Thompson DC; Department of Vascular Surgery, James Cook University Hospital, Middlesbrough, UK.
Hackett R; Wong PF; Danjoux G; Mofidi R;

European journal of vascular and endovascular surgery : the official journal of the European Society for Vascular Surgery [Eur J Vasc Endovasc Surg] 2024 Dec 03.
Date of Electronic Publication: 2024 Dec 03.

Objective: The decision to electively repair an abdominal aortic aneurysm (AAA) involves balancing the risk of rupture, periprocedural mortality, and life expectancy. Random forest classifiers (RFCs) are powerful machine learning algorithms. The aim of this study was to construct and validate a random forest machine learning tool to predict two year survival following elective AAA repair.
Methods: All patients who underwent elective open or endovascular repair of AAA from 1 January 2008 to 31 March 2021 were reviewed. They were assessed using the Vascular Surgery Quality Improvement Program pathway involving cardiopulmonary exercise testing, contrast enhanced computerised tomography scan, and multidisciplinary assessment. Patients were followed up for at least two years. A RFC was developed using 70% of the dataset and validated using 30% to predict survival for at least two years following AAA repair.
Results: A total of 925 patients (n = 836 men; n = 89 women) underwent elective repair of AAA; 126 (13.6%) died during the first two years; 11 (1.2%) died from periprocedural mortality. Variable importance analysis suggested that anaerobic threshold, pre-operative haemoglobin, maximal O ₂ consumption, body mass index, risk category, and forced expiratory volume in 1 second – forced vital capacity ratio were the most important contributors to the model. Sensitivity and specificity of the RFC for prediction of two year survival following surgery was 96.7% (95% CI 94.4 – 99%) and 67.1% (95% CI 61 – 72%); overall accuracy: 92.6% (95% CI 88 – 95%) (positive predictive value: 0.93, negative predictive value: 0.80); 10-fold cross validation revealed area under the receiver operator characteristic curve of 0.88.
Conclusion: RFCs based on readily available clinical data can successfully predict survival in the first two years following elective repair of AAA. Such information can contribute to the risk benefit assessment when deciding to electively repair AAAs.

Egbe AC; Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN.
Ali AE; Miranda WR; Connolly HM;Borlaug BA

Circulation. Heart failure [Circ Heart Fail] 2024 Dec 09, pp. e011981.
Date of Electronic Publication: 2024 Dec 09.

Background: Patients with Fontan palliation have reduced aerobic capacity because of impaired cardiac, pulmonary, and skeletal muscle function. However, the assessment of aerobic capacity in this population still relies on comparisons with people without cardiovascular disease rather than comparison with the expected aerobic capacity of other Fontan patients. The purpose of this study was to determine the expected aerobic capacity of adults with Fontan palliation.
Methods: Adults with Fontan palliation who underwent a cardiopulmonary exercise test at Mayo Clinic (2003-2023) were stratified into quartiles based on the predicted peak oxygen consumption (VO ₂ ). We assessed the correlates of predicted peak VO ₂ and the relationship between predicted peak VO ₂ quartiles and cardiovascular outcomes (death/transplant).
Results: Of 323 patients (age, 29±9 years; 177 [55%] men), the median peak VO ₂ was 19.1 (15.2-23.9) mL/kg per minute, and this corresponds to a predicted peak VO ₂ of 51% (range, 19-88; interquartile range, 41-62). After multivariable adjustments, the correlates of predicted peak VO ₂ were body mass index (β±SE, -2.61±0.95; 2.61% decrease in predicted peak VO ₂ per 5 kg/m ² increase in body mass index; P =0.009), systemic saturation (β±SE, 3.65±0.85; 3.65% increase in predicted peak VO ₂ per 5% increase in oxygen saturation; P <0.001), and Fontan pressure (β±SE, -1.24±0.22; 1.24% decrease in predicted peak VO ₂ per 1 mm Hg increase in Fontan pressures; P <0.001). There was a 47% increase in the risk for death/transplant from a higher predicted peak VO ₂ quartile to the next lower quartile (adjusted hazard ratio, 1.47 [95% CI, 1.09-2.05]; P =0.01).
Conclusions: The results of the current study would help calibrate the interpretation of exercise test data in adults with Fontan palliation and improve risk stratification in this population. It also underscores the need to maintain normal Fontan hemodynamics and body weight, which are important determinants of aerobic capacity.

Stark E; Department of Anaesthesiology and Intensive Care, Centre for Clinical Research, Sörmland, Nyköping Hospital, Nyköping, Sweden.
Gerring E; Hylander J; Björnsson B;Sandström P; Hedman K; Kristenson K

Acta anaesthesiologica Scandinavica [Acta Anaesthesiol Scand] 2025 Jan; Vol. 69 (1), pp. e14562.

