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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major risk factor associated with the appearance of adverse cardiovascular events and outcome attributable to cardiovascular disease is left ventricular hypertrophy (LVH). Why this should be so resides not in the increase in myocardial mass per se, but in the disruption of myocardial structure. An abnormal accumulation of fibrillar collagen within the adventitia of intramyocardial coronary arteries and neighboring interstitial spaces represents such a distortion in structure. Furthermore, this fibrosis disrupts the electrical and mechanical behavior of the hypertrophied myocardium. Mechanisms responsible for fibrillar collagen accumulation have been examined in intact animals and cultured cardiac fibroblasts. In vivo studies indicate that myocardial fibrosis is associated with the presence of chronic mineralocorticoid excess, relative to sodium intake and excretion, not hemodynamic workload. Accordingly, fibrosis can appear in both the hypertensive, hypertrophied and nonhypertensive, nonhypertrophied ventricles. In both primary and secondary hyperaldosteronism it was possible to prevent myocardial fibrosis with an aldosterone receptor antagonist, while in unilateral renal ischemia angiotensin converting enzyme (ACE) inhibition was similarly cardioprotective. A regression in fibrous tissue and normalization of diastolic stiffness has also been possible using ACE inhibition, bringing forward the concept of cardioreparation and the notion that heart failure due to fibrosis may be reversible. In vitro studies indicate that effector hormones of the renin-angiotensin-aldosterone system stimulate fibroblast collagen synthesis. Aldosterone, in pathophysiologic concentrations, and angiotensin II, in much larger concentrations, each enhance collagen synthesis without altering the mitogenic potential of these cells. Thus, elevations in circulating aldosterone and angiotensin II, relative to sodium intake, have the potential to not only alter sodium homeostasis and vascular tonicity, but also the structure of cardiovascular tissue. Thus, myocardial fibrosis represents a structural basis for pathologic hypertrophy and ultimately accounts for the appearance of adverse cardiovascular events and outcomes.
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PMID:Pathologic hypertrophy with fibrosis: the structural basis for myocardial failure. 136 63

An abnormal elevation in collagen concentration or myocardial fibrosis occurs in the hypertrophied left ventricle of the rat with renovascular hypertension (RHT). The structural nature and functional consequences of this fibrosis and the mechanisms involved in its appearance were reviewed for various phases of hypertrophy. Within days after the onset of renal ischemia, type I collagen messenger ribonucleic acid is expressed. An interstitial fibrosis follows, characterized by an increased dimension of existing perimysial fibers and the appearance of fibrillar collagen in spaces previously devoid of collagen, together with a perivascular fibrosis of intramyocardial coronary arteries. These expressions of myocardial fibrosis are associated with an increase in diastolic and systolic myocardial stiffness. Endomyocardial fibrosis serves to further increase diastolic stiffness while myocytes encircled by fibrillar collagen become atrophic. Each of these consequences of myocardial fibrosis reduce myocyte length-dependent force generation. At 32 weeks of RHT there is an obvious diastolic and systolic dysfunction of the ventricle together with heart failure that includes ventricular dilatation, wall thinning and reduced ejection fraction. The mechanisms involved in mediating fibrosis in RHT appear to be multiple. Myocyte necrosis and fibroblast proliferation have been associated with elevated circulating angiotensin II. Necrosis in RHT was not seen with captopril pretreatment or in the hypertension and hypertrophy that accompanied infrarenal aorta banding. An alteration in coronary artery permeability may be responsible for the perivascular fibrosis that is not seen with captopril pretreatment. Thus in RHT, the hemodynamic status of the ventricle determines myocyte hypertrophy while the elevation in circulating angiotensin II is responsible for the remodeling of nonmyocyte compartments, including the appearance of myocardial fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Myocardial fibrosis and pathologic hypertrophy in the rat with renovascular hypertension. 213 51

