Rehabilitation in Cardiac Patients

A method of determining anaerobic threshold from percutaneous oxygen saturation

The anaerobic threshold (AT) is the point of the aerobic-to-anaerobic metabolic switch. Despite the many clinical applications of AT, this measurement requires sophisticated equipment and skills. Here, we investigated a simple measurement method for AT using percutaneous oxygen saturation (SpO₂) and pulse rate (PR) with a pulse oximeter in a study of exercise stress on healthy volunteers. Twenty individuals (ten men and ten women) were included in the study. Various respiratory parameters, including AT, were measured using conventional analytical methods. The SpO₂ threshold (ST) was calculated using the SpO₂-Slope method. The mean ± standard deviations SpO₂ at ST was 97.8% ± 0.3% in men and 99.0 ± 0.3% in women. The concordance and interchangeability between ST and various five different types of AT, the ventilatory equivalent for oxygen (VE/VO₂_AT), V-Slope (V-Slope_AT), ventilatory equivalent (VE_AT), respiratory exchange ratio (R_AT), and partial pressure of end-tidal oxygen (PETO₂_AT) were generally high, with positive correlation coefficients in the range of [0.68-0.80]. These findings suggest that the SpO₂-Slope method with a pulse oximeter may be a useful and simple method to determine AT compared to conventional methods.

Resistance training is an effective exercise therapy in cardiac rehabilitation program for patients with coronary artery disease: a systematic review

Background

Exercise-based cardiac rehabilitation program is a comprehensive intervention for the rehabilitation of coronary artery disease patients. Exercise therapy is a valuable, effective, and integral intervention of cardiac rehabilitation. Aerobic training is the gold standard exercise therapy in cardiac rehabilitation programs. In addition, combined training with added resistant training is also used. This systematic review aimed to provide the physical therapy clinicians with a consensus regarding the effect of resistant training by answering the question of what is the cardiovascular and non-cardiovascular effect (s) of resistant training in the cardiac rehabilitation program for patients with coronary artery disease?

Main body

The Physiotherapy evidence database (PEDro) was used as a search engine to select articles through study eligibility criteria. Adult or adult and old stable coronary artery disease patients engaged in a site-based (Phase II) exercise-based cardiac rehabilitation program that includes aerobic and resistant training. Selected articles applied cardiovascular and non-cardiovascular outcome measures to measure the effectiveness of resistant training. The author reviewed the selected articles and applied quantitative non-statistical analysis and appraisal for these articles. The systematic selection process resulted in 10 studies with a total participants number of 3877. Analyzing the articles revealed that adding resistant training to aerobic training resulted in a favorable improvement in outcome measures for coronary artery disease patients. Resistant training produced improvement in the exercise capacity (VO2 peak), blood pressure, skeletal muscle strength, endurance, body composition, sleep quality, depression, and health-related quality of life.

Short conclusions

The addition of resistant training to aerobic training in cardiac rehabilitation induces more positive cardiovascular and non-cardiovascular effects for stable coronary artery disease patients.

Osteopathic treatment leads to significantly greater reductions in chronic thoracic pain after CABG surgery: A randomised controlled trial

BACKGROUND

There are a number of long-term postoperative complications after coronary artery bypass graft (CABG) surgery. Pulmonary function is decreased by 12% and 30%-50% of the patients have chronic thoracic pain.

METHODS

This randomised controlled trial with two parallel groups aimed to explore the effectiveness of osteopathic treatments (OTs) on these conditions. The standard care (SC) group and the and OT group received a 12-week standard cardiac rehabilitation programme, which was supplemented with four OTs for the OT group only. The outcome assessors were blinded to the patients' allocation.

