Subjective assessment underestimates surgical risk: On the potential benefits of cardiopulmonary exercise testing for open thoracoabdominal repair.

Bailey DM; Halligan CL; Davies RG; Funnell A; Appadurai IR; Rose GA;
Rimmer L; Jubouri M; Coselli JS; Williams IM; Bashir M

Journal of Cardiac Surgery. 37(8):2258-2265, 2022 Aug.

BACKGROUND: Initial clinical evaluation (ICE) is traditionally considered
a useful screening tool to identify frail patients during the preoperative
assessment. However, emerging evidence supports the more objective
assessment of cardiorespiratory fitness (CRF) via cardiopulmonary exercise
testing (CPET) to improve surgical risk stratification. Herein, we
compared both subjective and objective assessment approaches to highlight
the interpretive idiosyncrasies.

METHODS: As part of routine preoperative patient contact, patients
scheduled for major surgery were prospectively “eyeballed” (ICE) by two
experienced clinicians before more detailed history taking that also
included the American Society of Anesthesiologists score classification.
Each patient was subjectively judged to be either “frail” or “not frail”
by ICE and “fit” or “unfit” from a thorough review of the medical notes.
Subjective data were compared against the more objective validated
assessment of postoperative outcomes using established CPET “cut-off”
metrics incorporating peak pulmonary oxygen uptake, VO2PEAK at the
anaerobic threshold (VO2 -AT), and ventilatory equivalent for carbon
dioxide that collectively informed risk stratification. These data were
retrospectively extracted from a single-center prospective National Health
Service database. Data were analyzed using the Chi-square automatic
interaction detection decision tree method.

RESULTS: A total of 127 patients were examined that comprised 58% male
and 42% female patients aged 69 +/- 10 years with a body mass index of 29
+/- 7 kg/m2 . Patients were poorly conditioned with a VO2PEAK almost 20%
lower than predicted for age, sex-matched healthy controls with 35%
exhibiting a VO2 -AT < 11 ml/kg/min. Disagreement existed between the
subjective assessments of risk with ~34% of patients classified as not
frail on ICE were considered unfit by notes review (p < .0001).
Furthermore, ~35% of patients considered not frail on ICE and ~31% of
patients considered fit by notes review exhibited a VO2 -AT < 11
ml/kg/min, and of these, ~28% and ~19% were classified as intermediate to
high risk.

CONCLUSIONS: These findings highlight the interpretive limitations
associated with the subjective assessment of patient frailty with surgical
risk classification underestimated in up to a third of patients compared
to the validated assessment of CRF. They reinforce the benefits of a more
objective and integrated approach offered by CPET that may help us to
improve perioperative risk assessment and better direct critical care
provision in patients scheduled for “high-stakes” surgery including open
thoracoabdominal aortic aneurysm repair