Combining the ventilatory response to exercise and peak oxygen consumption is no better than peak oxygen consumption alone in predicting mortality in chronic heart failure

BACKGROUND: A low peak oxygen uptake (pVO(2)) and steep VE/VCO(2) slope are independently associated with a worse prognosis in patients with chronic heart failure (CHF). We wished to confirm whether combining these variables as a ratio would lead to a more accurate predictor of prognosis than using either alone. METHODS: 388 CHF patients completed a treadmill-based cardiopulmonary exercise test (CPET) to volitional exhaustion using a modified Bruce protocol. RESULTS: 212 CHF patients completed the CPET with a peak RER >or= 1.0. Of these, 48 patients died and one was transplanted during follow-up. In surviving patients, the median follow-up period was 42 months (IQR 34-49 months). The ratio VE/VCO(2) slope/pVO(2) was calculated for each individual and its ability to predict outcome compared with other variables. The Cox multivariable survival analysis showed that pVO(2) was the strongest independent predictor of mortality in CHF patients. CONCLUSION: Our study shows that the composite variable VE/VCO(2) slope/pVO(2) is a less effective prognosticator than pVO(2) alone in patients with CHF.     

Cardiopulmonary exercise testing for prognosis in chronic heart failure: continuous and independent prognostic value from VE/VCO(2)slope and peak VO(2).

BACKGROUND: Chronic heart failure carries a poor prognosis. Cardiopulmonary exercise testing is useful in predicting survival. We set out to establish the prognostic value of peak VO(2)and VE/VCO(2)slope across a range of threshold values. METHOD AND RESULTS: Three hundred and three consecutive patients with stable chronic heart failure underwent cardiopulmonary exercise testing between 1992 and 1996. Their age was 59+/-11 years (mean+/-SD), peak VO(2)17. 8+/- 6.6 ml. kg(-1)min(-1), VE/VCO(2)slope 37+/-12. At the end of follow-up in January 1999, 91 patients had died (after a median of 7 months, interquartile range 3-16 months). The median follow-up for the survivors was 47 months (interquartile range 37-57 months). The areas under the receiver-operating characteristic curves for predicting mortality at 2 years were 0.77 for both peak VO(2)and VE/VCO(2)slope. With peak VO(2)and VE/VCO(2)slope viewed as continuous variables in the Cox proportional-hazards model, they were both highly significant prognostic indicators, both in univariate analysis and bivariate analysis (P<0.001 for VE/VCO(2)slope, P<0.003 for peak VO(2)). CONCLUSIONS: Lower peak VO(2)implies poorer prognosis across a range of values from 10 to 20 ml. kg(-1)min(-1), without a unique threshold. Gradations of elevation of the VE/VCO(2)slope also carry prognostic information over a wide range (30-55). The two parameters are comparable in terms of prognostic power, and contribute complementary prognostic information.     

A neural network approach to predicting outcomes in heart failure using cardiopulmonary exercise testing

Objectives

To determine the utility of an artificial neural network (ANN) in predicting cardiovascular (CV) death in patients with heart failure (HF).

Background

ANNs use weighted inputs in multiple layers of mathematical connections in order to predict outcomes from multiple risk markers. This approach has not been applied in the context of cardiopulmonary exercise testing (CPX) to predict risk in patients with HF.

Methods

2635 patients with HF underwent CPX and were followed for a mean of 29 ± 30 months. The sample was divided randomly into ANN training and testing sets to predict CV mortality. Peak VO₂, VE/VCO₂ slope, heart rate recovery, oxygen uptake efficiency slope, and end-tidal CO₂ pressure were included in the model. The predictive accuracy of the ANN was compared to logistic regression (LR) and a Cox proportional hazards (PH) score. A multi-layer feed-forward ANN was used and was tested with a single hidden layer containing a varying number of hidden neurons.

Results

There were 291 CV deaths during the follow-up. An abnormal VE/VCO₂ slope was the strongest predictor of CV mortality using conventional PH analysis (hazard ratio 3.04; 95% CI 2.2–4.2, p < 0.001). After training, the ANN was more accurate in predicting CV mortality compared to LR and PH; ROC areas for the ANN, LR, and PH models were 0.72, 0.70, and 0.69, respectively. Age and BMI-adjusted odds ratios were 4.2, 2.6, and 2.9, for ANN, LR, and PH, respectively.

