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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The discovery of the endothelium as a major regulator of vascular tone triggered intense research among basic and clinical investigators to unravel the physiologic and pathophysiologic significance of this phenomenon. Importantly, endothelial modulation of the contractile state of vascular smooth muscle has been shown to be impaired in atherosclerosis and in several conditions known to be associated with the premature development of atherosclerosis. Studies in several different animal models of arterial hypertension, and in patients with both essential and secondary hypertension, have demonstrated an association between elevated systemic blood pressure and impaired endothelium-dependent vascular relaxation. More recently, a diminished bioavailability of nitric oxide (NO) has been identified as a mechanism responsible for endothelial dysfunction in hypertensive patients. Different processes may, in turn, explain this decreased vascular activity of NO. The present review focuses on those clinical studies that are aimed at identifying the precise abnormality responsible for reduced NO-dependent vasodilation in patients with essential hypertension. Understanding of the basic mechanisms of this process may prove to be beneficial for the development of more specific therapies and ultimately for the outcome of hypertensive patients.
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PMID:Impaired endothelial regulation of vascular tone in patients with systemic arterial hypertension. 979 77

Vascular endothelium releases nitric oxide (NO), an important vasodilator that is continuously synthesised by the constitutive enzyme, endothelial nitric oxide synthase (NOS). This maintains a constant vasodilator tone which is diminished in adult hypertension, due to reduced endothelium-dependent vascular relaxation, which is NO dependent. In childhood, however, hypertension is often secondary, and normalisation of blood pressure by removal of cause (e.g. renal artery stenosis, catecholamine-producing tumour) suggests reversibility of endothelial dysfunction, if it is present. Raised plasma levels of endogenous inhibitors have been found, especially in children with secondary hypertension due to renal parenchymal and renovascular disease, and may contribute to hypertension by more than just inhibition of vascular NO release; e.g. by reduction of glomerular filtration rate and promotion of salt and water retention. These inhibitors also modulate renin release, which may be of relevance in cardiovascular physiology, and may also interfere with the anti-platelet properties of NO, increasing the likelihood of vascular thrombotic events. NO inhibitors also promote endothelial activation, with increased expression of adhesion molecules that may form seedlings of atherosclerosis. In chronic renal impairment, accumulation of NO inhibitors may contribute to hypertension. Efficient long-session dialysis helps better interdialysis control of blood pressure in these subjects, independent of salt and water removal, suggesting that removal of such vasoactive agents may be important for efficient blood pressure control. There are a few studies assessing NO generation in hypertensive children via plasma nitrite and nitrate, the NO end products, which suggest normal or increased production as opposed to a reduction, perhaps as a compensatory phenomenon. In the treatment of hypertension, nitroprusside and nitrates exert their actions via NO donation. Excessive production of NO (usually via inducible NOS) or excessive administration (nitrovasodilators) can be cytotoxic and may cause hypotension and shock, as in severe sepsis. NOS inhibitors and NO therefore appear to play a crucial role in aetiology, complications and therapy of childhood hypertension.
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PMID:Vascular endothelium and nitric oxide in childhood hypertension. 981 94

The relationship between the kidneys and hypertension is multiple. Impaired renal function preventing adequate sodium excretion participates in the pathogenesis of primary hypertension. Renal diseases are the most frequent cause of secondary hypertension. Bilateral and unilateral parenchymatous affections predominate (5% of all hypertensions) over renovascular causes (2%). In the course of hypertension regardless of its etiology renal damage may develop--nephroangiosclerosis or atherosclerosis of the renal arteries with unilateral or bilateral affection (renal ischaemic disease). Hypertension is an important factor in progression of chronic renal diseases towards irreversible renal failure.
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PMID:[Hypertension and the kidneys]. 1095 52

