enalapril and Renal-Artery-Obstruction

Topics: Adrenal Cortex; Aldosterone; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Captopril; Enalapril; Glomerular Filtration Rate; Humans; Hypertension, Renovascular; Juxtaglomerular Apparatus; Kidney Function Tests; Radiography; Radionuclide Imaging; Radiopharmaceuticals; Renal Artery Obstruction; Renin-Angiotensin System; Technetium Tc 99m Pentetate; Vasoconstriction

Topics: Aged; Anastomosis, Surgical; Angiotensin-Converting Enzyme Inhibitors; Enalapril; Female; Humans; Renal Artery; Renal Artery Obstruction; Renal Dialysis; Renal Insufficiency; Splenic Artery; Time Factors

Although clinical reports have suggested that antihypertensive therapy can control blood pressure in patients with renovascular hypertension, adequate randomized studies comparing medical versus surgical management are lacking. It is well recognized that progressive deterioration in renal function can occur despite good blood pressure control. Recent experience suggests that higher-risk patients with atherosclerotic renovascular hypertension can benefit from an aggressive surgical approach, whereas newer medical therapies capable of specific inhibition of the renin-angiotensin system suggest greater potential benefits to other patients. Properly performed randomized trials comparing medical versus surgical therapy of renovascular hypertension are needed.

Topics: Adult; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Arteriosclerosis; Atenolol; Captopril; Dipeptides; Enalapril; Female; Humans; Hypertension, Renovascular; Male; Metoprolol; Middle Aged; Nadolol; Pindolol; Propanolamines; Propranolol; Renal Artery Obstruction; Renin-Angiotensin System; Saralasin; Timolol

Renal artery stenosis is among the most common curable causes of hypertension. The definitive diagnosis is made by renal angiography, an invasive and costly procedure. The prevalence of renal artery stenosis is less than 1% in non-selected hypertensive patients but is higher when hypertension is resistant to drugs.. To study the usefulness of standardised two-drug regimens for identifying drug-resistant hypertension as a predictor of renal artery stenosis.. Prospective cohort study carried out in 26 hospitals in The Netherlands.. Patients had been referred for analysis of possible secondary hypertension or because hypertension was difficult to treat. Patients < or =40 years of age were assigned to either amlodipine 10 mg or enalapril 20 mg, and patients >40 years to either amlodipine 10 mg combined with atenolol 50 mg or to enalapril 20 mg combined with hydrochlorothiazide 25 mg. Renal angiography was performed: (1) if hypertension was drug-resistant, ie if diastolic pressure remained > or =95 mm Hg at three visits 1-3 weeks apart or an extra drug was required, and/or (2) if serum creatinine rose by > or =20 micromol/L (> or =0.23 mg/dL) during ACE inhibitor treatment.. Of the 1106 patients with complete follow-up, 1022 had been assigned to either the amlodipine- or enalapril-based regimens, 772 by randomisation. Drug-resistant hypertension, as defined above, was identified in 41% of the patients, and 20% of these had renal artery stenosis. Renal function impairment was observed in 8% of the patients on ACE inhibitor, and this was associated with a 46% prevalence of renal artery stenosis. In the randomised patients, the prevalence of renal artery stenosis did not differ between the amlodipine- and enalapril-based regimens.. In the diagnostic work-up for renovascular hypertension the use of standardised medication regimens of maximally two drugs, to identify patients with drug-resistant hypertension, is a rational first step to increase the a priori chance of renal artery stenosis. Amlodipine- or enalapril-based regimens are equally effective for this purpose.

Topics: Adolescent; Adult; Aged; Amlodipine; Antihypertensive Agents; Atenolol; Blood Pressure; Cohort Studies; Drug Resistance; Drug Therapy, Combination; Enalapril; Female; Humans; Hydrochlorothiazide; Hypertension, Renal; Male; Middle Aged; Predictive Value of Tests; Prospective Studies; Radiography; Renal Artery; Renal Artery Obstruction

Topics: Adolescent; Adult; Aged; Amlodipine; Angiography; Antihypertensive Agents; Atenolol; Drug Resistance, Multiple; Enalapril; Female; Humans; Hydrochlorothiazide; Hypertension; Male; Middle Aged; Patient Selection; Radionuclide Imaging; Renal Artery Obstruction