RESULTS

Eighty-two patients with median sternotomy after CABG surgery were randomly allocated in a 1:1 ratio (SC: n = 42, OT: n = 42). Slow vital capacity and pain intensity were measured at baseline and at 12 weeks and 52 weeks after surgery. Pain intensity was significantly lower in the OT group 12 weeks after surgery (3.6-0.80 vs. 2.6 to 1.2, p = 0.030). One year after surgery, there still was a significantly lower pain intensity in the OT group (3.6-0.56, vs. 2.6 to 1.2, p = 0.014). No significant changes between groups were found in pulmonary function. There were no adverse events reported.

CONCLUSIONS

From this study, it can be concluded that the addition of OT to exercise-based cardiac rehabilitation may lead to significantly greater reductions in thoracic pain after CABG surgery.

TRIAL REGISTRATION

This study was registered on ClinicalTrials.gov (NCT01714791).

Cardiopulmonary exercise testing for evaluation of a randomized exercise training intervention following aortic valve replacement

Aortic valve surgery is the definitive treatment for aortic stenosis (AS). No specific recommendation is available on how exercise training should be conducted and evaluated after aortic valve replacement (AVR). This study aimed to examine the effect of aerobic exercise training on exercise capacity following AVR. In addition to our primary outcome variable, peak oxygen uptake (peakVO₂ ), the effect on submaximal cardiopulmonary variables including oxygen uptake kinetics (tau), oxygen uptake efficiency slope (OUES) and ventilatory efficiency (VE/VCO₂ slope) was evaluated. Following AVR due to AS, 12 patients were randomized to either a group receiving 12 weeks of supervised aerobic exercise training (EX) or a control group (CON). Exercise capacity was assessed by a maximal cardiopulmonary exercise test (CPET). There was a significant increase in peak load (+28%, P = 0·031) and in peakVO₂ (+23%, P = 0·031) in EX, corresponding to an increase in achieved percentage of predicted peakVO₂ from 88 to 104% (P = 0·031). For submaximal variables, there were only non-statistically significant trends in improvement between CPETs in EX. In CON, there were no significant differences in any maximal or submaximal variable between CPETs. We conclude that 12 weeks of supervised aerobic exercise training induces significant adaptations in cardiopulmonary function following AVR, especially in regard to maximal variables including peakVO₂ . In addition, we provide novel data on the effect on several submaximal variables following exercise training in this group of patients.

Very short/short-term benefit of inpatient/outpatient cardiac rehabilitation programs after coronary artery bypass grafting surgery

BACKGROUND

Exercise-based rehabilitation is an important part of treatment patients following coronary artery bypass graft (CABG) surgery.

HYPOTHESIS

To evaluate effect of very short/short-term exercise training on cardiopulmonary exercise testing (CPET) parameters.

METHODS

We studied 54 consecutive patients with myocardial infarction (MI) treated with CABG surgery referred for rehabilitation. The study population consisted of 50 men and 4 women (age 57.72 ± 7.61 years, left ventricular ejection fraction 55% ± 5.81%), who participated in a 3-week clinical and 6-month outpatient cardiac rehabilitation program. The Inpatient program consisted of cycling 7 times/week and daily walking for 45 minutes. The outpatient program consisted mainly of walking 5 times/week for 45 minutes and cycling 3 times/week. All patients performed symptom-limited CPET on a bicycle ergometer with a ramp protocol of 10 W/minute at the start, for 3 weeks, and for 6 months.

RESULTS

After 3 weeks of an exercise-based cardiac rehabilitation program, exercise tolerance improved as compared to baseline, as well as peak respiratory exchange ratio. Most importantly, peak VO₂ (16.35 ± 3.83 vs 17.88 ± 4.25 mL/kg/min, respectively, P < 0.05), peak VCO₂ (1.48 ± 0.40 vs 1.68 ± 0.43, respectively, P < 0.05), peak ventilatory exchange (44.52 ± 11.32 vs 52.56 ± 12.37 L/min, respectively, P < 0.05), and peak breathing reserve (52.00% ± 13.73% vs 45.75% ± 14.84%, respectively, P < 0.05) were also improved. The same improvement trend continued after 6 months (respectively, P < 0.001 and P < 0.0001). No major adverse cardiac events were noted during the rehabilitation program.

