Cardiopulmonary exercise testing (CPET) in the United Kingdom-a national survey of the structure, conduct, interpretation and funding

Biventricular responses to exercise and their relation to cardiorespiratory fitness in pediatric pulmonary hypertension

Despite exercise intolerance being predictive of outcomes in pulmonary arterial hypertension (PAH), its underlying cardiac mechanisms are not well described. The aim of the study was to explore the biventricular response to exercise and its associations with cardiorespiratory fitness in children with PAH. Participants underwent incremental cardiopulmonary exercise testing and simultaneous exercise echocardiography on a recumbent cycle ergometer. Linear mixed models were used to assess cardiac function variance and associations between cardiac and metabolic parameters during exercise. Eleven participants were included with a mean age of 13.4 ± 2.9 yr old. Right ventricle (RV) systolic pressure (RVsp) increased from a mean of 59 ± 25 mmHg at rest to 130 ± 40 mmHg at peak exercise (P < 0.001), whereas RV fractional area change (RV-FAC) and RV-free wall longitudinal strain (RVFW-Sl) worsened (35.2 vs. 27%, P = 0.09 and -16.6 vs. -14.6%, P = 0.1, respectively). At low- and moderate-intensity exercise, RVsp was positively associated with stroke volume and O2 pulse (P < 0.1). At high-intensity exercise, RV-FAC, RVFW-Sl, and left ventricular longitudinal strain were positively associated with oxygen uptake and O2 pulse (P < 0.1), whereas stroke volume decreased toward peak (P = 0.04). In children with PAH, the increase of pulmonary pressure alone does not limit peak exercise, but rather the concomitant reduced RV functional reserve, resulting in RV to pulmonary artery (RV-PA) uncoupling, worsening of interventricular interaction and LV dysfunction. A better mechanistic understanding of PAH exercise physiopathology can inform stress testing and cardiac rehabilitation in this population.NEW & NOTEWORTHY In children with pulmonary arterial hypertension, there is a marked increase in pulmonary artery pressure during physical activity, but this is not the underlying mechanism that limits exercise. Instead, right ventricle-to-pulmonary artery uncoupling occurs at the transition from moderate to high-intensity exercise and correlates with lower peak oxygen uptake. This highlights the more complex underlying pathological responses and the need for multiparametric assessment of cardiac function reserve in these patients when feasible.

Head-to-Head Comparison: P-POSSUM and ACS-NSQIP® in Predicting Perioperative Risk in Robotic Surgery for Gynaecological Cancers

Purpose: In this retrospective pilot study, we aim to evaluate the accuracy and reliability of the P-POSSUM and ACS-NSQIP surgical risk calculators in predicting postoperative complications in gynaecological-oncological (GO) robotic surgery (RS). Methods: Retrospective data collection undertaken through a dedicated GO database and patient notes at a tertiary referral cancer centre. Following data lock with the actual post-op event/complication, the risk calculators were used to measure predictive scores for each patient. Baseline analysis of 153 patients, based on statistician advice, was undertaken to evaluate P-POSSUM and ACS-NSQIP validity and relevance in GO patients undergoing RS performed. Results: P-POSSUM reports on mortality and morbidity only; ACS-NSQIP reports some individual complications as well. ACS-NSQIP risk prediction was most accurate for venous thromboembolism (VTE) (area under the curve (AUC)-0.793) and pneumonia (AUC-0.657) and it showed 90% accuracy in prediction of five major complications (Brier score 0.01). Morbidity was much better predicted by ACS-NSQIP than by P-POSSUM (AUC-0.608 vs. AUC-0.551) with the same result in mortality prediction (Brier score 0.0000). Moreover, a statistically significant overestimation of morbidity has been shown by the P-POSSUM calculator (p = 0.018). Conclusions: Despite the limitations of this pilot study, the ACS-NSQIP risk calculator appears to be a better predictor of major complications and mortality, making it suitable for use by GO surgeons as an informed consent tool. Larger data collection and analyses are ongoing to validate this further.

Wearable Sensors as a Preoperative Assessment Tool: A Review

Surgery is a common first-line treatment for many types of disease, including cancer. Mortality rates after general elective surgery have seen significant decreases whilst postoperative complications remain a frequent occurrence. Preoperative assessment tools are used to support patient risk stratification but do not always provide a precise and accessible assessment. Wearable sensors (WS) provide an accessible alternative that offers continuous monitoring in a non-clinical setting. They have shown consistent uptake across the perioperative period but there has been no review of WS as a preoperative assessment tool. This paper reviews the developments in WS research that have application to the preoperative period. Accelerometers were consistently employed as sensors in research and were frequently combined with photoplethysmography or electrocardiography sensors. Pre-processing methods were discussed and missing data was a common theme; this was dealt with in several ways, commonly by employing an extraction threshold or using imputation techniques. Research rarely processed raw data; commercial devices that employ internal proprietary algorithms with pre-calculated heart rate and step count were most commonly employed limiting further feature extraction. A range of machine learning models were used to predict outcomes including support vector machines, random forests and regression models. No individual model clearly outperformed others. Deep learning proved successful for predicting exercise testing outcomes but only within large sample-size studies. This review outlines the challenges of WS and provides recommendations for future research to develop WS as a viable preoperative assessment tool.

CT-derived measures of muscle quantity and quality predict poorer outcomes from elective colorectal surgery: a UK multicentre retrospective cohort study

PURPOSE

To assess whether preoperative radiologically defined lean muscle measures are associated with adverse clinical outcomes in patients undergoing elective surgery for colorectal cancer.

METHODS

This retrospective UK-based multicentre data collection study identified patients having had colorectal cancer resection with curative intent between January 2013 to December 2016. Preoperative computed-tomography (CT) scans were used to measure psoas muscle characteristics. Clinical records provided postoperative morbidity and mortality data.

RESULTS

This study included 1122 patients. The cohort was separated into a combined group (patients with both sarcopenia and myosteatosis) and others group (either sarcopenia or myosteatosis, or neither). For the combined group, anastomotic leak was predicted on univariate (OR 4.1, 95% CI 1.43-11.79; p = 0.009) and multivariate analysis (OR 4.37, 95% CI 1.41-13.53; p = 0.01). Also for the combined group, mortality (up to 5 years postoperatively) was predicted on univariate (HR 2.41, 95% CI 1.64-3.52; p < 0.001) and multivariate analysis (HR 1.93, 95% CI 1.28-2.89; p = 0.002). A strong correlation exists between freehand-drawn region of interest-derived psoas density measurement and using the ellipse tool (R2 = 81%; p < 0.001).

