Karine Marquis

Oxidative enzyme activities of the vastus lateralis muscle and the functional status in patients with COPD

BACKGROUND Enzymatic and histochemical abnormalities of the peripheral muscle may play a role in exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). A study was undertaken to measure the mitochondrial enzyme activity of the vastus lateralis muscle in patients with COPD and to evaluate the relationship between enzyme activities and functional status. METHODS Fifty seven patients with COPD of mean (SD) age 66 (7) years with forced expiratory volume in one second (FEV1) 39 (15)% predicted and peak oxygen uptake (V˙o 2) of 14 (4) ml/min/kg and 15 normal subjects of similar age were included in the study. Each subject performed a stepwise exercise test up to maximal capacity during which five-breath averages of V˙o 2were measured. Muscle specimens were obtained by percutaneous needle biopsy of the vastus lateralis muscle and the activity of two mitochondrial enzymes (citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HADH)) was measured. The functional status of the patients was classified according to peakV˙o 2. RESULTS CS and HADH activities were markedly reduced in patients with COPD compared with normal subjects (22.3 (2.7) versus 29.5 (7.3) μmol/min/g muscle (p<0.0001) and 5.1 (2.0) versus 6.7 (1.9) μmol/min/g muscle (p<0.005), respectively). The activity of CS decreased progressively with the deterioration in the functional status while that of HADH was not related to functional status. Using a stepwise regression analysis, percentage predicted functional residual capacity (FRC), the activity of CS, oxygen desaturation during exercise, age, and inspiratory capacity (% pred) were found to be significant determinants of peakV˙o 2. The regression model explained 59% of the variance in peak V˙o 2 (p<0.0001). CONCLUSIONS The oxidative capacity of the vastus lateralis muscle is reduced in patients with moderate to severe COPD compared with normal subjects of similar age. In these individuals the activity of CS correlated significantly with peak exercise capacity and independently of lung function impairment.

Determinants of Progression of Aortic Stiffness in Hemodialysis Patients A Prospective Longitudinal Study

Aortic stiffness is associated with increased cardiovascular mortality in patients with chronic kidney disease. However, the rate of progression of arterial stiffness and the role of cardiovascular risk factors in the progression of arterial stiffness has never been established in a longitudinal study. In a prospective, longitudinal, observational study, carotid-femoral pulse wave velocity and carotid-radial pulse wave velocity were assessed in 109 hemodialysis patients at baseline and after a mean follow-up of 1.2 years. We examined the impact of age, atherosclerotic cardiovascular disease, diabetes mellitus, dialysis vintage, and pentosidine (a well-characterized, advanced glycation end products) on the rate of progression of aortic stiffness. The annual rate of changes in carotid-femoral pulse wave velocity and carotid-radial pulse wave velocity were 0.84 m/s per year (95% confidence interval, 0.50–1.12 m/s per year) and −0.66 m/s per year (95% confidence interval, −0.85 to −0.47 m/s per year), respectively. Older subjects, and patients with diabetes mellitus or atherosclerotic cardiovascular disease had higher aortic stiffness at baseline, however, the rate of progression of aortic stiffness was only determined by plasma pentosidine levels (P=0.001). The degree of baseline aortic stiffness was a significant determinant of the regression of brachial stiffness (P<0.001) suggesting that the regression of brachial stiffness occurs in response to central aortic stiffness. These findings suggest that traditional cardiovascular risk factors may play some role in the progression of aortic stiffness before development of advanced chronic kidney disease, and that the enhanced rate of progression of aortic stiffness in chronic kidney disease patients on dialysis are probably determined by more specific chronic kidney disease–related risk factors such as advanced-glycation end products.

Aortic-Brachial Stiffness Mismatch and Mortality in Dialysis Population

We hypothesized that increased aortic stiffness (central elastic artery) combined with a decrease in brachial stiffness (peripheral muscular artery) leads to the reversal of the physiological stiffness gradient (ie, mismatch), promoting end-organ damages through increased forward pressure wave transmission into the microcirculation. We, therefore, examined the effect of aortic-brachial stiffness mismatch on mortality in patients in need of dialysis. In a prospective observational study, aortic-brachial arterial stiffness mismatch (pulse wave velocity ratio) was assessed using carotid-femoral pulse wave velocity divided by carotid-radial pulse wave velocity in 310 adult patients on dialysis. After a median follow-up of 29 months, 146 (47%) deaths occurred. The hazard ratio (HR) for mortality related to PWV ratio in a Cox regression analysis was 1.43 (95% confidence interval [CI], 1.24–1.64; P<0.001 per 1 SD) and was still significant after adjustments for confounding factors, such as age, dialysis vintage, sex, cardiovascular disease, diabetes mellitus, smoking status, and weight (HR, 1.23; 95% CI: 1.02–1.49). The HRs for changes in 1 SD of augmentation index (HR, 1.35; 95% CI, 1.12–1.63), carotid-femoral pulse wave velocity (HR, 1.29; 95% CI, 1.11–1.50), and carotid-radial pulse wave velocity (HR, 0.80; 95% CI, 0.67–0.95) were statistically significant in univariate analysis, but were no longer statistically significant after adjustment for age. In conclusion, aortic-brachial arterial stiffness mismatch was strongly and independently associated with increased mortality in this dialysis population. Further studies are required to confirm these finding in lower-risk groups.

