Peak power output testing: novel method for preoperative assessment of exercise capacity

Assessing the accuracy of Seismofit® as an estimate of preoperative maximal oxygen consumption in patients with hepato-pancreato-biliary, colorectal, and gastro-oesophageal cancer

Background

Peak oxygen uptake (VO2 peak) measured during cardiopulmonary exercise testing (CPET) is commonly used to objectively assess fitness and inform risk stratification. Preoperative CPET is not always universally available. Seismofit® offers a noninvasive, non-exercise alternative for estimating VO2 peak, though it has not been validated in patients awaiting major abdominal cancer surgery.

Methods

Prospective single-centre blinded observational study in patients with hepato-pancreato-biliary, colorectal, or gastro-oesophageal cancer undergoing preoperative assessment. Patients underwent Seismofit® assessment before routine CPET. Primary outcome was the relationship between Seismofit®-estimated VO2 peak and CPET-measured VO2 peak. Secondary outcomes explored the relationship between Seismofit® and CPET for (i) bias and agreement limits; (ii) surgical subgroup; (iii) commonly reported CPET variables; (iv) patient acceptance.

Results

Thirty-three participants (median [interquartile range] age: 67 yr [58-75 yr]; 20 [61%] males) completed both CPET and Seismofit®. No linear association was found between Seismofit®-estimated VO2 peak and CPET-measured VO2 peak: Pearson r=0.111 (95% confidence interval -0.242 to 0.437), R 2=0.012, P=0.539. Compared with CPET, Seismofit® demonstrated a large bias (standard deviation) 12.8 (8.8); 95% limits of agreement (-4.5 to 30.0). No association existed between Seismofit®-estimated VO2 peak and CPET-measured VO2 peak in the hepato-pancreato-biliary or gastro-oesophageal subgroup or between Seismofit®-estimated VO2 peak and commonly reported CPET variables.

Conclusions

There was no evidence of linear association between Seismofit®-estimated VO2 peak and objectively measured VO2 peak by CPET in patients undergoing assessment for major abdominal cancer surgery. This finding was consistent across all subgroup and exploratory analyses. Seismofit® tended to overestimate VO2 peak with a high degree of bias.

Clinical trial registration

NCT05831488.

Ventilatory efficiency as a prognostic factor for postoperative complications in patients undergoing elective major surgery: a systematic review

BACKGROUND

Major surgery is associated with high complication rates. Several risk scores exist to assess individual patient risk before surgery but have limited precision. Novel prognostic factors can be included as additional building blocks in existing prediction models. A candidate prognostic factor, measured by cardiopulmonary exercise testing, is ventilatory efficiency (VE/VCO2). The aim of this systematic review was to summarise evidence regarding VE/VCO2 as a prognostic factor for postoperative complications in patients undergoing major surgery.

METHODS

A medical library specialist developed the search strategy. No database-provided limits, considering study types, languages, publication years, or any other formal criteria were applied to any of the sources. Two reviewers assessed eligibility of each record and rated risk of bias in included studies.

RESULTS

From 10,082 screened records, 65 studies were identified as eligible. We extracted adjusted associations from 32 studies and unadjusted from 33 studies. Risk of bias was a concern in the domains 'study confounding' and 'statistical analysis'. VE/VCO2 was reported as a prognostic factor for short-term complications after thoracic and abdominal surgery. VE/VCO2 was also reported as a prognostic factor for mid- to long-term mortality. Data-driven covariable selection was applied in 31 studies. Eighteen studies excluded VE/VCO2 from the final multivariable regression owing to data-driven model-building approaches.

CONCLUSIONS

This systematic review identifies VE/VCO2 as a predictor for short-term complications after thoracic and abdominal surgery. However, the available data do not allow conclusions about clinical decision-making. Future studies should select covariables for adjustment a priori based on external knowledge.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42022369944).