CONCLUSION

Measures of lean muscle quality and quantity, which predict important clinical outcomes, can be quickly and easily taken from routine preoperative imaging in patients being considered for colorectal cancer surgery. As poor muscle mass and quality are again shown to predict poorer clinical outcomes, these should be proactively targeted within prehabilitation, perioperative and rehabilitation phases to minimise negative impact of these pathological states.

Myths and methodologies: Cardiopulmonary exercise testing for surgical risk stratification in patients with an abdominal aortic aneurysm; balancing risk over benefit

The extent to which patients with an abdominal aortic aneurysm (AAA) should exercise remains unclear, given theoretical concerns over the perceived risk of blood pressure-induced rupture, which is often catastrophic. This is especially pertinent during cardiopulmonary exercise testing, when patients are required to perform incremental exercise to symptom-limited exhaustion for the determination of cardiorespiratory fitness. This multimodal metric is being used increasingly as a complementary diagnostic tool to inform risk stratification and subsequent management of patients undergoing AAA surgery. In this review, we bring together a multidisciplinary group of physiologists, exercise scientists, anaesthetists, radiologists and surgeons to challenge the enduring 'myth' that AAA patients should be fearful of and avoid rigorous exercise. On the contrary, by appraising fundamental vascular mechanobiological forces associated with exercise, in conjunction with 'methodological' recommendations for risk mitigation specific to this patient population, we highlight that the benefits conferred by cardiopulmonary exercise testing and exercise training across the continuum of intensity far outweigh the short-term risks posed by potential AAA rupture.

Smoking Habit and Respiratory Function Predict Patients' Outcome after Surgery for Lung Cancer, Irrespective of Histotype and Disease Stage

BACKGROUND

Growing evidence suggests that sublobar resections offer more favorable outcomes than lobectomy in early-stage lung cancer surgery. However, a percentage of cases that cannot be ignored develops disease recurrence irrespective of the surgery performed with curative intent. The goal of this work is thus to compare different surgical approaches, namely, lobectomy and segmentectomy (typical and atypical) to derive prognostic and predictive markers.

PATIENTS AND METHODS

Here we analyzed a cohort of 153 NSCLC patients in clinical stage TNM I who underwent pulmonary resection surgery with a mediastinal hilar lymphadenectomy from January 2017 to December 2021, with an average follow-up of 25.5 months. Partition analysis was also applied to the dataset to detect outcome predictors.

RESULTS

The results of this work showed similar OS between lobectomy and typical and atypical segmentectomy for patients with stage I NSCLC. In contrast, lobectomy was associated with a significant improvement in DFS compared with typical segmentectomy in stage IA, while in stage IB and overall, the two treatments were similar. Atypical segmentectomy showed the worst performance, especially in 3-year DFS. Quite unexpectedly, outcome predictor ranking analysis suggests a prominent role of smoking habits and respiratory function, irrespective of the tumor histotype and the patient's gender.

CONCLUSIONS

Although the limited follow-up interval cannot allow conclusive remarks about prognosis, the results of this study suggest that both lung volumes and the degree of emphysema-related parenchymal damage are the strongest predictors of poor survival in lung cancer patients. Overall, these data point out that greater attention should be addressed to the therapeutic intervention for co-existing respiratory diseases to obtain optimal control of early lung cancer.

Machine Learning Models for the Automatic Detection of Exercise Thresholds in Cardiopulmonary Exercising Tests: From Regression to Generation to Explanation

The cardiopulmonary exercise test (CPET) constitutes a gold standard for the assessment of an individual's cardiovascular fitness. A trend is emerging for the development of new machine-learning techniques applied to the automatic process of CPET data. Some of these focus on the precise task of detecting the exercise thresholds, which represent important physiological parameters. Three are the major challenges tackled by this contribution: (A) regression (i.e., the process of correctly identifying the exercise intensity domains and their crossing points); (B) generation (i.e., the process of artificially creating a CPET data file ex-novo); and (C) explanation (i.e., proving an interpretable explanation about the output of the machine learning model). The following methods were used for each challenge: (A) a convolutional neural network adapted for multi-variable time series; (B) a conditional generative adversarial neural network; and (C) visual explanations and calculations of model decisions have been conducted using cooperative game theory (Shapley's values). The results for the regression, generation, and explanatory techniques for AI-assisted CPET interpretation are presented here in a unique framework for the first time: (A) machine learning techniques reported an expert-level accuracy in the classification of exercise intensity domains; (B) experts are not able to substantially differentiate between a real vs an artificially generated CPET; and (C) Shapley's values can provide an explanation about the choices of the algorithms in terms of ventilatory variables. With the aim to increase their technology-readiness level, all the models discussed in this contribution have been incorporated into a free-to-use Python package called pyoxynet (ver. 12.1). This contribution should therefore be of interest to major players operating in the CPET device market and engineering.

Retroperitoneal Compared to Transperitoneal Approach for Open Abdominal Aortic Aneurysm Repair Is Associated with Reduced Systemic Inflammation and Postoperative Morbidity

BACKGROUND

 In the United Kingdom, the most common surgical approach for repair of open abdominal aortic aneurysms (AAAs) is transperitoneal (TP). However, retroperitoneal (RP) approach is favored in those with more complex vascular anatomy often requiring a cross-clamp on the aorta superior to the renal arteries. This study compared these approaches in patients matched on all major demographic, comorbid, anatomic, and physiological variables.

METHODS

 Fifty-seven patients (TP: n = 24; RP: n = 33) unsuitable for endovascular aneurysm repair underwent preoperative cardiopulmonary exercise testing prior to open AAA repair. The surgical approach undertaken was dictated by individual surgeon preference. Postoperative mortality, complications, and length of hospital stay (LoS) were recorded. Patients were further stratified according to infrarenal (IR) or suprarenal/supraceliac (SR/SC) surgical clamping. Systemic inflammation (C-reactive protein) and renal function (serum creatinine and estimated glomerular filtration rate) were recorded.