Age-related and blood pressure-independent reduction in aortic stiffness after kidney transplantation.

Objectives Aortic stiffness is a novel cardiovascular risk factor in patients with chronic kidney disease (CKD). The purpose of the present study is to examine whether there is a blood pressure-independent improvement in aortic stiffness 3 months after successful kidney transplantation (KTx), and whether this improvement is age-dependent. Method In this prospective, longitudinal observational study, we studied hemodynamic and biological parameters prior to and 3 months after a KTx in 52 stage 5 CKD patients. Aortic stiffness was measured by carotido-femoral pulse wave velocity (c-f PWV) and enhanced central wave reflection was evaluated by the heart rate-adjusted central augmentation index (AIx) by means of arterial tonometry. Endothelin-1, L-arginine, asymmetric dimethylarginine (biomarkers of endothelial dysfunction), pentosidine (advanced glycation end-products) and mineral metabolism parameters were also measured. Results After adjusting for the reduction in mean blood pressure, c-f PWV decreased significantly from 12.1 ± 3.3 to 11.6 ± 2.3 m/s (P < 0.05). In an analysis stratified by age, this improvement was only present in patients older than 50 years of age as compared with patients younger than 50 years of age (−5.5 ± 2.2 vs. 2.1 ± 1.9%, P < 0.05). AIx decreased from 22 ± 11 to 14 ± 13% (P < 0.01), but this reduction was not age-dependent. We also observed a similar degree of improvement in the biomarker levels of endothelial dysfunction and pentosidine in both groups. Conclusion This study shows for the first time that there is an age-dependent improvement in aortic stiffness after KTx. These observations suggest that older patients may have an added cardiovascular risk reduction after a successful KTx.

Chronic obstructive pulmonary disease in women

BACKGROUND Little is known about the comparative impact of chronic obstructive pulmonary disease (COPD) between women and men and about womens response to pulmonary rehabilitation. OBJECTIVES To compare lung function, disability, mortality and response to pulmonary rehabilitation between women and men with COPD. METHODS In the present retrospective study, 68 women (mean age 62.5+/-8.9 years) and 168 men (mean age 66.3+/-8.4 years) were evaluated by means of pulmonary function testing and an incremental symptom-limited cycle exercise test. Forty women and 84 men also participated in a 12-week pulmonary rehabilitation program. A 6 min walking test and the chronic respiratory questionnaire were used to assess the effects of pulmonary rehabilitation. Survival status was also evaluated. RESULTS Compared with men, women had a smaller tobacco exposure (31+/-24 versus 48+/-27 pack-years, P<0.05), displayed better forced expiratory volume in 1 s (44+/-13 versus 39+/-14 % predicted, P<0.05), a higher functional residual capacity (161+/-37 versus 149+/-36 % predicted, P<0.05) and total lung capacity (125+/-20 versus 115+/-19 % predicted, P<0.001). Peak oxygen consumption was not different between women and men when expressed in predicted values but lower in women when expressed in absolute values. Pulmonary rehabilitation resulted in significant improvements in 6 min walking test and quality of life in both sexes, but women had a greater improvement in chronic respiratory questionnaire dyspnea. Survival status was similar between sexes, but predictors of mortality were different between sexes. CONCLUSIONS Women may be more susceptible to COPD than men. The clinical expression of COPD may differ between sexes with greater degree of hyperinflation in women, who also benefit from pulmonary rehabilitation.

The impact of warfarin on the rate of progression of aortic stiffness in hemodialysis patients: a longitudinal study

