Rationale and design of a randomized trial on the effectiveness of aerobic interval training in patients with coronary artery disease: The SAINTEX-CAD study

Effect of Different Endurance Training Protocols During Cardiac Rehabilitation on Quality of Life

BACKGROUND

This study aimed to assess the effect of different types of endurance training during outpatient cardiac rehabilitation on patients' health-related quality of life (HRQL).

METHODS

The MacNew Heart Disease HRQL questionnaire and the Hospital Anxiety and Depression Scale were used to assess changes in HRQL in 66 patients before and after 6 weeks of cardiac rehabilitation. Patients were randomized to 1 of 3 types of supervised endurance training: continuous endurance training, high-intensity interval training, and pyramid training. Two-way analysis of variance for repeated measure and chi-square test were used to analyze changes before and after rehabilitation.

RESULTS

Attendance rate during the 6 weeks of exercise training was 99.2%. Physical work capacity increased from 136.1 to 165.5 watts (+22.9%; P < .001), and there were no statistical differences between training protocols. Fully completed questionnaires at both time points were available in 46 patients (73.9%; 61.3±11.6 years, 34 males, 12 females). Regardless of the type of supervised endurance training, there was significant improvement during rehabilitation in each of the categories of the MacNew questionnaire (ie, emotion, physical, social, global; all P < .05) and the Hospital Anxiety and Depression Scale (anxiety: P = .05; depression: P = .032), without significant differences between protocols.

CONCLUSIONS

All 3 types of endurance training led to significant and well comparable increases in physical work capacity, which was associated with an increase in HRQL independent of the type of training. Our findings support further individualization of training regimes, which could possibly lead to better compliance during life-long home-based exercise training.

Effect of aerobic training on exercise capacity and quality of life in patients older than 75 years with acute coronary syndrome undergoing percutaneous coronary intervention

BACKGROUND

Limited clinical studies are available on early exercise-based cardiac rehabilitation in elderly acute coronary syndrome (ACS) patients.

OBJECTIVE

To evaluate the effect of aerobic exercise on exercise capacity and quality of life (QoL) in such patients.

METHODS

Seventy elderly patients with ACS undergoing percutaneous coronary intervention in Zhejiang Hospital during August 2016-June 2017 were randomly divided into the control (n = 35) or cardiac rehabilitation group (CR, n = 35). The control group was treated with standard medical treatments without exercise, whereas the CR group was treated with standard medical treatments and exercise-based cardiac rehabilitation. General information, cardiopulmonary exercise test (CPET) results, responses to QoL and mental health questionnaires, and clinical outcomes and safety were collected.

RESULTS

The CR group safely finished CPET and the 12-week exercise-based cardiac rehabilitation. After the 12-week intervention, the CR group showed significant differences in maximal oxygen uptake (VO_2max) and greater improvements in VO_2max, compared with the control group. The CR group showed statistically significant differences in QoL and mental health compared with the control group.

CONCLUSION

CPET-based exercise in cardiac rehabilitation can safely increase exercise capacity and QoL in such patients.

Impact of aerobic interval training and continuous training on left ventricular geometry and function: a SAINTEX-CAD substudy

BACKGROUND

Increase of exercise capacity (peak VO₂) after cardiac rehabilitation improves outcome in patients with coronary artery disease (CAD). Systolic and diastolic function have been associated with peak VO₂, but their role towards improvement of exercise capacity remains unclear. It is unknown which exercise intensity has the most beneficial impact on left ventricular (LV) geometry and function in CAD patients without heart failure.

METHODS

200 stable CAD patients without heart failure were randomized to 3months of aerobic interval training (AIT) or aerobic continuous training (ACT). Cardiopulmonary exercise test and transthoracic echocardiography were scheduled before and after 3months of training.

RESULTS

At baseline, a higher peak VO₂ correlated with lower LV posterior wall thickness (p=0.002), higher LV ejection fraction (p=0.008), better LV global longitudinal strain (p=0.043) and lower E/e' (0=0.001). After multivariate stepwise regression analysis only E/é remained an independent predictor of peak VO₂ (p=0.042). Improvement of peak VO₂ after 3months of training correlated with reverse remodeling of the interventricular septum (p=0.005), enlargement of LV diastolic volume (p=0.007) and increase of LV stroke volume (p=0.018) but not with other indices of systolic or diastolic function. Significant reduction of the interventricular septum thickness after cardiac rehabilitation was observed (p=0.012), with a trend towards more reverse remodeling after ACT compared to AIT (p=0.054). In contrast, there were no changes in other parameters of LV geometry, diastolic or systolic function.