RESULTS

 Twenty-three (96%) of TP patients only required an IR clamp compared with 12 (36%) in the RP group. Postoperative systemic inflammation was lower in RP patients (p = 0.002 vs. TP) and fewer reported pulmonary/gastrointestinal complications whereas renal impairment was more marked in those receiving SR/SC clamps (p < 0.001 vs. IR clamp). RP patients were defined by lower LoS (p = 0.001), while mid-/long-term mortality was low/comparable with TP, resulting in considerable cost savings.

CONCLUSION

 Despite the demands of more complicated vascular anatomy, the clinical and economic benefits highlighted by these findings justify the more routine adoption of the RP approach for complex AAA repair.

Identifying the limitations of cardiopulmonary exercise testing prior to esophagectomy using a pooled analysis of patient-level data

Preoperative cardiopulmonary exercise testing (CPET) provides an objective assessment of aerobic fitness in patients undergoing surgery. While peak oxygen uptake during exercise (VO2peak) and anaerobic threshold have demonstrated a moderate correlation with the development of complications following esophagectomy, no clinically useful threshold values have been defined. By pooling patient level data from existing studies, we aimed to define optimal thresholds for preoperative CPET parameters to predict patients at high risk of postoperative complications. Studies reporting on the relationship between preoperative CPET variables and post-esophagectomy complications were determined from a comprehensive literature search. Patient-level data were obtained from six contributing centers for pooled-analyses. Outcomes of interest included cardiopulmonary and non-cardiopulmonary complications, unplanned intensive care unit readmission, and 90-day and 12-month all-cause mortality. Receiver operating characteristic curves and logistic regression models estimated the predictive value of CPET parameters for each individual outcome of interest. This analysis comprised of 621 patients who underwent CPET prior to esophagectomy during the period from January 2004 to March 2017. For both anaerobic threshold and VO2peak, none of the receiver operating characteristic curves achieved an area under the curve value > 0.66 for the outcomes of interest. The discriminatory ability of CPET for determining high-risk patients was found to be poor in patients undergoing an esophagectomy. CPET may only carry an adjunct role to clinical decision-making.

Neural network methods for diagnosing patient conditions from cardiopulmonary exercise testing data

BACKGROUND

Cardiopulmonary exercise testing (CPET) provides a reliable and reproducible approach to measuring fitness in patients and diagnosing their health problems. However, the data from CPET consist of multiple time series that require training to interpret. Part of this training teaches the use of flow charts or nested decision trees to interpret the CPET results. This paper investigates the use of two machine learning techniques using neural networks to predict patient health conditions with CPET data in contrast to flow charts. The data for this investigation comes from a small sample of patients with known health problems and who had CPET results. The small size of the sample data also allows us to investigate the use and performance of deep learning neural networks on health care problems with limited amounts of labeled training and testing data.

METHODS

This paper compares the current standard for interpreting and classifying CPET data, flowcharts, to neural network techniques, autoencoders and convolutional neural networks (CNN). The study also investigated the performance of principal component analysis (PCA) with logistic regression to provide an additional baseline of comparison to the neural network techniques.

RESULTS

The patients in the sample had two primary diagnoses: heart failure and metabolic syndrome. All model-based testing was done with 5-fold cross-validation and metrics of precision, recall, F1 score, and accuracy. As a baseline for comparison to our models, the highest performing flow chart method achieved an accuracy of 77%. Both PCA regression and CNN achieved an average accuracy of 90% and outperformed the flow chart methods on all metrics. The autoencoder with logistic regression performed the best on each of the metrics and had an average accuracy of 94%.

CONCLUSIONS

This study suggests that machine learning and neural network techniques, in particular, can provide higher levels of accuracy with CPET data than traditional flowchart methods. Further, the CNN performed well with a small data set showing that these techniques can be designed to perform well on small data problems that are often found in health care and the life sciences. Further testing with larger data sets is needed to continue evaluating the use of machine learning to interpret CPET data.

Perioperative Risk Stratification and Modification

This article discusses the important topic of perioperative risk stratification and the interventions that can be used in the perioperative period for risk modification. It begins with a brief overview of the commonly used scoring systems, risk-prediction models, and assessments of functional capacity and discusses some of the evidence behind each. It then moves on to examine how perioperative risk can be modified through the use of shared decision making, management of multimorbidity, and prehabilitation programs, before considering what the future of risk stratification and modification may hold.

'Fit for surgery': The relationship between cardiorespiratory fitness and postoperative outcomes

New Findings

What is the topic of this review?

The relationships and physiological mechanisms underlying the clinical benefits of cardiorespiratory fitness (CRF) in patients undergoing major intra‐abdominal surgery.

What advances does it highlight?

Elevated CRF reduces postoperative morbidity/mortality, thus highlighting the importance of CRF as an independent risk factor. The vascular protection afforded by exercise prehabilitation can further improve surgical risk stratification and postoperative outcomes.

Abstract

Surgery accounts for 7.7% of all deaths globally and the number of procedures is increasing annually. A patient's ‘fitness for surgery’ describes the ability to tolerate a physiological insult, fundamental to risk assessment and care planning. We have evolved as obligate aerobes that rely on oxygen (O₂). Systemic O₂ consumption can be measured via cardiopulmonary exercise testing (CPET) providing objective metrics of cardiorespiratory fitness (CRF). Impaired CRF is an independent risk factor for mortality and morbidity. The perioperative period is associated with increased O₂ demand, which if not met leads to O₂ deficit, the magnitude and duration of which dictates organ failure and ultimately death. CRF is by far the greatest modifiable risk factor, and optimal exercise interventions are currently under investigation in patient prehabilitation programmes. However, current practice demonstrates potential for up to 60% of patients, who undergo preoperative CPET, to have their fitness incorrectly stratified. To optimise this work we must improve the detection of CRF and reduce potential for interpretive error that may misinform risk classification and subsequent patient care, better quantify risk by expressing the power of CRF to predict mortality and morbidity compared to traditional cardiovascular risk factors, and improve patient interventions with the capacity to further enhance vascular adaptation. Thus, a better understanding of CRF, used to determine fitness for surgery, will enable both clinicians and exercise physiologists to further refine patient care and management to improve survival.

