Michele Felisatti

Resting Muscle Oxygen Consumption by Near-Infrared Spectroscopy in Peripheral Arterial Disease: A Parameter to be Considered in a Clinical Setting?

Resting muscle VO 2 consumption (rmVO2) as measured by near-infrared spectroscopy (NIRS) has been poorly studied in peripheral arterial disease (PAD). We studied the feasibility of its assessment in a clinical setting, compared values from PAD and healthy participants, and identified factors affecting rmVO 2 in PAD. A total of 119 PAD patients with claudication and 30 healthy participants were enrolled. Ankle brachial index (ABI), adipose tissue thickness, and rmVO2 in the gastrocnemius after venous (rmVO2ven) or arterial (rmVO2art) occlusion were measured with NIRS. Compared to rmVO2art, rmVO2ven determination was less painful (P = .001), with higher values (P < .0001). rmVO2ven of PAD patients was not significantly different from healthy participants and was inversely correlated with the corresponding ABI (P = .018). rmVO2ven from severely diseased legs was higher than values from borderline/moderately diseased legs (P = .003). The determination of rmVO2ven by NIRS is suitable for the clinical setting and allows noninvasive quantification of a compensatory peripheral adaptation in patients with PAD.

A Dynamic Objective Evaluation of Peripheral Arterial Disease by Near-Infrared Spectroscopy

OBJECTIVES Near-Infrared Spectroscopy (NIRS), suitable for dynamic measurements, is not routinely used for peripheral arterial disease (PAD). We propose a dynamic NIRS-based measurement to quantify variations in muscle metabolism in PAD. METHOD Sixty-seven consecutive PAD patients (males=56, age 71.6+/-8.7 years) and 28 healthy subjects (males=12, age 30.4+/-11.9 years) were studied. An echo-colour Doppler (ECD) was performed and the ankle-brachial index (ABI) was calculated. Participants performed an incremental treadmill test with NIRS probes on the gastrocnemius. Variations in oxygenated (HbO(2)), deoxygenated (HHb), total (tHb=HbO(2)+HHb), and differential (dHb=HbO(2)-HHb) haemoglobin were recorded and quantified as area-under-curve (AUC) within the range 1.7-3.0 km h(-1). Heart rate was recorded, and the number of beats in the same interval was calculated (dHr). RESULTS O(2)Hb(AUC), HHb(AUC) and dHb(AUC) differed between diseased and non-diseased legs (P<0.0001) and exhibited different patterns related to PAD severity according to the ABI value. A compensatory heart rate increase was observed in PAD patients. Compared with the ECD positivity for occlusions/stenoses or multiple plaques, only the receiver-operating characteristic (ROC) analysis of dHb(AUC) (area=0.932, P<0.0001) showed a sensitivity/specificity of 87.6/93.4 for values <or=-197 (LR+LR-: 13.36/0.13). CONCLUSION The dynamic NIRS-based test, quantifying muscle metabolic response according to presence and degree of PAD, allows the evaluation of patients with walking disabilities.

Near-Infrared Spectroscopy Assessment Following Exercise Training in Patients With Intermittent Claudication and in Untrained Healthy Participants

Selected near-infrared spectroscopy (NIRS) parameters were assessed in healthy untrained participants and in peripheral arterial disease (PAD) trained patients to evaluate their usefulness in rehabilitative outcome. Forty-five PAD and 15 healthy participants were studied at entry and at 34 ± 2 weeks. Healthy participants performed their usual activities. Patients with PAD performed 2 home-based programs: structured at prescribed pace (S-pre, n = 31) and unstructured at free pace (U-free, n = 14). We measured ankle–brachial index (ABI), NIRS calf oxygen consumption at rest, NIRS dynamic muscle perfusion during an incremental test, and walking capacity. In all patients with PAD the NIRS parameters significantly increased approaching the stable values of untrained healthy participants. Among PAD, only S-pre group showed significant improvements in hemodynamic, functional, and NIRS parameters with selective adaptations in the worse legs. The assessment of NIRS parameters, that were found stable without training in healthy and modified in PAD only following structured training, might outline the local exercise-induced adaptations.

Exercise in Patients on Dialysis: A Multicenter, Randomized Clinical Trial.