CONCLUSIONS

Very short/short-term exercise training in patients with MI treated with CABG surgery is safe and improves functional capacity.

Effects of osteopathic treatment on pulmonary function and chronic thoracic pain after coronary artery bypass graft surgery (OstinCaRe): study protocol for a randomised controlled trial

Background

Coronary artery bypass graft surgery (CABG) is an effective and widespread coronary revascularisation technique, nevertheless there are a number of long-term postoperative complications from which patients can suffer. One year after CABG surgery pulmonary function is decreased by 12% and 30% of the patients suffer from chronic thoracic pain. To date and to our knowledge there are no effective treatments for these conditions. The aim of the present clinical trial is to explore the effectiveness of osteopathic treatment on these conditions.

Methods

The study is designed as a randomised controlled trial with two parallel groups. Group A will receive a standard cardiac rehabilitation programme during 12 weeks and group B will receive the same standard cardiac rehabilitation programme supplemented with four osteopathic treatments (OT). OT will be performed at week 4, 5, 8 and 12 after surgery. Three hundred and eight patients (Group A: n = 154, Group B: n = 154) will be enrolled from the cardiothoracic surgery department of the Jessa Hospital Hasselt. Blinding will be assured for the staff of the cardiac rehabilitation centre and outcome assessors. Primary outcome measure will be the mean difference in change from baseline in slow vital capacity (SVC) at 12 weeks after surgery between groups. Secondary outcome measures will be the change from baseline in quality of life, pain, thoracic stiffness and maximal aerobic capacity at 12 weeks after surgery. A follow-up is planned 52 weeks after surgery for SVC, quality of life, pain and thoracic stiffness. Intention to treat analysis will be executed.

Discussion

The OstinCare study has been designed to explore the potential long-term added value of osteopathic treatment in the management of decreased pulmonary function, chronic thoracic pain and diminished thoracic mobility after CABG surgery.

Trial registration

The protocol has been retrospectively registered on ClinicalTrials.gov (NCT01714791).

Aerobic exercise intensity assessment and prescription in cardiac rehabilitation: a joint position statement of the European Association for Cardiovascular Prevention and Rehabilitation, the American Association of Cardiovascular and Pulmonary Rehabilitation and the Canadian Association of Cardiac Rehabilitation

Aerobic exercise intensity prescription is a key issue in cardiac rehabilitation, being directly linked to both the amount of improvement in exercise capacity and the risk of adverse events during exercise. This joint position statement aims to provide professionals with up-to-date information regarding the identification of different exercise intensity domains, the methods of direct and indirect determination of exercise intensity for both continuous and interval aerobic training, the effects of the use of different exercise protocols on exercise intensity prescription and the indications for recommended exercise training prescription in specific cardiac patients' groups. The importance of functional evaluation through exercise testing prior to starting an aerobic training program is strongly emphasized, and ramp incremental cardiopulmonary exercise test, when available, is proposed as the gold standard for a physiologically comprehensive exercise intensity assessment and prescription. This may allow a shift from a 'range-based' to a 'threshold-based' aerobic exercise intensity prescription, which, combined with thorough clinical evaluation and exercise-related risk assessment, could maximize the benefits obtainable by the use of aerobic exercise training in cardiac rehabilitation.