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

BACKGROUND

Assessment of exercise capacity is an important component of risk assessment before major surgery. Cardiopulmonary exercise testing (CPET) provides comprehensive assessment but is resource-intensive, limiting widespread adoption. Measurement of a patient's peak power output (PPO) using a simplified test on a cycle ergometer has the potential to identify patients likely to have abnormal CPET findings and to be at increased perioperative risk. The aim of this study was to investigate the potential for PPO to identify those with abnormal CPET and to determine whether PPO predicted the risk of adverse postoperative outcomes.

METHODS

In a retrospective analysis of a single-centre cohort, the ability of PPO to predict a high-risk CPET result in patients undergoing major cancer surgery was analysed. The assessment was validated in patients undergoing major abdominal surgery from a UK national multicentre cohort. The association between PPO and adverse postoperative outcomes to traditional CPET-derived variables were compared.

RESULTS

In 2262 patients from a single centre, PPO was an excellent discriminator of high-risk CPET, with an area under the receiver operating characteristic curve (AUROC) of 0.901 (95 per cent c.i. 0.888 to 0.913). In the national cohort of 2742 patients, there was excellent discrimination, with an AUROC of 0.856 (0.842 to 0.871). A PPO cut-off of 1.5 W/kg may be appropriate for use in screening, with a sensitivity of 90 per cent in both cohorts. PPO and traditional CPET-derived predictors demonstrated similar discrimination of major postoperative complications and death. The association between PPO and major postoperative complications persisted on multivariable analysis.

CONCLUSION

These results suggest a role for the PPO test in preoperative screening and risk stratification for major surgery. Prospective evaluation is recommended.

Cardiopulmonary Exercise Testing and Other Tests of Functional Capacity

Purpose of Review

Assessment of functional capacity is a cornerstone of preoperative risk assessment. While subjective clinician assessment of functional capacity is poorly predictive of postoperative outcomes, other objective functional assessment measures may provide more useful information.

Recent Findings

Cardiopulmonary exercise testing (CPET) is generally accepted as the gold standard for functional capacity assessment. However, CPET is resource-intensive and not universally available. Simpler objective tests of functional capacity such as the Duke Activity Status Index (DASI) and the 6-min walk test (6MWT) are cheap and efficient. In addition, they predict important postoperative outcomes including death, disability, and myocardial infarction.

Summary

Simple preoperative tests such as the DASI may be useful for routine preoperative assessment. CPET may be helpful to investigate further patients with functional status limitation, and to guide prehabilitation and perioperative shared decision-making in high-risk patients.

Making Cardiopulmonary Exercise Testing Interpretable for Clinicians

ABSTRACT

Cardiopulmonary exercise testing (CPET) is a dynamic clinical tool for determining the cause for a person's exercise limitation. CPET provides clinicians with fundamental knowledge of the coupling of external to internal respiration (oxygen and carbon dioxide) during exercise. Subtle perturbations in CPET parameters can differentiate exercise responses among individual patients and disease states. However, perhaps because of the challenges in interpretation given the amount and complexity of data obtained, CPET is underused. In this article, we review fundamental concepts in CPET data interpretation and visualization. We also discuss future directions for how to best use CPET results to guide clinical care. Finally, we share a novel three-dimensional graphical platform for CPET data that simplifies conceptualization of organ system-specific (cardiac, pulmonary, and skeletal muscle) exercise limitations. Our goal is to make CPET testing more accessible to the general medical provider and make the test of greater use in the medical toolbox.

Protocol for a multi-centre observational and mixed methods pilot study to identify factors predictive of poor functional recovery after major gastrointestinal surgery and strategies to enhance uptake of perioperative optimization: Optimizing the care and treatment pathways for older patients facing major gastrointestinal surgery (OCTAGON)

INTRODUCTION

National datasets report large variations in outcomes from older people (≥65 years) between different UK surgical units. This implies that not all patients receive the same level of care or access to resources, such as rehabilitation or allied health professional input. This might impact functional decline.

AIMS

Our aim is to evaluate the baseline status of older patients facing major gastrointestinal surgery and the impact of variation in perioperative assessment and provision of perioperative support on functional outcomes. Patients' experiences and views of assessment and optimization will be explored via integrated qualitative semi-structured interviews.

METHODS AND ANALYSIS

This multi-centre, pilot cohort study will include patients ≥65 years presenting via both elective and emergency pathways at three to five South Yorkshire NHS hospitals (Clinical Trials registration NCT04545125). The primary outcome is functional recovery measured using the World Health Organization Disability Assessment Schedule 2.0 at 6 weeks post-operation. Secondary outcomes include feasibility, quality of life, length of stay and complication rate. An opportunistic sample size of 120 has been estimated and will inform the design of a future, adequately powered study. For the qualitative study, 20-30 semi-structured patient interviews will be undertaken with patients from the cohort study to explore experiences of assessment and optimization. Interviews will be digitally recorded, transcribed verbatim and analysed according to the framework approach.

ETHICS AND DISSEMINATION

This study has been approved by the National Health Service Research Ethics Committee and is registered centrally with Health Research Authority. It has been adopted by the National Institute for Health Research Portfolio scheme. Dissemination will be via international and national surgical and geriatric conferences.

Perioperative risk assessment - focus on functional capacity

PURPOSE OF REVIEW

This review examines how functional capacity informs preoperative risk stratification, as well as strengths and limitations of options for estimating functional capacity.

RECENT FINDINGS

Functional capacity (or cardiopulmonary fitness) overlaps with other important characteristics, including muscular strength, balance, and frailty. Poor functional capacity is associated with postoperative morbidity, especially noncardiovascular complications. Both patient interviews and exercise tests are used to assess functional capacity. The usual approach of an unstructured patient interview does not predict outcomes. Structured interviews that incorporate validated questionnaires (Duke Activity Status Index) or standardized questions about physical activity (ability to climb stairs) do predict moderate-or-severe complications and cardiovascular complications. Among exercise tests, cardiopulmonary exercise testing (CPET) has shown the most consistent association with risks of complications. Other tests (6-min walk test, incremental shuttle walk test, stair climbing) might predict complications, but still require further high-quality evaluation.

