Physical capacity increase in patients with heart failure is associated with improvement in muscle sympathetic nerve activity

BACKGROUND

Exercise training improves physical capacity in patients with heart failure with reduced ejection fraction (HFrEF), but the mechanisms involved in this response is not fully understood. The aim of this study was to determine if physical capacity increase in patients HFrEF is associated with muscle sympathetic nerve activity (MSNA) reduction and muscle blood flow (MBF) increase.

METHODS

The study included 124 patients from a 17-year database, divided according to exercise training status: 1) exercise-trained (ET, n = 83) and 2) untrained (UNT, n = 41). MSNA and MBF were obtained using microneurography and venous occlusion plethysmography, respectively. Physical capacity was evaluated by cardiopulmonary exercise test. Moderate aerobic exercise was performed 3 times/wk. for 4 months.

RESULTS

Exercise training increased peak oxygen consumption (V̇O2, 16.1 ± 0.4 vs 18.9 ± 0.5 mL·kg-1·min-1, P < 0.001), LVEF (28 ± 1 vs 30 ± 1%, P = 0.027), MBF (1.57 ± 0.06 vs 2.05 ± 0.09 mL.min-1.100 ml-1, P < 0.001) and muscle vascular conductance (MVC, 1.82 ± 0.07 vs 2.45 ± 0.11 units, P < 0.001). Exercise training significantly decreased MSNA (45 ± 1 vs 32 ± 1 bursts/min, P < 0.001). The logistic regression analyses showed that MSNA [(OR) 0.921, 95% CI 0.883-0.962, P < 0.001] was independently associated with peak V̇O2.

CONCLUSIONS

The increase in physical capacity provoked by aerobic exercise in patients with HFrEF is associated with the improvement in MSNA.

Nutritional Risk by Mini Nutritional Assessment (MNA), but Not Anthropometric Measurements, Has a Good Discriminatory Power for Identifying Frailty in Elderly People: Data from Brazilian Secondary Care Clinic

OBJECTIVES

To investigate, in elderly individuals registered at a secondary outpatient clinic, the prevalence of frailty and pre-frailty and to identify the discriminatory power of anthropometric measurements and nutritional risk in identifying these conditions.

DESIGN

Cross-sectional study with data extracted from medical records.

SETTING AND PARTICIPANTS

Elderly patients (60+ years) from a geriatric outpatient clinic, located in the southeast area of São Paulo, Brazil.

MEASUREMENTS

Frailty was assessed using five criteria proposed by Fried et al (2001), with some modifications. Nutritional risk was identified using Mini Nutritional Assessment (MNA). Body weight and body height were measured and used to calculate the body mass index (BMI). The discriminatory power of these parameters for the identification of frailty was determined by Receiver Operating Characteristics (ROC) curves.

RESULTS

The final sample was composed of 254 patients, from which 31.1% were identified as frail and 53.5% as prefrail. The MNA indicated that 3.1% were malnourished and 35.4% were at risk of malnutrition. The BMI values 39.4% as overweight/obese and 19.9% as undernourished. As just the MNA revealed differences for frailty classification, only this parameter was investigated by ROC curve. The discriminatory power of the MNA for frailty presented a best cut-off point of ≤23.0 and the AUC was 0.812 (sensitivity=55.7; specificity=94.9), with a youden index of 0.5057 (95%CI= 0.3146-0.5946). MNA did not present sufficient discriminatory power to detect pre-frailty.

CONCLUSION

The MNA was capable of indicating frailty, but not pre-frailty in this sample. BMI did not display significant predictive power for frailty or pre-frailty.