Peak VO(2) is more potent than B-type natriuretic peptide as a prognostic parameter in cardiac patients

Development of deep-learning models for real-time anaerobic threshold and peak VO2 prediction during cardiopulmonary exercise testing

AIMS

Exercise intolerance is a clinical feature of patients with heart failure (HF). Cardiopulmonary exercise testing (CPET) is the first-line examination for assessing exercise capacity in patients with HF. However, the need for extensive experience in assessing anaerobic threshold (AT) and the potential risk associated with the excessive exercise load when measuring peak oxygen uptake (peak VO2) limit the utility of CPET. This study aimed to use deep-learning approaches to identify AT in real time during testing (defined as real-time AT) and to predict peak VO2 at real-time AT.

METHODS AND RESULTS

This study included the time-series data of CPET recorded at the Department of Cardiovascular Medicine, Kyushu University Hospital. Two deep neural network models were developed to: (i) estimate the AT probability using breath-by-breath data and (ii) predict peak VO2 using the data at the real-time AT. The eligible CPET contained 1472 records of 1053 participants aged 18-90 years and 20% were used for model evaluation. The developed model identified real-time AT with 0.82 for correlation coefficient (Corr) and 1.20 mL/kg/min for mean absolute error (MAE), and the corresponding AT time with 0.86 for Corr and 0.66 min for MAE. The peak VO2 prediction model achieved 0.87 for Corr and 2.25 mL/kg/min for MAE.

CONCLUSION

Deep-learning models for real-time CPET analysis can accurately identify AT and predict peak VO2. The developed models can be a competent assistant system to assess a patient's condition in real time, expanding CPET utility.

Factors contributing to exercise tolerance in patients with coronary artery disease undergoing percutaneous coronary intervention

BACKGROUND

Exercise tolerance plays a vital role in the process of cardiac rehabilitation in patients undergoing percutaneous coronary intervention (PCI). The study sought to determine the characteristics, risks and correlates of post-PCI exercise tolerance in patients with coronary artery disease (CAD).

METHODS

We analyzed clinical data of 299 CAD patients undergoing elective PCI and completing cardiopulmonary exercise testing (CPET). According to the Weber classification, post-PCI exercise tolerance was evaluated by peak oxygen uptake (VO₂ peak). We assessed the impact of 34 predefined clinical features, cardiac functional parameters, and blood biochemistry data on exercise tolerance by univariate analysis and logistics regression analysis.

RESULTS

Of 299 patients, 74.92% were men and average age was 60.90 ± 10.68 years. VO₂ peak in the entire population was 17.54 ± 3.38 ml/kg/min, and 24.41% (n = 73) were less than 16 ml/kg/min, who were considered to have exercise intolerance. Multivariate logistics regression results showed that sex, diabetes mellitus, number of stents, left atrial diameter (LAD), end-diastolic volume (EDV), and hemoglobin influenced the peak oxygen uptake of CAD patients undergoing elective PCI. (All p < 0.05).

CONCLUSIONS

Nearly one quarter of CAD patients have exercise intolerance in the early post-PCI period. Female, diabetes mellitus, number of stents, LAD, EDV might negatively impacted post-PCI exercise tolerance, which need further warrant by large scale cohort study.

Association of post-diagnosis cardiorespiratory fitness with cause-specific mortality in cancer

AIMS

The prognostic importance of post-diagnosis assessment of cardiorespiratory fitness (CRF) in cancer patients is not well established. We sought to examine the association between CRF and mortality in cancer patients.

METHODS AND RESULTS

This was a single-centre cohort analysis of 1632 patients (58% male; 64 ± 12 years) with adult-onset cancer who were clinically referred for exercise treadmill testing a median of 7 [interquartile range (IQR): 3-12] years after primary diagnosis. Cardiorespiratory fitness was defined as peak metabolic equivalents (METs) achieved during standard Bruce protocol and categorized by tertiles. The association between CRF and all-cause and cause-specific mortality was assessed using multivariable Cox proportional hazard models adjusting for important covariates. Median follow-up was 4.6 (IQR: 2.6-7.0) years; a total of 411 deaths (229, 50, and 132 all-cause, cardiovascular (CV), and cancer related, respectively) occurred during this period. Compared with low CRF (range: 1.9-7.6 METs), the adjusted hazard ratio (HR) for all-cause mortality was 0.38 [95% confidence interval (CI): 0.28-0.52] for intermediate CRF (range: 7.7-10.6 METs) and 0.17 (95% CI: 0.11-0.27) for high CRF (range: 10.7-22.0 METs). The corresponding HRs were 0.40 (95% CI: 0.19-0.86) and 0.41 (95% CI: 0.16-1.05) for CV mortality and 0.40 (95% CI: 0.26-0.60) and 0.16 (95% CI: 0.09-0.28) for cancer mortality, respectively. The adjusted risk of all-cause, CV, and cancer mortality decreased by 26%, 14%, and 25%, respectively with each one MET increment in CRF.

