[The neurovascular costoclavicular compression syndrome does not exist]. / Het neurovasculair costoclaviculair compressiesyndroom bestaat niet.

The term 'neurovascular compression syndrome' refers to a heterogeneous group of signs and symptoms thought to be generated by the compression of arteries, veins or nerves, which is caused by the anatomical relationships of muscles, ligaments and bony structures in the thoracic outlet. Most cases are related to nerve compression; arterial and venous compression accounts for 1-3% of cases. The term 'neurovascular compression syndrome', which does not refer to a single entity, is confusing and should be avoided. Rather, a clinical problem thought to arise in the thoracic outlet should be described in terms of the underlying arterial, venous or nerve impairment. Indications for surgical intervention are limited: there is no evidence to suggest that patients who undergo surgery fare better than those who receive non-surgical treatment.

Homozygosity for 807 T polymorphism in alpha(2) subunit of platelet alpha(2)beta(1) is associated with increased risk of cardiovascular mortality in high-risk women.

BACKGROUND: Platelet adhesion to collagen is the initial step in both hemostasis and thrombosis; this adhesion is mediated by alpha(2)beta(1) on the surface of platelet membranes. An 807 C to T single nucleotide exchange polymorphism close to the gene coding for the alpha(2) subunit of alpha(2)beta(1) is associated with the density of alpha(2)beta(1) on the platelet membrane. METHODS AND RESULTS: We studied the relation of the alpha(2)beta(1) 807 C/T genotype to cardiovascular mortality in a prospective cohort study of 12 239 women who were invited for the breast cancer screening program of Utrecht, the Netherlands. The initial age was between 52 and 67 years. Women were followed on vital status between 1976 and 1995 (168 513 women-years). Data were analyzed by using a nested case-control design. The alpha(2)beta(1) 807 C/T genotype was not associated with cardiovascular mortality in the total population: the rate ratio for cardiovascular mortality in 807 TT homozygotes compared with 807 CC wild types was 1.2 (95% CI 0.8 to 1.7). However, the alpha(2)beta(1) 807 T polymorphism was associated with an increased risk of cardiovascular mortality in women who smoked or in women who had indications of compromised endothelium, such as diabetes and microalbuminuria. In those who were exposed to >/=2 of these factors, the risk ratio (95% CI) between alpha(2)beta(1) 807 TT homozygotes and 807 CC wild types was 14.1 (5.0 to 39.9). CONCLUSIONS: alpha(2)beta(1) 807 TT homozygosity, coding for increased alpha(2)beta(1) density on the platelet membrane, is associated with an increased risk of cardiovascular mortality in those women with indications of compromised endothelium.

Heterozygosity for a hereditary hemochromatosis gene is associated with cardiovascular death in women.

Background-The genetic background of hereditary hemochromatosis (HH) is homozygosity for a cysteine-to-tyrosine transition at position 282 in the HFE gene. Heterozygosity for HH is associated with moderately increased iron levels and could be a risk factor for cardiovascular death. Methods and Results-We studied the relation between HH heterozygosity and cardiovascular death in a cohort study among 12 239 women 51 to 69 years of age residing in Utrecht, the Netherlands. Women were followed for 16 to 18 years (182 976 follow-up years). The allele prevalence of the HH gene in the reference group was 4.0 (95% CI 2.9 to 5.4). The mortality rate ratios for HH heterozygotes compared with wild types was 1.5 (95% CI 0.9 to 2.5) for myocardial infarction (n=242), 2.4 (95% CI 1.3 to 3. 5) for cerebrovascular disease (n=118), and 1.6 (95% CI 1.1 to 2.4) for total cardiovascular disease (n=530). The population-attributable risks of HH heterozygosity for myocardial infarction and cerebrovascular and total cardiovascular death were 3. 3%, 8.8%, and 4.0%, respectively. In addition, we found evidence for effect modification by hypertension and smoking. Conclusions-We found important evidence that inherited variation in iron metabolism is involved in cardiovascular death in postmenopausal women, especially in women already carrying classic risk factors.

