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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Unilateral parenchymatous kidney disease associated with high blood pressure represents a potentially curable form of hypertension. Surgery may normalize blood pressure in a substantial number of these patients. Curable renal parenchymatous hypertension includes unilateral tubulointerstitial kidney diseases such as chronic pyelonephritis, reflux nephropathy, segmental hypoplasia and radiation nephritis, hydronephrosis, simple renal cysts, traumatic kidney lesions and renal tumors associated with high blood pressure. Renal ischemia and in turn activation of the renin angiotensin system is involved in the pathogenesis of hypertension in most of these patients. In patients with unilateral kidney disease and hypertension, both an operative and a medical therapeutic approach have a high success rate. Good candidates for nephrectomy are young patients with severe hypertension, strict unilateral disease, normal plasma creatinine levels and minimal function of the involved kidney. In unilateral hydronephrosis reconstructive surgery or nephrectomy may cure or improve hypertension in the vast majority of the patients. Surgically correctable hypertension has also been reported in some patients with large renal cysts and renal tumors (hemangiopericytoma, Wilm's tumor, hypernephroma, renal pelvic tumor).
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PMID:Curable renal parenchymatous hypertension: current diagnosis and management. 390 29

The operative treatment of 77 patients with atherosclerotic aneurysms of the pararenal aorta (54 juxtarenal and 23 suprarenal) is analyzed. Repair of these complex lesions is formidable because of difficult exposure, renal ischemia and myocardial strain as a result of proximal aortic occlusion, and associated renal atherosclerosis with secondary renal functional impairment. Nineteen (25%) patients were normotensive with normal renal function. Sixteen patients (21%) had hypertension alone and 42 (54%) were hypertensive with abnormal renal function. There were multiple renal arteries in 22% of patients. Aortic reconstruction involved infrarenal graft in 27 patients (35%), infrarenal graft plus pararenal aortic endarterectomy (TEA) in 26 (34%), and infra- and pararenal aortic graft in 24 (31%). Twenty-two patients (30%) had normal renal arteries and therefore no renal reconstruction. Of the 55 patients who required combined aortic and renal artery repair, 24 required renal artery repair because of involvement of the renal arteries by the aneurysm and 31 because of atherosclerotic renal artery disease. TEA was the most common technique of renal artery repair (54 of 93 arteries, 58%), followed by reimplantation (18 arteries) and prosthetic graft (13). The perioperative mortality rate was 1.3%. The perioperative morbidity rate was 28% and consisted principally of renal insufficiency (23%). This was usually transient (44%) and (89%) mild. Renal morbidity was adversely affected by renal ischemia status, severity of renal artery disease and extent of renal revascularization. Following reconstruction, hypertension was cured or improved in 77% of patients and abnormal renal function was cured or improved in 46% and stabilized in an additional 39% of patients. These results show that combined aortic aneurysm repair and renal artery reconstruction can be performed with minimal mortality and an acceptable morbidity. Aggressive intraoperative monitoring is necessary to minimize myocardial complications. Careful attention must be paid to the technical details of the reconstruction, especially in minimizing renal ischemia, to reduce the subsequent incidence of renal function deterioration.
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PMID:Management of pararenal aneurysms of the abdominal aorta. 394 85

It is controversial whether dopamine (DA) is a peripheral neurotransmitter in the cardiovascular/renal system. The endogenous concentration of DA in the heart and blood vessels is generally only a fraction (5%) of that of norepinephrine (NE). With perhaps the exception of the kidney, the majority of the evidence suggests a precursor role for this amine rather than that of a neurotransmitter. The main weakness of arguments favoring DA as a vascular neurotransmitter is relative lack of data showing selective DA release and lack of effects of selective DA antagonists on neural stimulation. However, DA receptors have been characterized in cardiovascular tissues and are of two types: DA1 receptors located on vascular smooth muscle (postjunctional), which appear to mediate relaxation of the muscle, and DA2 receptors located on sympathetic nerves (pejunctional), which inhibit NE release. These receptors are interesting and potential target sites for novel cardiovascular drug action for the treatment of hypertension and renal ischemia. Moreover, selective DA receptor agonists will be important tools in understanding the role of DA receptors in normal and disease states.
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PMID:Dopamine and dopamine receptors as target sites for cardiovascular drug action. 613 21

Studies of the renin-angiotension system and the effects of pharmacologic blockade have enhanced our understanding of renovascular hypertension. A critical degree of arterial stenosis produces kidney ischemia sufficient to activate this hormonal system, whose actions include vasoconstriction and sodium retention. Accurate clinical evaluation may depend upon recognizing the differences in pathophysiology between "one-kidney" and "two-kidney" forms and the dynamic nature of this condition.
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PMID:Pathophysiology of renovascular hypertension. 638 77

Ninety patients underwent combined aortic (90) and renal artery (138 arteries) reconstruction for severe, symptomatic aortic occlusive disease (47 patients), aortic aneurysmal disease (30 patients), and visceral atherosclerosis (13 patients). Transaortic endarterectomy was used for 67% of renal artery reconstructions and 69% of visceral arteries. Aortic reconstruction required prosthetic grafting in 74%. A standard transabdominal approach was used in 72 of 90 patients (80%), and thoraco-retroperitoneal exposure was necessary in 18 patients. Perioperative mortality was 9% (8/90) and morbidity 16% (14/90). Ninety per cent of the patients were evaluated at long-term (mean 32 months). Hypertension was cured or improved at discharge in 82% (59/72), and in 96% hypertension improvement was sustained during the follow-up interval. Renal function was improved or preserved in 93% (40/43) at discharge, and this response was sustained in 84% during the follow-up period. Late mortality (8/74, 11%) was lower than expected and is attributed to the technique of combined repair, the cure and control of hypertension, the prevention of ongoing renal ischemia, and the preservation of renal function.
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PMID:Juxtarenal aortic atherosclerosis. Surgical experience and functional result. 646 85