BACKGROUND Accelerated progression of aortic stiffness in patients with advanced chronic kidney disease is not well explained by the traditional cardiovascular risk factors. We hypothesized that vitamin K deficiency may result in an accelerated progression of aortic stiffness in the pro-calcifying uremic milieu. METHOD Eighteen hemodialysis (HD) patients on warfarin were matched to 54 HD patients without warfarin (control). Aortic stiffness was determined by carotid-femoral pulse wave velocity (cf-PWV) at baseline and after a mean follow-up of 1.2 years. In the control group, spontaneous vitamin K deficiency was defined as proteins induced by vitamin K deficiency/absence-II >median. RESULTS At baseline, clinical characteristics and cf-PWV were similar. Adjusted cf-PWV increased by 0.86 ± 1.87 m/s in control and by 2.24 ± 2.68 m/s in warfarin group (P = 0.024). After adjustments for confounders, warfarin therapy was independently associated with progression of aortic stiffness (P = 0.016). The rate of progression of aortic stiffness showed a linear trend in response to vitamin K status and warfarin therapy, suggesting that at least part of the effects are mediated through reduced availability of vitamin K. The unadjusted and adjusted hazard ratio (HR) of warfarin therapy on mortality were, respectively, 2.40 (P = 0.006) and 2.53 (P = 0.006). In a forward conditional Cox regression analysis, age, albumin, augmentation index (AIx) and a cf-PWV > 13.8 m/s at the time of follow-up (HR: 2.11, P = 0.05) were independent determinants of mortality, whereas warfarin use was not retained as an independent factor. Finally, control patients with poor vitamin K status had an intermediate survival as compared with controls with better vitamin K status and patients with warfarin (P = 0.01). CONCLUSION This is the first study to show a temporal association between warfarin, functional vitamin K deficiency and progression of aortic stiffness in HD patients. These findings suggest that the net cardiovascular benefit of long-term warfarin therapy may need to be reevaluated in this population.

Reduced Heart Rate Variability in Patients with Chronic Obstructive Pulmonary Disease Independent of Anticholinergic or β-agonist Medications

ABSTRACT Reduced heart rate variability (HRV) is a predictor of poor outcome in several pathologies and in general population. Whether HRV is altered during normal daily activities or influenced by anticholinergic and β-adrenergic medications in chronic obstructive pulmonary disease (COPD) remains unknown. Forty-one clinically stable COPD patients and 19 healthy controls matched for age, sex and smoking history underwent a 24-hour ambulatory ECG recording during normal daily activities. HRV was assessed by standardized temporal and spectral analysis. COPD patients showed a reduced HRV (LF/HF ratio) compared with healthy controls (median [interquartile range]) during daytime (2.6 [1.5–3.8] vs. 3.5 [2.9–5.6]), nighttime (1.8 [1.1–4.3] vs. 4.2 [2.7–6.9]) as well as during the entire 24-hour (1.9 [1.5–3.4] vs. 3.9 [3.2–5.6]) recordings (all P < 0.005). There was no significant difference between the two groups in the time domain and in the low frequency or high frequency domain for the 24-hour period analysis. In COPD patients, the 24-hour LF/HF ratio positively correlated with forced expiratory volume in 1 second (FEV1) (r = 0.342, P = 0.028) and negatively correlated with age (r = −0.317, P = 0.044). In multiple regression analysis, LF/HF ratio was associated with FEV1 (P = 0.05) but not with age (P = 0.08). There was no difference of HRV between patients using or not anticholinergic or β-agonist medications. These results demonstrate that COPD patients have a reduced sympatho-vagal balance compared with healthy subjects. HRV correlates with disease severity and does not seem to be influenced by anticholinergic or adrenergic medications.

Les manifestations cardiovasculaires chez les patients atteints d’une BPCO

Introduction  La bronchopneumopathie obstructive chronique (BPCO) affecte principalement la fonction respiratoire. Or, cette maladie est frequemment associee a d’autres problemes de sante appeles manifestations systemiques. Notamment, les patients atteints d’une BPCO presentent un risque eleve de maladies cardiovasculaires. Etat des connaissances  La majeure partie des connaissances actuelles en ce qui a trait aux problemes cardiovasculaires chez les patients atteints d’une BPCO porte sur les arythmies cardiaques. Outre les arythmies, l’hypertension arterielle, les maladies cardiovasculaires, l’insuffisance cardiaque et les accidents vasculaires cerebraux font partie des problemes cardiovasculaires qui surviennent chez ces patients. Ce manuscrit a essentiellement pour objectif de dresser le portrait des maladies cardiovasculaires qui surviennent chez les patients atteints d’une BPCO. Il exclut le champ relatif a l’hypertension pulmonaire et ses consequences cardiaques droites. Perspectives et conclusion  De plus en plus, la communaute medicale s’interesse aux manifestations systemiques dont les problemes cardiovasculaires chez les patients atteints d’une BPCO. D’autres etudes seront toutefois necessaires afin d’approfondir les connaissances a ce propos. Celles-ci permettront une meilleure prise en charge des patients souffrant d’une BPCO.