SUMMARY

A straightforward way to better assess functional capacity is a structured interview with validated questionnaires or standardized questions about physical activities. Functional capacity can also be assessed by exercise tests, with the strongest evidence supporting CPET. Although some simpler exercise tests have shown promise, more research remains needed to better define their role in preoperative evaluation.

Poor anaerobic threshold and VO2 max recorded during cardiopulmonary exercise testing (CPET) prior to cytoreductive surgery in advanced (stage 3/4) ovarian cancer (AOC) is associated with suboptimal cytoreduction but does not preclude maximum effort cytoreduction

This study assessed Cardiopulmonary Exercise Testing (CPET) in predicting oncological outcomes, post-operative recovery and complications in advanced ovarian cancer (AOC) cytoreductive surgery. We reviewed all patients who had CPET prior to AOC cytoreductive surgery with evidence of upper abdominal disease on preoperative imaging at the University Hospitals of Derby and Burton (UHDB) between August 2016 and July 2019. Patients were stratified by AT and maximum VO₂ levels. 43 patients were identified. AT showed no relationship with major complications. 100% of patients in the AT ≥11 group received R0 (n = 21, 91.30%), or R1 (n = 2, 8.70%) cytoreduction, whereas in the AT <11 group, only 75.00% achieved and R0 or R1 resection (p = .02). Surgical complexity was higher in the AT ≥11 group (p = .001) and the VO₂ ≥15 group (p = .0006). No other correlations were seen between AT or VO₂ max and complications or readmissions. No difference in overall survival was seen if R0 resection was achieved.IMPACT STATEMENTWhat is already known on this subject? CPET testing allows pre-operative assessment of functional capacity to generate variables that can be used as a risk-stratification tool for major surgery. Whilst CPET testing has been shown to predict morbidity in non-gynaecological surgery, it remains unproven in cytoreductive surgery for ovarian cancer surgery despite being increasingly utilised.What do the results of study add? Our data suggest that CPET testing does not predict complication rates or survival in AOC. Patients with poor CPET performance are more likely to receive suboptimal cytoreductive outcomes from surgery.What are the implications of these findings for clinical practice and/or further research? CPET results should not be used to discount patients from cytoreductive surgery further research should address the interplay with nutrition, haematological markers, neoadjuvant chemotherapy and CPET performance.

Systematic Review of Treatments for Colorectal Metastases in Elderly Patients to Guide Surveillance Cessation Following Hepatic Resection for Colorectal Liver Metastases

BACKGROUND

Although included in surveillance programmes for colorectal cancer (CRC) metastases, elderly patients are susceptible to declines in health and quality of life that may render them unsuitable for further surveillance. Deciding when to cease surveillance is challenging.

METHODS

There are no publications focused on surveillance of elderly patients for CRC metastases. A systematic review of studies reporting treatment outcomes for CRC metastases in elderly patients was performed to assess the risk-benefit balance of the key objectives of surveillance; detecting and treating CRC metastases.

RESULTS

Sixty-eight eligible studies reported outcomes for surgery and chemotherapy in the elderly. Liver resections and use of chemotherapy, including biologics, are more conservative and have poorer outcomes in the elderly compared with younger patients. Selected studies demonstrated poorer quality-of-life (QoL) following surgery and chemotherapy. Studies of ablation in elderly patients are limited.

DISCUSSION

The survival benefit of treating CRC metastases with surgery or chemotherapy decreases with advancing age and QoL may decline in the elderly. The relatively lower efficacy and detrimental QoL impact of multimodal therapy options for detected CRC metastases in the elderly questions the benefit of surveillance in some elderly patients. Care of elderly patients should thus be customized based on their preference, formal geriatric assessment, natural life-expectancy, and the perceived risk-benefit balance of treating recurrent CRC metastases. Clinicians may consider surveillance cessation in patients aged 75 years and above if geriatric assessment is unsatisfactory, patients decline surveillance, or patient fitness deteriorates catastrophically.

Actual Issues of the Cardiac Complications Risk Assessment and Correction in Non-Cardiac Surgery

Worldwide, more than 200 million non-cardiac surgeries are performed annually, and this number is constantly increasing; cardiac complications are the leading cause of death in such surgeries. So, in a multicenter study conducted in 27 countries, cardiovascular complications were present in 68% of cases of death in the postoperative period. Registers of recent years have shown that the number of such complications remains high, for example, with a dynamic assessment of troponins, perioperative myocardial damage was detected in 13-18% of cases. This review provides a critical analysis of the step-by-step algorithm for assessing cardiac risk of non-cardiac operations considering the emergence of new publications on this topic. The review discusses new data on risk assessment scales, functional state assessment, the use of non-invasive tests, biomarkers, the role of preventive myocardial revascularization in the preoperative period, and drug therapy. The issues of non-cardiac operations after percutaneous coronary intervention, perioperative myocardial damage are considered separately. The review emphasizes the difficulties in obtaining evidence, conducting randomized clinical trials in this section of medicine, which do not allow obtaining unambiguous conclusions in most cases and lead to inconsistencies and ambiguities in the recommendations of various expert groups. This review will help practitioners navigate this issue and help to use the optimal diagnostic and treatment strategy before performing non-cardiac surgery.

Cardiopulmonary Exercise Testing Versus Frailty, Measured by the Clinical Frailty Score, in Predicting Morbidity in Patients Undergoing Major Abdominal Cancer Surgery

BACKGROUND

The primary outcome of this study is to investigate the association between the cardiopulmonary exercise testing (CPET) variables: anaerobic threshold (AT), peak oxygen uptake (VO₂ peak), peak work rate (WR), ventilatory equivalence of CO₂ (VE/VCO₂) at the anaerobic threshold (AT) with frailty, measured by the clinical frailty scale (CFS) in patients planned to undergo major abdominal cancer surgery. The secondary outcome is to compare the CPET variables (VO₂ peak, peak WR, VE/VCO₂ at AT) with frailty measured by the CFS in predicting postoperative surgical morbidity in patients following major abdominal cancer surgery.

METHODS

This study was a single-centre prospective cohort analysis of consecutive adult patients undergoing CPET and CFS scoring as part of their pre-operative work-up for major abdominal cancer surgery.