Background: Ventilation as a function of elimination of CO ₂ during incremental exercise (VE/VCO ₂ slope) has been shown to be a valuable predictor of complications and death after major non-cardiac surgery. VE/VCO ₂ slope and partial pressure of end-tidal carbon dioxide (PetCO ₂ ) are both affected by ventilation/perfusion mismatch, but research on the utility of PetCO ₂ for risk stratification in major abdominal surgery is limited.
Aim: We aimed to determine the correlation between VE/VCO ₂ slope and PetCO ₂ measured during preoperative cardiopulmonary exercise testing (CPET) and its association with major cardiopulmonary complications (MCPCs) or death following oesophageal and other major abdominal cancer surgeries.
Method: In a retrospective cohort of 116 patients undergoing preoperative CPET 2008-2023, VE/VCO ₂ slope and PetCO ₂ (kPa) were recorded. The main outcome was MCPC during hospitalisation or death ≤90 days of surgery. We determined threshold values for each measure, corresponding to 90% specificity, using receiver operating characteristics analysis.
Results: A strong negative correlation was found between PetCO ₂ after a 5-minute warm-up and VE/VCO ₂ slope (Pearson r = -.88). In oesophagus cancer, VE/VCO ₂ slope >38 and PetCO ₂  < 4.1 kPa (30.8 mmHg) were both significant thresholds for the main outcome. For other major abdominal surgery patients, threshold analyses were non-significant. The area under the curve to predict outcome was similar using VE/VCO ₂ slope (0.70, 95% confidence interval 0.51-0.89) as compared to PetCO ₂ (0.71, 0.53-0-90).
Conclusion: Both preoperative VE/VCO ₂ slope and PetCO ₂ could identify subjects with a very high risk of complications following oesophageal resection, with similar prognostic utility. PetCO ₂ can be measured with simpler equipment and could therefore be useful when CPET is not available.

Crispino SP; Department of Cardiovascular Sciences, Fondazione Policlinico Universitario Campus Bio-Medico di Roma, 00128 Rome, Italy.
Segreti A; Ciancio M; Polito D; Guerra E; Di Gioia G; Ussia GP; Grigioni F;

Journal of cardiovascular development and disease [J Cardiovasc Dev Dis] 2024 Nov 05; Vol. 11 (11).
Date of Electronic Publication: 2024 Nov 05.

Coronary artery disease (CAD) remains a leading cause of morbidity and mortality worldwide, accounting for over 9 million deaths annually. The prevalence of CAD continues to rise, driven by ageing and the increasing prevalence of risk factors such as hypertension, diabetes, and obesity. Current clinical guidelines emphasize the importance of functional tests in the diagnostic pathway, particularly for assessing the presence and severity of ischemia. While recommended tests are valuable, they may not fully capture the complex physiological responses to exercise or provide the necessary detail to tailor personalized treatment plans. Cardiopulmonary exercise testing (CPET) offers a comprehensive assessment of the cardiovascular, pulmonary, and muscular systems under stress, potentially addressing these gaps and providing a more precise understanding of CAD, particularly in settings where traditional diagnostics may be insufficient. By enabling more personalized and precise treatment strategies, CPET could play a central role in the future of CAD management. This narrative review examines the current evidence supporting the use of CPET in CAD diagnosis and management and explores the potential for integrating CPET into existing clinical guidelines, considering its diagnostic and prognostic capabilities, cost-effectiveness, and the challenges associated with its adoption.

Dixit S; King Khalid University, Abha, , Saudi Arabia. & Federal University of Maranhao, São Luís 65080-805, MA, Brazil.
Bassi-Dibai D; Dibai-Filho AV; l.Mendes RG; Alqahtani AS; Alshehri MM; DAldhahi MI; Alkhamis BA; Reddy RS; Tedla JS; Borghi-Silva A;

Medicina (Kaunas, Lithuania) [Medicina (Kaunas)] 2024 Nov 06; Vol. 60 (11).
Date of Electronic Publication: 2024 Nov 06.