Effects of Aerobic Exercise Training and Irbesartan on Blood Pressure and Heart Rate Variability in Patients with Chronic Obstructive Pulmonary Disease

BACKGROUND AND OBJECTIVES The present pilot study was undertaken to evaluate the efficacy of an aerobic exercise training (AET) program alone or combined with an antihypertensive agent (irbesartan) to reduce blood pressure (BP) and enhance heart rate variability (HRV) in chronic obstructive pulmonary disease patients. METHODS Twenty-one patients were randomly assigned to a double-blind treatment with exercise and placebo (n=11) or exercise and irbesartan (n=10). Subjects underwent 24 h BP monitoring and 24 h electrocardiographic recording before and after the 12-week AET. HRV was investigated using three indexes from the power spectral analysis and three indexes calculated from the time domain. The AET program consisted of exercising on a calibrated ergocycle for 30 min three times per week. Five patients in the placebo group were excluded during follow-up because they were not compliant. RESULTS There was no change in 24 h systolic and diastolic BP before (130+/-14 mmHg and 70+/-3 mmHg, respectively) and after (128+/-8 mmHg and 70+/-8 mmHg, respectively) exercise training in the placebo group, whereas in the irbesartan group systolic and diastolic BP decreased from 135+/-9 mmHg and 76+/-9 mmHg to 126+/-12 mmHg and 72+/-8 mmHg, respectively (P<0.02). There were no changes in HRV parameters in either group. CONCLUSIONS The present study suggests that a 12-week AET program is not associated with a significant reduction in BP or enhancement in HRV, whereas an AET program combined with irbesartan is associated with a reduction in 24 h BP.

Aortic-Brachial Pulse Wave Velocity Ratio: A Blood Pressure-Independent Index of Vascular Aging.

Aortic stiffness, a cardiovascular risk factor, depends on the operating mean arterial pressure (MAP). The impact of aortic stiffness on cardiovascular outcomes is proposed to be mediated by the attenuation or the reversal of the arterial stiffness gradient. We hypothesized that arterial stiffness gradient is less influenced by changes in MAP. We aimed to study the relationship between MAP and aortic stiffness, brachial stiffness, and arterial stiffness gradient. In a cross-sectional study of a dialysis cohort (group A, n=304) and a cohort of hypertensive or kidney transplant recipient with an estimated glomerular filtration rate of >45 mL/min/1.73 m2 (group B, n=114), we assessed aortic and brachial stiffness by measuring carotid–femoral and carotid–radial pulse wave velocities (PWV). We used aortic–brachial PWV ratio as a measure of arterial stiffness gradient. Although there was a positive relationship between MAP and carotid–femoral PWV (R2=0.10 and 0.08; P<0.001 and P=0.003) and MAP and carotid–radial PWV (R2=0.22 and 0.12; P<0.001 and P<0.001), there was no statistically or clinically significant relationship between MAP and aortic–brachial PWV ratio (R2=0.0002 and 0.0001; P=0.8 and P=0.9) in group A and B, respectively. Dialysis status and increasing age increased the slope of the relationship between MAP and cf-PWV. However, we found no modifying factor (age, sex, dialysis status, diabetes mellitus, cardiovascular disease, and class of antihypertensive drugs) that could affect the lack of relationship between MAP and aortic–brachial PWV ratio. In conclusion, these results suggest that aortic–brachial PWV ratio could be considered as a blood pressure–independent measure of vascular aging.Aortic stiffness, a cardiovascular risk factor, depends on the operating mean arterial pressure (MAP). The impact of aortic stiffness on cardiovascular outcomes is proposed to be mediated by the attenuation or the reversal of the arterial stiffness gradient. We hypothesized that arterial stiffness gradient is less influenced by changes in MAP. We aimed to study the relationship between MAP and aortic stiffness, brachial stiffness, and arterial stiffness gradient. In a cross-sectional study of a dialysis cohort (group A, n=304) and a cohort of hypertensive or kidney transplant recipient with an estimated glomerular filtration rate of >45 mL/min/1.73 m2 (group B, n=114), we assessed aortic and brachial stiffness by measuring carotid–femoral and carotid–radial pulse wave velocities (PWV). We used aortic–brachial PWV ratio as a measure of arterial stiffness gradient. Although there was a positive relationship between MAP and carotid–femoral PWV ( R 2=0.10 and 0.08; P <0.001 and P =0.003) and MAP and carotid–radial PWV ( R 2=0.22 and 0.12; P <0.001 and P <0.001), there was no statistically or clinically significant relationship between MAP and aortic–brachial PWV ratio ( R 2=0.0002 and 0.0001; P =0.8 and P =0.9) in group A and B, respectively. Dialysis status and increasing age increased the slope of the relationship between MAP and cf-PWV. However, we found no modifying factor (age, sex, dialysis status, diabetes mellitus, cardiovascular disease, and class of antihypertensive drugs) that could affect the lack of relationship between MAP and aortic–brachial PWV ratio. In conclusion, these results suggest that aortic–brachial PWV ratio could be considered as a blood pressure–independent measure of vascular aging. # Novelty and Significance {#article-title-24}