Aortic ligation between the origins of the renal arteries in the rat produces a left renal ischemia, renin-dependent hypertension, and a transitory hindlimb paralysis of less than 2 h. Removal of the left ischemic kidney at the time of aortic ligation curtails the rise of blood pressure, plasma renin activity is normal, and paralysis is still present 24 h after surgery. Administration of an angiotensin-converting enzyme inhibitor or saralasin also prevents recuperation from paralysis after aortic ligation. Independent manipulation of the mean arterial pressure or plasma renin activity by pretreatment with reserpine or deoxycorticosterone before surgery shows that the presence or absence of paralysis is dependent on the plasma renin activity and not on the high blood pressure. Blood flow measurements show that paralysis is due to a persistent impairment of blood supply to the hindlimb muscle and not to ischemia of the spinal cord. Infusion of angiotensin II to aortic-ligated, left-renoprival animals tends to restore blood flow to muscle. It is concluded that after renal ischemia the renin-angiotensin system, independent of its hypertensive effect, restores blood flow by stimulating the development of collateral circulation.
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PMID:Renin-angiotensin and development of collateral circulation after renal ischemia. 675 70

Forty pediatric patients (16 girls and 24 boys) 22 months to 17 years old underwent operation for renovascular hypertension. Ostial stenoses were present in 20 children; midrenal lesions were present in eight; and isolated segmental disease was present in 12 patients and was combined with main renal artery stenoses in three patients. Neurofibromatosis affected ten patients, including three having abdominal aortic anomalies. Abdominal aortic coarctation affected five other children. Hypertensive urograms were abnormal only 27% of the time. Renin assays were helpful in identifying functionally important renal ischemia. Fifty-one primary surgical procedures were undertaken, including one simultaneous and nine staged operations for bilateral disease. There were two primary nephrectomies. Six patients underwent later secondary operations. Thirty-four patient (85%) were cured of hypertension, the conditions of five (12.5%) were improved, and one (2.5%) was classified a therapeutic failure. Carefully performed arterial reconstructive surgery will benefit most pediatric patients with renovascular hypertension.
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PMID:Pediatric renal artery occlusive disease and renovascular hypertension. Etiology, diagnosis, and operative treatment. 678 60

The rather common coexistence of arterial aneurysm and systemic hypertension may be attributed to their respective frequency as clinical findings. The development of hypertension secondary to renal ischemia that can occur as a complication of certain types of aneurysmal disease is well recognized. Less well appreciated is the evidence to implicate hypertension as a factor in the pathogenesis of arterial aneurysms, perhaps in their progressive enlargement, and even in rupture. Furthermore, after resection of an aneurysm, systemic hypertension adversely influences survival, and it is an important contributing factor in the development of false aneurysms. A relation between hypertension and aortic dissection has received more recognition. Just how systemic hypertension contributes to the occurrence of aortic dissection is not clear, but the effective control of hypertension has the potential for decreasing the incidence of aortic dissection. The curious clinical association of hypertension with the location of the primary tear in the proximal part of the descending aorta (type III or type B) has several plausible explanations.
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PMID:Hypertension and arterial aneurysm. 682 62

The objective of the present work was to study the changes in the brain and renal renin-angiotensin system (RAS) during their simultaneous stimulation by ischemia. Experiments were carried out on the following groups of male normotensive Wistar rats: intact, with brain ischemia, with renal ischemia, with combined brain and renal ischemia. The three ischemic groups of animals had some arterial pressure elevation without reaching hypertensive values. In animals with combined brain and renal ischemia brain renin concentration (BRC) was raised, while plasma renin activity (PRA) was reduced relative to the intact controls, i.e. as in animals with brain ischemia alone. Renal renin concentration (RRC) in the ischemic kidney was at the level of the one in intact animals and in animals with brain ischemia. In the intact contralateral kidney of rats with combined ischemia RRC was reduced relative to the intact kidney of animals with renal ischemia and statistically insignificantly reduced relative to the RRC in intact controls and in animals with brain ischemia. The results of this study showed that inverse ratio between renal and brain RAS exists also in the single clamped--birenal model of hypertension. Interaction between the two RAS is manifested when they both are simultaneously stimulated, with prevalence of the effect of brain RAS, which affects renin secretion in the kidney.
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PMID:[Brain and kidney renin-angiotensin system in rats with simultaneously induced cerebral and renal ischemia]. 699 Dec 47

To study the role of renal prostaglandins (PGs) in renovascular hypertension, PGE2 and PGF2 alpha concentrations in both inner and outer medullae of the kidney were measured by radioimmunoassay in rabbits with hypertension produced by left renal artery constriction. In the acute phase, a week after surgery, PGE2 in the inner and outer medullae and PGF2 alpha in the inner medulla were significantly increased in both the constricted and opposite kidneys (p less than 0.01). In chronic phase, 5 weeks after surgery, PGs returned to normal concentrations with the exceptions of PGE2 in the outer medulla and PGF2 alpha in the inner medulla of the constricted kidney. These results suggest that increased renal PGs may not be the cause of hypertension but a defensive reaction to renal ischemia, hypertension and sodium load.
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PMID:Intrarenal prostaglandins E2 and F2 alpha in experimental renovascular hypertension. 728 73


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