Excessive urinary albumin levels are associated with future cardiovascular mortality in postmenopausal women.

BACKGROUND: Microalbuminuria is an early predictor of cardiovascular morbidity and mortality, in both diabetic patients and hypertensive patients. Little is known about the relation of microalbuminuria to cardiovascular disease in women of the general population. METHODS AND RESULTS: We have studied the relation of urinary albumin levels to cardiovascular mortality in a cohort study of 12 239 postmenopausal women living in Utrecht, the Netherlands. The initial age was between 52 and 67 years. Women were followed on vital status between 1976 and 1995 (168 513 women-years). Albumin was determined in the urine of 561 cases and 557 controls. Data were analyzed by using a nested case-control design. The cardiovascular mortality rate (95% CI) for women who were in the highest quintile of urinary albumin levels was 13.2/1000 years (8.1 to 20.9) compared with 2.6/1000 years (2.3 to 3.1) in women without detectable urinary albumin. The age-adjusted rate ratio (95% CI) between these groups was 4.4 (2.6 to 7.6). CONCLUSIONS: This is the first large cohort study that confirms a predictive role of urinary albumin for the risk of future cardiovascular mortality independent of hypertension and diabetes. Our findings support the hypothesis that microalbuminuria is a reflection of vascular damage and a marker of early arterial disease in women from the general population.

Effect of extracellular matrix glycation on endothelial cell adhesion and spreading: involvement of vitronectin.

Glycation of proteins of the vessel wall is thought to play an important role in the pathogenesis of vascular complications in diabetes by affecting structure and function of these proteins. Adhesive proteins in the extracellular matrix (ECM) of endothelial cells (ECs) are essential for attachment of ECs to the subintima. In this study, we investigated the effect of glycation of ECM and purified adhesive proteins on EC adhesion and spreading. ECM was incubated with the reactive sugar glucose-6-phosphate (0-500 mmol/l) for different time periods (0-14 days) at 37 degrees C. Degree of glycation, measured in an enzyme-linked immunosorbent assay using a monoclonal antibody specific for advanced glycation end products, increased in a time- and concentration-dependent manner. Glycation of ECM with 50 mmol/l glucose-6-phosphate resulted in increased coverage by ECs as measured in a cell adhesion assay and was the result of an increase in number of adhered cells, while cell size was unaffected. Glycation of ECM with higher concentrations of glucose-6-phosphate resulted in decreased coverage by ECs caused by both a reduction in number of adhered ECs and impaired spreading. Experiments with purified glycated matrix proteins indicate that the decrease in EC adhesion and spreading on glycated ECM may result from glycation of vitronectin. Impaired EC adhesion and spreading caused by vitronectin glycation may result in impaired endothelial function and contribute to vascular disease.

Platelet adhesion and aggregate formation in type I diabetes under flow conditions.

To study platelet activation as a phenomenon that may precede development of angiopathy in diabetes mellitus, we compared platelet adhesion and thrombus formation in a flow system with blood from insulin-dependent (type I) diabetic subjects with and without macroangiopathy and age- and sex-matched control subjects. Adhesion and thrombus formation on matrix of cultured human endothelial cells (ECM) and adhesion on matrix of human fibroblasts (FBM) were studied after exposure to flowing blood at shear rates of 300 and 1300 s-1 and exposure times of 1, 3, 5, and 10 min (and 20 min in adhesion experiments). Blood was anticoagulated with trisodium citrate (1:10 vol/vol, 110 mM) or low-molecular-weight heparin ([LMWH] 20 U/ml). Endothelial cell cultures were either unstimulated or stimulated with 4 beta-phorbol 12-myristate 13-acetate (PMA) 16 h before isolating their matrix. Platelet adhesion on ECM and FBM in citrated and LMWH-anticoagulated blood was identical in diabetic patients and control subjects, with comparable increases of adhesion with increasing perfusion times. Platelet aggregate formation on ECM of PMA-stimulated cells with LMWH-anticoagulated blood was similar in diabetic patients, whether macroangiopathy was present, compared with control subjects. Fibrin deposition and fibrinopeptide A generation during perfusion were comparable in diabetic and control subjects. Platelet thromboxane B2 formation after stimulation with arachidonic acid was increased in diabetic patients without macroangiopathy compared with age- and sex-matched control subjects. In the perfusion system, the patterns of platelet adhesion and aggregate formation on extracellular matrix in flowing blood of diabetic patients (with or without macroangiopathy), and healthy age- and sex-matched control subjects followed a similar pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of angiotensin-converting enzyme inhibition and angiotensin II type 1 receptor antagonism on postprandial endothelial function.