Previous studies have suggested the benefits of physical exercise for patients on dialysis. We conducted the Exercise Introduction to Enhance Performance in Dialysis trial, a 6-month randomized, multicenter trial to test whether a simple, personalized walking exercise program at home, managed by dialysis staff, improves functional status in adult patients on dialysis. The main study outcomes included change in physical performance at 6 months, assessed by the 6-minute walking test and the five times sit-to-stand test, and in quality of life, assessed by the Kidney Disease Quality of Life Short Form (KDQOL-SF) questionnaire. We randomized 296 patients to normal physical activity (control; n=145) or walking exercise (n=151); 227 patients (exercise n=104; control n=123) repeated the 6-month evaluations. The distance covered during the 6-minute walking test improved in the exercise group (mean distance±SD: baseline, 328±96 m; 6 months, 367±113 m) but not in the control group (baseline, 321±107 m; 6 months, 324±116 m; P<0.001 between groups). Similarly, the five times sit-to-stand test time improved in the exercise group (mean time±SD: baseline, 20.5±6.0 seconds; 6 months, 18.2±5.7 seconds) but not in the control group (baseline, 20.9±5.8 seconds; 6 months, 20.2±6.4 seconds; P=0.001 between groups). The cognitive function score (P=0.04) and quality of social interaction score (P=0.01) in the kidney disease component of the KDQOL-SF improved significantly in the exercise arm compared with the control arm. Hence, a simple, personalized, home-based, low-intensity exercise program managed by dialysis staff may improve physical performance and quality of life in patients on dialysis.

Sport Therapy for Hypertension: Why, How, and How Much?

Exercise may prevent or reduce the effects of metabolic and cardiovascular diseases, including arterial hypertension. Both acute and chronic exercise, alone or combined with lifestyle modifications, decrease blood pressure and avoid or reduce the need for pharmacologic therapy in patients with hypertension. The hypotensive effect of exercise is observed in a large percentage of subjects, with differences due to age, sex, race, health conditions, parental history, and genetic factors. Exercise regulates autonomic nervous system activity, increases shear stress, improves nitric oxide production in endothelial cells and its bioavailability for vascular smooth muscle, up-regulates antioxidant enzymes. Endurance training is primarily effective, and resistance training can be combined with it. Low-to-moderate intensity training in sedentary patients with hypertension is necessary, and tailored programs make exercise safe and effective also in special populations. Supervised or home-based exercise programs allow a nonpharmacological reduction of hypertension and reduce risk factors, with possible beneficial effects on cardiovascular morbidity.

Muscle oxygen consumption by NIRS and mobility in multiple sclerosis patients

BackgroundThe study of muscle metabolism by near-infrared spectroscopy (NIRS) has been poorly implemented in multiple sclerosis (MS). Aims of the study were to compare resting muscle oxygen consumption (rmVO2) at gastrocnemius in MS patients and in age-matched healthy controls (HC) measured using NIRS, and to evaluate its possible relationship with patients’ mobility.MethodsTwenty-eight consecutively enrolled MS patients (male, n = 16; age = 42.7 ± 14.0 y, Relapsing-Remitting, n = 19; Primary-Progressive, n = 9) and 22 HC (male, n = 13; age = 36.0 ± 8.2 y) were studied during rest applying the NIRS probes at gastrocnemius, producing a venous occlusion at the thigh using a cuff, and analyzing the slope of the total hemoglobin to calculate rmVO2. Mobility was assessed by a 6-Minute Walking Test and 6-Minute Walking Distance (6MWD) was recorded.ResultsrmVO2 was higher in MS compared to HC (0.059 ± 0.038 vs 0.039 ± 0.016 mlO2/min/100 g, P < 0.003), not different in clinical subtypes, not correlated to patients’ characteristics (age, disease duration, Expanded Disability Status Scale, resting heart rate, skinfold thickness), and significantly higher in patients with lower walking ability (6MWD < 450 m, n = 12) compared to those at better performance (respectively, 0.072 ± 0.043 vs 0.049 ± 0.032 mlO2/min/100 g, P = 0.03).ConclusionrmVO2 values, significantly higher in MS patients compared to HC, and in low versus high performing patients, might represent a marker of peripheral adaptations occurred to sustain mobility, as observed in other chronic diseases.

The Role of Deconditioning in the End-Stage Renal Disease Myopathy: Physical Exercise Improves Altered Resting Muscle Oxygen Consumption