Conclusion

An ANN model slightly improves upon conventional methods for estimating CV mortality risk using established CPX responses.     

The prognostic value of exercise testing in elderly men

PURPOSE: Our purposes were to compare the responses to exercise testing in elderly (> or =65 years of age) and younger men, and to investigate whether exercise testing has similar prognostic value in the two age groups. METHODS: We included all elderly (n = 1185) and younger (n = 2789) male veterans without established coronary heart disease who underwent routine clinical exercise testing between 1987 and 2000 at two academically affiliated Veteran's Affairs medical center laboratories. Measurements included a standardized medical history, exercise testing, and all-cause mortality. RESULTS: Compared with younger patients, elderly patients achieved a lower workload (a mean [+/- SD] of 7 +/- 3 vs. 10 +/- 4 metabolic equivalents [METs], P <0.001) and were more likely to have abnormal ST depression (27% [n = 324] vs. 16% [n = 436], P <0.001). During the mean follow-up of 6 years, annual mortality was twice as high among elderly patients as among younger patients (4% vs. 2%, P <0.001). The only exercise test variable that was associated significantly with time to death in both age groups was maximal METs achieved: each 1 MET increase in exercise capacity was associated with an 11% reduction in annual mortality. Exercise-induced ST depression was more common in those who subsequently died, but was not an independent predictor of mortality. CONCLUSION: In elderly men, exercise testing provided prognostic information incremental to clinical data. Achieved workload (in METs) was the major exercise testing variable associated with all-cause mortality. Its prognostic importance was the same in elderly as in younger men.     

Effects of combined exercise on gait variability in community-dwelling older adults

Training that focuses on strength, balance, and endurance, the so-called combined exercise, can enhance physical function, including gait, according to a literature review. However, the effects of combined exercise on improving gait variability are limited. The objective of this study is to investigate the effects of 12 weeks of combined exercise comprised of resistance, endurance, and balance training on gait performance in older adults. Twenty-nine community-dwelling older adults were recruited and assigned to either the experimental group (n = 17) or the control group (n = 12). The 12-week intervention was a combined exercise program at 1 h per day and 3 days per week. The participants received an assessment for both a 6-min walk and gait during both habitual walking and fast walking conditions at pre-intervention and after 8 and 12 weeks of exercise. The 6-min walk was used to assess gait endurance. GAITRite was used to evaluate gait. An analysis of covariance with the pretest score as the covariate was used to determine the difference in each dependent variable between groups. The level of significance was set as p less than 0.05. Our results showed significant between-group effects in the 6-min walk and velocity, stride time, and stride length in both conditions after 8 weeks of exercise and significant between-group effects in the 6-min walk test and all selected gait parameters in both conditions after 12 weeks of exercise. Our findings demonstrate that a 12-week combined exercise program may positively affect gait endurance and gait performance including gait variability in habitual walking and fast walking conditions among older adults. The current study provides important evidence of short-term combined exercise effects on improvements in gait performance.     

Effects of exercise on dual-task ability and balance in older adults: A systematic review

The interest in research on exercise and physical activity effects on dual-task performance has grown rapidly in the last decade due to the aging global population. Most of the available literature is focused on exercise benefits for the risk of falls, attention, and gait-speed; however, there is a lack of evidence reporting the exercise effects on balance in healthy older adults during dual-task performance. The objective of this study was to critically review the existing evidence of a potential relationship between exercise and improvement of static and dynamic balance during dual-task in healthy older adults and secondary outcomes in other physical and cognitive indices. A systematic search using online databases was used to source articles. Inclusion criteria included articles classified as randomized controlled trials (RCT), controlled trials (CT) and uncontrolled trials (UT). Moreover, the studies had to include an exercise or physical activity protocol in the intervention. Eight studies met the eligibility criteria and included 6 RCTs, 1 CT, and 1 UT. Several limitations were identified, mainly focused on the lack of a common and standardized method to evaluate the balance during the dual-task performance. Additionally, exercise protocols were extensively different, and generally lacked reporting measures. Preliminary findings show that the current body of evidence does not support that exercises used in these interventions entail clear and noteworthy benefits on static or dynamic balance improvements during dual-task performance. Innovative measures and exercise programs may need to be developed before efficacious screening and treatment strategies can be used in clinical settings.     