CONCLUSION

Cardiorespiratory fitness is a strong, independent predictor of all-cause, CV, and cancer mortality, even after adjustment for important clinical covariates in patients with certain cancers.

Prognostic value of the heart rate profile during exercise in patients with atrial fibrillation

Aims

This study aimed to investigate the correlation of heart rate profile during exercise with exercise capacity and heart failure occurrence in patients with atrial fibrillation compared with patients with sinus rhythm.

Methods

We analyzed 2231 patients (atrial fibrillation: n = 321, sinus rhythm: n = 1910) who underwent a symptom-limited maximal cardiopulmonary exercise test at our institute. Their heart rate profile during exercise was assessed using peak heart rate and chronotropic response; (peak heart rate−resting heart rate)/(220−age−resting heart rate). The endpoint was the occurrence of heart failure events, defined as hospitalization for heart failure or heart failure-related death.

Results

There were significant positive correlations of peak heart rate and chronotropic response to peak oxygen consumption, both in atrial fibrillation and sinus rhythm. During a median follow-up period of 1262 (interquartile range 974–2921) days, 117 (5.2%) heart failure events were observed. Multivariate analyses showed that peak heart rate and chronotropic response were statistically significant predictors of heart failure events both in atrial fibrillation (peak heart rate: heart rate 0.975, p = 0.002, chronotropic response: heart rate 0.196, p = 0.003) and in sinus rhythm (peak heart rate: heart rate 0.988, p = 0.036, chronotropic response: heart rate 0.347, p = 0.020). Bivariate models showed that compared with chronotropic response, peak heart rate was a stronger predictor of heart failure in atrial fibrillation, whereas the finding was reversed in sinus rhythm.

Conclusion

The exercise- heart rate profile was significantly related to exercise capacity and future heart failure events, regardless of rhythm. However, the impacts of peak heart rate and chronotropic response on the endpoint varied according to the cardiac rhythm.

Cancer Treatment as an Accelerated Aging Process: Assessment, Biomarkers, and Interventions

An accumulating body of evidence supports the hypothesis that cancer and/or cancer treatment is associated with accelerated aging. The majority of these data come from the pediatric literature; however, a smaller yet growing body of literature points toward similar findings in the geriatric population. This is a key survivorship issue the growing number of older adults with cancer face, along with the short- and long-term impact of cancer therapy on the aging process. This article will review clinical and biologic markers of aging in older adults with cancer, use cardiovascular disease as a model of accelerated aging, and discuss potential interventions to decrease the risk.

Cardiopulmonary function and age-related decline across the breast cancer survivorship continuum

PURPOSE

To evaluate cardiopulmonary function (as measured by peak oxygen consumption [VO(2peak)]) across the breast cancer continuum and its prognostic significance in women with metastatic disease.

PATIENTS AND METHODS

Patients with breast cancer representing four cross-sectional cohorts--that is, (1) before, (2) during, and (3) after adjuvant therapy for nonmetastatic disease, and (4) during therapy in metastatic disease--were studied. A cardiopulmonary exercise test (CPET) with expired gas analysis was used to assess VO(2peak). A Cox proportional hazards model was used to estimate the risk of death according to VO(2peak) category (< 15.4 v ≥ 15.4 mL · kg(-1) · min(-1)) with adjustment for clinical factors.

RESULTS

A total of 248 women (age, 55 ± 8 years) completed a CPET. Mean VO(2peak) was 17.8 ± a standard deviation of 4.3 mL · kg(-1) · min(-1), the equivalent of 27% ± 17% below age-matched healthy sedentary women. For the entire cohort, 32% had a VO(2peak) less than 15.4 mL · kg(-1) · min(-1)--the VO(2peak) required for functional independence. VO(2peak) was significantly different across breast cancer cohorts for relative (mL · kg(-1) · min(-1)) and absolute (L · min(-1)) VO(2peak) (P = .017 and P < .001, respectively); VO(2peak) was lowest in women with metastatic disease. In patients with metastatic disease (n = 52), compared with patients achieving a VO(2peak) ≤ 1.09 L · min(-1), the adjusted hazard ratio for death was 0.32 (95% CI, 0.16 to 0.67, P = .002) for a VO(2peak) more than 1.09 L · min(-1).

CONCLUSION

Patients with breast cancer have marked impairment in VO(2peak) across the entire survivorship continuum. VO(2peak) may be an independent predictor of survival in metastatic disease.

