Cardiopulmonary exercise testing and efficacy of percutaneous coronary intervention: a substudy of the ORBITA trial

The association between O2-pulse slope ratio and functional severity of coronary stenosis: A combined cardiopulmonary exercise testing and quantitative flow ratio study

Background

The role of cardiopulmonary exercise testing (CPET) parameters in evaluating the functional severity of coronary disease remains unclear. The aim of this study was to quantify the O2-pulse morphology and investigate its relevance in predicting the functional severity of coronary stenosis, using Murray law-based quantitative flow ratio (μQFR) as the reference.

Methods

CPET and μQFR were analyzed in 138 patients with stable coronary artery disease (CAD). The O2-pulse morphology was quantified through calculating the O2-pulse slope ratio. The presence of O2-pulse plateau was defined according to the best cutoff value of O2-pulse slope ratio for predicting μQFR ≤ 0.8.

Results

The optimal cutoff value of O2-pulse slope ratio for predicting μQFR ≤ 0.8 was 0.4, with area under the curve (AUC) of 0.632 (95 % CI: 0.505-0.759, p = 0.032). The total discordance rate between O2-pulse slope ratio and μQFR was 27.5 %, with 13 patients (9.4 %) being classified as mismatch (O2-pulse slope ratio > 0.4 and μQFR ≤ 0.8) and 25 patients being classified as reverse-mismatch (O2-pulse slope ratio ≤ 0.4 and μQFR > 0.8). Angiography-derived microvascular resistance was independently associated with mismatch (OR 0.07; 95 % CI: 0.01-0.38, p = 0.002) and reverse-mismatch (OR 9.76; 95 % CI: 1.47-64.82, p = 0.018).

Conclusion

Our findings demonstrate the potential of the CPET-derived O2-pulse slope ratio for assessing myocardial ischemia in stable CAD patients.

A Narrative Review of Revascularization in Chronic Coronary Syndrome/Disease: Concepts and Misconceptions

Ischemic heart disease represents a significant global burden of morbidity and mortality. While revascularization strategies are well defined in acute settings, there are uncertainties regarding chronic coronary artery disease treatment. Recent trials have raised doubts about the necessity of revascularization for "stable", chronic coronary syndromes or disease, leading to a shift towards a more conservative approach. However, the issue remains far from settled. In this narrative review, we offer a summary of the most pertinent evidence regarding revascularization for chronic coronary disease, while reflecting on less-often-discussed details of major clinical trials. The cumulative evidence available indicates that there can be a prognostic benefit from revascularization in chronic coronary syndrome patients, provided there is significant ischemia, as demonstrated by either imaging or coronary physiology. Trials that have effectively met this criterion consistently demonstrate a reduction in rates of spontaneous myocardial infarction, which holds both prognostic and clinical significance. The prognostic benefit of revascularization in patients with heart failure with reduced ejection fraction remains especially problematic, with a single contemporary trial favouring surgical revascularization. The very recent publication of a trial focused on revascularizing non-flow-limiting "vulnerable" plaques adds further complexity to the field. The ongoing debates surrounding revascularization in chronic coronary syndromes emphasize the importance of personalized strategies. Revascularization, added to the foundational pillar of medical therapy, should be considered, taking into account symptoms, patient preferences, coronary anatomy and physiology, ischemia tests and intra-coronary imaging.

The evolving role of cardiopulmonary exercise testing in ischemic heart disease - state of the art review

PURPOSE OF REVIEW

Cardiopulmonary exercise testing (CPET) is the gold standard for directly assessing cardiorespiratory fitness (CRF) and has a relatively new and evolving role in evaluating atherosclerotic heart disease, particularly in detecting cardiac dysfunction caused by ischemic heart disease. The purpose of this review is to assess the current literature on the link between cardiovascular (CV) risk factors, cardiac dysfunction and CRF assessed by CPET.