OBJECTIVES: The purpose of this study was to determine whether endothelial dysfunction as a consequence of direct postprandial lipid response might be favorably influenced by angiotensin-converting enzyme inhibitors or angiotensin AT1 receptor antagonists. BACKGROUND: Postprandial triglyceride-rich lipoproteins cause endothelial dysfunction. Angiotensin-converting enzyme inhibitors have been shown to improve vascular reactivity. For angiotensin II type 1 receptor antagonists this effect is as yet uncertain. METHODS: A randomized, double-blind, placebo-controlled crossover study in 30 healthy volunteers, aged 18 to 33 years, evaluated the effect of quinapril (40 mg daily for two weeks) and losartan (50 mg daily for two weeks) on basal as well as postprandial endothelial function measured noninvasively as percentage diameter change in the brachial artery after reactive hyperemia. Endothelium-independent dilation was measured after nitroglycerine spray sublingual. RESULTS: An acute oral fat load impaired endothelial function. Flow-mediated vasodilation (FMD) decreased from a median of 6.2% to 4.2% (p < 0.05). There was no significant difference in preprandial endothelial function after two weeks of treatment with either quinapril or losartan compared with placebo in these healthy volunteers. Both quinapril (FMD 6.4% to 6.3%) and losartan (7.1% to 5.4%) prevented endothelial dysfunction induced by an oral fat load, although the protective effect of quinapril appeared to be more profound. The response to the endothelium-independent vasodilator nitroglycerine was unaltered throughout the study. CONCLUSIONS: Both losartan and quinapril prevent endothelial dysfunction induced by triglyceride-rich lipoproteins in healthy volunteers. However, the protective effect of quinapril is more pronounced.

[The metabolic syndrome: a cluster of vascular risk factors]. / Het metabool syndroom: een cluster van vasculaire risicofactoren.

The metabolic syndrome is a cluster of several vascular risk factors (impaired glucose metabolism, dyslipidaemia, hypertension and central adiposity). The prevalence of the metabolic syndrome is high, varying between 10 and 40% depending on age and sex. This prevalence will increase in the years to come due to the increased prevalence of overweight/obesity. To identify the metabolic syndrome, there is a readily applicable definition for daily clinical practice, i.e. the presence of three or more of the following characteristics: hyperglycaemia, hypertension, low plasma HDL cholesterol level, high plasma triglyceride level and central adiposity. The underlying pathophysiology is not fully clarified, but insulin resistance plays an important role in this syndrome. The metabolic syndrome is associated with increased cardiovascular morbidity and mortality and an increased risk for the development of diabetes mellitus type 2. In subjects with one or two components of the metabolic syndrome and in patients with manifest vascular disease, it seems advisable to be alert to the presence of the other components in order to either diagnose or exclude the metabolic syndrome. Although clinical evidence is lacking, from a pathophysiological point of view it seems reasonable to focus the treatment on reducing insulin resistance, which can be achieved by weight reduction and an increase in physical activity. Treatment of the individual risk factors may also be considered, depending on the degree of vascular risk.

[The diagnosis of pulmonary embolism: the best strategies according to the results of a large Dutch multicentre study]. / Diagnostiek bij longembolie; de beste strategieën volgens de resultaten van een grote Nederlandse multicenterstudie.