心肺运动试验摄氧量恢复延迟对经皮冠状动脉介入治疗术后患者预后的影响

目的探讨心肺运动试验(CPET)摄氧量恢复延迟(VO₂RD)对经皮冠状动脉介入治疗(PCI)术后心电图运动试验阴性患者预后的影响。方法回顾性分析北京大学第三医院2018年1月至2019年9月在PCI术后半年内行CPET且心电图运动试验阴性患者1268例,收集患者的临床资料、冠状动脉造影及介入操作资料、实验室检查、超声心动图及CPET检查结果。所有患者通过门诊或电话随访,记录患者不良心血管事件,包括死亡、心肌梗死、卒中、短暂性脑缺血发作、非计划再次PCI、周围血管介入治疗、不稳定型心绞痛和急性心力衰竭事件引起的住院。采用多因素Cox回归分析探讨CPET VO₂RD是否影响PCI术后心电图运动试验阴性患者的预后。结果1268例入选患者中完成随访1218例,失访50例,随访14(10,20)个月,共发生不良心血管事件105例(8.6%)。不良事件组年龄[(62.4±9.9)岁比(60.3±10.2)岁,P=0.020]、不完全血运重建比例(42.9%比31.6%,P=0.022)以及合并高脂血症比例(79.0%比68.0%,P=0.020)均显著高于无不良事件组;糖化血红蛋白值[(7.3±1.1)%比(6.6±1.2)%,P=0.001]、空腹血糖[(7.1±2.6)mmol/L比(6.5±1.9)mmol/L,P=0.010]及N末端B型脑钠肽前体[107.5(50.1,399.8)pg/ml比88.2(39.2,225.0)pg/ml,P=0.017]显著高于无不良事件组;峰值心率[(121±18)次/分比(126±20)次/分,P=0.012]、无氧阈心率[(99±12)次/分比(102±14)次/分,P=0.029]和峰值摄氧量[(17.3±4.7)ml/(min·kg)比(18.7±2.1)ml/(min·kg),P=0.003]显著低于无不良事件组,二氧化碳通气当量斜率[(33.3±9.2)比(28.1±5.1),P=0.001]和VO₂RD[(21.4±4.5)s比(18.5±5.4)s,P=0.001]显著高于无不良事件组。多因素Cox回归分析显示VO₂RD>20 s(HR 1.594,95%CI 1.026~2.476,P=0.038)是PCI术后心电图运动试验阴性患者发生不良心血管事件的独立危险因素。结论PCI术后心电图运动试验阴性的患者仍有一定的不良心血管事件发生风险,CPET恢复期指标VO₂RD>20 s是此类患者发生不良心血管事件的独立预测因素。     

Prediction of mortality in patients without angina: use of an exercise score and exercise echocardiography.

BACKGROUND: Exercise testing has limited efficacy for identifying coronary artery disease (CAD) in the absence of anginal symptoms. Exercise echocardiography is more accurate than standard exercise testing, but its efficacy in this situation has not been defined. We sought to identify whether the Duke treadmill score or exercise echocardiography (ExE) could be used to identify risk in patients without anginal symptoms. METHODS: We studied 1859 patients without typical or atypical angina, heart failure, or a history or ECG evidence of infarction or CAD, who were referred for ExE, of whom 1832 (age 51+/-15 years, 944 men) were followed for up to 10 years. The presence and extent of ischaemia and scar were interpreted by expert reviewers at the time of the original study. RESULTS: Exercise provoked significant (>0.1mV) ST segment depression in 215 patients (12%), and wall motion abnormalities in 137 (8%). Seventy-eight patients (4%) died before revascularization, only 17 from known cardiac causes. The independent predictors of death were age (RR 1.1, p<0.0001), smoking, Duke treadmill score (RR 0.9, p<0.0001) and resting LV dysfunction (RR 1.9, p<0.04), but did not include ischaemia at ExE. Echocardiography was not predictive of outcome in subgroups with an intermediate or high risk Duke score, nor in patients with two or more risk factors. CONCLUSIONS: Patients without anginal symptoms have a low mortality, especially from cardiac causes. If such individuals undergo exercise testing and a resting echocardiogram, exercise echocardiography does not offer additional prognostic information.     