The high blood flow rate/gram of kidney tissue supplies mainly the renal cortex. The net effect of the interaction of the renin-angiotensin system, the kallikrein-kinin system and prostaglandins is to autoregulate renal blood flow within a narrow range. Drugs and neurogenic factors also influence renal hemodynamics. The renal circulation responds to changes in extracellular fluid volume, and in cardiac output. Renal ischemia occurs readily as these parameters decrease and prompt correction of circulatory dynamics can restore renal blood flow and prevent tubular necrosis. With hypovolemia or heart failure, angiotensin II is a mediator of efferent arteriolar constriction promoting a proportionately greater fall in renal plasma flow than in glomerular filtration rate, thereby augmenting sodium reabsorption. With renal failure, glomerulotubular balance is affected conversely promoting sodium loss. Appreciating these distinctions allows recognition of inappropriate sodium retention or loss. With such data, prognosis can be estimated more accurately and attempts to restore circulatory dynamics can be guided.
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PMID:Pathophysiology of renal hemodynamics. 726 10

NSAIDs pose little threat of renal insult in normal, healthy persons at therapeutic dosages. However, NSAID administration to susceptible persons may cause decrements in renal plasma flow and glomerular filtration rate within hours. Such acute noxious renal effects are mediated by products of arachidonic acid metabolism. Precipitous decrements in glomerular filtration and renal ischemia, manifested by increased serum creatinine and urea nitrogen, are possible. However, these effects are usually fully reversible with prompt discontinuation of the offending NSAID. Risk factors for the development of these acute renal effects are known. Acute interstitial nephritis with or without nephrotic syndrome is a rare form of renal toxicity that typically occurs between 2-18 months of use. Renal impairment may be so severe as to require temporary hemodialysis; however, renal function usually returns to normal upon discontinuation of the NSAID. The mechanism of acute interstitial nephritis is presumed to be of allergic origin but could also be caused by a reactive metabolite. Fenoprofen use appears to be associated with a much higher risk for its development. In contrast to the acute effects of NSAIDs, irreversible, analgesic-associated nephropathy manifested by papillary necrosis and chronic interstitial nephritis may occur following months to years of high doses of analgesic mixtures. The mechanism by which combination analgesics produce this form of renal injury is unknown and could be either a result of medullary ischemia or a direct effect of a reactive metabolite. An important issue to be resolved is the relationship between the acute, reversible, prostaglandin-mediated renal effects of the NSAIDs and chronic, irreversible destruction, if such a relationship exists. Theoretically, continual or repeated decrements in renal function in patients with predisposing risk factors could cause or contribute to progressive deterioration in renal function. Elevations in blood pressure or interference with the effects of antihypertensive medications could theoretically also contribute to long-term renal deterioration. In addition to renal syndromes caused by NSAIDs that result in renal impairment, other transient effects on electrolyte and water metabolism may also occur. Reduced secretion of sodium may result in formation of edema, exacerbation of heart failure, or increased blood pressure. Hyporeninemic-hypoaldosteronism may produce hyperkalemia. Finally, reduced excretion of water has rarely caused hyponatremia. It has been suggested that NSAIDs may be renoprotective in patients with nephrotic syndrome. Others have suggested that sulindac is "renal-sparing" because of a unique metabolic pathway that supposedly limits the exposure of the kidney to the active sulfide metabolite.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Renal toxicity of the nonsteroidal anti-inflammatory drugs. 849 47