The Dutch national guidelines for the diagnosis of patients with clinically suspected pulmonary embolism (from 1992 en 1998) are poorly followed in clinical practice, due especially to practical objections. A large multicentre trial to investigate the diagnostic accuracy of the available modalities and of recently developed techniques such as D-dimer determination, (99m)Tc-gas-scintigraphy and spiral CT scanning was started in I997. In the first phase, the diagnostic value was assessed of: spiral CT (sensitivity 69%, specificity 84%; sensitivity for segmental and larger pulmonary embolisms (PE) 86% and for subsegmental PE 21%), (99m)Tc-gas-ventilation scintigraphy (no improvement compared to conventional ventilation scintigraphy), D-dimer determination (sensitivity for segmental PE 93% and for subsegmental PE 53%, specificity 63%), clinical decision rules (in combination with D-dimer determination; sensitivity 100%, specificity 11%) and echography of the deep venous system (sensitivity 26% for segmental PE and 7% for subsegmental PE, specificity 97%). In the second phase, the feasibility of two new potentially cost-effective diagnostic algorithms was evaluated on the basis of the results obtained in the first phase and data in the literature. In 631 patients, a clinical risk estimate was made and D-dimer determination was done, followed by a ventilation-perfusion scan and serial compression echography of the leg veins. An apparent recurrence of PE occurred in 6 of 466 patients in whom no PE had been found originally (1.3%; 95% CI: 0.5-2.8). The average costs were 812 Euro,--per patient. In 510 patients, a spiral CT followed by compression echography was performed. Recurrent PE occurred in 3 of 378 patients with initial normal tests (0.8%; 95% CI: 0.2-2.3). The average costs were 883 Euro,--per patient. A combination of both strategies can be cost-effective with a cost 674 Euro,--per patient (recurrence rate: 1.9%). Both the strategy starting with a clinical-risk estimate and a D-dimer determination as well as the strategy consisting of spiral CT and serial echography were safe and cost-effective. According to the results of a survey of hospital directors, internists and pulmonologists, both are well accepted in clinical practice.

Carotid intima-media thickness in hyperlipidemic type I and type II diabetic patients.

OBJECTIVE: Ultrasonographic measurements of the combined thickness of the carotid intima and media can be used to examine early vessel wall changes in atherosclerosis. Premature atherosclerosis is common in diabetes, especially when other risk factors are present. Intima-media thickness was quantified in hyperlipidemic type I and type II diabetic patients, and relationships between various risk factors and intima-media thickness were investigated. RESEARCH DESIGN AND METHODS: Thirty-one patients with type I diabetes and 56 with type II diabetes were examined, with an LDL cholesterol of > 2.6 mmol/l and/or triglycerides of > 1.7 mmol/l and/or HDL cholesterol of < 0.9 mmol/l for men or < 1.1 mmol/l for women. Intima-media thickness was measured on-line, over a length of 1 cm in the common carotid artery. Later, the mean and the maximum of six measurements was calculated (left and right side, both in three directions). RESULTS: Mean intima-media thickness was 0.63 +/- 0.18 (+/-SD) mm for type I diabetes and 0.80 +/- 0.31 mm for type II diabetes. Adjusted for age, the difference was 0.06 mm, with a 95% CI of -0.08 to 0.20 mm. In multivariate regression analysis, age over 50 years and higher HbA1c were independently associated with an increase in mean intima-media thickness in type I diabetes. In type II diabetes, none of the variables reached a significance level of < or = 0.10. Results for maximum intima-media thickness were essentially the same. CONCLUSIONS: In general, intima-media thickness is larger in type II diabetes than in type I diabetes. The effect of age is absent in type II diabetes, whereas in type I diabetes, age and blood glucose control have an important effect on intima-media thickness.

Plasma levels of cellular fibronectin in diabetes.