Comparison of usefulness of each of five predictors of mortality and urgent transplantation in patients with advanced heart failure

B-type natriuretic peptide (BNP), peak oxygen consumption (VO(2)), blood urea nitrogen (BUN), systolic blood pressure (SBP), and pulmonary capillary wedge pressure are all established predictors of mortality or urgent transplantation in patients with advanced heart failure (HF). However, their comparative predictive ability in estimating prognosis has not been well studied. We analyzed 1,215 patients with advanced systolic HF referred to a university center from 1999 to 2009. BUN, BNP, VO(2), SBP, and pulmonary capillary wedge pressure were measured as a part of the initial evaluation. The patients were divided into groups according to the best cutoffs for predicting both 1- and 2-year mortality from the analysis of the receiver operating characteristic curves (BNP > or =579 pg/ml, peak VO(2) <14 ml/kg/min, BUN > or =53 mg/dl, SBP <118 mm Hg, and pulmonary capillary wedge pressure > or =21 mm Hg). During a 2-year follow-up, 234 patients (19%) died, and 208 (17%) required urgent transplantation. BNP (odds ratio 4.3, 95% confidence interval 3.3 to 5.5) and peak VO(2) (odds ratio 4.5, 95% confidence interval 2.6 to 7.8) were the strongest predictors for death or urgent transplantation. On multivariate analyses, BNP and peak VO(2) were the strongest predictors for both death or urgent transplantation and all-cause mortality. The c-statistic was 0.756 for BNP, 0.701 for VO(2), 0.659 for BUN, 0.638 for SBP, and 0.650 for pulmonary capillary wedge pressure. In conclusion, of the 5 established predictors of outcomes in advanced HF, BNP was the most robust discriminator of risk and thus could be useful, along with other more traditional prognostic variables, in patient counseling regarding prognosis and determining the timing for heart transplantation.

Irrelevant B-type natriuretic peptide levels in patients with mechanical prostheses in the mitral position presenting with congestive heart failure

BACKGROUND

Plasma B-type natriuretic peptide (BNP) level is reported to be a strong marker of congestive heart failure (CHF). Heterogeneity of the BNP levels among individuals with CHF, however, can cause confusion in interpreting the results. The influence of mitral mechanical prostheses on BNP levels in patients presenting with CHF is not well known.

METHODS AND RESULTS

In the present study 214 consecutive patients with CHF diagnosed using the Framingham criteria were enrolled and divided into 2 groups with and without mitral mechanical prostheses (prosthesis group, n=31; native group, n=183). The plasma BNP levels were measured, and clinical examinations including echocardiography were performed at the same time to assess cardiac performance. There was no difference in the left ventricular ejection fractions between the 2 groups. Despite having a lower body mass index, larger prevalence ratio of atrial fibrillation and larger size of the left atrium, the prosthesis group had a significantly lower logBNP level than the native group (prosthesis group vs native group: 5.12+/-1.01 vs 6.21+/-0.92, P<0.001; BNP level: 167+/-324 pg/ml vs 498+/-380 pg/ml). On multivariate analysis the presence of a mitral mechanical prosthesis was extracted as an independent predictor for decreased BNP level in patients with CHF.

CONCLUSIONS

Plasma BNP level cannot correctly reflect the severity of CHF in patients with mechanical prostheses in the mitral position.

Change in ischemia-modified albumin and its clinical significance during exercise stress testing

BACKGROUND

There is little data about the additive effects of ischemia-modified albumin (IMA) on the exercise stress test (EST) used for the screening of ischemic heart disease. The relationship between myocardial ischemic burden and the change in IMA (DeltaIMA) during EST was investigated.

METHODS AND RESULTS

EST was performed using the Bruce protocol to evaluate chest pain or exertional dyspnea in 155 patients (men 89, 53+/-13 years). Blood samples for IMA were obtained before and immediately after EST. According to the EST results and the pattern of DeltaIMA, patients were categorized into 3 groups (none was classified as EST(-)/DeltaIMA(+)): (1) (EST(-); (2) EST(+)/DeltaIMA(-); and (3) EST(+)/DeltaIMA(+). After EST, 60 of 155 (38.7%) patients were EST(+) and 14/60 (23.3%) were EST(+)/DeltaIMA(+). Duke treadmill score was significantly lower in the EST(+)/DeltaIMA(+) group compared with the other groups (-9.0+/-7.9, -1.7+/-4.2, 6.7+/-4.4, respectively, P<0.001); 43/60 (72%) patients with EST(+) underwent coronary angiography and the proportion of patients with a large ischemic burden was higher in the EST(+)/DeltaIMA(+)group compared with the EST(+)/DeltaIMA(-) group (72.7% vs 15.6%, P=0.001).

CONCLUSIONS

Increased IMA after EST suggests a large ischemic burden in coronary artery disease, so the DeltaIMA during EST may be useful for predicting the severity of myocardial ischemia.