CONCLUSION

Systolic and diastolic function are determinants of baseline exercise capacity in CAD patients without heart failure, but do not seem to mediate improvement of peak VO₂ after either AIT or ACT.

The effect of aerobic interval training and continuous training on exercise capacity and its determinants

Objective We aimed to investigate (1) the effects of aerobic interval training (AIT) and aerobic continuous training (ACT) on (sub)maximal exercise measures and its determinants including endothelial function, muscle strength and cardiac autonomic function, and (2) the relationship between exercise capacity and these determinants. Methods Two-hundred coronary artery disease (CAD) patients (58.4 ± 9.1 years) were randomized to AIT or ACT for 12 weeks. All patients performed a cardiopulmonary exercise test and endothelial function measurements before and after the intervention; a subpopulation underwent muscle strength and heart rate variability (HRV) assessments. Results The VO₂, heart rate and workload at peak and at first and second ventilatory threshold increased (P-time <0.001); the oxygen uptake efficiency slope (P-time <0.001) and half time of peak VO₂ (P-time <0.001) improved. Endothelial function and heart rate recovery (HRR) at 1 and 2 min improved (P-time <0.001), while measures of muscle strength and HRV did not change. Both interventions were equally effective. Significant correlations were found between baseline peak VO₂ and (1) quadriceps strength (r = 0.44; P < 0.001); (2) HRR at 2 min (r = 0.46; P < 0.001). Changes in peak VO₂ correlated significantly with changes in (1) FMD (ρ = 0.17; P < 0.05); (2) quadriceps strength (r = 0.23; P < 0.05); (3) HRR at 2 min (ρ = 0.18; P < 0.05) and Total power of HRV (ρ = 0.41; P < 0.05). Conclusions This multicentre trial shows equal improvements in maximal and submaximal exercise capacity, endothelial function and HRR after AIT and ACT, while these training methods seem to be insufficient to improve muscle strength and HRV. Changes in peak VO₂ were linked to changes in all underlying parameters.

Effect of High-Intensity Interval Versus Continuous Exercise Training on Functional Capacity and Quality of Life in Patients With Coronary Artery Disease: A RANDOMIZED CLINICAL TRIAL

PURPOSE

There is strong evidence that exercise training has beneficial health effects in patients with cardiovascular disease. Most studies have focused on moderate continuous training (MCT); however, a body of evidence has begun to emerge demonstrating that high-intensity interval training (HIIT) has significantly better results in terms of morbidity and mortality. The aim of this study was to compare the effects of MCT versus HIIT on functional capacity and quality of life and to assess safety.

METHODS

Seventy-two patients with ischemic heart disease were assigned to either HIIT or MCT for 8 weeks. We analyzed cardiopulmonary exercise test data, quality of life, and adverse events.

RESULTS

High-intensity interval training resulted in a significantly greater increase in (Equation is included in full-text article.)O2peak (4.5 ± 4.7 mL·kg·min) compared with MCT (2.5 ± 3.6 mL·kg·min) (P < .05). The aerobic threshold (VT1) increased by 21% in HIIT and 14% in MCT. Furthermore, there was a significant (P < .05) increase in the distance covered in the 6-minute walk distance test in the HIIT group (49.6 ± 6.3 m) when compared with the MCT group (29.6 ± 12.0 m). Both training protocols improved quality of life. No adverse events were reported in either of the groups.

CONCLUSIONS

On the basis of the results of this study, HIIT should be considered for use in cardiac rehabilitation as it resulted in a greater increase in functional capacity compared with MCT. We also observed greater improvement in quality of life without any increase in cardiovascular risk.