Background and Objective: The aim of this study was to evaluate cardiorespiratory fitness (CRF) measures, maximal oxygen consumption (VO ₂ max), and minute ventilation/carbon dioxide production (V _E /VCO ₂ slope and others) among the T2DM population based on glycated haemoglobin (HBA1c). Material and Methods: The present study comprised a cross-sectional design, with two groups, based on HbA1c values (≤7 and ≥7.1). Laboratory samples were taken to evaluate glycated haemoglobin and fasting blood glucose (FBS). Cardiopulmonary exercise testing was performed to calculate various fitness-related parameters. Data analysis: An independent t -test was used to analyse the outcomes in the two groups. p < 0.05 was considered significant. Linear regression was used to examine the influence of predictor variables on dependent variables.
Results: A total of 70 patients agreed to participate in the study, with 19 females and 51 males. The mean (standard deviation) BMI (body mass index) of all participants was 29.7(5.2), the mean (SD) weight was 84.4 (18.9) kg, and the mean height was 167.4 (23) cm. The average age of the individuals was 52 ± 8 years. The independent t -test revealed a significant difference between the two groups in terms of CRF measures.
Conclusions: The current research identified the presence of poor glycaemic control and cardiorespiratory fitness measures among the Brazilian population with T2DM. HBA1c, duration of diabetes, age, and BMI can be employed to predict the ventilatory threshold (VT) and VO ₂ max.

Edwards T; Arkansas Children’s Nutrition Center, Little Rock, AR.;  Little Rock, AR.
Børsheim E; Tomlinson AR;

Mayo Clinic proceedings. Innovations, quality & outcomes [Mayo Clin Proc Innov Qual Outcomes] 2024 Nov 13; Vol. 8 (6), pp. 530-535.
Date of Electronic Publication: 2024 Nov 13 (Print Publication: 2024).

A 20-year-old male underwent diagnostic testing due to unexplained shortness of breath and chest discomfort. He had no previous medical problems and was not taking any medications. Initial evaluations included cardiopulmonary exercise testing (CPET), which yielded results that were reported as normal. However, over the following 2 months, his symptoms worsened considerably, including dyspnea with climbing stairs and then hemoptysis. Seeking urgent medical care, he presented to the emergency department, where he underwent further testing and was admitted to the hospital. Computed tomography angiogram reported bilateral pulmonary emboli. His parents requested a second opinion regarding the analysis of the CPET data, which revealed previously overlooked abnormalities. This overlooked data delayed pulmonary embolism diagnosis, and the patient ultimately required bilateral pulmonary thromboendarterectomy. In this case, we describe the hallmark signs of pulmonary vascular disease seen during CPET and offer clinical pearls to aid in timely detection.

Marzolini S; KITE Research Institute; Rehabilitation Sciences Institute, University of Toronto.
Oh P; Peterman JE; Wallace P; Yadollahi A;Rivera F; Carvalho C; Kaminsky LA

The Canadian journal of cardiology [Can J Cardiol] 2024 Nov 25.
Date of Electronic Publication: 2024 Nov 25.

Background: Despite the importance of objective measures for prescribing aerobic exercise for mitigating cardiovascular risk in people with coronary artery disease (CAD), no study has examined sex differences in the utility of the cardiopulmonary exercise test (CPET) for developing the exercise prescription.
Methods: CPET results from 1,352 females and 5,875 males with CAD were analyzed to determine if there was a sex difference in achieving maximal oxygen uptake (VO2max) or an identifiable first ventilatory threshold (VT1). Secondary outcomes were to determine correlates of not achieving VO2max or VT1 in all patients and males and females separately.
Results: A greater proportion of males than females achieved VO2max or VT1 (89.7% vs 71.3%; p<0.001), specifically achieving VO2max (40.2% vs 26.7%; p<.001) and VT1 (88.0% vs 69.2%; p<.001). The most influential correlates of not achieving VO2max or VT1 were female sex (OR=3.1:95% CI, 2.6-3.7), age >60 yrs, tested on treadmill vs cycle, depressive symptoms, and a secondary heart failure diagnosis. At entry to cardiac rehabilitation, these correlates were more prevalent in females than males. Correlates differed by sex. The threshold for when age affected achieving VO2max or VT1 on the cycle CPET was earlier for females (>50 yrs) than males (>70 yrs) with no difference on treadmill (>80 yrs, both).
Conclusions: While most patients achieved VO2max or VT1 on the CPET, females were 3 times less likely to achieve VO2max or VT1 than males. Strategies to improve utility of CPETs for females such as alternative exercise test protocols and investigation into underlying mechanisms for effects of depressive symptoms should be conducted.

Shibata A; Department of Cardiovascular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan.
Izumiya Y; Yoshida T;Tanihata A; Kitada R;Otsuka K; Ito A; DepYamazaki T; Fukuda D;

Journal of cardiology [J Cardiol] 2024 Nov 27.
Date of Electronic Publication: 2024 Nov 27.