RECENT FINDINGS

We summarize the basics of exercise physiology and the key determinants of CRF. Prognostically, several studies have been published relating directly measured CRF by CPET and outcomes allowing for more precise risk assessment. Diagnostically, this review describes in detail what is considered healthy and abnormal cardiac function assessed by CPET. New studies demonstrate that cardiac dysfunction on CPET is a common finding in asymptomatic individuals and is associated with CV risk factors and lower CRF. This review covers how key CPET parameters change as individuals transition from the asymptomatic to the symptomatic stage with progressively decreasing CRF. Finally, a supplement with case studies with long-term longitudinal data demonstrating how CPET can be used in daily clinical decision making is presented.

SUMMARY

In summary, CPET is a powerful tool to provide individualized CV risk assessment, monitor the effectiveness of therapeutic interventions, and provide meaningful feedback to help patients guide their path to improve CRF when routinely used in the outpatient setting.

Establishment and effectiveness evaluation of pre-test probability model of coronary heart disease combined with cardiopulmonary exercise test indexes

To establish a pre-test probability model of coronary heart disease (CHD) combined with cardiopulmonary exercise test (CPET) indexes and to compare the clinical effectiveness with Duke clinical score (DCS) and updated Diamond-Forrester model (UDFM), thus further explore the predictive value. 342 cases were used to establish the prediction model equation and another 80 cases were used to verify the effectiveness. The patients were divided into CHD group (n = 157) and non-CHD group (n = 185) according to coronary artery stenosis degree >50% or not. Combining DCS and UDFM as reference models with CPET indexes, a multivariate logistic regression model was established. The area under the ROC curve of the three models were calculated to compare the predictive effectiveness. There were significant differences in gender, chest pain type, myocardial infarction history, hypertension history, smoking, pathological Q wave and ST-T change between two groups (P < 0.01), as well as age, LVEF, heart rate at anaerobic domain, peak oxygen uptake in kilograms of body weight, percentage of peak oxygen uptake to the predicted value, the oxygen uptake efficiency slope and carbon dioxide ventilation equivalent slope (P < 0.05). Multivariate analysis showed gender, age, chest pain type, myocardial infarction history, hypertension history, smoking, pathological Q wave, ST-T change, and peak oxygen pulse were independent risk factors of CHD. The pre-test probability model of CHD combined with CPET indexes has good distinguish and calibrate ability, its prediction accuracy is slightly better than DCS and UDFM, which still needs to be verified externally in more samples.

The cardiorespiratory optimal point as a discriminator of lesion severity in adults with congenital heart disease

BACKGROUND

Peak oxygen consumption (VO2peak), which depends on maximal exertion and is reduced in adults with congenital heart disease (ACHD), is associated with lesion severity. The lowest ventilatory equivalent for oxygen (the minimum value of VE/VO2) reflects the cardiorespiratory optimal point (COP) as best possible respiration-circulatory interaction and may discriminate between lesion types without the need for maximal exertion. However, data on COP in ACHD is scarce.

METHODS

We retrospectively analyzed stable ACHD with moderate (N.=13) and severe lesions (N.=17) reporting to our outpatient clinic undergoing cardiopulmonary exercise testing. The primary outcome of the study was the difference of COP between moderate and severe lesions. Secondary outcomes were between group differences of the submaximal variable exercise oxygen uptake efficiency slope (OUES) and peak O2 pulse (O2pulsemax) as a surrogate for peripheral oxygen extraction and stroke volume increase during exercise.

RESULTS

The group of severe lesions displayed higher COP (29.5±7.0 vs. 25.2±6.2, P=0.028) as well as lower O2pulsemax (13.3±8.4 vs. 14.9±3.4 mL/beat/kg 102, P=0.038). VO2peak (17.4±6.5 vs. 20.8±8.5 mL/kg/min, P=0.286) and OUES (1.5±0.7 vs. 1.8±0.9, P=0.613) showed a trend towards lower values in severe lesions. COP was a better between group discriminator than O2pulsemax (area under the curve 73.8% vs. 72.4%).

CONCLUSIONS

As a submaximal variable, COP discriminated between moderate and severe lesions and may prove beneficial in a highly vulnerable population that is often unable to undergo exertional testing.

