Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0085580 (essential hypertension)
 14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sympathetic nervous system activation has been documented in several cardiovascular disorders. In some, characterized by cardiac failure and portal hypertension accompanying hepatic cirrhosis, the sympathetic nervous stimulation is reflex and, to some extent, compensatory but has adverse consequences. For example, in cardiac failure, the sympathetic nerves of the heart are preferentially stimulated, providing adrenergic support to the failing myocardium but at the probable cost of arrhythmogenesis and progressive myocardial deterioration. The sympathetic activation present in patients with essential hypertension, which involves the sympathetic outflows to skeletal muscle, heart, and kidneys and is seen particularly in younger patients, differs from these examples in that the sympathetic nervous stimulation is apparently not reflex and the primary cause is unknown. There is, however, evidence that activation of forebrain pressor noradrenergic nuclei may be of importance as an underlying central nervous system mechanism. This sympathetic nervous stimulation in patients with essential hypertension, in addition to initiating the blood pressure elevation, may also contribute to the commonly associated metabolic abnormalities of insulin resistance and hyperlipidemia, with neural vasoconstriction having metabolic consequences, impairing glucose delivery and causing insulin resistance in muscle, and retarding postprandial clearing of lipids in liver. Trophic effects of sympathetic activation on cardiovascular growth are claimed but have yet to be demonstrated conclusively in humans.
 ...
PMID:Sympathetic nervous system: contribution to human hypertension and related cardiovascular diseases. 864 1

Although the underlying mechanisms no doubt differ, activation of the sympathetic nervous system is an important pathophysiological feature in primary arterial hypertension, in portal hypertension accompanying hepatic cirrhosis, and in heart failure, and is a logical therapeutic target for centrally acting sympathetic nervous system suppressant drugs. Portal hypertension: The sympathetic outflows to skeletal muscle vasculature, the heart, the kidneys and to the hepatomesenteric circulation are stimulated in patients with alcoholic cirrhosis of the liver, perhaps as a reflex response to the vasodilatation and vascular shunting present. Acute dosing with clonidine produces dose dependent reduction in noradrenaline spillover from visceral organs and reduction in hepatic vein wedge pressure, with preservation of hepatic blood flow and negligible fall in arterial pressure. These findings indicate the clinical potential of drugs such as clonidine, moxonidine and rilmenidine for chronically lowering portal venous pressure in cirrhosis. Arterial hypertension: Activation of the sympathetic outflow to the heart, kidneys and skeletal muscle vasculature is commonly present in younger (< 45 years) patients with essential hypertension. The sympathetic stimulation appears to have adverse consequences in hypertensive patients beyond blood pressure elevation. Neural vasoconstriction in skeletal muscle has metabolic effects by impairing glucose delivery, which is a basis for insulin resistance and hyperinsulinemia. Within the heart a trophic effect of sympathetic activation on cardiac growth, contributing to the development of left ventricular hypertrophy, and an arrhythmogenic effect are also likely. Cardiac failure: The cardiac sympathetic nerves are preferentially stimulated in severe heart failure, with norepinephrine release from the failing heart at rest being increased as much as 50-fold, similar to the level seen in healthy people during near maximum exercise. This preferential activation of the cardiac sympathetic outflow contributes to arrhythmogenesis and possibly to progression of the heart failure, and has been directly linked to mortality; a high rate of spillover of noradrenaline from the heart is a strong, independent predictor of poor prognosis in severe cardiac failure. The mechanisms underlying sympathetic nervous stimulation are not entirely clear. Increased intracardiac diastolic pressure seems to be one peripheral signal, and increased forebrain norepinephrine turnover an important central mechanism. Following the demonstration of the beneficial effect of the beta-adrenergic blocker, carvedilol, and with second generation centrally acting sympathetic suppressants now under clinical investigation, elucidation of the abnormalities in central nervous control of sympathetic outflow in heart failure has become clinically relevant.
 ...
PMID:Increased sympathetic nervous system activity and its therapeutic reduction in arterial hypertension, portal hypertension and heart failure. 985 71

Splenic artery aneurysms (SAA), although rare, are the most common visceral artery aneurysms and are known for their potential for rupture. Pregnancy and portal hypertension have been known as major risk factors. With improved methods of diagnosis and minimally invasive therapy, management and outcome of SAA may change significantly. The purpose of this study was to analyze our institutional experience with SAA during the past decade. Charts of all patients (six women, three men; mean age, 60.5 [range: 31 to 81] years) with diagnoses of SAA from 1988 to 1999 were reviewed. Associated conditions included essential hypertension (6), portal hypertension (3), diabetes (1), intracranial aneurysm (1), and polyarteritis nodosa (1). Six patients were asymptomatic, and three had ruptured SAA. Diagnosis was made by angiography (2), computed tomography (3), ultrasonography (3), and exploratory laparotomy (1). Six patients underwent surgery (five required splenectomy), one had embolization, and two had no intervention. Three postoperative deaths occurred-two (intracranial aneurysm, myocardial infarction) in the first month, one (sepsis) in the ninth month. An association of liver disease with SAA was confirmed; however, no association with pregnancy was noted. Surgical treatment followed traditional methods, and mortality correlated with presence of severe comorbidity.
 ...
PMID:Splenic artery aneurysm in the 1990s. 1079 53

Over the last decade the role of diuretics as first-line agents for the treatment of hypertension has diminished substantially. The present review encourages the reader to reconsider the current trend for a decline in the use of these inexpensive antihypertensive drugs whose efficacy is well documented. Diuretics have been used in 16 placebo controlled studies with over 13,000 patients as first-line drugs to lower blood pressure. These drugs were shown to reduce total mortality by 11%, cerebrovascular events by 34% and coronary morbidity by 29%. The magnitude of blood pressure reduction with low-dose thiazide diuretics is comparable to that of a therapy with high-dose thiazides, without the serious metabolic side effects observed with the higher dosage. In combination with other antihypertensive agents, diuretics counteract the compensatory regulatory responses, such as volume expansion and edema formation. Moreover, it has been shown that a combination with low-dose thiazides may not only further decrease blood pressure but also reduce cerebrovascular and coronary mortality. Advantages of diuretics in the treatment of hypertension can be appreciated in special clinical conditions, for instance in patients with edema, heart failure, renal failure, nephrotic syndrome and portal hypertension. Low-dose diuretics still have a place as first-line drugs for the treatment of mild, uncomplicated essential hypertension. Moreover, as opposed to other blood pressure lowering agents, there is sufficient scientific evidence for the primary preventive effect of low-dose thiazide.
 ...
PMID:[Which hypertensive patient requires diuretic therapy?]. 1089 23