During the course of a long-term, prospective, randomized study in 77 hypertensive nephrosclerosis patients, five patients developed evidence suggestive of renal artery stenosis. However, arteriography demonstrated patent renal arteries. The evidence suggestive of renal artery stenosis was: (1) converting-enzyme inhibitor (CEI)-induced renal dysfunction including marked and reversible increases in serum creatinine and urea concentrations, (2) minoxidil-induced hyperreninemia despite beta-adrenoceptor blockade and volume expansion, and (3) minoxidil-induced salt and water retention with diuretic resistant edema. Thus, the renal dysfunction induced by CEI in these patients with patent renal arteries is similar to the alterations occurring in patients having bilateral renal artery stenosis. The diuretic resistant edema and the beta-adrenoceptor blocker resistant high renin release are also functional alterations of renal artery stenosis. We suspect that the long-standing and usually severe hypertension in these patients has caused sufficient arteriolar hypertrophy or sclerosis to interfere with renal blood flow and to induce these functional lesions of renal artery stenosis. With widespread use of the new CEI agents in patients with renal disease, this syndrome suggestive of renal artery stenosis may be encountered in as many as 10% of hypertensive nephrosclerosis patients during long-term treatment with converting-enzyme inhibitors.

Topics: Angiography; Blood Pressure; Body Weight; Creatinine; Double-Blind Method; Enalapril; Humans; Hydralazine; Hypertension; Minoxidil; Nephrosclerosis; Prospective Studies; Random Allocation; Renal Artery; Renal Artery Obstruction; Renin; Syndrome

The converting enzyme inhibitor, enalapril, was given to 20 hypertensive patients with renal artery stenosis in a single daily dose of 10-40 mg. Enalapril effectively controlled hypertension long-term, and only two of the 20 patients required concomitant diuretic treatment. The blood pressure reduction 6 h after the first dose of enalapril was significantly related to pre-treatment plasma concentrations of active renin and angiotensin II (AII), and to the concurrent fall in AII. Blood pressure fell further with continued treatment; the long-term reduction was not significantly related to pretreatment plasma renin or angiotensin II. At three months, 24 h after the last dose of enalapril, blood pressure, plasma AII and converting enzyme activity remained low, and active renin and angiotensin I (AI) high; 6 h after dosing, AII had, however, fallen further. During prolonged therapy, the increase of active renin was proportionately greater than that of angiotensin I. Enalapril alone caused a long-term reduction in exchangeable sodium, with slight increases in serum potassium, creatinine and urea. Enalapril alone did not impair overall renal function in five patients with bilateral renal lesions despite effective blood pressure reduction. Enalapril was well tolerated with no serious side-effects. Enalapril given once daily is effective in controlling hypertension associated with renal artery stenosis.

Topics: Adolescent; Adult; Blood Pressure; Clinical Trials as Topic; Creatinine; Enalapril; Female; Humans; Hypertension, Renovascular; Male; Middle Aged; Peptidyl-Dipeptidase A; Placebos; Renal Artery Obstruction; Renin-Angiotensin System

The authors describe the clinical investigation and progress of a 13-year-old girl diagnosed with hypertension 4 years prior to her admission. A thorough history was taken and physical examination performed. Laboratory analysis and relevant radiological evaluation were obtained in order to determine the etiology for suspected secondary hypertension, and later to differentiate between the possible causes of hyperreninemic hypertension. The patient had an accessory left renal artery, presumptively leading to renin secretion by the underperfused kidney. The patient was treated medically with spontaneous resolution of her hypertension and near normalization of plasma renin activity. On repeat imaging, the artery was not demonstrated. The authors concluded that the diagnosis of hyperreninemic hypertension in young ages should prompt investigation for the etiology. However, cautious observation is a valid option that might lead to spontaneous resolution.

Topics: Adolescent; Enalapril; Female; Humans; Hypertension, Renovascular; Renal Artery Obstruction; Treatment Outcome

Renovascular hypertension is an uncommon disease, but it causes 5-10% of all childhood hypertension. The most common cause of renal artery stenosis is fibromuscular dysplasia, resulting in at least 60% of renovascular hypertension cases. This report describes a case of a renal artery stenosis confirmed by multidetector computed tomographic angiography.

Topics: Angiography; Angioplasty, Balloon; Antihypertensive Agents; Atenolol; Child; Combined Modality Therapy; Drug Therapy, Combination; Enalapril; Humans; Hypertension, Renovascular; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Male; Renal Artery Obstruction; Tomography, Spiral Computed; Ultrasonography, Doppler, Color

Topics: Adult; Angiography; Enalapril; Graft Occlusion, Vascular; Humans; Hypertension; Male; Nifedipine; Recurrence; Renal Artery Obstruction; Ultrasonography, Doppler, Duplex; Vasodilator Agents