Reproducibility of cardiopulmonary exercise testing in men following myocardial infarction

Peak oxygen consumption during progressive exercise is of clinicalrelevance in the functional evaluation of the cardiac patient.The use of cardiopulmonary exercise testing for the evaluationof the efficacy of therapeutic intervention requires that themethods used yield reproducible results. This study comparedthe results of two consecutive, symptom-limited, maximal exercisetests in 170 men following confirmed myocardial infarction.On-line, real-time respiratory gas exchange was measured ona breath-by-breath basis. The data were processed by the systemusing a 9 s moving average filter and the peak values were determinedas averaged over a representative 20-s interval during the final1 min of the test. The mean (±SD) total exercise timesfor the two tests were 635 (±109) vs.652(±112)(r=0.946). The mean (±SD) peak VO₂ values were 1480 (±337)vs. 1495 (±350) ml min^–1 (r=0.923). Performancecould not be predicted by routine assessment of infarct typeor size. This study demonstrates that maximal cardiopulmonaryexercise testing in men following myocardial infraction yieldshighly reproducible results.     

Prognostic value of aerobic capacity and exercise oxygen pulse in postaortic dissection patients

BackgroundAlthough recommendations encourage daily moderate activities in post aortic dissection, very little data exists regarding cardiopulmonary exercise testing (CPET) to personalize those patient''s physical rehabilitation and assess their cardiovascular prognosis.DesignWe aimed at testing the prognostic insight of CPET regarding aortic and cardiovascular events by exploring a prospective cohort of patients followed‐up after acute aortic dissection.MethodsPatients referred to our department after an acute (type A or B) aortic dissection were prospectively included in a cohort between September 2012 and October 2017. CPET was performed once optimal blood pressure control was obtained. Clinical follow‐up was done after CPET for new aortic event and major cardio‐vascular events (MCE) not directly related to the aorta.ResultsAmong the 165 patients who underwent CPET, no adverse event was observed during exercise testing. Peak oxygen pulse was 1.46(1.22‐1.84) mlO2/beat, that is, 97 (83–113) % of its predicted value, suggesting cardiac exercise limitation in a population under beta blockers (92% of the population). During a follow‐up of 39(20‐51) months from CPET, 42 aortic event recurrences and 22 MCE not related to aorta occurred. Low peak oxygen pulse (<85% of predicted value) was independently predictive of aortic event recurrence, while low peak oxygen uptake (<70% of predicted value) was an independent predictor of MCE occurrence.ConclusionCPET is safe in postaortic dissection patients should be used to not only to personalize exercise rehabilitation, but also to identify those patients with the highest risk for new aortic events and MCE not directly related to aorta.     

Usefulness of cardiopulmonary exercise testing to predict the development of arterial hypertension in adult patients with repaired isolated coarctation of the aorta

Background

Patients who underwent surgery for aortic coarctation (COA) have an increased risk of arterial hypertension. We aimed at evaluating (1) differences between hypertensive and non-hypertensive patients and (2) the value of cardiopulmonary exercise testing (CPET) to predict the development or progression of hypertension.

Methods

Between 1999 and 2010, CPET was performed in 223 COA-patients of whom 122 had resting blood pressures of < 140/90 mm Hg without medication, and 101 were considered hypertensive. Comparative statistics were performed. Cox regression analysis was used to assess the relation between demographic, clinical and exercise variables and the development/progression of hypertension.