OBJECTIVE: Cellular fibronectin is an endothelium-derived protein involved in subendothelial matrix assembly. Elevated plasma levels of cellular fibronectin therefore reflect loss of endothelial cell polarization or injury to blood vessels. Consequently, elevated plasma levels of circulating cellular fibronectin have been described in clinical syndromes with vascular damage, although not in diabetes or atherosclerosis. RESEARCH DESIGN AND METHODS: We determined fibronectin levels in 52 patients with type 1 diabetes, 50 patients with type 2 diabetes, 54 patients with a history of ischemic stroke, 23 patients with renal artery stenosis, and 64 healthy subjects. RESULTS: Circulating cellular fibronectin was significantly elevated in patients with diabetes (4.3 +/- 2.8 microg/ml) compared with patients with ischemic stroke (2.0 +/- 0.9 microg/ml), patients with renovascular hypertension (1.7 +/- 1.1 microg/ml), and healthy subjects (1.4 +/- 0.6 microg/ml). Patients with diabetes and at least one cardiovascular risk factor had an almost 2.5-fold increase in cellular fibronectin compared with diabetic subjects without such a risk factor. In multivariate regression analysis, higher triglycerides, current or past cigarette smoking, and higher urinary albumin excretion were independently associated with an increase in circulating cellular fibronectin in diabetes. CONCLUSIONS: These results suggest that circulating cellular fibronectin may be a marker protein for endothelial cell activation, especially in diabetes. Prospective studies are needed to explore this possibility

Effects of low-dose EPA-E on glycemic control, lipid profile, lipoprotein(a), platelet aggregation, viscosity, and platelet and vessel wall interaction in NIDDM.

OBJECTIVE: To assess the effects of low-dose eicosapentaenoic acid-ethyl-ester on diabetes regulation, lipid metabolism, blood rheology, and platelet reactivity. RESEARCH DESIGN AND METHODS: In a double-blind, randomized, placebo-controlled study, 24 NIDDM subjects received 1800 mg of EPA-E, 900 mg of EPA-E, or a placebo (1656 mg olive oil) daily for 8 wk. RESULTS: The EPA:arachidonic acid plasma ratio increased over an 8-wk period, then declined after a 4-wk wash-out period in the fish-oil groups in a dose-dependent way. Platelet-activating factor-induced platelet aggregation decreased from 75 +/- 7% at wk 0 to 35 +/- 21% at wk 8 in the 900-mg group (P = 0.016) and from 72 +/- 11 to 40 +/- 30% in the 1800-mg group (P = 0.039), but did not change in the placebo group. No effects on ADP- or collagen-induced aggregation could be attributed to EPA-E. In the 1800-mg group low-density-lipoprotein cholesterol increased significantly, without concomitant rise in apolipoprotein B. Triglycerides, glycemic control, lipoprotein (a), blood and plasma viscosity, erythrocyte deformability, and platelet adhesion to and aggregate formation on extracellular endothelial cell matrix were not significantly influenced. CONCLUSIONS: Purified EPA-E in doses of 900 and 1800 mg reduces Platelet-activating factor-induced platelet aggregation without negatively affecting glycemic control. Low-density-lipoprotein cholesterol was elevated in the 1800-mg group.

Aggressive lipid lowering does not improve endothelial function in type 2 diabetes: the Diabetes Atorvastatin Lipid Intervention (DALI) Study: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: Endothelial dysfunction is considered an important early marker of atherosclerosis and cardiovascular risk and is currently used as a surrogate end point for cardiovascular risk in clinical trials. Type 2 diabetic patients show a characteristic dyslipidemia. Aggressive lipid lowering might be an effective method to improve endothelial function in these patients. RESEARCH DESIGN AND METHODS: A randomized, double-blind, placebo-controlled trial was completed to study the effect of 30 weeks' administration of atorvastatin 10 mg and 80 mg on endothelial function, as assessed by B-mode ultrasound of the brachial artery, in 133 patients with type 2 diabetes without a history of cardiovascular disease. RESULTS: Patients with diabetes and diabetic dyslipidemia had considerable endothelium-dependent and endothelium-independent dysfunction; mean flow-mediated vasodilation (SD) was 3.16% (3.56), and mean response on sublingual nitroglycerin was 6.58% (6.04). Despite substantial lowering of all atherogenic lipid parameters, no improvement of endothelium-dependent vasodilatation was found (P > 0.8). CONCLUSIONS: We observed considerable baseline endothelium-dependent and endothelium-independent dysfunction in patients with diabetes and diabetic dyslipidemia without a history of cardiovascular disease. Aggressive lipid lowering by administration of atorvastatin, resulting in substantial improvement of the lipid profile, did not reverse endothelial dysfunction.