This study aims to assess the feasibility of a protocol to diagnose renovascular disease using dual MR renography acquisitions: before and after administration of angiotensin-converting enzyme inhibitor (ACEi). Results of our simulation study aimed at testing the reproducibility of glomerular filtration rate (GFR) and renal plasma flow demonstrate that for a fixed overall dose of 12 ml gadolinium-based contrast material (500 mmol/l), the second dose should be approximately twice as large as the first dose. A three-compartment model for analyzing the second-injection data was shown to appropriately handle the tracer residue from the first injection. The optimized protocol was applied to 18 hypertensive patients without renovascular disease, showing minimal systematic difference in GFR measurements before and after ACEi of 0.8 +/- 4.4 ml/min or 2.7 +/- 14.9%. For 10 kidneys with significant renal artery stenosis, GFR decreased significantly after ACEi (P < 0.001, T value = 3.79), and the difference in GFR measurements before and after ACEi averaged 8.3 +/- 6.9 ml/min or 26.2 +/- 43.9%. Dual-injection MRI with optimized dose distribution appears promising for ACEi renography by offering measures of GFR changes with clinically acceptable precision and accuracy.

Topics: Adult; Aged; Aged, 80 and over; Angiotensin-Converting Enzyme Inhibitors; Computer Simulation; Contrast Media; Enalapril; Feasibility Studies; Female; Gadolinium DTPA; Glomerular Filtration Rate; Humans; Hypertension, Renovascular; Injections, Intravenous; Magnetic Resonance Angiography; Male; Middle Aged; Models, Biological; Monte Carlo Method; Predictive Value of Tests; Radioisotope Renography; Renal Artery Obstruction; Renal Plasma Flow; Reproducibility of Results; Time Factors

Topics: Adult; Angiotensin-Converting Enzyme Inhibitors; Cardiomegaly; Enalapril; Fibrosis; Heart Ventricles; Humans; Hypertension; Male; Renal Artery Obstruction; Renin-Angiotensin System; Treatment Outcome

Topics: Aged; Aged, 80 and over; Angiography; Angioplasty, Balloon; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Diagnosis, Differential; Electrocardiography; Emergencies; Enalapril; Female; Follow-Up Studies; Humans; Hypertension; Pulmonary Edema; Radiography, Thoracic; Renal Artery Obstruction; Stents; Time Factors; Tomography, X-Ray Computed; Treatment Outcome; Ultrasonography, Doppler

Renal artery stenosis may present as acute pulmonary oedema and be misinterpreted as congestive heart failure. ACE inhibitors and angiotensin-II antagonists are widely used among patients with congestive heart failure and hypertension.. The authors present a patient with congestive heart failure caused by a combination of coronary heart disease and bilateral renal artery stenosis. The patient developed acute kidney failure secondary to ACE inhibitor and angiotensin II antagonist treatment.. Mechanisms behind pulmonary oedema secondary to renovascular hypertension are discussed.. Revascularisation is the treatment of choice for this patient category.

Topics: Acute Kidney Injury; Adult; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Diagnosis, Differential; Enalapril; Heart Failure; Humans; Hypertension; Hypertension, Renovascular; Male; Pulmonary Edema; Renal Artery Obstruction

Acute renal failure is a well-known complication in patients with renal artery stenosis during treatment with ACE inhibitor. Renal artery thrombosis after withdrawal of ACE inhibitor has not been reported previously.. We describe a patient with acute renal failure with an unexpected course.. A 67-year-old man was admitted with acute anuric renal failure during treatment with hydrochlorothiazide and enalapril. His blood pressure was 165/60 mm Hg. Renal ultrasound was normal. After initial rehydration and dialysis, diuresis resumed until a sudden unexpected anuric renal failure recurred on day 12. Angiography disclosed bilateral renal artery occlusion. The right renal artery was successfully opened and a stenosis was blocked and stented, and brisk diuresis ensued. Two days later hypertension accelerated, and a new invasive procedure on day 24 succeeded in opening, blocking and stenting a proximal stenosis in the left artery; a mobile thrombus was located behind the stenosis and successfully treated with intraarterial thrombolysis. Blood pressure rapidly normalized, and serum creatinine was normal on visits 1.5 and 4 months later.. General aspects and prevention of acute renal failure during ACE inhibitor therapy are discussed. Acute renal thrombosis after withdrawal of ACE inhibitor in patients with stimulated renin angiotensin system and significant renal artery stenosis may be causally related to the antifibrinolytic effects of angiotensin II and aldosterone. Endovascular reconstruction of renal artery occlusion may completely restore the kidney function.

