperative pneumonia in patients
undergoing elective cardiac valve surgery. Whether baseline peak oxygen
consumption (peak VO2), a marker of cardiorespiratory reserve, modifies
the effect of this intervention remains uncertain.

OBJECTIVES: To evaluate whether the association between perioperative
rehabilitation and postoperative outcomes differs according to baseline
peak VO2 (<= 20 vs. > 20 mL.kg-1.min-1).

METHODS: This exploratory subgroup analysis included 702 participants
from the PORT trial who underwent preoperative cardiopulmonary exercise
testing. Patients were stratified by baseline peak VO2 and randomized to
perioperative rehabilitation-comprising education, inspiratory muscle
training, active cycle of breathing techniques, and early mobilization-or
usual care. The primary endpoint was a composite of in-hospital all-cause
mortality, postoperative pulmonary complications (PPCs), and prolonged
hospitalization (> 7 days). Logistic and Cox regression models adjusted
for prespecified covariates were used to estimate treatment effects within
peak VO2 strata, and treatment-by-peak VO2 interactions were tested.

RESULTS: Of 702 participants, 202 (29%) had peak VO2 >20 and 500 (71%)
had peak VO2 <=20 mL.kg-1.min-1. The composite primary endpoint did not
differ significantly between rehabilitation and usual care in either
stratum (interaction P = 0.62). Perioperative rehabilitation was
associated with a lower incidence of postoperative pneumonia in both peak
VO2 >20 mL.kg-1.min-1 (adjusted OR 0.30; 95% CI 0.13-0.71) and <= 20
mL.kg-1.min-1 (adjusted OR 0.65; 95% CI 0.47-0.90), with no significant
interaction between peak VO2 category and treatment effect (P for
interaction = 0.12). No significant effect modification was observed for
other outcomes, including SICU stay, total hospitalization duration, or
3-month mortality.

CONCLUSIONS: In this exploratory analysis of the PORT trial, the
reduction in postoperative pneumonia associated with short-term
perioperative rehabilitation was consistent across strata of baseline peak
VO2. These findings suggest that the pneumonia benefit of
respiratory-focused perioperative rehabilitation may not depend on
baseline cardiorespiratory fitness, although adequately powered studies
are required to definitively assess effect modification. Although the
observed reduction in pneumonia was statistically significant and
biologically plausible, it arose from a secondary exploratory analysis
without adjustment for multiple comparisons and should therefore be
interpreted with caution.