Broad-band spectral analysis of 24 h continuous finger blood pressure: comparison with intra-arterial recordings. (33/1777)

The present study compares the spectral characteristics of 24-h blood pressure variability estimated invasively at the brachial artery level with those estimated by measurement of blood pressure at the finger artery using the non-invasive Portapres device. Broad-band spectra (from 3x10(-5) to 0.5 Hz) were derived from both finger and intra-brachial pressures recorded simultaneously for 24 h in eight normotensive and twelve hypertensive ambulant subjects. At frequencies lower than 0.07 Hz, higher spectral estimates were obtained by Portapres than by intra-brachial measurements. The maximum overestimation occurred in systolic pressure at around 10(-2) Hz, where the amplitude of the oscillations was two times greater when measured by Portapres. A less pronounced overestimation was found for diastolic pressures. The maximum overestimation was greater during daytime than during night-time. At around 0.1 Hz, invasive and non-invasive spectra were similar. At the respiratory frequencies (0.15-0.50 Hz), the power spectra were overestimated by Portapres during daytime, and underestimated at night. These results provide reference information for the correct interpretation of Portapres data in the estimation of 24-h blood pressure spectral power.  (+info)

Acute administration of 17beta-oestradiol does not improve endothelium-dependent vasodilatation in young men. (34/1777)

Studies have recently demonstrated that long-term oestrogen therapy improves endothelium-dependent and endothelium-independent vasodilatation in the conductance vessels of biological males. We sought to determine if an acute single dose of oestrogen might similarly improve vasodilator function in young males. In a randomized, double-blind, placebo-controlled, crossover study, we compared the effects of 1 mg of sublingual 17beta-oestradiol (E(2)) and placebo on endothelium-dependent and endothelium-independent vasodilatation in the brachial artery using a non-invasive ultrasound technique. We recruited 30 young males based on a power calculation. Neither acute sublingual oestrogen nor placebo affected flow-mediated vasodilatation [5.32+/-0.78% and 5.28+/-0.60% respectively (mean+/-S.E.M.), P=0.94]. Responses to nitroglycerine were similar after oestrogen or placebo (16.01+/-0.86% and 15.29+/-1. 19%, P=0.47). Basal blood flow and flow during reactive hyperaemia did not differ after oestrogen or placebo. Heart rate and blood pressure were similar during both treatment phases of the study. The absolute change in serum oestradiol levels was greater after the oestrogen treatment phase than after placebo (1509+/-87 versus -13+/-4 pmol/l, P<0.0001). Despite achieving supra-physiological oestradiol levels, the acute administration of sublingual E(2) does not appear to improve endothelium-dependent or endothelium-independent vasodilatation, at least acutely, in the brachial artery of young males. In keeping with our previous study, these data suggest that a period of oestrogen 'priming' (possibly to induce receptor-mediated nitric oxide synthesis) may be required to yield an improvement in vascular function in males.  (+info)

Flow ratios to express results obtained with the human in vivo 'perfused forearm technique'. (35/1777)

AIMS: To determine the accuracy of forearm blood flow (FBF) ratio (flow in infused arm/flow in control arm) to detect unilateral increases in forearm blood flow. METHODS: In nine healthy male volunteers, we measured the effect of infusion of saline into the brachial artery at a rate of 2 ml/100 ml forearm min-1 on FBF ratio during control, mental arithmetic (MAR) and lower body negative pressure (LBNP) at -40 mmHg. RESULTS: Saline infusion increased FBF ratio from baseline by 115.9+/-17.4, 82.0+/-19.0 and 159.6+/-53.3% for control, MAR and LBNP, respectively (P<0.05 for MAR vs control). CONCLUSIONS: FBF ratio may underestimate unilateral increases in forearm blood flow during simultaneous mental arousal.  (+info)

Plasma homocysteine is weakly correlated with plasma endothelin and von Willebrand factor but not with endothelium-dependent vasodilatation in healthy postmenopausal women. (36/1777)