Topics: Acute Kidney Injury; Aged; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Diuretics; Enalapril; Humans; Hydrochlorothiazide; Male; Radiography; Renal Artery Obstruction; Renin-Angiotensin System; Sodium Chloride Symporter Inhibitors

Prognosis in Takayasu's arteritis is limited owing to renovascular hypertension. The authors report a patient with Takayasu's arteritis who had been unilaterally nephrectomized and presented with malignant hypertension due to renal artery stenosis. Hypertension was refractory to conventional antihypertensive treatment, and stenosis was not accessible by interventional angioplasty. Initiation of enalapril and losartan therapy was successful in improving blood pressure without deterioration of renal function due to ischemic failure. Antihypertensive treatment resulted in dramatically stimulated endogenous nitric oxide (NO) synthesis, while elevated plasma endothelin-1 levels were unchanged. Renovascular hypertension in Takayasu's arteritis is associated with an imbalance of vasoconstrictor peptide endothelin-1 and vasodilator peptide NO. Successful treatment of hypertension by enalapril or losartan results in improved endogenous NO synthesis, which putatively counterbalances excessive vasoconstrictor actions and may retard the progression of renal failure.

Topics: Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Enalapril; Endothelin-1; Female; Humans; Hypertension, Renovascular; Losartan; Middle Aged; Nephrectomy; Nitric Oxide; Prognosis; Renal Artery Obstruction; Takayasu Arteritis; Vasoconstrictor Agents; Vasodilator Agents

Successful bilateral renal revascularization was performed 24 days after the development of angiotensin converting enzyme-inhibitor-induced bilateral renal artery thrombosis and anuric acute renal failure in a patient with Takayasu's arteritis. Excellent results were obtained after an unusually long ischemic time for a patient with active-phase disease. The outcome suggests that aggressive surgical revascularization can benefit patients with renal failure caused by renal arterial occlusion during the active phase of Takayasu's arteritis.

Topics: Acute Kidney Injury; Adult; Angiotensin-Converting Enzyme Inhibitors; Anuria; Collateral Circulation; Enalapril; Female; Humans; Radiography; Renal Artery Obstruction; Takayasu Arteritis; Thrombosis

Topics: Adolescent; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Enalapril; Glomerulosclerosis, Focal Segmental; Humans; Hypertension, Renovascular; Kidney Glomerulus; Male; Proteinuria; Radiography; Renal Artery Obstruction

We performed a retrospective study on 26 patients with moderate renal failure (mean GFR = 51 +/- 21 ml min-1 1.73 m-2), hypertension and atherosclerosis. Apart from three patients who had completely normal renal Doppler ultrasonography, all patients underwent renal angiography. Three groups of kidneys with different atherosclerotic renal artery involvement were identified: Group 1, 24 kidneys with no renal artery stenosis (RAS); Group 2, 18 kidneys with mild (> 25% and < 50% diameter) RAS; and Group 3, 10 kidneys with moderate (> 50% diameter) RAS. We used a two-day protocol with frusemide plus enalapril 99Tcm-MAG3 scintigraphy. The mean parenchymal transit time (MPTT), time to the maximum activity (time to peak) of the renal curve (Tmax), residual activity and split renal uptake were evaluated. The measured parameters did not differ before and after enalapril in Group 1 or in Group 2. In Group 3, MPTT and residual activity differed significantly (P < 0.025) before and after enalapril. The Tmax before and after enalapril, MPTT before and after enalapril and residual activity after enalapril differed significantly (P < 0.05) between Groups 1 and 3 and between Groups 2 and 3. Threshold values were obtained to maximize diagnostic accuracy. The Tmax, MPTT and residual activity after enalapril gave satisfactory results, and MPTT performed best with a 75% positive predictive value and a 98% negative predictive value for the diagnosis of renal artery stenosis. We conclude that MPTT, measured after enalapril administration, is a useful parameter to detect renal artery stenosis in patients with hypertension, atherosclerosis and moderate renal insufficiency.

Topics: Adult; Aged; Angiotensin-Converting Enzyme Inhibitors; Arteriosclerosis; Diuretics; Enalapril; Furosemide; Glomerular Filtration Rate; Humans; Hypertension; Kidney Failure, Chronic; Middle Aged; Radionuclide Imaging; Radiopharmaceuticals; Renal Artery Obstruction; Retrospective Studies; Technetium Tc 99m Mertiatide

Topics: Aged; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Biphenyl Compounds; Enalapril; Humans; Imidazoles; Kidney Failure, Chronic; Losartan; Male; Renal Artery Obstruction; Tetrazoles

Topics: Angioplasty; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Creatinine; Enalapril; Heart Transplantation; Humans; Hypertension; Magnetic Resonance Angiography; Male; Middle Aged; Renal Artery Obstruction