Renal artery stenosis is the most common cause of potentially remediable secondary hypertension. The most common causes include atherosclerosis and fibromuscular dysplasia. Particularly the atherosclerotic form is a progressive disease that may lead to gradual and silent loss of renal functional tissue. Thus, early diagnosis of renal artery stenosis is an important clinical objective since interventional therapy may improve or cure hypertension and preserve renal function. Screening for renal artery stenosis is indicated in the suspicion of renovascular hypertension or ischemic nephropathy in order to identify patients in which an endoluminal or a surgical revascularization is advisable. In the recent years many noninvasive tests have been proposed and evaluated in the clinical practice, in alternative to arteriography. These include nuclear scan, color Doppler sonography, CT angiography and MR angiography. Sonography is usually the first diagnostic modality for the non invasive evaluation of renal vascular disease with 95% sensitivity and 90% specificity when performed in dedicated laboratories. Despite sonography is highly affected by operator dependence, and it takes a lot of time to train good operators, actually is the best screening test because it is not expensive, non invasive and accurate. When a discrepancy exists between the clinical data and the results of US, other tests are mandatory.
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PMID:Duplex scan sonography of renal artery stenosis. 1286 75

Essential hypertension accounts for 95% of all cases of hypertension. A small number of patients (between 2% and 5%) have a reversible disease as the cause for raised blood pressure. Unilateral and bilateral renal artery stenosis may be responsible for secondary hypertension. Diagnosis and treatment of renal artery stenosis are of a great importance. Revascularization of ischemic kidney may correct blood pressure control and preserve renal function. Much data suggest close pathophysiological relation between renal artery stenosis, ischemic nephropathy and development of hypertension. However, it should be stressed that not every renal artery stenosis leads to hypertension and ischemic nephropathy. Therefore diagnosis of renal artery stenosis in hypertensive patient is not always equivalent with renovascular hypertension. The true prevalence of renal artery stenosis is unknown. In unselected population it accounts for less than 1% of hypertensive patients. Renovascular etiology of hypertension may be suggested by abrupt onset of hypertension, resistant and malignant hypertension or recurrent pulmonary edema of unknown etiology. Physical examination may reveal bruits over major vessels, including the abdominal aorta and renal arteries. The principle aim of the renal artery stenosis investigation is to confirm presence and size of vessel obstruction and its association with hypertension. Typical evaluation is based on imaging techniques and physiological studies. Former include: doppler duplex ultrasonography, conventional angiography, intraarterial and intravenous digital subtraction angiography, computed axial tomography, magnetic resonance angiography and intravascular ultrasonography. Functional studies are occasionally used. These are renal scintigraphy, evaluation of plasma renin activity in renal veins and evaluation of plasma rennin activity after ACE inhibition. Treatment of patients with renal artery stenosis and hypertension should restore vessel patency and inhibit its occlusion. Revascularization should elicit an improvement in or normalization of blood pressure control and renal function. Therapeutic approach include percutaneous renal artery angioplasty (PTRA), with or without stenting, revascularization by surgery and pharmacotherapy. PTRA is currently the first choice option. In general, it is simpler and similarly effective as surgical reconstruction. In some cases PTRA is completed with stent placement. It prevents immediate recoil but does not completely eliminate restenosis of revascularized artery. Surgical bypass is currently reserved for patients in whom PTRA and stenting fail and in patients with extensive atherosclerotic lesions. Patients with renal artery stenosis and hypertension should be provided with pharmacological treatment according to current recommendations. Specific procedures to limit associated risk factors of atherosclerosis should also be introduced.
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PMID:[Renovascular hypertension: is it only the top of the iceberg?]. 1497 69

Renal artery stenosis (RAS) is a significant cause of secondary hypertension, the progression of which can lead to renal insufficiency, uncontrolled hypertension, and even end-stage renal disease. The 2 most common forms of RAS are atherosclerotic renovascular disease and fibromuscular dysplasia (FMD). Atherosclerosis accounts for 90% of all cases of RAS and generally affects an elderly population. Conversely, FMD accounts for approximately 10% of all RAS cases and is described as affecting a younger population. Four cases of FMD in individuals older than 70 years are presented, in a period of 1 year at 1 facility. This case series calls into question the previously reported low prevalence of FMD in elderly persons. It is conceivable that renal artery investigation might be denied an elderly patient thought to have atherosclerotic disease. Because conventional angioplasty is considered the treatment of choice for patients with FMD because of the high response rate for uncontrolled hypertension, the prevalence of FMD in the elderly population should be reevaluated to detect and treat this population accordingly.
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PMID:Renal fibromuscular dysplasia in elderly persons. 1580 62