Review of High-intensity Interval Training in Cardiac Rehabilitation

For the secondary prevention of cardiovascular disease, comprehensive cardiac rehabilitation is required. This involves optimal medical therapy, education on nutrition and exercise therapy, and smoking cessation. Of these, efficient exercise therapy is a key factor. A highly effective training protocol is therefore warranted, which requires a high rate of compliance. Although moderate-intensity continuous training has been the main training regimen recommended in cardiac rehabilitation guidelines, high-intensity interval training has been reported to be more effective in the clinical and experimental setting from the standpoint of peak oxygen uptake and central and peripheral adaptations. In this review, we illustrate the scientific evidence for high-intensity interval training. We then verify this evidence and discuss its significance and the remaining issues.

Effects of aerobic interval training and continuous training on cellular markers of endothelial integrity in coronary artery disease: a SAINTEX-CAD substudy

In this large multicenter trial, we aimed to assess the effect of aerobic exercise training in stable coronary artery disease (CAD) patients on cellular markers of endothelial integrity and to examine their relation with improvement of endothelial function. Two-hundred CAD patients (left ventricular ejection fraction > 40%, 90% male, mean age 58.4 ± 9.1 yr) were randomized on a 1:1 base to a supervised 12-wk rehabilitation program of either aerobic interval training or aerobic continuous training on a bicycle. At baseline and after 12 wk, numbers of circulating CD34+/KDR+/CD45dim endothelial progenitor cells (EPCs), CD31+/CD3+/CXCR4+ angiogenic T cells, and CD31+/CD42b− endothelial microparticles (EMPs) were analyzed by flow cytometry. Endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery. After 12 wk of aerobic interval training or aerobic continuous training, numbers of circulating EPCs, angiogenic T cells, and EMPs were comparable with baseline levels. Whereas improvement in peak oxygen consumption was correlated to improvement in FMD (Pearson r = 0.17, P = 0.035), a direct correlation of baseline or posttraining EPCs, angiogenic T cells, and EMP levels with FMD was absent. Baseline EMPs related inversely to the magnitude of the increases in peak oxygen consumption (Spearman rho = −0.245, P = 0.027) and FMD (Spearman rho = −0.374, P = 0.001) following exercise training. In conclusion, endothelial function improvement in response to exercise training in patients with CAD did not relate to altered levels of EPCs and angiogenic T cells and/or a diminished shedding of EMPs into the circulation. EMP flow cytometry may be predictive of the increase in aerobic capacity and endothelial function.

Aerobic interval training and continuous training equally improve aerobic exercise capacity in patients with coronary artery disease: the SAINTEX-CAD study

BACKGROUND

Exercise-based cardiac rehabilitation increases peak oxygen uptake (peak VO₂), which is an important predictor of mortality in cardiac patients. However, it remains unclear which exercise characteristics are most effective for improving peak VO₂ in coronary artery disease (CAD) patients. Proof of concept papers comparing Aerobic Interval Training (AIT) and Moderate Continuous Training (MCT) were conducted in small sample sizes and findings were inconsistent and heterogeneous. Therefore, we aimed to compare the effects of AIT and Aerobic Continuous Training (ACT) on peak VO₂, peripheral endothelial function, cardiovascular risk factors, quality of life and safety, in a large multicentre study.

METHODS

Two-hundred CAD patients (LVEF >40%, 90% men, mean age 58.4 ± 9.1 years) were randomized to a supervised 12-week cardiac rehabilitation programme of three weekly sessions of either AIT (90-95% of peak heart rate (HR)) or ACT (70-75% of peak HR) on a bicycle. Primary outcome was peak VO₂; secondary outcomes were peripheral endothelial function, cardiovascular risk factors, quality of life and safety.

RESULTS

Peak VO₂ (ml/kg/min) increased significantly in both groups (AIT 22.7 ± 17.6% versus ACT 20.3 ± 15.3%; p-time<0.001). In addition, flow-mediated dilation (AIT+34.1% (range -69.8 to 646%) versus ACT+7.14% (range -66.7 to 503%); p-time<0.001) quality of life and some other cardiovascular risk factors including resting diastolic blood pressure and HDL-C improved significantly after training. Improvements were equal for both training interventions.

CONCLUSIONS

Contrary to earlier smaller trials, we observed similar improvements in exercise capacity and peripheral endothelial function following AIT and ACT in a large population of CAD patients.