RESULTS

A total of n = 317 patients underwent CPET and CFS assessment ahead of planned abdominal oncological surgery. Negative correlations were observed between the CPET variables: AT - 0.42 p < 0.01; VO₂ peak - 0.53 p < 0.01; peak WR - 0.54 p < 0.01 with CFS scores and a positive correlation between CFS scores and VE/VCO₂ 0.29 p < 0.01. Only CFS remained statistically significant in a multivariate model OR 2.11 (1.42-3.15) 95% CI associated with Clavien-Dindo (CD) ≥ 1 defined morbidity including the significant univariate variables (VO₂ peak, peak WR and CFS scores). No variables were associated with CD ≥ 3 morbidity.

CONCLUSIONS

In patients scheduled to have major abdominal cancer surgery there was a weak association between poor performance on CPET and increasing frailty measured by the CFS. The CFS score unlike CPET was associated with all post-operative morbidity, but not major complications alone, in these patients. This suggests that CFS may be used as a less expensive alternative to CPET for predicting any postoperative morbidity in major abdominal cancer surgery.

Cardiorespiratory fitness fails to predict short-term postoperative mortality in patients undergoing elective open surgery for abdominal aortic aneurysm

INTRODUCTION

Preoperative cardiopulmonary exercise testing aids surgical risk stratification and is an established predictor of mid- to long-term survival in patients undergoing elective open abdominal aortic aneurysm repair. Whether cardiopulmonary exercise testing also predicts 30-day mortality in this population remains to be established.

MATERIALS AND METHODS

Data for 109 patients (mean age 72 years) who underwent cardiopulmonary exercise testing to assess risk for surgical abdominal aortic aneurysm repair was analysed. Patients were classified according to cardiopulmonary fitness as fit (peak oxygen uptake ≥ 15ml O₂.kg^-1.min^-1) or unfit (peak oxygen uptake less than 15ml O₂.kg^-1.min^-1) and further stratified according to clamp position (infrarenal or suprarenal). Between-group postoperative outcomes were compared for in-hospital 30-day mortality, postoperative morbidity scale scores (day 5) and hospital length of stay.

RESULTS

Seventy-nine patients underwent open surgery and 30 patients were treated conservatively. No deaths were recorded at 30 days post-surgery. Unfit patients with infrarenal clamping exhibited higher postoperative morbidity scale scores (64% vs 26%) and longer length of stay (four days) than fit patients (p < 0.05). Conversely, with suprarenal clamping, postoperative morbidity scale scores were similar and length of stay longer (three days) in fit compared with unfit patients (p < 0.05).

DISCUSSION AND CONCLUSION

Preoperative fitness level defined by peak oxygen uptake failed to identify patients at risk of 30-day mortality when undergoing elective abdominal aortic aneurysm repair. Postoperative morbidity and length of stay in patients with suprarenal clamping was high independent of cardiopulmonary fitness. These findings suggest that cardiopulmonary exercise testing may be a useful predictor of complications following infrarenal rather than suprarenal clamping but may not be a good predictor of 30-day mortality.

Why women are not small men: sex-related differences in perioperative cardiopulmonary exercise testing

Background

The use of preoperative cardiopulmonary exercise testing (CPET) to evaluate the risk of adverse perioperative outcomes is increasingly prevalent. CPET-derived information enables personalised perioperative care and enhances shared decision-making. Sex-related differences in physical fitness are reported in non-perioperative literature. However, little attention has been paid to sex-related differences in the context of perioperative CPET.

Aim

We explored differences in the physical fitness variables reported in a recently published multi-centre study investigating CPET before colorectal surgery. We also report the inclusion rate of females in published perioperative CPET cohorts that are shaping guidelines and clinical practice.

Methods

We performed a post hoc analysis of the trial data of 703 patients who underwent CPET prior to major elective colorectal surgery. We also summarised the female inclusion rate in peer-reviewed published reports of perioperative CPET.

Results

Fitness assessed using commonly used perioperative CPET variables—oxygen consumption at anaerobic threshold (AT) and peak exercise—was significantly higher in males than in females both before and after correction for body weight. In studies contributing to the development of perioperative CPET, 68.5% of the participants were male.

Conclusion

To our knowledge, this is the first study to describe differences between males and females in CPET variables used in a perioperative setting. Furthermore, there is a substantial difference between the inclusion rates of males and females in this field. These findings require validation in larger cohorts and may have significant implications for both sexes in the application of CPET in the perioperative setting.

High-intensity exercise training improves perioperative risk stratification in the high-risk patient

Exercise prehabilitation prior to major surgery can improve cardiorespiratory fitness (CRF) and clinical outcome. However, in patients deemed "high--risk" for surgery, the feasibility, optimum training modality and its intensity, duration, and frequency are yet to be defined. We assessed the cardiorespiratory fitness of a 70-year-old female patient requiring major thoraco-abdominal surgery for reconstruction of her esophagus. Cardiopulmonary exercise testing (CPET) on a cycle ergometer was used to determine CRF. A baseline CPET confirmed poor CRF and placed her in a high surgical risk group. This was followed by 16 weeks of unsupervised, home-based, moderate-intensity steady-state (MISS) training followed by 10 weeks of high-intensity interval training (HIIT) under the combined supervision of an exercise physiologist and clinician in hospital. Following MISS training, CPET metrics failed to improve: peak oxygen uptake decreased (14.7-13.7 ml O2 ·kg-1 ·min-1 ; -7%) together with peak power (73-70 W; -4%) and anaerobic threshold (AT) increased (7.8-8.3 ml O2 ·kg-1 ·min-1 ; +6%). However, HIIT resulted in impressive improvement in CRF. Peak oxygen uptake (13.7-18.6 ml O2 ·kg-1 ·min-1 ; +36%), AT (8.3-10.5 ml O2 ·kg-1 ·min-1 ; +27%), peak power (70-102 W; +46%), minute ventilation (35.8-57.7 L·min-1 ; +61%), and peak heart rate (100-133 b·min-1 ; +33%) all increased. Ventilatory equivalents for carbon dioxide at AT ( V ˙ E / V ˙ CO2 -AT) improved (30-28; -7%). The improvement in CRF resulted in surgical reclassification from high to low risk. In conclusion, preoperative HIIT training can confer a marked improvement in CRF in an elderly surgical patient and is associated with a corresponding reduction in perioperative risk.