Results

At baseline, hypertensive patients were older (p = 0.007), were more often male (p = 0.004) and had repair at later age (p = 0.008) when compared to normotensive patients. After 3.6 ± 1.2 years, 29/120 (25%) normotensive patients developed hypertension. In normotensives, VE/VCO₂-slope (p = 0.0016) and peak systolic blood pressure (SBP; p = 0.049) were significantly related to the development of hypertension during follow-up. Cut-off points related to higher risk for hypertension, based on best sensitivity and specificity, were defined as VE/VCO₂-slope ≥ 27 and peak SBP ≥ 220 mm Hg. In the hypertensive group, antihypertensive medication was started/extended in 48/101 (48%) patients. Only age was associated with the need to start/extend antihypertensive therapy in this group (p = 0.042).

Conclusions

Higher VE/VCO₂-slope and higher peak SBP are risk factors for the development of hypertension in adults with COA. Cardiopulmonary exercise testing may guide clinical decision making regarding close blood pressure control and preventive lifestyle recommendations.     

性别差异对中重度慢性阻塞性肺疾病患者运动耐力的影响

目的 比较中重度慢性阻塞性肺疾病(COPD)患者运动耐力的性别差异.方法 本研究对151例中、重度COPD患者的肺功能(PFT)和功率递增心肺运动试验(CPET)结果进行了分析.将患者分为Ⅱ级COPD组和Ⅲ级COPD组.并选择43例年龄、性别、身高、体质量相匹配的正常人作为对照组.本研究测定第1秒用力呼气容积(FEV1)、用力肺活量(FVC)、峰值运动功率(Peak Load)、峰值摄氧量(Peak (V)O2)、峰值心率(Peak HR)、峰值氧脉搏(Peak(V)O2/HR)、最大分钟通气量(M(V)E)、气促指数(M(V)E/MVV)等指标.本研究分别在不同COPD分级和性别之间分析比较了上述指标的差异.结果 Ⅱ级COPD组和Ⅲ级COPD组的女性患者的Peak (V)O2实/预％和Peak (V)O2/HR实/预％较同组男性更高(P值均＜0.05).Ⅲ级COPD男性患者的运动耐力较Ⅱ级有明显降低(P＜0.0001),然而,Ⅲ级、Ⅱ级COPD女性患者之间运动耐力差异无统计学意义(P=0.246).结论 在中、重度COPD患者中,男性运动耐力下降较女性更为严重,吸烟可能是造成这一差异的重要因素.     

两种运动试验对慢性阻塞性肺疾病患者运动低氧的比较

目的:对比6min步行试验(6MWT)与心肺运动试验(CPET)对慢性阻塞性肺疾病(COPD)患者运动低氧敏感性的差别。方法:选择30例稳定期COPD患者,分别行6MWT与CPET,两个试验的先后顺序随机,比较两种运动试验中运动低氧发生情况的差异。结果:6MWT中运动低氧发生率为46.6%(14/30),CPET中发生运动低氧发生率为50.0%(15/30),两种试验运动低氧的发生率,差异无统计学意义(P=0.796)。运动开始第2min至第6min,6MWT每分钟末脉搏血氧饱和度(SpO2)值低于心肺运动试验(P均0.05)。运动低氧发生时间6MWT(M=2)秒,明显早于CPET(M=8)秒(P=0.01)。结论:6MWT与CPET在COPD患者运动低氧发生率差异无统计学意义,运动低氧发生时间6MWT早于CPET。6MWT是一个简单、可行的COPD患者运动低氧的评价方案。     

800例平板运动试验资料关于冠心病危险因素的外析

目的:探讨冠心病与性别、年龄、血压、血脂或血粘度、体重、生活方式(包括体育锻炼、生活规律性,不良嗜好、饮食习惯)、精神卫生等因素的关系。方法:对我院1997年9月~2001年12月作平板运动试验,资料完全的800例患者的资料进行回顾性分析。结果:与平板运动试验阳性相关的诸因素有年龄大,女性,高血压,高血脂,不良生活方式(P<0.05~<0.01)。结论:为防治冠心病的发生,建议人们采取良好的生活方式,戒烟、戒酒,均衡饮食,保持健康的心理状态,参加适量体育锻炼。     

Congenital heart disease in adults: Assessmentof functional capacity using cardiopulmonary exercise testing

Aim

The aim of the study was to compare functional capacity in different types of congenital heart disease (CHD), as assessed by cardiopulmonary exercise testing (CPET).