The inability to separate irreversible lesions of tubular epithelia from reversible tubular atrophy constitutes a major problem in histopathology and in decisions for revascularization of shrunken kidneys with renal artery stenosis. In order to characterize reversible tubular atrophy ('kidney hibernation') we studied the physiological and biochemical parameters and morphology including histochemistry in rat kidneys made atrophic by renal artery stenosis and treatment with the angiotensin-converting enzyme inhibitor, enalapril. Renal artery stenosis was induced by a 0.2-mm clip around the left renal artery. Following 7 weeks of clipping and 2 concomitant weeks of enalapril treatment, the kidney length decreased from 17.8 +/- 0.3 to 13.7 +/- 0.7 mm (mean +/- SEM). Renal blood flow and glomerular filtration rate decreased to 39 +/- 3% and to approximately 3% of control values, respectively. The activities of the intracellular proteolytic enzymes cathepsin B and L and of Na-K-ATPase in microdissected proximal tubular segments decreased to values below 50 and 10%, respectively. All changes were significant (p < 0.05). Histochemical staining for ATPase activity in the distal tubule segments remained unchanged. Tubular cells were atrophic but not necrotic. Histochemical staining of alkaline phosphatase in the tubular brush border and of acid phosphatase and peroxidase in lysosomes was greatly reduced. All observed changes were reversible within 2-3 weeks following removal of the clip and withdrawal of enalapril either with or without contralateral nephrectomy. Thus, a form of kidney hibernation with readily reversible tubular atrophy has been described. Based on this description it may be possible in consecutive experiments to differentiate between reversible and irreversible tubular atrophy.

Topics: Acid Phosphatase; Alkaline Phosphatase; Angiotensin-Converting Enzyme Inhibitors; Animals; Atrophy; Cathepsins; Enalapril; Glomerular Filtration Rate; Hemodynamics; Hibernation; Hypertension, Renovascular; Kidney; Kidney Tubules; Male; Rats; Rats, Wistar; Renal Artery Obstruction; Renal Circulation; Sodium-Potassium-Exchanging ATPase

Topics: Aged; Angioplasty, Balloon; Enalapril; Humans; Hypertension, Renovascular; Hyponatremia; Male; Renal Artery Obstruction; Syndrome

Topics: Anesthesia, General; Animals; Dogs; Enalapril; Hemodynamics; Iodohippuric Acid; Radioisotope Renography; Renal Artery Obstruction

A 65-year-old man presented proteinuria in the nephrotic range that occurs in the setting of high renin hypertension. Proteinuria persisted after normalizing blood pressure by nifedipine. In contrast, treatment with an ACE-inhibitor (enalapril) resulted in the prompt resolution of the proteinuria. Interestingly, proteinuria relapsed after removing the ACE-inhibition. These observations suggest a causal relation between the overactivity of the renin-angiotensin system in this patient and his proteinuria.

Topics: Aged; Enalapril; Humans; Hypertension, Renovascular; Male; Nephrotic Syndrome; Proteinuria; Recurrence; Renal Artery Obstruction; Renin

Topics: Enalapril; Humans; Kidney Diseases; Renal Artery Obstruction

The Authors describe a clinical case of a patient affected by arterial hypertension of severe degree (IV grade OMS) that during therapy with ACE inhibitors and diuretics developed acute renal failure that reversed after stopping treatment. The clinical course was quite similar to acute renal failure induced by ACE inhibitors and diuretics in patient with bilateral renal artery stenosis. In interpreting the pathogenesis, the Authors suppose, beside a reductions of effective plasma flow, the coexistence of hyalinosis of renal arterioles. They underline the necessity of monitoring renal function at least in the first weeks of therapy when a treatment with ACE inhibitors and diuretics is started especially in patients with hypertension of high degree and/or reduced renal function.

Topics: Acute Kidney Injury; Adult; Angiotensin-Converting Enzyme Inhibitors; Chlorthalidone; Diuretics; Enalapril; Humans; Hypertension; Kidney Function Tests; Male; Renal Artery Obstruction

Topics: Angiotensin-Converting Enzyme Inhibitors; Enalapril; Humans; Hypertension; Male; Middle Aged; Renal Artery Obstruction

This is a report of a case history of a child with cerebral Moyamoya disease and gradual development of systemic hypertension. Sodium depletion combined with enalapril induced renal failure. A bilateral renal artery stenosis was found. Percutaneous transluminal angioplasty was not successful and was followed by autotransplantation of both kidneys. Histopathological examination of the renal arteries revealed intimal hyperplasia.