Renal artery disease is the most common cause of potentially curable secondary hypertension, with atherosclerosis as the major cause of renal artery stenosis. Fibromuscular dysplasia is a less common cause of renal artery stenosis and is most frequently observed in premenopausal women. Renal artery stenosis is likely to be underappreciated and is more common in patients with other vascular disease (e.g., coronary or peripheral arterial disease). The diagnosis of renal artery stenosis requires a high clinical index of suspicion as well as an appropriate imaging strategy, with currently effective diagnostic modalities including magnetic resonance imaging, computed tomography and renal artery duplex ultrasonography. The current treatment of choice for atherosclerotic renal artery stenosis is balloon angioplasty and secondary stenting, whereas angioplasty alone is the treatment for renal artery stenosis secondary to fibromuscular dysplasia. Expected outcomes following revascularization include improved blood pressure control and possibly renal preservation. Ongoing studies will hopefully identify patient characteristics that will achieve the most benefit from percutaneous revascularization as well as the impact of percutaneous revascularization with drug-eluting stents and embolic protection devices.
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PMID:Renovascular hypertension. 1588 69

The prevalence of secondary hypertension is higher in the elderly population. Renal hypertension is the most prevalent. The prevalence of renovascular hypertension (RVH) increases with age. Since RVH in the elderly is frequently associated with systemic atherosclerosis, other atherosclerotic disorders including ischemic heart disease need to be evaluated. The prevalence of primary aldosteronism and Cushing's syndrome decreases with age, while that of pheochromocytoma persists in the elderly population. Due to lack of classical symptoms, special attention should be paid to find pheochromocytoma in the elderly.
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PMID:[Clinical characteristic of secondary hypertension in the elderly]. 1594 96

The development of a national database on normative blood pressure levels throughout childhood has contributed to the recognition of elevated blood pressure in children and adolescents. The epidemic of childhood obesity, the risk of developing left ventricular hypertrophy, and evidence of the early development of atherosclerosis in children would make the detection of and intervention in childhood hypertension important to reduce long-term health risks; however, supporting data are lacking. Secondary hypertension is more common in preadolescent children, with most cases caused by renal disease. Primary or essential hypertension is more common in adolescents and has multiple risk factors, including obesity and a family history of hypertension. Evaluation involves a thorough history and physical examination, laboratory tests, and specialized studies. Management is multifaceted. Nonpharmacologic treatments include weight reduction, exercise, and dietary modifications. Recommendations for pharmacologic treatment are based on symptomatic hypertension, evidence of end-organ damage, stage 2 hypertension, stage 1 hypertension unresponsive to lifestyle modifications, and hypertension with diabetes mellitus.
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PMID:Hypertension in children and adolescents. 1671 48

Most children who are normal weight for height and otherwise healthy have risk factor levels associated with the absence of heart disease (ie, they do not smoke, do not have diabetes, are physically active, have low-density lipoprotein levels < 110 mg/dL, and have blood pressure < 120/80 mm Hg). However, by adolescence, the earliest lesions in the atherosclerotic process, fatty streaks and raised lesions, are present in the coronary arteries and the abdominal aorta. The severity of early atherogenesis is related to the coexistence of the major cardiovascular risk factors. Most commonly, the associated risk disturbances are mild: borderline hypertension, mild dyslipidemia, insulin resistance, overweight, physical inactivity, and initiation of tobacco use. Rarely, more severe risk factors are present: familial hypercholesterolemia (a genetic disorder of lipid metabolism), diabetes mellitus, secondary hypertension of long standing, or risk factors associated with chronic conditions such as end-stage renal disease. Thus, cardiovascular risk management in this age group has two components: primordial prevention (the prevention of the development of cardiovascular risk in the first place) and primary prevention (more aggressive treatment of identified risk factors in high-risk individuals either through behavioral or pharmacologic means). Trials beginning in adolescence of the primary prevention of atherosclerosis-related diseases have not been undertaken; thus, the decision to initiate pharmacologic management in high-risk adolescents requires careful thought.
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PMID:Cardiovascular risk factors in adolescents. 1703 66


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