Simona Mandini

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.

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.

Exercise Training and Endothelial Progenitor Cells in Haemodialysis Patients

Haemodialysis patients have few endothelial progenitor cells (EPCs) and an unfavourable cardiovascular outcome. The effects on peripheral blood CD34+ cells and EPCs of a 6-month walking exercise programme were studied. Thirty dialysis patients (20 males, age 67 ± 12 years) were prescribed exercise (two daily 10-min home walking sessions at moderate intensity, group E, n = 16) or not prescribed exercise (control, group C, n = 14). On entry and after 6 months peripheral blood CD34+ cells, EPCs (assessed as CD34+ cells co-expressing AC133 and vascular endothelial growth factor receptor 2 [VEGFR2], and as endothelial colony-forming units [e-CFU]) and exercise capacity (6-min walking distance, 6MWD) were evaluated. In group E, 6MWD and e-CFU increased significantly during the study period, with no significant changes in CD34+ or CD34+AC133+VEGFR2+ cell numbers. The change in e-CFU was directly and significantly correlated to patient-reported training load. Group C showed no significant change in any variable. In haemodialysis patients, moderate-intensity exercise selectively increased the number of e-CFU.

Influence of lifestyle measures on hypertriglyceridaemia.

Hypertriglyceridaemia is a common dyslipidaemia encountered in clinical practice. People with hypertriglyceridaemia are frequently obese, insulin-resistant, hypertensive or diabetic, all of which are risk factors for cardiovascular diseases. Hypertriglyceridaemia also contributes to metabolic syndrome, in which an atherogenic diet, sedentary lifestyle, overweight/obesity and genetic factors interact. A multi-factorial intervention for all risk factors is necessary, including weight reduction, dietary modification and increased physical exercise. This review focuses on the influence of diet, sedentary lifestyle and negative habits (such as excessive alcohol intake, smoking and drug addiction) on hypertriglyceridaemia as well as the effects of lifestyle change.

A moderate 1-km treadmill walk predicts mortality in men with mid-range left ventricular dysfunction

The prevalence of heart failure considerably increased over the last three decades because of the aging population and the improved survival rate after acute cardiac events. Clinical and research programs more frequently are directed to patients with severely impaired functional capacity. Nevertheless, heart failure with mid-range left ventricular dysfunction (HFmrEF) has been recently defined as a distinct clinical entity. Cardiorespiratory fitness (CRF), usually best reflected by peak oxygen consumption (VO2peak), has been shown to be a powerful and independent prognostic marker in patients with heart failure. CRF has been linked to both cardiovascular and non-cardiovascular outcomes in ambulatory patients with heart failure. VO2peak is strongly related to walking capacity in older adults, and among heart failure patients. The walking speed maintained during a submaximal 1-km treadmill walk (1 k-TWT) has been demonstrated to be a valid and simple tool for VO2peak estimation, 12–14 and is inversely related to survival, and hospitalization, in outpatients with cardiovascular disease and preserved left ventricular ejection fraction (LVEF). We examine the association between VO2peak estimated by the 1 k-TWT and all-cause mortality in men with HFmrEF. We studied 209 medically stable male outpatients aged 65 10 years, with LVEF 40% 5%, referred to our exercise-based secondary prevention program. Each patient performed the moderate perceptually-regulated (11–13 on the 6–20 Borg scale) 1 k-TWT. Time to walk 1-km, mean and maximal heart rates during the walk, age, height, and weight were entered into the equations for VO2 peak estimation. Based on the VO2peak, the sample was subdivided into tertiles and mortality risks were calculated during a median follow up of 9.4 years. The local Ethics Committee approved the study protocol, and all patients gave written informed consent. Survival decreased in a graded fashion from the highest VO2peak tertile to the lowest tertile (p< 0.0001, Figure 1). During the follow-up period, 23, 11, and 3 all-cause deaths occurred among the lowest, intermediate, and highest VO2peak tertile respectively. Mortality rate was independent from traditional cardiovascular risk factors, including LVEF and clinical history. Compared with the lowest tertile (mean walking speed 2.8 km/h), the full-adjusted mortality risk decreased for the second (mean walking speed 3.8 km/h), and third tertile (mean walking speed 4.6 km/h), with hazard ratios of 0.64 (95% confidence interval (CI): 0.33–1.20, p1⁄4 0.18), and 0.26 (95% CI: 0.08–0.80, p1⁄4 0.02), respectively (p for trend< 0.0001). These results are similar to those obtained by other studies in which VO2peak was determined by maximal cardiopulmonary exercise testing. Consistent with previous studies, we observed a 24.5% reduction in all cause mortality associated with each 1-Metabolic equivalent (MET) increment in VO2peak (p1⁄4 0.04). In conclusion, our findings show that VO2peak estimated from a simple moderate 1 k-TWT predicts

Moderate walking speed predicts hospitalisation in hypertensive patients with cardiovascular disease

