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

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, V?O-2PEAK at the anaerobic threshold (V?O-2-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/m(2). Patients were poorly conditioned with a V?O-2PEAK almost 20% lower than predicted for age, sex-matched healthy controls with 35% exhibiting a V?O-2-AT < 11 ml/kg/min. Disagreement existed between the subjective assessments of risk with similar to 34% of patients classified as not frail on ICE were considered unfit by notes review (p < .0001). Furthermore, similar to 35% of patients considered not frail on ICE and similar to 31% of patients considered fit by notes review exhibited a V?O-2-AT < 11 ml/kg/min, and of these, similar to 28% and similar to 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.