Background: Tafamidis is used as disease-modifying treatment for patients with wild-type transthyretin cardiac amyloidosis (ATTRwt CA). However, the effects of tafamidis on exercise tolerance are unclear.
Methods: This single-center, prospective, observational study aimed to assess the effect of tafamidis on exercise tolerance in 36 patients with ATTRwt CA. Exercise tolerance was evaluated by the peak oxygen uptake (peak VO ₂ ) measured by the cardiopulmonary exercise test (CPX).
Results: The baseline CPX showed a mean anaerobic threshold value of 11.6 ± 2.2 ml/kg/min and peak VO ₂ of 15.6 ± 4.1 ml/kg/min. Twenty-eight of the 36 patients underwent a follow-up CPX after 6 months. There was no significant change in peak VO ₂ before and 6 months after tafamidis therapy (16.0 ± 4.2 vs. 14.7 ± 4.0 ml/kg/min). The baseline CPX data showed that the mean peak VO ₂ was significantly lower in the increased peak VO ₂ group than in the non-increased peak VO ₂ group (13.7 ± 3.1 vs. 17.7 ± 4.1 ml/kg/min, p = 0.008). A multivariate logistic regression analysis showed that the baseline peak VO ₂ value was an independent predictor of improved exercise tolerance by tafamidis therapy (odds ratio: 0.646, 95 % confidence interval: 0.449-0.930, p = 0.019).
Conclusions: Tafamidis prevents deterioration of exercise tolerance in patients with ATTRwt CA. In some patients with ATTRwt CA, exercise tolerance may improve with the use of tafamidis, and those with lower exercise tolerance before tafamidis administration are likely to show improved exercise tolerance.

Dhont S; Department of Cardiology, Ziekenhuis Oost-Limburg, 3600 Genk, Belgium.
Verwerft J; Bertrand PB;

European heart journal. Cardiovascular Imaging [Eur Heart J Cardiovasc Imaging] 2024 Nov 27; Vol. 25 (12), pp. 1614-1619.

Exercise-induced pulmonary hypertension (exPHT) is a haemodynamic condition linked to increased morbidity and mortality across various cardiopulmonary diseases. Traditional definitions of exPHT rely on absolute cut-offs, such as mean pulmonary artery pressure (mPAP) above 30 mmHg during exercise. However, recent research suggests that these cut-offs may not accurately reflect pathophysiological changes, leading to false positives and false negatives. Instead, the mPAP over cardiac output (CO) slope, which incorporates both pressure and flow measurements, has emerged as a more reliable indicator. A slope exceeding 3 mmHg/L/min is now considered diagnostic for exPHT and strongly correlates with adverse outcomes. Stress echocardiography serves as a viable alternative to invasive assessment, enabling broader implementation. This review discusses the physiological basis of pulmonary haemodynamics during exercise, the advantages of the mPAP/CO slope over absolute pressure measurements, the evidence supporting its inclusion in clinical guidelines, and provides a practical guide for non-invasive determining the mPAP/CO slope in clinical practice.

Song J;  Department of Cardiology, School of Medicine, Xiamen University, Xiamen, Fujian, China
Chen X; Wang B; Cheng Y; Wang Y;

Journal of cardiopulmonary rehabilitation and prevention [J Cardiopulm Rehabil Prev] 2024 Nov 28.
Date of Electronic Publication: 2024 Nov 28.

Purpose: The objective of this study was to assess the effect of exercise-based cardiac rehabilitation (CR) with individualized exercise prescription in patients with chronic heart failure (HF) undergoing transcatheter aortic valve replacement (TAVR) in a randomized controlled trial.
Methods: A total of 60 patients with chronic HF who received TAVR treatment were randomly divided into the control group (n = 30) and exercise training (ET) group (n = 30). The control group was treated with conventional rehabilitation, and the ET group was given personalized exercise-based CR based on a cardiopulmonary exercise test (CPX). The CPX parameters, echocardiography, 6-minute walk test distance, and quality of life were evaluated in the two groups.
Results: All patients who completed symptom-restricted CPX showed no complications. After the 12-week rehabilitation period, the levels of anaerobic threshold, peak oxygen uptake, peak oxygen pulse, peak power, left ventricular ejection fraction, and 6-minute walk test distance in the ET group were significantly higher than those in the control group (P < .05). Scores on the Minnesota Life with Heart Failure Questionnaire in the ET group were lower than those in the control group (P < .05).
Conclusion: Exercise-based CR significantly improves cardiopulmonary function, exercise tolerance, and quality of life in patients with chronic HF who undergo TAVR.