An intracardiac aldosterone system which responds to short- and long-term physiological stimuli has been described. This cardiac generated aldosterone has possibly autocrine or paracrine actions. Normal cardiac tissue contains mineralocorticoid receptors (MR) and cardiac high affinity MR are localized in cardiac myocytes and endothelial cells. Data concerning the presence of MR in cardiac fibroblasts are, however, controversial. MR are not specific for aldosterone but they also bind glucocorticoids. Cardiac fibroblasts however contain the enzyme 11beta-hydroxy-steroid dehydrogenase II which converts these glucocorticoids to inactive metabolites. Discordant findings on the in vitro effect of aldosterone on the collagen synthesis in cardiac fibroblasts are reported and can at least partly attributed to the presence of various fibroblasts phenotypes. During chronic aldosterone infusion in uninephrectomized rats on a high-salt diet, a marked accumulation of interstitial and to a lesser extent perivascular collagen occurs in the heart in both ventricles. This cardiac fibrosis in this aldosteronism model is prevented by spironolactone. This effect of aldosterone is crucially dependent on the salt status of the rat. Indeed, rats on a restricted salt intake infused with aldosterone had no cardiac fibrosis above control levels. During the continuous infusion of aldosterone in the rat the appearance of fibrosis was delayed and starts 4 weeks after the beginning of the infusion which argues against a direct effect of aldosterone. The mechanism of aldosterone-salt induced cardiac fibrosis possibly involves angiotensin II acting through upregulated AT1 receptors and the cardiac AT1 receptor is the target for aldosterone. An accumulation of collagen in the heart has also been found in patients with adrenal adenomas and during chronic activation of the renin-angiotensin-aldosterone system such as in surgically induced unilateral renal ischemia, unilateral renal artery banding or renovascular hypertension. Spironolactone prevents aortic collagen accumulation in spontaneously hypertensive rats. In patients with stable chronic heart failure spironolactone treatment in addition to diuretics and angiotensin-converting enzyme (ACE) inhibition reduced circulating levels of procollagen type III N-terminal aminopeptide. Also, in the Randomized Aldactone Evaluation Study spironolactone coadministered with conventional therapy of ACE inhibitors, loop diuretics and digitalis in patients with symptomatic heart failure defined as NYHA classes III-IV reduces total mortality by 30%.
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PMID:Induction of cardiac fibrosis by aldosterone. 1088 42

The appropriate choice of anesthesia for patients (pts) undergoing renal transplantation (Ktx) requires minimal toxicity and accurate monitoring for pts at high risk for metabolic, cardiovascular, and respiratory perioperative complications. We evaluated the anesthetic management and postoperative follow-up in pediatric Ktx performed in the last 12 years in our institution. From 1988 to 1999, 75 ASA class II-III pts (45 males, 22 females) younger than 18 years scheduled for Ktx were studied: 49 received a graft from a cadaveric donor (CD) and 26 from a living donor (LD). All pts were treated with dialysis within 24 h before the procedure. Standard monitoring consisted of an electrocardiogram, central venous pressure, non-invasive arterial pressure, pulse oximetry, and inspiratory and expiratory gas analysis. If necessary, an arterial cannula and pediatric pulmonary catheter were introduced. Anesthesia was induced with sodium thiopental, propofol, halothane, or sevoflurane and maintained with isoflurane and/or fentanyl and droperidol in O2:N2O (FiO2 0.4%). As muscle relaxants atracurium or cisatracurium besilate were used, except in allergic pts, in whom vecuronium or rocuronium bromide was administered. Dopamine, 20% mannitol, and furosemide were used to increase diuresis. Continuous morphine and ketoralac infusions were used for postoperative pain relief. The surgical technique was the same in all cases. Complications and renal-function (RF) recovery were evaluated relating to CD and LD using the chi-square test; differences in mean anesthesia and surgical time were evaluated by Student's t-test; survival curves were calculated from the day of Ktx to death or last follow-up and estimated by the Kaplan-Meier method. Values of P below 0.05 were considered significant. Postoperative immunosuppressive therapy was based on cyclosporine together with other conventional drugs. Mean anesthesia time was 228 +/- 65 min. Mean kidney ischemia time for CD was 16.5 +/- 4 h. Four pts (3 CD, 1 LD) died within 72 h postoperatively: 3 due to cardiac failure and 1 to metabolic coma. Six pts showed cardiovascular and 3 had infective complications, all successfully treated. Three pts (2 CD, 1 LD) died within 2 to 12 months after, surgery; 10 (6 CD, 4 LD) had graft failure and are still alive on dialysis; 58 (38 CD, 20 LD) are alive in good health after a mean follow-up of 57.6 +/- 36.6 months (range 12-120 months). Fifteen of 26 pts younger than 12 years (21 CD and 5 LD) recovered RF intraoperatively (10 CD, 5 LD); 1 with CD and 1 with LD showed postoperative graft failure and 2 with CD died within 72 h postoperatively, 22 (18 CD and 4 LD) are alive in good health. This group showed no statistical difference compared to pts older than 12 years. Of 16 pts (15 CD and 1 LD) with body weight (BW) less than 25 kg, 6 showed intraoperative (5 CD, 1 LD) recovery of RF. The 3 deaths were all in CD pts, 2 within 72 h and one 2 months after surgery; only 1 LD had postoperative graft failure. Twelve pts (75%) (12 CD, 80%) are alive in good health. Compared to pts with BW of 25 kg or more, this group showed lower intraoperative recovery of RF (P < or = 0.05). No peri- and postoperative complications occurred in all 26 LD pts (100%). Recent advances in surgery, anesthesia, immunosuppression, and antimicrobial prophylaxis have made Ktx a more predictable procedure even in pediatric pts. For high-risk pts, mortality and morbidity can be controlled by accurate surgical, anesthetic, and postoperative management. Pts younger than 12 years and with BW less than 25 kg are more likely to develop peri- and postoperative complications.
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PMID:Pediatric renal transplantation: anesthesia and perioperative complications. 1131 82