Effect of ubiquinol on cardiorespiratory fitness during high-altitude acclimatization and de-acclimatization in healthy adults: the Shigatse CARdiorespiratory fitness study design

Cardiorespiratory function influences exercise capacity and is an important determinant of high-altitude adaptation. Some studies have investigated the characteristics of changes in cardiorespiratory fitness during high-altitude acclimatization. However, studies on changes in cardiorespiratory fitness during high-altitude de-acclimatization are still lacking and have not yet been elucidated. Furthermore, few drugs have been studied to improve cardiorespiratory function during both processes. The Shigatse CARdiorespiratory Fitness (SCARF) study is a single-center, randomized, double-blind, placebo-control clinical trial to explore the effects of ubiquinol on cardiorespiratory fitness during high-altitude acclimatization and de-acclimatization in healthy adults. Participants will be randomly assigned 1:1 to ubiquinol 200 mg daily or a placebo for 14 days before departure until the end of data collection after return in 7 days. Cardiorespiratory fitness is the primary outcome, while acute mountain sickness and high-altitude de-acclimatization symptoms are secondary endpoints. In addition, laboratory measurements, including routine blood tests and serological measurements, will be performed. To the best of our knowledge, the SCARF study will be the first to reveal the changes in the cardiorespiratory fitness characteristics during high-altitude acclimatization and de-acclimatization. Furthermore, the results of this study will contribute to exploring whether ubiquinol supplementation could be beneficial for endurance exercise capacity at different altitudes and help improve adaptation to acute hypoxia and de-acclimatization. Clinical Trial Registration: This study has been registered in the Chinese Clinical Trial Register (www.chictr.org.cn) as ChiCTR2200059900 and ChiCTR2200066328.

Smartwatch-Based Maximum Oxygen Consumption Measurement for Predicting Acute Mountain Sickness: Diagnostic Accuracy Evaluation Study

BACKGROUND

Cardiorespiratory fitness plays an important role in coping with hypoxic stress at high altitudes. However, the association of cardiorespiratory fitness with the development of acute mountain sickness (AMS) has not yet been evaluated. Wearable technology devices provide a feasible assessment of cardiorespiratory fitness, which is quantifiable as maximum oxygen consumption (VO2max) and may contribute to AMS prediction.

OBJECTIVE

We aimed to determine the validity of VO2max estimated by the smartwatch test (SWT), which can be self-administered, in order to overcome the limitations of clinical VO2max measurements. We also aimed to evaluate the performance of a VO2max-SWT-based model in predicting susceptibility to AMS.

METHODS

Both SWT and cardiopulmonary exercise test (CPET) were performed for VO2max measurements in 46 healthy participants at low altitude (300 m) and in 41 of them at high altitude (3900 m). The characteristics of the red blood cells and hemoglobin levels in all the participants were analyzed by routine blood examination before the exercise tests. The Bland-Altman method was used for bias and precision assessment. Multivariate logistic regression was performed to analyze the correlation between AMS and the candidate variables. A receiver operating characteristic curve was used to evaluate the efficacy of VO2max in predicting AMS.

RESULTS

VO2max decreased after acute high altitude exposure, as measured by CPET (25.20 [SD 6.46] vs 30.17 [SD 5.01] at low altitude; P<.001) and SWT (26.17 [SD 6.71] vs 31.28 [SD 5.17] at low altitude; P<.001). Both at low and high altitudes, VO2max was slightly overestimated by SWT but had considerable accuracy as the mean absolute percentage error (<7%) and mean absolute error (<2 mL·kg-1·min-1), with a relatively small bias compared with VO2max-CPET. Twenty of the 46 participants developed AMS at 3900 m, and their VO2max was significantly lower than that of those without AMS (CPET: 27.80 [SD 4.55] vs 32.00 [SD 4.64], respectively; P=.004; SWT: 28.00 [IQR 25.25-32.00] vs 32.00 [IQR 30.00-37.00], respectively; P=.001). VO2max-CPET, VO2max-SWT, and red blood cell distribution width-coefficient of variation (RDW-CV) were found to be independent predictors of AMS. To increase the prediction accuracy, we used combination models. The combination of VO2max-SWT and RDW-CV showed the largest area under the curve for all parameters and models, which increased the area under the curve from 0.785 for VO2max-SWT alone to 0.839.