Effect of statin versus fibrate on postprandial endothelial dysfunction: role of remnant-like particles.

BACKGROUND: Postprandial lipemia is associated with endothelial dysfunction. Remnant-like particles (RLP) have been suggested to contribute to these adverse vascular effects. We investigated the effect of cerivastatin and gemfibrozil upon oral fat load induced changes in endothelial function and postprandial lipid profile in vivo. METHODS: In a randomized cross-over trial, 15 healthy volunteers received cerivastatin (0.4 mg once daily), gemfibrozil (900 mg once daily) or placebo for 3 weeks. Lipid profiles and flow mediated dilation (FMD) were assessed before and 4 h after an oral fat load. Endothelium-independent dilation was tested after nitroglycerine 0.4 mg sublingual spray. RESULTS: After the placebo period, the oral fat load induced an increase in triglycerides (TG) and RLP-cholesterol (RLP-C) (0.9 +/- 0.7 and 0.08 +/- 0.04 mmol/l, respectively) and a significant decrease in FMD (9.1 +/- 3.4 to 4.3 +/- 3.3%, P < 0.05). After gemfibrozil, TG increase was attenuated (0.5 +/- 0.5 mmol/l), whereas RLP-C increase (0.05 +/- 0.09 mmol/l) and FMD decrease (9.0 +/- 3.8 to 5.2 +/- 2.6%, P < 0.05) were not different from placebo therapy. Cerivastatin did not affect TG increase (0.7 +/- 0.8 mmol/l). RLP-C increase (0.02 +/- 0.07 mmol/l) and FMD (7.9 +/- 2.6 to 8.4 +/- 2.8%) change were attenuated significantly compared to placebo. Endothelium-independent vasodilatation remained unaltered throughout the protocol. CONCLUSION: Cerivastatin, but not gemfibrozil significantly reduces RLP-C increase after an oral fat load in combination with a reversal of fat-load induced endothelial dysfunction. The present data imply that lowering of RLP-C, rather than lowering of total TG levels, may contributes to the prevention of endothelial dysfunction after an oral fat load during statin use.

NO activity in familial combined hyperlipidemia: potential role of cholesterol remnants.

OBJECTIVE: Patients with familial combined hyperlipidemia (FCH) have an increased cardiovascular mortality despite only moderate elevations of LDL-cholesterol. Since endothelial NO release is intimately involved in the anti-atherosclerotic effects of the endothelium, we studied the effect of short-term lipid-lowering therapy on NO-mediated vasodilatation in patients with FCH. In view of only moderate LDL elevations, we evaluated whether alterations in other lipid fractions upon therapy correlated to changes in NO-mediated vasodilatation. METHODS: NO activity was assessed by serotonin-induced, nitric oxide-mediated increase in forearm blood flow (FBF). Measurements were performed 2 weeks off and 4 weeks on lipid-lowering therapy in 12 FCH patients using forearm venous occlusion plethysmography. Control experiments were performed in 12 healthy subjects. RESULTS: Serotonin-induced vasodilatation was impaired in FCH patients (FBF (unit ml/100 ml forearm tissue/min) from 3.0 (0.3) to 4.8 (0.4)) compared to controls (FBF from 2.9 (0.3) to 6.5 (0.6); p < 0.05 vs. FCH). FBF response to serotonin improved significantly upon lipid-lowering therapy (from 3.0 (0.3) to 5.7 (0.5); p < 0.05 treated vs. untreated). The level of improvement in endothelial function was significantly correlated to the absolute reduction of intermediate density lipoproteins upon lipid-lowering therapy (r = -0.64; p < 0.05), whereas it did not correlate to changes in VLDL- or LDL-cholesterol, nor to Lp(a). CONCLUSION: Patients with familial combined hyperlipidemia have impaired NO-mediated vasodilatation, that responds rapidly to lipid lowering medication, and may be related to changes in intermediate density lipoproteins.