BACKGROUND: Hyperhomocysteinemia is an independent cardiovascular risk factor, possibly through the induction of endothelial dysfunction. The postmenopausal state is associated with increased plasma homocysteine. We examined whether increased homocysteine is associated with impaired endothelial function. METHODS: Sixty-three hysterectomized but otherwise healthy postmenopausal women (54.8 +/- 3.5 years) participated in this study. Fasting total plasma homocysteine (tHcy) was measured as free plus protein-bound homocysteine. Endothelial function was assessed by measuring plasma concentrations of the endothelium-derived proteins endothelin (ET), von Willebrand factor (vWF), and plasminogen activator inhibitor type 1 (PAI-1) as well as brachial artery flow-mediated, endothelium-dependent vasodilatation (FMD). RESULTS: Plasma tHcy was 9.6 +/- 2.5 micromol/L. After adjustment for possible confounders, a 1 micromol/L increase in tHcy was associated with an increase in ET of 0.08 ng/L (P = 0.045) and an increase in vWF of 4.2% (P = 0.05). No statistically significant association was present between tHcy and PAI-1 or FMD. CONCLUSIONS: Increased fasting homocysteine in postmenopausal women may impair some aspects of endothelial function. It is of clinical interest to study whether homocysteine lowering can improve endothelial function and thus cardiovascular morbidity and mortality in postmenopausal women.  (+info)

Purple grape juice improves endothelial function and reduces the susceptibility of LDL cholesterol to oxidation in patients with coronary artery disease. (37/1777)

BACKGROUND: In vitro, the flavonoid components of red wine and purple grape juice are powerful antioxidants that induce endothelium-dependent vasodilation of vascular rings derived from rat aortas and human coronary arteries. Although improved endothelial function and inhibition of LDL oxidation may be potential mechanisms by which red wine and flavonoids reduce cardiovascular risk, the in vivo effects of grape products on endothelial function and LDL oxidation have not been investigated. This study assessed the effects of ingesting purple grape juice on endothelial function and LDL susceptibility to oxidation in patients with coronary artery disease (CAD). METHODS AND RESULTS: Fifteen adults with angiographically documented CAD ingested 7.7+/-1.2 mL. kg(-1). d(-1) of purple grape juice for 14 days. Flow-mediated vasodilation (FMD) was measured using high-resolution brachial artery ultrasonography. Susceptibility of LDL particles to oxidation was determined from the rate of conjugated diene formation after exposure to copper chloride. At baseline, FMD was impaired (2.2+/-2. 9%). After ingestion of grape juice, FMD increased to 6.4+/-4.7% (P=0.003). In a linear regression model that included age, artery diameter, lipid values, and use of lipid-lowering and antioxidant therapies, the effect of grape juice on FMD remained significant (mean change 4.2+/-4.4%, P<0.001). After ingestion of grape juice, lag time increased by 34.5% (P=0.015). CONCLUSIONS: Short-term ingestion of purple grape juice improves FMD and reduces LDL susceptibility to oxidation in CAD patients. Improved endothelium-dependent vasodilation and prevention of LDL oxidation are potential mechanisms by which flavonoids in purple grape products may prevent cardiovascular events, independent of alcohol content.  (+info)

Healing rates and cost efficacy of outpatient compression treatment for leg ulcers associated with venous insufficiency. (38/1777)