Hypertension (HTN) is a leading risk factor for developing cardiovascular disease (CVD), and carries a major global burden of disease. Blood pressure (BP) and CVD are strongly associated, with even small increments in BP leading to an increased risk of CVD. The prevalence of HTN is influenced by several lifestyle factors, including smoking, diet, body mass and insufficient physical activity. On the other hand, it is well known that healthy lifestyle changes, including increased physical activity, contribute significantly to better BP control. Epidemiological studies have demonstrated an inverse relationship between physical activity, cardiorespiratory fitness (CRF) and HTN. In addition, a considerable number of studies have shown significant lowering of BP through regular aerobic exercise of moderate intensity in patients with HTN. Even though higher CRF has been associated with lower risk of future events among people with HTN, hypertensive patients are less physically active than normotensive people. The gold standard for the assessment of CRF is the direct determination of the peak oxygen uptake (VO2peak) by measuring gas exchange during incremental and maximal exercise testing. The assessment of VO2peak is recommended for assessing CVD severity, predicting prognosis and evaluating the efficacy of cardiac rehabilitation/secondary prevention programmes. When added to common risk factors, including systolic blood pressure, VO2peak significantly improves the estimation of both shortand long-term risk for CVD mortality. However, practical, financial and time constraints limit the direct determination of VO2peak in many clinical settings. VO2peak has been demonstrated to be strongly associated with walking capacity in well-functioning older adults and among heart failure patients. Walking is the most common physical activity among adults, and is the preferred mode of exercise testing. A simple, submaximal 1-km treadmill walking test (1 k-TWT) has been validated for the estimation of VO2peak among stable outpatients with CVD, with and without preserved left ventricular ejection fraction. In addition, walking speed is a well-known indicator of health and function in aging and disease. Whether higher walking speed attenuates the risk of hospitalisation in adults with HTN is less known. Thus, we aimed to examine the association between walking speed and long-term all-cause hospitalisation in patients with HTN and CVD. Hospitalisation was assessed in 1078 patients (male/ female 867/211, age 64 10 years) with HTN and CVD (&85% with coronary heart disease) three years after enrolment in an exercise-based secondary prevention programme. All patients completed a baseline health examination and a 1-km treadmill walk at a moderate intensity, perceptually regulated at 11–13/20 on the Borg Scale. All-cause hospitalisation was assessed as function of the walking speed during the 1 k-TWT. At baseline subjects were subdivided into three groups based on walking speed as follows: SLOW (2.6 0.5 km/h, n1⁄4 359), INTERMEDIATE (3.9 0.3 km/h, n1⁄4 362) and FAST (5.1 0.5 km/h, n1⁄4 357). During the following three years all-cause

P-9 Reduction of risk factors for cardiovascular diseases and long lasting walking practice following one year of walking guided by exercise physiologists. a study on 326 sedentary subjects

Objectives The aims of the study were to organise a program of guided walking for sedentary subjects, to analyse the changes of some risk factors for cardiovascular diseases after one year of walking and to check the permanence of unsupervised walking practice months after the program was over. Methods 650 adults and elderly subjects, declaring only occasional physical activity, were enrolled. Weight, height, waist circumference, systolic and diastolic blood pressure and walking speed (measured on a 100 metres course, at an intensity of 12-14 on the Borg scale) were determined at enrolment. Subjects were invited to walk as frequently as possible alone or with one of the several walking groups organised for the project. Walking groups were active five days a week with walking sessions of approximately one hour. The variables measured at enrolment were re-determined after one year. Sixteen month after the end of the project the participants completing the program fill in a questionnaire on the weekly walking hours they were still doing. Results 326 subjects (212 women and 114 men) walked from three to seven days a week and completed the one-year project. After 12 months of walking, highly significant reductions of body weight, BMI, waist circumference, systolic and diastolic blood pressure and highly significant increase in walking speed were documented1(Table 1). Identical results were obtained for both women and men. Abstract P-9 Table 1 Values (mean ± standard deviation) at baseline and change after 12 months of walking in the 326 subjects completing the project Baseline At 12 months p Change Weight (kg) 74.5 ± 15.6 72.2 ± 14.2 p < 0.0001 -2.2 ± 2.9 BMI (kg/m2) 27.0 ± 4.4 26.2 ± 4.0 p < 0.0001 -0.8 ± 1.0 Waist Circumference (cm) 95.2 ± 13.4 92.4 ± 12.4 p < 0.0001 -2.8 ± 3.3 Systolic Blood Pressure (mmHg) 134.2 ± 16.2 128.1 ± 11.3 p < 0.0001 -6.1 ± 8.2 Diastolic Blood Pressure (mmHg) 77.3 ± 9.2 74.8 ± 6.8 p < 0.0001 -2.5 ± 7.6 Walking Speed (km/h) 5.6 ± 0.7 6.3 ± 0.7 p < 0.0001 0.8 ± 0.5 Sixteen months after the end of the project 258 subjects declared 170 ± 110 minutes a week of independent walking (Figure 1), a time superimposable to the one indicated by the 2008 Physical Activity Guidelines for Americans. Conclusions One year of guided walking has been followed by highly significant reductions of some risk factors for cardiovascular diseases and by a highly significant improvement of the walking speed. Sixteen months after the end of the project, 77% of the participants were independently maintaining the walking practice, indicating that guided walking is effective in permanently modifying the lifestyle of sedentary subjects. Acknowledgments Supported by the Italian Ministry of Education and Scientific Research and the Ministry of Sport. References Murphy MH, Nevill AM, Murtagh EM, Holder RL. The effect of walking on fitness, fatness and resting blood pressure: a meta-analysis of randomised, controlled trials. Prev Med. 2007;44(5):377–85. Abstract P-9 Figure 1 Minutes of walking per week of 258 subjects 16 months after the end of the project