The renin-angiotensin system is initiate by numerous pathological situations which release the renal ischemia: heart failure, arterial hypertension, renal pathology with or without diabetes mellitus. Therapeutic possibilities in renin-angiotensin system control are offered by angiotensin-converting enzyme inhibitors, angiotensin II type-1 receptors antagonists, angiotensin converting enzyme inhibitors and neutral endopeptidase inhibitors and angiotensin II type 2 receptors agonists.
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PMID:[The renin-angiotensin system:implications, pathology, therapeutic possibilities, perspectives]. 1209 17

Renal ischemia/reperfusion injury could arise as a consequence of clinical conditions such as renal transplantation, shock, cardiac arrest, hemorrhage and renal artery surgery. In this experimental study, we aimed to determine the preventive effects of amrinone on bilateral renal ischemia/reperfusion injury in rats. A total of 60 Wistar-albino rats were divided into six groups ( n=10). Midline laparotomies were made under ketamine anesthesia. In the sham, amrinone1 and amrinone2 without ischemia (AWI1 and AWI2) groups saline, 5 and 10 mg/kg of amrinone was infused, respectively. In the ischemia, ischemia plus amrinone1 (IPA1) and ischemia plus amrinone2 (IPA2) groups, saline and 5 and 10 mg/kg of amrinone was infused, respectively, at the beginning of reperfusion, subsequent to 45 min of bilateral renal artery occlusion. Following 6 h of reperfusion, blood was drawn to study serum BUN and creatinine and a bilateral nephrectomy was done to determine tissue malonyldialdehyde ( MDA) and myeloperoxidase (MPO) levels. The results were analysed by Mann-Whitney U-test. The parameters studied were statistically higher in the ischemia group compared with the other groups ( P<0.05 for each comparison), indicating renal I/R injury. These parameters were lower in the amrinone without ischemia groups (AWI1 and AWI2) than in the sham group, however there were no significant differences between the groups ( P>0.05, for each comparison). The treatment groups IPA1 and IPA2 had statistically similar results compared with the sham group, showing the preventive effect of amrinone on renal I/R injury at the given doses. We conclude that amrinone prevented experimental renal ischemia/reperfusion injury in rats, independently of the administered doses. This preventive effect of the agent could depend on its effect of regulating the microcirculation, in decreasing intracellular calcium and in preventing neutrophil activation. We propose that this preventive effect of amrinone - which has gained clinical application especially in cases of cardiac insufficiency - could also be exploited in clinical conditions related with renal ischemia/reperfusion.
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PMID:Effects of amrinone on bilateral renal ischemia/reperfusion injury. 1211 Nov 79