Cardiopulmonary exercise variables and their association with postoperative morbidity and mortality after major oesophagogastric cancer surgery-a multicentre observational study

Background

Outcomes after oesophagogastric cancer surgery remain poor. Cardiopulmonary exercise testing (CPET) used for risk stratification before oesophagogastric cancer surgery is based on conflicting evidence. This study explores the relationship between CPET and postoperative outcomes, specifically for patients undergoing neoadjuvant treatment.

Methods

Patients undergoing oesophagogastric cancer resection and CPET (pre- or post-neoadjuvant treatment, or both) were retrospectively enrolled into a multicentre pooled cohort study. Oxygen uptake at peak exercise (VO2 peak) was compared with 1-yr postoperative survival. Secondary analyses explored relationships between patient characteristics, tumour pathology characteristics, CPET variables (absolute, relative to weight, ideal body weight, and body surface area), and postoperative outcomes (morbidity, 1-yr and 3-yr survival) were assessed using logistic regression analyses.

Results

Seven UK centres recruited 611 patients completing a 3-yr postoperative follow-up period. Oesophagectomy was undertaken in 475 patients (78%). Major complications occurred in 25%, with 18% 1-yr and 43% 3-yr mortality. No association between VO2 peak or other selected CPET variables and 1-yr survival was observed in the overall cohort. In the overall cohort, the anaerobic threshold relative to ideal body weight was associated with 3-yr survival (P=0.013). Tumour characteristics (ypT/ypN/tumour regression/lymphovascular invasion/resection margin; P<0.001) and Clavien-Dindo ≥3a (P<0.001) were associated with 1-yr and 3-yr survival. On subgroup analyses, pre-neoadjuvant treatment CPET; anaerobic threshold (absolute; P=0.024, relative to ideal body weight; P=0.001, body surface area; P=0.009) and VE/VCO2 at anaerobic threshold (P=0.026) were associated with 3-yr survival. No other CPET variables (pre- or post-neoadjuvant treatment) were associated with survival.

Conclusions

VO2 peak was not associated with 1-yr survival after oesophagogastric cancer resection. Tumour characteristics and major complications were associated with survival; however, only some selected pre-neoadjuvant treatment CPET variables were associated with 3-yr survival. CPET in this cohort of patients demonstrates limited outcome predictive precision.

Clinical trial registration

NCT03637647.

COVID-19 reduces cardiorespiratory fitness even months after a mild to moderate acute phase: a retrospective cohort study

BACKGROUND

COVID-19 survivors may experience long-term health problems, including deterioration of cardiorespiratory fitness (CRF), as demonstrated by several cross-sectional studies that compared the results of cardiopulmonary exercise tests (CPET) performed only after COVID-19 with predicted values. This study aimed to analyze a change in CRF between repeated CPETs in response to suffered COVID-19.

METHODS

A total of 127 healthcare workers (HCWs; mean age 55.7 years) underwent two CPETs with a mean interval of 762 days. Forty HCWs suffered from COVID-19 (mild to moderate severity) in the interim (321 days before the second CPET), and 87 HCWs formed a control group. Mixed-effects regression with multiple adjustment and interaction terms was used for two response variables - maximum oxygen uptake (VO2 max) and power output.

RESULTS

Between both CPETs, mean VO2 max decreased statistically significantly in the COVID-19 subgroup (by 3.12 mL/kg/min, p = .034) and insignificantly in controls (by 0.56 mL/kg/min, p = .412). The proportion of HCWs achieving predicted VO2 max decreased from 75.9% to 59.5% (p = .161) in COVID-19 survivors, while it increased from 73.8% to 81% (p = .274) in controls. COVID-19 (β = -0.66, p = .014) and body mass index (β = -0.49, p < .001) were independent negative predictors of VO2 max change. COVID-19 was not associated with a change in power output.

CONCLUSIONS

On the basis of repeated CPETs, COVID-19 significantly, albeit rather modestly, reduces CRF almost one year after infection. The reduction persists even after the acute phase with mild or moderate severity.