Topics: Arterial Occlusive Diseases; Enalapril; Humans; Hypertension, Renovascular; Infant; Kidney Transplantation; Male; Moyamoya Disease; Radiography; Renal Artery Obstruction

Iodine-123 hippurate renography, [99mTc]diethylenetriaminepentaacetic acid (DTPA) renography, and [99mTc]dimercapto succinic acid (DMSA) renal scintigraphy were performed before and during angiotensin converting enzyme (ACE) inhibition in a group of 15 hypertensive patients with angiographically "significant" unilateral renal artery stenosis. Visual and quantitative evaluation of the three radioisotope methods before ACE inhibition already disclosed abnormalities suggestive of renal artery stenosis in a high percentage (87%, 60%, and 60%, respectively) in this group of patients, but ACE inhibition further improved the diagnostic yield in all three methods (93%, 86%, and 80%). Iodine-123 hippurate renography was at least as useful as [99mTc]DTPA renography in this respect, while [99mTc]DMSA scintigraphy can be used particularly in segmental stenosis. Despite a large drop in blood pressure after ACE inhibition little adverse reactions were seen and overall renal function was fairly well maintained, the exceptions noted in patients with initially a more impaired renal function.

Topics: Adolescent; Adult; Angiotensin-Converting Enzyme Inhibitors; Blood Pressure; Drug Evaluation; Enalapril; Female; Humans; Hypertension, Renovascular; Iodohippuric Acid; Kidney; Male; Middle Aged; Organometallic Compounds; Pentetic Acid; Radionuclide Imaging; Renal Artery Obstruction; Succimer; Technetium; Technetium Tc 99m Dimercaptosuccinic Acid; Technetium Tc 99m Pentetate

Topics: Aged; Arteriosclerosis; Enalapril; Female; Humans; Renal Artery Obstruction

A case of irreversible renal failure during treatment with enalapril in bilateral renal artery stenosis is described. In the use of converting enzyme inhibitors, caution and monitoring of renal function during treatment is advised.

Topics: Adult; Enalapril; Humans; Hypertension; Kidney Failure, Chronic; Male; Middle Aged; Renal Artery Obstruction

The influence of the renin-angiotensin system on renal hemodynamics, tubular pressure and tubulo-glomerular feedback was investigated with the angiotensin converting enzyme inhibitor MK 421 (enalapril), in uninephrectomized rats with and without ischemia-induced acute renal failure. In animals with normal renal function proximal tubular pressure and tubulo-glomerular feedback response were lowered by enalapril long-term treatment, whereas glomerular filtration rate and renal blood flow were not influenced by the drug. After 45 and 70 minutes ischemia there was no difference between treated and untreated animals in the severely impaired glomerular filtration rate. Renal blood flow remained unaffected by the treatment. The histological damage due to ischemia (tubular casts, tubular necrosis and medullary capillary congestion) was not influenced by enalapril. As tubulo-glomerular feedback had been significantly inhibited during renin-angiotensin inhibition, its importance in mediating acute renal failure remains doubtful; other factors such as tubular obstruction and medullary congestion may be crucial.

Topics: Acute Kidney Injury; Angiotensin-Converting Enzyme Inhibitors; Animals; Enalapril; Feedback; Female; Hemodynamics; Ischemia; Kidney Glomerulus; Kidney Tubules; Rats; Rats, Inbred Strains; Renal Artery Obstruction; Renal Circulation; Thrombosis

Deterioration in renal function after the use of angiotensin converting-enzyme inhibitors may be the first clue to the presence of bilateral renal arterial stenosis. In order to avoid serious threat to the patient, early detection of the insidious decline in renal function is necessary and depends on routine biochemical monitoring after the initiation of therapy. Six cases are described here, to illustrate the very real danger of this class of drugs in this chemical setting; the grave risk of their combination with potassium-sparing diuretic agents is highlighted.

Topics: Acute Kidney Injury; Aged; Captopril; Creatinine; Enalapril; Female; Humans; Hypertension; Male; Middle Aged; Renal Artery Obstruction; Smoking

Angiotensin converting enzyme (ACE) inhibitors have been recommended for the treatment of diabetic nephropathy. However, it should be remembered that diabetic patients may also develop atheromatous renal artery stenosis. In such patients ACE inhibitors may have adverse effects on renal function. Careful investigation and monitoring is essential when ACE inhibitors are used in diabetes.