Is gender still a risk factor for mortality in patients who undergo elective repair of abdominal aortic aneurysms? Experience of a single center

BACKGROUND

Vascular Services Quality Improvement Program (VSQIP) was introduced to reduce mortality from elective repair of AAA in the UK. This study examines the differences in perioperative mortality and postoperative survival between men and women following elective repair of AAAs in the 10 years after implementation of the (VSQIP).

METHODS

Consecutive patients who underwent elective repair of AAA between 1^st January 2008 and 31^st March 2018 were included. All patients were assessed using the nationally agreed VSQIP pathway which involved cardiopulmonary exercise testing as well as contrast enhanced CT scan of aorta and multidisciplinary assessment to plan each treatment. CT scans were examined to assess the morphology of AAA. Patients were stratified by age, gender, AAA morphology and preoperative anaerobic threshold. Postoperative survival was assessed using Kaplan-Meier analysis. Cox regression analysis was used to determine predictors of postoperative mortality.

RESULTS

A total of 702 patients underwent elective repair of AAA of whom 632 were men and 70 were women. The mean age of study cohort was 73.5±7.3 years and mean AAA diameter was 62±9.9 mm. Two hundred and forty-four patients underwent open repair, 402 underwent infrarenal endovascular aneurysm repair (EVAR) and 56 underwent complex EVAR with perioperative and 30-day mortality of 1.13%. No significant difference was observed in perioperative/30-day mortality between men and women (χ²=0.06, P=0.81). Anaerobic threshold <8 (HR=0.68 [95% CI: 0.51-0.92]), complex aneurysm morphology (HR=1.7 [95% CI: 1.39-2.19]) risk category (HR=1.89 [95% CI: 1.48-2.42]) and patients age (HR=1.41 [95% CI: 1.13-1.89]) were independent risk factor for mortality following repair of AAA, whilst female gender (HR=0.89 [95% CI: 0.54-1.48]) and AAA size (HR=1.01 [95% CI: 0.84-1.22]) were not. There was no difference in postoperative survival between men and women who underwent elective repair of AAA (Log rank: 1.82, P=0.61).

CONCLUSIONS

Following the implementation of VSQIP female gender is no longer a significant risk factor for perioperative mortality or reduced survival following elective repair of large asymptomatic AAA.

Cardiopulmonary Exercise Testing for Preoperative Evaluation: What Does the Future Hold?

Purpose of Review

Cardiopulmonary exercise testing (CPET) informs the preoperative evaluation process by providing individualised risk profiles; guiding shared decision-making, comorbidity optimisation and preoperative exercise training; and informing perioperative patient management. This review summarises evidence on the role of CPET in preoperative evaluation and explores the role of novel and emerging CPET variables and alternative testing protocols that may improve the precision of preoperative evaluation in the future.

Recent Findings

CPET provides a wealth of physiological data, and to date, much of this is underutilised clinically. For example, impaired chronotropic responses during and after CPET are simple to measure and in recent studies are predictive of both cardiac and noncardiac morbidity following surgery but are rarely reported. Exercise interventions are increasingly being used preoperatively, and endurance time derived from a high intensity constant work rate test should be considered as the most sensitive method of evaluating the response to training. Further research is required to identify the clinically meaningful difference in endurance time. Measuring efficiency may have utility, but this requires exploration in prospective studies.

Summary

Further work is needed to define contemporaneous risk thresholds, to explore the role of other CPET variables in risk prediction, to better characterise CPET’s role in combination with other tools in multifactorial risk stratification and increasingly to evaluate CPET’s utility for preoperative exercise prescription in prehabilitation.

Performance in 6-min walk test in prediction of post-operative pulmonary complication in major oncosurgeries: A prospective observational study

Background and Aims

Post-operative pulmonary complications (PPC) contribute to increased morbidity and mortality, necessitating pre-operative functional assessment. Six-minute walk test (6MWT) is a simple option for functional assessment.

Methods

This is a prospective observational study conducted in 75 patients who underwent elective abdominal or thoracic oncosurgery under general anaesthesia with either age above 60 years or with cardiopulmonary diseases or obstructive sleep apnoea or low serum albumin or smoking. Patients with history of acute coronary syndrome in past 6 months, dyspnoea at rest, severe pain, inability to walk or interpret instructions and haemodynamic instability were excluded. Preoperatively 6MWT was conducted according to the American Thoracic Society guidelines and patients were observed for PPC. Patients were divided into two groups: group 1-no PPC and group 2-developed PPC. Statistical analysis was done using SPSS software (version 11.0.1). Categorical variables were assessed using Chi-square/Fisher's exact test and continuous variables using student's t-test/Mann-Whitney U test. Association was tested using logistic regression.

Results

Out of the 75 patients, 40 patients had no PPC (group 1) and 35 patients had PPC (group 2) including a death. The 6MWD of group with PPCs was significantly less (344 ± 61.927 m) compared to the group without PPCs (442.28 ± 83.194 m, P value = 0.001). The cut-off 6MWD obtained was 390 m, which correlated with longer duration of hospital stay and ICU stay (P = 0.001).

Conclusion

Six-minute walk test is a reliable predictor of post-operative pulmonary complications with a cut-off 6MWD of 390 m in the studied oncosurgery patients.

Shared decision making for elective abdominal aortic aneurysm surgery

Decisions on how and when to treat an abdominal aortic aneurysm involve a number of clinicians; interventional radiologists and vascular surgeons assess the technical ability to repair the aneurysm. Patients' fitness and past medical history is assessed to estimate their short- and long-term survival with or without surgery. Most importantly the patients' personal preference for treatment must be identified. Getting a patient to share what matters most to them requires shared decision making.

Anaerobic threshold as an independent predictor of mid-term survival following elective endovascular repair of abdominal aortic aneurysm

BACKGROUND

The aim of this study was to examine the value preoperative AT as predictor of postoperative survival in patients who underwent elective EVAR for repair of asymptomatic AAA.

METHODS

Consecutive patients who underwent elective EVAR between 2008 and 2018 were analyzed. Cardiopulmonary exercise testing was performed. Perioperative 30-day mortality was compared between patients who had AT ≥8 mL/kg/min and those with AT<8 mL/kg/min. Risk factors for postoperative survival following EVAR were examined using Cox's regression analysis.

