Original clinical science
Skeletal muscle microcirculatory abnormalities are associated with exercise intolerance, ventilatory inefficiency, and impaired autonomic control in heart failure

https://doi.org/10.1016/j.healun.2011.08.020Get rights and content

Background

Several skeletal muscle abnormalities have been identified in patients with chronic heart failure (CHF), including endothelial dysfunction. We hypothesized that skeletal muscle microcirculation, assessed by near-infrared spectroscopy (NIRS), is impaired in CHF patients and is associated with disease severity.

Methods

Eighty-three stable patients with mild–moderate CHF (72 males, mean age 54 ± 14 years, body mass index 26.7 ± 3.4 kg/m2) and 8 healthy subjects, matched for age, gender and body mass index, underwent NIRS with the vascular occlusion technique and cardiopulmonary exercise testing (CPET) evaluation on the same day. Tissue oxygen saturation (StO2, %), defined as the percentage of hemoglobin saturation in the microvasculature compartments, was measured in the thenar muscle by NIRS before, during and after 3-minute occlusion of the brachial artery. Measurements included StO2, oxygen consumption rate (OCR, %/min) and reperfusion rate (RR, %/min). All subjects underwent a symptom-limited CPET on a cycle ergometer. Measurements included VO2 at peak exercise (VO2peak, ml/kg/min) and anaerobic threshold (VO2AT, ml/kg/min), VE/VCO2 slope, chronotropic reserve (CR, %) and heart rate recovery (HRR1, bpm).

Results

CHF patients had significantly lower StO2 (75 ± 8.2 vs 80.3 ± 6, p < 0.05), lower OCR (32.3 ± 10.4 vs 37.7 ± 5.5, p < 0.05) and lower RR (10 ± 2.8 vs 15.7 ± 6.3, p < 0.05) compared with healthy controls. CHF patients with RR ≥9.5 had a significantly greater VO2peak (p < 0.001), VO2AT (p < 0.01), CR (p = 0.01) and HRR1 (p = 0.01), and lower VE/VCO2 slope (p = 0.001), compared to those with RR <9.5. In a multivariate analysis, RR was identified as an independent predictor of VO2peak, VE/VCO2 slope and HRR1.

Conclusions

Peripheral muscle microcirculation, as assessed by NIRS, is significantly impaired in CHF patients and is associated with disease severity.

Section snippets

Study population

The study group consisted of 83 patents with stable CHF (72 males; mean age 54 ± 14 years, body mass index 26.7 ± 3.4 kg/m2) with a left ventricular ejection fraction (LVEF) ≤45%. All patients were on a stable optimal medical regimen for at least 3 months. They were referred to our laboratory from the heart failure clinic of our institution to perform a symptom-limited cardiopulmonary exercise test (CPET), as part of heart failure evaluation. Exclusion criteria from the study were moderate to

Results

All subjects completed the exercise protocol and none complained of unbearable pain or discomfort during the arm circulatory occlusion. HR recovery could not be calculated with accuracy in 6 CHF patients due to consistent artifacts from the signal of electrodes during recovery period. Similarly, VO2/t-slope could not be calculated in 3 patients as they removed the low-resistance valve due to discomfort during the recovery period.

No statistical differences were noted regarding age, gender and

Discussion

In this study we have demonstrated that: (1) patients with CHF present several skeletal muscle tissue microcirculation abnormalities as assessed by the near-infrared spectroscopy vascular occlusion technique; and (2) peripheral microcirculation alterations are associated with disease severity as expressed by exercise intolerance, ventilatory inefficiency and autonomic nervous system abnormalities in CHF patients. To our knowledge, this is the first study to evaluate peripheral microcirculation

Clinical implications

The NIRS occlusion technique through reperfusion rate measurement, an indirect indication of endothelial function, may be used to evaluate CHF severity. This technique is a relatively new approach that has been applied in healthy subjects,6 smokers,7 critically ill patients9 and CHF patients.8, 15, 17 This simple, bedside, non-invasive method could also be used as a monitoring and prognostic tool in patients unable to undergo CPET for evaluation of functional status. Future studies are needed

Study limitations

The results of our study should be applied mainly to male CHF patients. Although we did not directly evaluate endothelial function, the NIRS occlusion technique was applied as an indirect evaluation of peripheral tissue microcirculation.6, 7, 8, 9, 15, 17 Thus, the effects of central factors, such as reduced cardiac output or oxygen delivery, cannot be addressed easily by NIRS, requiring the use of invasive methodology—yet this was beyond the scope our study. Although there were no artifact

Disclosure statement

None of the authors have any conflicts of interest to disclose. This work was supported by a grant from the special account for research grants of the National and Kapodistrian University of Athens, Athens, Greece.

References (20)

There are more references available in the full text version of this article.

Cited by (41)

  • The acute and long-term effects of a cardiac rehabilitation program on endothelial progenitor cells in chronic heart failure patients: Comparing two different exercise training protocols

    2021, IJC Heart and Vasculature
    Citation Excerpt :

    Chronic heart failure (CHF) remains a leading cause of morbidity and mortality with a significant financial and social burden [1]. Vascular endothelial dysfunction, impaired microcirculation and increased inflammation are important underlying pathophysiological features of CHF [2,3]. During the last decades, endothelial progenitor cells (EPCs) have been used as an index of the endothelium restoration potential, therefore reflecting the vascular endothelial function [4].

  • Effects of High-Intensity Interval Exercise Training on Skeletal Myopathy of Chronic Heart Failure

    2017, Journal of Cardiac Failure
    Citation Excerpt :

    For each leg, 5–6 attempts were performed with 1-minute rest intervals. Subjects performed a ramp-incremental exercise test aiming at a test of 8–12 minutes' duration (work increments calculated as previously described19). Gas exchange was studied with the patient breathing through a low-resistance valve (Cosmed; Quark PFT, Italy).

View all citing articles on Scopus
View full text