Topics: Angiotensin-Converting Enzyme Inhibitors; Captopril; Diabetes Complications; Enalapril; Humans; Hypertension; Kidney Diseases; Male; Middle Aged; Renal Artery Obstruction

Enalapril maleate (MK-421) is a new non-sulfhydryl-containing converting-enzyme inhibitor that has been shown to be effective and well tolerated in patients with essential hypertension. Data on its effectiveness and safety in patients with renovascular hypertension are limited and have involved predominantly short-term observations. This is particularly true with respect to the long-term effects of enalapril on renal function. We report our experience using the combination of enalapril and hydrochlorothiazide (HCTZ) in a group of nine patients with moderate to severe hypertension associated with renal artery stenosis. The enalapril-HCTZ combination successfully controlled blood pressure in seven patients during a six-week period of study. Adverse effects were not noted, and detailed renal hemodynamic studies did not reveal any significant changes of renal plasma flow and glomerular filtration rate during this time interval. Five patients were continued on this regimen for a period of six to 18 months. In this group of patients, the regimen continued to be well tolerated and to provide excellent blood pressure control: glomerular filtration rate was maintained in two patients and variable grades of decrease were noted in three. The mechanism of this delayed renal dysfunction as well as its relationship to enalapril treatment remain unclear. The long-term impact of converting-enzyme inhibition on renal function requires further study.

Topics: Adult; Aged; Aldosterone; Blood Pressure; Enalapril; Female; Humans; Hypertension, Renovascular; Male; Middle Aged; Pulse; Renal Artery Obstruction; Renin

Topics: Adult; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Aorta; Enalapril; Female; Humans; Hypertension, Renovascular; Male; Middle Aged; Renal Artery Obstruction; Renal Veins; Renin

Renal DTPA studies were analysed to produce numerical data of renal function (blood flow, glomerular filtration, and excretion), and this was used as an adjunct to the routine imaging information in a study of renal artery stenosis (RAS). The results show an overall accuracy of 81%, with a sensitivity of 96% and a specificity of 61%. In patients with RAS, beta-blocking drugs reduced the difference between the two kidneys. ACE-inhibiting drugs appeared to preserve renal blood flow but also to cause a deterioration in the glomerular filtration rate of kidneys with RAS. An explanation is proposed, in which renal capillary pressure is more important for function than is renal blood flow.

Topics: Adrenergic beta-Antagonists; Captopril; Enalapril; Glomerular Filtration Rate; Humans; Kidney Transplantation; Middle Aged; Organometallic Compounds; Pentetic Acid; Radionuclide Imaging; Renal Artery Obstruction; Renal Circulation; Technetium Tc 99m Pentetate

Topics: Enalapril; Humans; Hypertension, Renovascular; Male; Middle Aged; Renal Artery Obstruction

We have investigated the role of angiotensin II in the development of high blood pressure and in the maintenance of renal function during 2 weeks of one-kidney renal artery stenosis in conscious dogs. Responses to a fixed degree of inflation of a balloon cuff around the renal artery were compared in dogs with or without continuous enalapril (MK 421) treatment. In six untreated dogs, mean aortic pressure was increased by 17.1 +/- 2.0 mm Hg, due primarily to increases in total peripheral resistance with little change in cardiac output, while glomerular filtration rate, renal blood flow, renal artery pressure, and plasma renin activity were back to prestenosis levels. In seven enalapril-treated dogs mean aortic pressure was increased by 23.0 +/- 2.7 mm Hg and was not significantly different from that occurring in untreated dogs. This rise was due to increases in total peripheral resistance (10%) and cardiac output (12%). In the absence of angiotensin II, glomerular filtration rate remained low, at only 56 +/- 6% of prestenosis levels. Renal blood flow returned to normal, but the renal artery pressure remained 25% lower than control values. Thus, the main role of angiotensin II in chronic one-kidney Goldblatt hypertension does not appear to be through its pressor properties but rather through its actions in the kidney to preserve glomerular filtration. This effect on renal function persisted throughout the course of the hypertension, even when the plasma renin levels returned to normal.

Topics: Angiotensin II; Animals; Blood Pressure; Cardiac Output; Dogs; Enalapril; Glomerular Filtration Rate; Hypertension, Renovascular; Kidney; Male; Renal Artery; Renal Artery Obstruction; Renin; Vascular Resistance; Vasopressins; Water-Electrolyte Balance

All four factors which theoretically may affect the renal vein renin ratio in unilateral renal artery stenosis--increased renin secretion and diminished renal plasma flow on the stenotic side; suppressed renin secretion and renin extraction on the contralateral side--have been assessed. In a series of patients with unilateral renal artery stenosis, the renal vein ratio of active renin was more closely related to the reduction of renal plasma flow than to renin secretion rate on the affected side. On the contralateral side renin secretion was suppressed while angiotensin II was extracted. During long-term treatment with the converting enzyme inhibitor enalapril, peripheral plasma angiotensin II was lowered, while active renin concentration was markedly elevated, both in arterial plasma and in renal venous plasma of the stenotic kidney; the contralateral kidney became a net extractor of active renin. Thus, all 4 factors which theoretically affect the renal vein renin ratio can operate clinically. Both before and during enalapril, the affected kidney secreted inactive renin.