Decreased aerobic capacity 4 years after aortic valve replacement in male patients operated upon for chronic aortic regurgitation

Exercise testing is underutilized in patients with valve disease. We have previously found a low physical work capacity in patients with aortic regurgitation 6 months after aortic valve replacement (AVR). The aim of this study was to evaluate aerobic capacity in patients 4 years after AVR, to study how their peak oxygen uptake (peakVO₂) had changed postoperatively over a longer period of time. Twenty-one patients (all men, 52 ± 13 years) who had previously undergone cardiopulmonary exercise testing (CPET) pre- and 6 months postoperatively underwent maximal exercise testing 49 ± 15 months postoperatively using an electrically braked bicycle ergometer. Breathing gases were analysed and the patients' physical fitness levels categorized according to Åstrand's and Wasserman's classifications. Mean peakVO₂ was 22·8 ± 5·1 ml × kg⁻¹ × min⁻¹ at the 49-month follow-up, which was lower than at the 6-month follow-up (25·6 ± 5·8 ml × kg⁻¹ × min⁻¹, P = 0·001). All but one patient presented with a physical fitness level below average using Åstrand's classification, while 13 patients had a low physical capacity according to Wasserman's classification. A significant decrease in peakVO₂ was observed from six to 49 months postoperatively, and the decrease was larger than expected from the increased age of the patients. CPET could be helpful in timing aortic valve surgery and for the evaluation of need of physical activity as part of a rehabilitation programme.

The impact of training modalities on the clinical benefits of exercise intervention in patients with cardiovascular disease risk or type 2 diabetes mellitus

Exercise training intervention represents an effective means to reduce adipose tissue mass, improve glycaemic control and increase whole-body oxygen uptake capacity (VO(2peak)) in obesity, metabolic syndrome, type 2 diabetes mellitus (T2DM) and heart disease patients. In this manuscript, we review the impact of different exercise training modalities on clinical benefits of prolonged exercise intervention in these patient (sub)populations. By changing training modalities, significantly greater clinical benefits can be obtained. Greater training frequency and longer programme duration is associated with greater reduction in adipose tissue mass in obesity patients. A greater training frequency (up to 2 days/week) and a longer programme duration (up to 38 weeks) seems to be associated with greater improvements in VO(2peak) in heart disease patients. Longer programme duration and addition of resistance-type exercise further improve glycaemic control in T2DM patients. The first line of evidence seems to indicate that high-intensity interval exercise training has a greater impact on VO(2peak) in heart disease patients and insulin sensitivity in subjects with metabolic syndrome, but not on adipose tissue mass in obese subjects. However, it remains unclear whether addition of resistance-type exercise and continuous higher-intensity endurance-type exercise training are accompanied by greater improvements in VO(2peak) in heart disease patients. Furthermore, the impact of training session duration/volume on adipose tissue mass loss and glycaemic control in obesity and T2DM patients, respectively, is currently unknown. The impact of training frequency on glycaemic control remains to be investigated in T2DM patients.

Special needs to prescribe exercise intensity for scientific studies

There is clear evidence regarding the health benefits of physical activity. These benefits follow a dose-response relationship with a particular respect to exercise intensity. Guidelines for exercise testing and prescription have been established to provide optimal standards for exercise training. A wide range of intensities is used to prescribe exercise, but this approach is limited. Usually percentages of maximal oxygen uptake (VO₂) or heart rate (HR) are applied to set exercise training intensity but this approach yields substantially variable metabolic and cardiocirculatory responses. Heterogeneous acute responses and training effects are explained by the nonuniform heart rate performance curve during incremental exercise which significantly alters the calculations of %HR_max and %HRR target HR data. Similar limitations hold true for using %VO_2max and %VO₂R. The solution of these shortcomings is to strictly apply objective submaximal markers such as thresholds or turn points and to tailor exercise training within defined regions.

Long-term effect of rehabilitation in coronary artery disease patients: randomized clinical trial of the impact of exercise volume

OBJECTIVE

To assess whether exercise volume during phase II rehabilitation affects long-term clinical benefits in patients with coronary artery disease.

DESIGN

Prospective randomized clinical trial with long-term follow-up.

SETTING

Hospital outpatient clinic.

