Home-based inspiratory muscle training for management of older patients with heart failure with preserved ejection fraction: does baseline inspiratory muscle pressure matter?

Cardiopulmonary Exercise Testing in Heart Failure With Preserved Ejection Fraction: Technique Principles, Current Evidence, and Future Perspectives

Heart failure with preserved ejection fraction (HFpEF) is a multifactorial clinical syndrome involving a rather complex pathophysiologic substrate and quite a challenging diagnosis. Exercise intolerance is a major feature of HFpEF, and in many cases, diagnosis is suspected in subjects presenting with exertional dyspnea. Cardiopulmonary exercise testing (CPET) is a noninvasive, dynamic technique that provides an integrative evaluation of cardiovascular, pulmonary, hematopoietic, neuropsychological, and metabolic functions during maximal or submaximal exercise. The assessment is based on the principle that system failure typically occurs when the system is under stress, and thus, CPET is currently considered to be the gold standard for identifying exercise intolerance, allowing the differential diagnosis of underlying causes. CPET is used in observational studies and clinical trials in HFpEF; however, in most cases, only a few from a wide variety of CPET parameters are examined, while the technique is largely underused in everyday cardiology practice. This article discusses the basic principles and methodology of CPET and studies that utilized CPET in patients with HFpEF, in an effort to increase awareness of CPET capabilities among practicing cardiologists.

Correlation between respiratory muscle weakness and frailty status as risk markers for poor outcomes in patients with cardiovascular disease

AIMS

Although the developmental mechanism of respiratory muscle weakness (RMW) and frailty are partly similar in patients with cardiovascular disease (CVD), their relationship remains unclear. This study aimed to investigate the correlation between RMW and frailty and its impact on clinical outcomes in patients with CVD.

METHODS AND RESULTS

In this retrospective observational study, consecutive 1217 patients who were hospitalized for CVD treatment were enrolled. We assessed frailty status by using the Fried criteria and respiratory muscle strength by measuring the maximal inspiratory pressure (PImax) at hospital discharge, with RMW defined as PImax <70% of the predicted value. The endpoint was a composite of all-cause death and/or readmission for heart failure. We examined the prevalence of RMW and frailty and their correlation. The relationships of RMW with the endpoint for each presence or absence of frailty were also investigated. Respiratory muscle weakness and frailty were observed in 456 (37.5%) and 295 (24.2%) patients, respectively, and 149 (12.2%) patients had both statuses. Frailty was detected as a significant indicator of RMW [odds ratio: 1.84, 95% confidence interval (CI): 1.39-2.44]. Composite events occurred in 282 patients (23.2%). Respiratory muscle weakness was independently associated with an increased incidence of events in patients with both non-frailty [hazard ratio (HR): 1.40, 95% CI: 1.04-1.88] and frailty (HR: 1.68, 95% CI: 1.07-2.63).

CONCLUSIONS

This is the first to demonstrate a correlation between RMW and frailty in patients with CVD, with 12.2% of patients showing overlap. RMW was significantly associated with an increased risk of poor outcomes in patients with CVD and frailty.

Inspiratory muscle training in patients with heart failure: A systematic review and meta-analysis

Objective

To explore the effect of inspiratory muscle training (IMT) on patients with heart failure and further explore the impact of IMT on patients with heart failure with preserved ejection fraction.

Methods

PubMed, EMBASE, Cochrane Library, CNKI, Wanfang and VIP databases were systematically searched. Randomized controlled trials of inspiratory muscle training in patients with heart failure were included. Revman 5.3 software was used to calculate the weighted mean difference (MD) of the combined effect size. The effects of IMT on the maximum oxygen uptake (peakVO2), maximum inspiratory pressure (PI_max), ventilation efficiency (V_E/VCO₂), six-minute walking distance (6MWD), forced expiratory volume (FEV₁), forced vital capacity (FVC) and quality of life in patients with heart failure were compared and analyzed.

Results

After systematic retrieval and screening, 17 studies were included in this study, and the quality of the included studies was good. The results showed that IMT could increase peakVO2 (MD 2.53; 95% CI 1. 54, 3. 51; P < 0.0001) and PI_max (MD 17.25; 95% CI 13. 75, 20. 75; P < 0.00001); improve the V_E/VCO₂ (MD −4.22; 95% CI −6.78, −1.66; P = 0.001) and significantly improve the quality of life in patients with heart failure (MD −13.34; 95% CI −20.42, −6.26; P = 0.0002). However, the effect of IMT on 6MWD in patients with heart failure was not statistically significant (MD 74.45; 95% CI −12.88,161.79; P = 0.09), and the effect on lung function (FEV₁ and FVC) was also not statistically significant (P = 0.08; P = 0.86). IMT had a more significant positive effect on peakVO2 (MD 2.98; 95% CI 1.63, 4.34; P < 0.0001) and quality of life (MD −14.52; 95% CI −18.53, −10.52; P < 0.00001) in patients with heart failure with preserved ejection fraction. Descriptive analysis suggested that IMT may positively affect dyspnoea in patients with heart failure. In addition, the choice of evaluation scale may affect the evaluation results of quality of life and dyspnoea.