Increased arterial stiffness is independently related to cerebrovascular disease and aneurysms of the abdominal aorta: the Second Manifestations of Arterial Disease (SMART) Study.

BACKGROUND: Arterial stiffness is a risk factor for stroke and myocardial infarction. We investigated whether carotid arterial stiffness is related to other localizations of manifest arterial disease. METHODS: Carotid artery stiffness was measured by ultrasonography as the change in diameter in systole relative to the diastolic diameter in patients enrolled in the Second Manifestations of Arterial Disease (SMART) Study, a cohort study among patients with manifest cardiovascular disease or cardiovascular risk factors. The first consecutive 1561 patients with manifest cardiovascular disease were classified in 4 categories: cerebrovascular disease, coronary artery disease, peripheral artery disease, or aneurysm of the abdominal aorta (AAA). Differences in arterial stiffness among the categories were studied by linear regression analyses. Patients with coronary artery disease as single diagnosis (n=482) served as reference group. RESULTS: Patients with cerebrovascular disease (arterial distension -42.0 microm [95% CI, -57.2 to -26.8]) and those with an AAA (-64.4 microm [95% CI, -84.8 to -44.0]) had an increased carotid stiffness compared with the reference group. Adjustment for confounders attenuated the relations, which remained statistically significant (-34.2 microm [95% CI, -47.8 to -20.7] and -33.2 microm [95% CI, -51.8 to -14.6], respectively). CONCLUSIONS: Our study suggests that increased arterial stiffness is important in the pathophysiology of especially cerebrovascular disease and AAA. That the differences in arterial stiffness between disease categories attenuated after adjustment for important risk factors but remained significant suggests that besides being an element in the causal pathway, arterial stiffness is also a risk factor for cardiovascular disease itself.

Is plaque formation in the common carotid artery representative for plaque formation and luminal stenosis in other atherosclerotic peripheral arteries? A post mortem study.

The atherosclerotic carotid artery is easily accessible for non-invasive duplex investigation. The aim of the present post mortem study was to examine whether plaque accumulation and luminal stenosis in the common carotid artery is representative for atherosclerotic plaque accumulation and luminal stenosis in other peripheral arteries. A total of 3765 cross-sections were obtained at regular intervals from 240 arteries (24 individuals). Five types of peripheral arteries were investigated: common carotid, femoral, common iliac, external iliac and renal arteries. In each cross-section, the lumen area, vessel area, plaque area and maximal plaque thickness was measured. For each location, the percentage luminal stenosis and relative plaque area was calculated. Relative plaque area was defined as the percentage of the vessel area which was occupied by plaque. Weak correlations (r=0.41-0.59) were observed between percentage relative plaque area or maximal plaque thickness in the common carotid artery and percentage relative plaque area in other peripheral arteries. Neither plaque accumulation nor luminal stenosis in the common carotid artery correlated with the percentage luminal stenosis in other peripheral arteries (P > 0.05). We conclude that plaque area in the common carotid artery is weakly correlated with plaque area and not correlated with luminal stenosis in other peripheral arteries.

Variability of flow mediated dilation: consequences for clinical application.