SUBJECTS

Coronary artery disease patients (age 65 +/- 9 years, 82% males) attending a phase II rehabilitation programme were randomized into two groups of exercise volumes: 40- versus 60-minute training sessions. Patients exercised for three days per week for seven weeks, at 65% of baseline oxygen uptake capacity. Next, they were followed up for 18 months. Out of 165 patients with coronary artery disease who completed the exercise intervention, 119 attended the 18-month follow-up assessment.

MAIN MEASUREMENTS

Body anthropometrics, resting haemodynamics, blood lipid profile, glycaemia, and C-reactive protein level, smoking behaviour, habitual physical activity, cardiovascular disease incidence and mortality.

RESULTS

In total population, a significant worsening of various cardiovascular disease risk factors was found at 18 months follow-up (P<0.05), and few patients (27% of total group) adhered to the recommended minimal physical activity level. No difference in change of body anthropometrics, resting haemodynamics, blood lipid profile, glycaemia, and C-reactive protein level, and smoking behaviour was seen between different exercise volumes (P>0.05). In addition, total cardiovascular disease incidence (13% versus 22% in 40- versus 60-minute group, respectively) and habitual physical activity were not different between groups (P>0.05).

CONCLUSION

In patients with coronary artery disease following cardiac rehabilitation, the cardiovascular disease risk profile worsened significantly during long-term follow-up. A smaller exercise volume during phase II rehabilitation generated equal long-term clinical benefits compared to a greater exercise volume.

Standards for the use of cardiopulmonary exercise testing for the functional evaluation of cardiac patients: a report from the Exercise Physiology Section of the European Association for Cardiovascular Prevention and Rehabilitation

Cardiopulmonary exercise testing (CPET) is a methodology that has profoundly affected the approach to patients' functional evaluation, linking performance and physiological parameters to the underlying metabolic substratum and providing highly reproducible exercise capacity descriptors. This study provides professionals with an up-to-date review of the rationale sustaining the use of CPET for functional evaluation of cardiac patients in both the clinical and research settings, describing parameters obtainable either from ramp incremental or step constant-power CPET and illustrating the wealth of information obtainable through an experienced use of this powerful tool. The choice of parameters to be measured will depend on the specific goals of functional evaluation in the individual patient, namely, exercise tolerance assessment, training prescription, treatment efficacy evaluation, and/or investigation of exercise-induced adaptations of the oxygen transport/utilization system. The full potentialities of CPET in the clinical and research setting still remain largely underused and strong efforts are recommended to promote a more widespread use of CPET in the functional evaluation of cardiac patients.

Low agreement of ventilatory threshold between training modes in cardiac patients

In cardiac rehabilitation, different endurance exercises such as walking and cycling are often performed. The training intensity for these modes is determined from a single treadmill or bicycle test by ventilatory threshold (VT). In this study, differences of VT between walking and cycling and agreement of VT between training modes were assessed in cardiac patients. A total of 46 cardiac rehabilitation patients (mean age 59.5+/-8.4 years, 45 males) (31 untrained and 15 trained) completed a maximal exercise test on bicycle and treadmill, with breath-by-breath analysis of oxygen uptake (VO2), carbon dioxide production and expiratory volume. VT was determined by V-slope method. Correlations of VT and VO2peak were calculated between exercise modes. Bland-Altman plots were made for determining VT agreement between modes. VT was significantly different between walking and cycling in trained patients (P<0.05), but not in untrained patients (P>0.05). When untrained and trained patients were compared, VT correlation was lower (r=0.50) in the former group, as compared to the latter group (r=0.78). Also, Bland-Altman plots showed smaller limits of agreement for VT in trained (2 SD -1.6 to 7.8 ml/min/kg), as compared to untrained patients (2 SD -7.0 to 9.6 ml/min/kg). In trained patients, VT correlates well between training methods, but is highly exercise mode specific. In untrained patients, VT is not exercise mode specific, but the VT has a low correlation between training modes. This study shows that VT should be assessed by the appropriate exercise model for determining exercise intensity in cardiac rehabilitation.