Conclusion

IMT has a significant positive effect on respiratory status in patients with heart failure, but different dyspnoea and quality of life evaluation scales can affect the final evaluation results.

Unraveling the Role of Respiratory Muscle Metaboloreceptors under Inspiratory Training in Patients with Heart Failure

Exercise intolerance may be considered a hallmark in patients who suffer from heart failure (HF) syndrome. Currently, there is enough scientific evidence regarding functional and structural deterioration of skeletal musculature in these patients. It is worth noting that muscle weakness appears first in the respiratory muscles and then in the musculature of the limbs, which may be considered one of the main causes of exercise intolerance. Functional deterioration and associated atrophy of these respiratory muscles are related to an increased muscle metaboreflex leading to sympathetic–adrenal system hyperactivity and increased pulmonary ventilation. This issue contributes to increased dyspnea and/or fatigue and decreased aerobic function. Consequently, respiratory muscle weakness produces exercise limitations in these patients. In the present review, the key role that respiratory muscle metaboloreceptors play in exercise intolerance is accurately addressed in patients who suffer from HF. In conclusion, currently available scientific evidence seems to affirm that excessive metaboreflex activity of respiratory musculature under HF is the main cause of exercise intolerance and sympathetic–adrenal system hyperactivity. Inspiratory muscle training seems to be a useful personalized medicine intervention to reduce respiratory muscle metaboreflex in order to increase patients’ exercise tolerance under HF condition.

Inspiratory Muscle Training in Patients With Heart Failure With Preserved Ejection Fraction: A Meta-Analysis

Objectives To explore the role of inspiratory muscle training (IMT) in improving cardiorespiratory fitness of stable heart failure with preserved ejection fraction (HFpEF) patients. Background There is a paucity of data on the role of IMT in patients with HFpEF. HFpEF is a growing problem in the developed world, especially in the aging population. Methods We conducted a systematic literature search for English studies in PubMed, EMBASE, and Cochrane Central Register of Controlled Trials. We searched databases using terms relating to or describing breathing exercise, IMT, and HFpEF. RevMan 5.4 (The Cochrane Collaboration, 2020) was used for data analysis, and two independent investigators performed literature retrieval and data extraction. Results We identified three randomized controlled trials (RCTs) and one prospective study on the role of IMT in HFpEF. We calculated the pooled mean difference of peak oxygen consumption (Peak VO2) and six-min walk distance (6MWD) between the IMT and standard care (SC) groups. Our meta-analysis showed that compared with SC, IMT could significantly improve peak VO2 with a mean difference (MD) of 2.82 ml/kg/min, 95% CI [1.90, 3.74] P < 0.00001 and improve 6MWD with MD of 83.97 meters, 95% CI [59.18, 108.76] P< 0.00001 to improve cardiorespiratory fitness at 12 weeks of IMT and improve peak VO2 with MD of 2.18 ml/kg/min, 95% CI [0.38, 3.99] P < 0.00001 at 24 weeks of therapy. Conclusion IMT should be further studied as a possible treatment option to improve cardiorespiratory fitness for patients with stable HFpEF.

Inspiratory Muscle Training in Patients with Heart Failure

Background: Prior systematic reviews and meta-analysis addressed that inspiratory muscle training (IMT) improved inspiratory muscle weakness, cardiorespiratory fitness and quality of life similar to conventional exercise training as a first alternative in deconditioned patients with heart failure (HF) lead to a better adaptation to posterior exercise training. The heterogeneity and variability in a wide range of new studies about this topic led to the necessity of an updated and comprehensive narrative review. The present review aimed to analyze and update the most relevant studies about IMT in patients who suffer from HF. Methods: A narrative review was carried out about IMT in HF patients including 26 experimental studies divided into 21 clinical trials and 5 quasi-experimental studies identified through database searching in PubMed, Cochrane and PEDro. Results: There is enough evidence to state that IMT produces improvements in functional capacity of patients with HF. Nevertheless, there is not enough evidence to support that IMT could improve cardiovascular parameters, blood biomarkers or quality of life in these patients. Conclusions: Thus, IMT may be recommended to improve functional capacity in patients who suffer from HF; nevertheless, more evidence is needed regarding cardiovascular parameters, biomarkers and quality of life. Furthermore, mortality or HF hospitalization was not evaluated and most studies were not longer than 3 months. According to IMT protocols and study designs heterogeneity and mid-term follow-up, further investigations through high-quality long-term randomized clinical trials should be performed to achieve systematic reviews and meta-analysis to support strong evidence for IMT in HF patients.