BACKGROUND: Flow mediated vasodilatation (FMD), a non-invasive tool to assess endothelial function, has been shown to have prognostic value for the development of cardiovascular disease. Conventional B-mode ultrasonography has been criticised for its 'limited' resolution in vivo, which complicates reliable detection of the minute diameter changes during reactive hyperaemia. In the present study we evaluated the physical resolution, reproducibility and the capability to detect FMD impairment of a wall tracking system (WTS). METHODS: The resolution of WTS was compared with that of intravascular ultrasound (IVUS) in pig femoral arteries in vivo. Subsequently, intra- and interobserver variability of FMD testing with WTS was evaluated in 75 healthy volunteers. Finally, the effect of smoking as single risk factor for atherosclerosis on FMD in vivo was assessed. RESULTS: WTS and IVUS readings were not different (difference in arterial cross sectional area 1.97 mm(2), r=0.87). Intrasession coefficient of variation in baseline diameter was 1.1% (extremes 0.06--2.0%). Inter-session baseline diameter variation was 3.6 and 3.8% for each observer and 4.1% between observers. Intra-individual variability in FMD between sessions was considerable with coefficients of variation of 13.9% for FMD and 9.3% for NTG. Smokers had impaired FMD responses compared with matched non-smokers (4.7+/-2.4 vs. 9.6+/-4.4%, P<0.001), whereas NTG induced vasodilatation did not differ (13.4+/-6.2 vs. 15.4+/-5.1%; p=ns). CONCLUSION: WTS is a suitable technique for reproducibly assessing the brachial artery diameter in vivo with a accuracy comparable to that of IVUS. Using this sensitive technique the reproducibility of FMD in vivo proves to be poor mainly due to physiological factors. Whereas this seriously limits the use of FMD as follow-up parameter for individual subjects, FMD is demonstrated to be a useful research tool at group level.

Combination of low-dose folic acid and pyridoxine for treatment of hyperhomocysteinaemia in patients with premature arterial disease and their relatives.

Hyperhomocysteinaemia is an independent risk factor for atherosclerotic disease and venous thrombosis. The optimal homocysteine-lowering vitamin dose and target total homocysteine (tHcy) concentration are currently unknown. We prospectively studied the homocysteine-lowering effect after 8 weeks low-dose combination of folic acid (0.5 mg) and pyridoxine (100 mg) in 49 hyperhomocysteinaemic persons (33 patients with documented premature arterial disease and 16 of their first-degree relatives). Hyperhomocysteinaemia was in both sexes defined as fasting tHcy concentration > 12 micromol/l and/or post-methionine load tHcy concentration > 38 micromol/l. Low-dose vitamin therapy significantly reduced fasting tHcy concentration (median 13.9 to 9.3 micromol/l, reduction 32% (95% CI: 27-37%)) and post-load tHcy concentration (median 55.2 to 36.5 micromol/l, reduction 30% (95% CI: 25-35%)). Fasting tHcy reduction was similar in women and men, as well as in patients and relatives. Post-load tHcy reduction was significantly less in men compared to women (P = 0.04) and in relatives compared to patients (P = 0.03). Although low-dose combination of folic acid and pyridoxine results in a substantial reduction of tHcy concentrations (30-32%) in subjects with hyperhomocysteinaemia, the normalisation percentage to predefined criteria was less impressive (49%).

Common carotid intima-media thickness in patients with peripheral arterial disease or abdominal aortic aneurysm: the SMART study. Second Manifestations of ARTerial disease.

Evidence is emerging that the contribution of atherosclerosis to the development of abdominal aortic aneurysm may differ from that of other manifestations of arterial disease. B-mode ultrasound may be helpful in understanding the characteristics and factors that contribute to the development of different manifestations of arterial disease. We examined whether there is a difference in common carotid intima-media thickness (IMT), an indicator of generalized atherosclerosis, in patients with peripheral arterial disease (PAD) and abdominal aortic aneurysm (AAA). IMT of the left and right common carotid artery was measured in the first 172 patients (123 PAD and 49 AAA) enrolled in the Second Manifestations of ARTerial disease (SMART) study, a cohort study among patients with a manifestation of atherosclerotic vascular disease or risk factors for atherosclerosis. Mean IMT was 0.98 +/- 0.34 mm in patients with PAD and 0.91 +/- 0.20 mm in patients with AAA, with an age and sex adjusted mean difference of 0.18 mm (95% CI 0.08; 0.28). After additional adjustments for cardiovascular risk factors, the difference remained 0.11 mm (95% Cl 0.01; 0.21). Common carotid IMT in patients with AAA is on average smaller than in patients with PAD, independent of other determinants of IMT. These findings support the view that the development of AAA cannot completely be explained by atherosclerosis and is in part due to other pathophysiological mechanisms.