Background: Skeletal muscle dysfunction and poor exercise tolerance are hallmarks of end-stage renal disease (ESRD). Noninvasively measured (near-infrared spectroscopy, NIRS) resting muscle oxygen consumption (rmVO2) is a biomarker of muscle dysfunction, which can be applied to study the severity and the reversibility of ESRD myopathy. We tested the hypothesis that deconditioning is a relevant factor in ESRD myopathy. Methods: The whole dialysis population (n = 59) of two of the eight centers participating into the EXCITE study (ClinicalTrials.gov NCT01255969), a randomized trial evaluating the effect of a home-based exercise program on the functional capacity of these patients was studied. Thirty-one patients were in the active arm (exercise group) and 28 in the control arm (no intervention). Normative data for rmVO2 were obtained from a group of 19 healthy subjects. Results: rmVO2 was twice higher (p < 0.001) in ESRDs patients (0.083 ± 0.034 ml/100 g/min) than in healthy subjects (0.041 ± 0.020 ml/100 g/min) indicating substantial skeletal muscle dysfunction in ESRD. rmVO2 correlated with resting heart rate (r = 0.34, p = 0.009) but was independent of age, dialysis vintage, biochemical, vascular and nutrition parameters. After the 6-month exercise program, rmVO2 reduced to 0.064 ± 0.024 ml/100 g/min (-23%, p < 0.001) in the exercise group indicating that skeletal muscle dysfunction is largely reversible but remained identical in the control group (0.082 ± 0.032 to 0.082 ± 0.031 ml/100 g/min). Conclusion: Deconditioning has a major role in ESRD myopathy. rmVO2 is a marker of physical deconditioning and has the potential for monitoring re-conditioning programs based on physical exercise in the ESRD population.

Effects of low-intensity endurance and resistance training on mobility in chronic stroke survivors. A pilot, randomized, controlled study.

BACKGROUND Chronic stroke survivors are exposed to long-term disability and physical deconditioning, effects that may impact their independence and quality of life. Community-based programs optimizing the dose of exercise therapy that are simultaneously low risk and able to achieve high adherence should be identified. AIM We tested the hypothesis that an 8-week, community-based, progressive mixed endurance-resistance exercise program at lower cardiovascular and muscular load yielded more mobility benefits than a higher-intensity program in chronic stroke survivors. DESIGN A two-arm, parallel-group, pilot randomized, controlled clinical trial. SETTING Hospital (recruitment); community-based adapted physical activity center (training). POPULATION Thirty-five chronic stroke patients (mean age: 68.4±10.4 years; 27 males). METHODS Participants were randomized to a low-intensity experimental (LI-E; N.=18) or a high-intensity active control group (HI-C; N.=17). Patients in the LI-E group performed over-ground intermittent walking (weeks 1-8) and muscle power training with portable tools (weeks 5-8); patients in the HI-C group executed treadmill walking (weeks 1-8) and strength training with gym machines (weeks 5-8). Changes in mobility, assessed using the 6-Minute Walking Distance test, were the primary outcome. Secondary outcomes included quality of life (Short-Form-36 Questionnaire), gait speed (10-Meter Walking Test), balance (Berg Balance Scale) and muscle performance of the lower limbs (strength and power of the quadriceps and femoral biceps). RESULTS After 8 weeks, the 6MWD revealed more improvement for the LI-E group than the HI-C group (P=0.009). The SF36 physical activity domain (P=0.012) and peak power of the femoral quadriceps and biceps were also significantly improved for the LI-E group (P=0.008 and P<0.001, respectively) compared with the HI-C. Gait speed, balance and lower-limb strength increased in both groups; no significant differences were noted. The muscle power of the affected limb was the muscle parameter most correlated with mobility in the entire population. CONCLUSIONS A low-intensity exercise program exhibited better results in terms of mobility, quality of life and muscle power compared with a higher-intensity program. Data need to be confirmed in a larger trial. CLINICAL REHABILITATION IMPACT The effectiveness, low-intensity and possible implementation in poorly equipped community-based settings make the LI-E program potentially suitable for stroke survivors and frail individuals.

Moderating healthcare costs through an assisted physical activity programme

BACKGROUND During the last decades, physical inactivity has become increasingly important due to its effects on health; in the medical field, it has been highlighted that physical inactivity is one of the leading cause of death. Moreover, the increasing trend in a sedentary lifestyle has also led to economic concerns; for this reason, the need to develop healthcare programmes to raise awareness of the benefits of physical exercise among the global population has arisen. OBJECTIVE This paper analyses the relationship between moderate physical activity, cost of pharmaceuticals and health services utilization with regard to a primary care community programme based on moderate exercise intervention. The study highlights the effect of an exercise programme for people in sheltered accommodation in terms of effects on their quality of life and in terms of economic sustainability. METHODOLOGY A randomized controlled trial of an exercise programme was designed. A total of 150 patients were randomized in two groups. The intervention group was recruited from Centro Esercizio Vita whereas the participants of the control group were recruited from general practitioners. RESULTS At 9 months after randomization, the exercise-based group presented a lower average cost for drugs (p-value 0.039), an overall better health status perception (p-value 0.0019) and accessed general practitioners less frequently (p-value 0.058). CONCLUSIONS Our study shows that assisted physical activity practiced on the basis of an exercise programme, over a period of nine months, has overall positive consequences in terms of reduction in health expenditure and quality of life.