Functional angiotensin II receptors have been documented in cardiac fibroblasts as well as an intracardiac aldosterone system that responds to short- and long-term physiological stimuli. In vitro, angiotensin II increased cardiac fibroblast-mediated collagen synthesis and mRNA levels of collagen type I, type III, pro-alpha1 (I) collagen, pro-alpha1 (III) collagen and fibronectin, and inhibited matrix metalloproteinase I activity. The angiotensin II-stimulated secretion and expression of collagen was completely abolished by AT1 receptor antagonism, but not affected by AT2 receptor antagonism. In vivo, chronic infusion of angiotensin II increased the collagen volume fraction in the ventricles. Angiotensin-converting enzyme (ACE) inhibition and AT1 receptor antagonism, but not AT2 receptor antagonism, reduced collagen deposition in the myocardium in spontaneously hypertensive rats and in rat myocardium following myocardial infarction. During chronic aldosterone infusion in uninephrectomized rats on a high-salt diet, a marked accumulation of interstitial and to a lesser extent perivascular collagen occurs in the heart in both ventricles. The cardiac fibrosis in this aldosterone model is prevented by spironolactone. During the continuous infusion of aldosterone in the rat, the appearance of fibrosis was delayed and started 4 weeks after the beginning of the infusion, which argues against a direct effect of aldosterone. The mechanism of aldosterone-salt-induced cardiac fibrosis possibly involves angiotensin II acting through upregulated AT1 receptors and the cardiac AT1 receptor is the target for aldosterone. An accumulation of collagen in the heart has also been found in patients with adrenal adenomas and during chronic activation of the renin-angiotensin-aldosterone system such as in surgically-induced unilateral renal ischemia, unilateral renal artery banding or renovascular hypertension. Spironolactone prevents aortic collagen accumulation in spontaneously hypertensive rats. In patients with stable chronic heart failure, spironolactone treatment in addition to diuretics and ACE inhibition reduced circulating levels of procollagen type III N-terminal aminopeptide. Also, in the Randomized Aldactone Evaluation Study, spironolactone coadministered with conventional therapy of ACE inhibitors, loop diuretics and digitalis in patients with symptomatic heart failure defined as NYHA classes III-IV, reduced total mortality by 30%.
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PMID:Role of intracardiac renin-angiotensin-aldosterone system in extracellular matrix remodeling. 1457 Dec 85

The major message from this discussion is that the end points from hypertensive disease (stroke, CHD, and hypertensive emergencies) are now preventable. Cardiac failure and ESRD, however, two exceedingly common end points from long-standing hypertension, remain as major disabilities and causes of death. The former is the most common cause of hospitalization in industrialized societies; hypertension and diabetes mellitus are the most common causes of the latter. The mechanisms of risk of these target organ diseases is not LVH per se, or the elevated arterial pressure alone in the kidney, but the coronary and renal ischemia, organ fibrosis, and, perhaps, apoptosis. Present day therapy now can effectively reverse these costly (economically and by human suffering) complications. Recent experimental studies suggest that, when used early enough, these newer pharmacologic agents may even prevent their occurrences and consequences. The very practical lesson from these experiences is that early detection and treatment of hypertension, effective control of arterial pressure, and the suppression of the underlying disease mechanisms markedly reduce the now increasing prevalence of both cardiac and renal failure.
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PMID:Target organ involvement in hypertension: a realistic promise of prevention and reversal. 1487 Oct 60


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