OBJECTIVE: Although newer techniques to promote the healing of leg ulcers associated with chronic venous insufficiency are promising, improved healing rates and cost effectiveness are unproven. We prospectively followed a series of patients who underwent treatment with outpatient compression for venous stasis ulcers without adjuvant techniques to determine healing rates and costs of treatment. METHODS: Two hundred fifty-two patients with clinical or duplex scan evidence of chronic venous insufficiency and active leg ulcers underwent treatment with ambulatory compression techniques. The patients were prospectively followed with wound measurements at 1-week to 2-week intervals, and the factors that were associated with delayed healing were determined. RESULTS: Of all the ulcers, 57% were healed at 10 weeks of treatment and 75% were healed at 16 weeks. Ultimately, 96% of the ulcers healed, and only 1 major amputation was necessitated (0.4%). Initial ulcer size and moderate arterial insufficiency (ankle brachial index, 0.5 to 0.8; n = 34) were factors that were independently associated with delayed healing (P <.01). Patient age, ulcer duration before treatment, and morbid obesity did not significantly affect healing times. The cost of 10 weeks of outpatient treatment with compression techniques ranged from $1444 to $2711. CONCLUSION: The treatment of venous stasis ulcers with compression techniques results in reliable, cost-effective healing in most patients. Current adjuvant techniques may prove to be useful but are likely to be cost effective only in a minority of cases, particularly in patients with large initial ulcer size or arterial insufficiency.  (+info)

Vascular injuries of the limbs: a fifteen-year Georgian experience. (39/1777)

OBJECTIVES: to analyse the causes of injury, surgical approaches, outcome and complication of vascular trauma of the upper and lower limbs in patients with vascular injuries operated on over a period between 1981 and 1995. PATIENTS: in 157 patients, the injuries were penetrating in 136 cases and blunt in 21. Isolated vascular trauma was present in 92 (58.6%) patients, 65 cases (41.4%) were aggrevated by concomitant bone fractures, severe nerve and soft tissue damage. The most frequently injured vessels were the superficial femoral (20. 6%) and brachial (19.1%) arteries. RESULTS: saphenous vein interposition grafting was applied with good results in 34 patients, polytetrafluoroethylene grafts were used in three cases, end-to-end anastomoses in 42 cases, venous bypasses in five cases, and venous patches in seven cases. Seventeen patients underwent arterial repair and nine, venous repair. Fasciotomy was used in 18 cases, and vessels were ligated in 14 cases. Blood flow was restored in 91 patients (58.0%), and collaterals compensated in 31 cases (19.7%). Fourteen primary and nine secondary amputations were performed. Twelve patients died. The limb salvage rate was 77.7% (84.1% among surviving patients). CONCLUSIONS: most vascular injuries associated with limb trauma can be managed successfully unless associated by severe concomitant damage to bones, nerves and soft tissues.  (+info)

Impaired endothelium-dependent vascular responses of retinal and intrarenal arteries in patients with type 2 diabetes. (40/1777)

Endothelial dysfunction has been implicated in the pathogenesis of diabetic microangiopathies such as retinopathy and nephropathy as well as macrovascular diseases. The aim of the current study was to determine whether endothelial function in the retinal and renal arteries is impaired in type 2 diabetes mellitus. We examined the effects of an intravenous infusion of L-arginine and a sublingual administration of nitroglycerin on the brachial, retinal, and interlobar arterial hemodynamics in 20 type 2 diabetic patients (10 with normoalbuminuria and 10 with microalbuminuria) and 10 aged-matched control subjects. Despite no difference in the nitroglycerin-induced vascular response of the brachial or retinal artery among the 3 groups, the L-arginine-induced vascular response of each artery was significantly lower in both the normoalbuminuric and microalbuminuric patients than in the control subjects and the microalbuminuric patients showed the lowest value among the 3 groups (P<0.01, each artery, respectively). The L-arginine-induced vascular response of each artery was significantly correlated with HbA1c levels (brachial artery, r=0.617, P=0.0003; retinal artery, r=0.599, P=0.0005; interlobar artery, r=0.636, P=0.0002). In addition, stepwise multiple regression analysis of all subjects showed that HbA1c level was an independent determinant for the L-arginine-induced vascular response of each artery. The results showed that the endothelium-dependent vascular responses of the retinal and intrarenal arteries as well as the brachial artery were impaired in diabetic patients before the clinical manifestation of diabetic nephropathy, and suggest that endothelial dysfunction in these arteries is associated with hyperglycemia in these patients.  (+info)