RESULTS

Between 1^st January 2008 and 31^st December 2017, 430 patients underwent elective EVAR (standard device: N.=374, fenestrated/branched: N.=56); their median age was 76 years (range: 53-91 years), median AT was 9.3 (range: 5.4-16.1), and 30-day mortality was 0.9%. These patients were followed up for a median of 1630 days. There was no significant difference in perioperative 30-day mortality between patients who had AT≥8 and those who had AT<8 (χ²=1.56, P=0.22). Age (HR=1.51 [CI: 1.07-1.99], P<0.05) and AT (HR=0.59 [CI: 0.45-0.76], P=0.0003) were predictors of reduced postoperative survival following elective EVAR whereas gender (HR=0.75 [CI: 0.4-1.4], P=0.37), AAA diameter (HR=0.95 [CI: 0.77-1.16], P=0.6), and AAA morphology (HR=1.23 [CI: 0.68-1.76], P=0.95) were not.

CONCLUSIONS

Anaerobic threshold is an independent predictor of prolonged survival following elective EVAR and can be used to identify patients who receive most benefit from elective EVAR.

Myosteatosis is associated with poor physical fitness in patients undergoing hepatopancreatobiliary surgery

BACKGROUND

Body composition assessment, measured using single-slice computed tomography (CT) image at L3 level, and aerobic physical fitness, objectively measured using cardiopulmonary exercise testing (CPET), are each independently used for perioperative risk assessment. Sarcopenia (i.e. low skeletal muscle mass), myosteatosis [i.e. low skeletal muscle radiation attenuation (SM-RA)], and impaired objectively measured aerobic fitness (reduced oxygen uptake) have been associated with poor post-operative outcomes and survival in various cancer types. However, the association between CT body composition and physical fitness has not been explored. In this study, we assessed the association of CT body composition with selected CPET variables in patients undergoing hepatobiliary and pancreatic surgery.

METHODS

A pragmatic prospective cohort of 123 patients undergoing hepatobiliary and pancreatic surgery were recruited. All patients underwent preoperative CPET. Preoperative CT scans were analysed using a single-slice CT image at L3 level to assess skeletal muscle mass, adipose tissue mass, and muscle radiation attenuation. Multivariate linear regression was used to test the association between CPET variables and body composition. Main outcomes were oxygen uptake at anaerobic threshold ( V̇ O₂ at AT), oxygen uptake at peak exercise ( V̇ O₂ peak), skeletal muscle mass, and SM-RA.

RESULTS

Of 123 patients recruited [77 men (63%), median age 66.9 ± 11.7, median body mass index 27.3 ± 5.2], 113 patients had good-quality abdominal CT scans available and were included. Of the CT body composition variables, SM-RA had the strongest correlation with V̇ O₂ peak (r = 0.57, P < 0.001) and V̇ O₂ at AT (r = 0.45, P < 0.001) while skeletal muscle mass was only weakly associated with V̇ O₂ peak (r = 0.24, P < 0.010). In the multivariate analysis, only SM-RA was associated with V̇ O₂ peak (B = 0.25, 95% CI 0.15-0.34, P < 0.001, R²  = 0.42) and V̇ O₂ at AT (B = 0.13, 95% CI 0.06-0.18, P < 0.001, R²  = 0.26).

CONCLUSIONS

There is a positive association between preoperative CT SM-RA and preoperative physical fitness ( V̇ O₂ at AT and at peak). This study demonstrates that myosteatosis, and not sarcopenia, is associated with reduced aerobic physical fitness. Combining both myosteatosis and physical fitness variables may provide additive risk stratification accuracy and guide interventions during the perioperative period.

Cardiorespiratory fitness is impaired and predicts mid-term postoperative survival in patients with abdominal aortic aneurysm disease

NEW FINDINGS

What is the central question of this study? To what extent cardiorespiratory fitness is impaired in patients with abdominal aortic aneurysmal (AAA) disease and corresponding implications for postoperative survival requires further investigation. What is the main finding and its importance? Cardiorespiratory fitness is impaired in patients with AAA disease. Patients with peak oxygen uptake of <13.1 ml O₂  kg^-1  min^-1 and ventilatory equivalent for carbon dioxide at anaerobic threshold ≥34 are associated with increased risk of postoperative mortality at 2 years. These findings demonstrate that cardiorespiratory fitness can predict mid-term postoperative survival in AAA patients, which may help to direct care provision.

ABSTRACT

Preoperative cardiopulmonary exercise testing is a standard assessment of cardiorespiratory fitness (CRF) and risk stratification. However, to what extent CRF is impaired in patients undergoing surgical repair of abdominal aortic aneurysm (AAA) disease and the corresponding implications for postoperative outcome requires further investigation. We measured CRF during an incremental exercise test to exhaustion using online respiratory gas analysis in patients with AAA disease (n = 124, aged 72 ± 7 years) and healthy sedentary control subjects (n = 104, aged 70 ± 7 years). Postoperative survival was examined for association with CRF, and threshold values were calculated for independent predictors of mortality. Patients who underwent preoperative cardiopulmonary exercise testing before surgical repair had lower CRF [age-adjusted mean difference of 12.5 ml O₂  kg^-1  min^-1 for peak oxygen uptake ( V ̇ O 2 peak ), P < 0.001 versus control subjects]. After multivariable analysis, both V ̇ O 2 peak and the ventilatory equivalent for carbon dioxide at anaerobic threshold ( V ̇ E / V ̇ C O 2 - AT ) were independent predictors of mid-term postoperative survival (2 years). Hazard ratios of 5.27 (95% confidence interval 1.62-17.14, P = 0.006) and 3.26 (95% confidence interval 1.00-10.59, P = 0.049) were observed for V ̇ O 2 peak  < 13.1 ml O₂  kg^-1  min^-1 and V ̇ E / V ̇ C O 2 - AT ≥ 34, respectively. Thus, CRF is lower in patients with AAA, and those with a V ̇ O 2 peak  < 13.1 ml O₂  kg^-1  min^-1 and V ̇ E / V ̇ C O 2 - AT ≥ 34 are associated with a markedly increased risk of postoperative mortality. Collectively, our findings demonstrate that CRF can predict mid-term postoperative survival in AAA patients, which may help to direct care provision.