CONCLUSIONS

Our study demonstrates that the smartwatch device can be a feasible approach for estimating VO2max. In both low and high altitudes, VO2max-SWT showed a systematic bias toward a calibration point, slightly overestimating the proper VO2max when investigated in healthy participants. The SWT-based VO2max at low altitude is an effective indicator of AMS and helps to better identify susceptible individuals following acute high-altitude exposure, particularly by combining the RDW-CV at low altitude.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2200059900; https://www.chictr.org.cn/showproj.html?proj=170253.

Cardiopulmonary Profiling of Athletes with Post-Exertional Malaise after COVID-19 Infection-A Single-Center Experience

(1) Background: Cardiopulmonary exercise testing (CPET) has been suggested by the European Society of Cardiology (ESC) for assessing the exercise limitations of apparently healthy individuals, but data on elite athletes regarding this test are scarce. (2) Methods: We analyzed CPET in elite (n = 43, 21.9 ± 3.7 years) and recreational (n = 40, 34.7 ± 13.0 years) athletes with persistent subjective exercise intolerance and post-exertional malaise (PEM) after COVID-19 infection. The primary outcome was the point prevalence of the adequate cardiopulmonary response (ACPR), defined by the presence of all of the following ESC criteria for apparently healthy individuals: (1) >100% of predicted peak oxygen consumption (predVO2peak), (2) VE/VCO2 < 30, (3) no exercise oscillatory ventilation (EOV), and (4) heart rate recovery of ≥12 beats/minute 1 min after exercise termination (HRR1). Results: ACPR occurred more frequently in elite athletes than in recreational athletes (70.0% vs. 39.5%; p = 0.005), mainly driven by the lower VE/VCO2 (<30: 97.7% vs. 65%, p < 0.001). Elite (11.6%) and recreational athletes (22.5%) showing a plateau of O2 pulse did not display ACPR. Conclusions: ACPR was not observed in all recreational and elite athletes with PEM. In particular, perturbed VE/VCO2 and the plateauing of O2 pulse are suitable for quantifying exercise limitations and may identify a high-risk population with long-COVID-19 syndrome who require their training intensities to be adapted.

Effect of kidney transplantation on indices of cardiorespiratory fitness assessed with cardiopulmonary exercise testing: a systematic review and meta-analysis

BACKGROUND

Patients with kidney failure often present with reduced cardiovascular reserve. Kidney transplantation (KT) is the optimal treatment for patients with end-stage kidney disease as it is associated with longer survival and improved quality of life compared to dialysis.

METHODS

This is a systematic review and meta-analysis of studies using cardiopulmonary-exercise-testing to examine the cardiorespiratory fitness of patients with kidney failure before and after KT. The primary outcome was difference in pre- and post-transplantation values of peak oxygen uptake (VO2peak). Literature search involved three databases (PubMed-Web of Science-Scopus), manual search, and grey literature.

RESULTS

From 379 records initially retrieved, six studies were included in final meta-analysis. A marginal, but not significant, improvement was observed in VO2peak after KT compared to pre-transplantation values (SMD: 0.32, 95%CI -0.02; 0.67). Oxygen consumption at anaerobic threshold was significantly improved after KT (WMD: 2.30 ml/kg/min, 95%CI 0.50; 4.09). Consistent results were shown between preemptive and after-dialysis-initiation transplantation and a trend for improvement in VO2peak was observed at least 3 months post-transplantation, but not earlier.

CONCLUSION

Several major indices of cardiorespiratory fitness tend to improve after KT. This finding may represent another modifiable factor contributing to better survival rates of kidney transplant recipients compared to patients undergoing dialysis.