Topics: Angiotensin II; Enalapril; Humans; Hypertension; Hypertension, Renovascular; Kidney; Renal Artery Obstruction; Renal Circulation; Renal Veins; Renin

Topics: Acute Kidney Injury; Antihypertensive Agents; Dipeptides; Enalapril; Glomerulonephritis; Glomerulosclerosis, Focal Segmental; Humans; Hypertension, Renovascular; Male; Middle Aged; Renal Artery Obstruction

Topics: Enalapril; Humans; Kidney Diseases; Renal Artery Obstruction

Enalapril, an angiotensin converting enzyme (ACE) inhibitor, was given to 12 patients with renovascular hypertension: To five of them as a single drug after discontinuing other medications, and to seven patients as a substitute for one of their previous medications. The drug proved effective in controlling hypertension in all patients. Flushing and palpitations occurred in two of them, one of whom also showed a rise in creatinine and mild hyperkalemia. Two patients who had developed side effects while on captopril (renal deterioration in one, and severe rash in the other) tolerated enalapril well. Enalapril effectively reduced the blood pressure in the one patient with bilateral renal artery stenosis without causing renal failure.

Topics: Adult; Aged; Angiotensin-Converting Enzyme Inhibitors; Enalapril; Female; Humans; Hypertension, Renovascular; Male; Middle Aged; Renal Artery Obstruction

The converting enzyme inhibitor enalapril, in single daily doses of 10 to 40 mg, was given to 20 hypertensive patients with renal artery stenosis. The decrease in blood pressure six hours after the first dose of enalapril was significantly related to the pretreatment plasma concentrations of active renin and angiotensin II, and to the concurrent decrease in angiotensin II. Blood pressure decreased further with continued treatment; the long-term decrease was not significantly related to pretreatment plasma renin or angiotensin II levels. At three months, 24 hours after the last dose of enalapril, blood pressure, plasma angiotensin II, and converting enzyme activity remained low, and active renin and angiotensin I high; six hours after dosing, angiotensin II had, however, decreased further. The increase in active renin during long-term treatment was proportionately greater than the increase in angiotensin I; this probably reflects the diminution in renin substrate that occurs with converting enzyme inhibition. Long-term enalapril treatment increased renin secretion by more than 10-fold, and renal venous and peripheral plasma renin concentration by more than 20-fold; however, the mean renal venous renin ratio was not changed. Enalapril caused a reduction in effective renal plasma flow via the affected kidney but a marked and consistent increase on the contralateral side, where renal vascular resistance decreased. The overall increase in effective renal plasma flow was significantly related to the decrease in angiotensin II. Overall glomerular filtration rate was lowered, and serum creatinine and urea increased. Enalapril alone caused a long-term reduction in exchangeable sodium, with slight but distinct increases in serum potassium. In five patients with bilateral renal artery lesions, enalapril given alone for three months did not cause renal function to deteriorate. Enalapril was well tolerated and provided effective long-term control of hypertension; only two of the 20 patients studied required concomitant diuretic treatment.

Topics: Administration, Oral; Adult; Aldosterone; Angiotensin I; Angiotensin II; Blood Pressure; Body Composition; Creatinine; Dipeptides; Drug Evaluation; Enalapril; Female; Heart Rate; Humans; Hypertension; Kidney; Male; Middle Aged; Posture; Potassium; Renal Artery Obstruction; Renin; Sodium

Enalapril alone, 10-40 mg given once-daily, controlled systemic hypertension long-term (mean follow-up time 19 months) in patients with renal artery stenosis. Significant, but usually modest, increases in serum creatinine and urea were observed. No serious side-effects were seen. A highly significant reduction in peripheral plasma angiotensin II was maintained 24 h after the previous dose of enalapril. Plasma active renin concentration rose 20-fold with long-term enalapril, when the stenotic kidney showed significant secretion of inactive, as well as of active renin. With enalapril therapy, the contralateral kidney showed net extraction of active renin. In unilateral renal artery stenosis, circulation on the affected side is diminished and is mainly via the juxtamedullary nephrons, which become rich in associated renin. Important intrarenal compensatory actions of the renin-angiotensin system include support of glomerular filtration, enhancement of vasa recta-mediated counter-current exchange, sustained urea excretion and maintenance of renal artery pressure distal to the stenosis. These compensatory effects are lost with converting enzyme inhibition. Thus in patients who are candidates for operation, enalapril should usually be given for no more than one month before proceeding to corrective surgery, to allow maximum blood pressure reduction without endangering the stenotic kidney for too long. Enalapril can nevertheless be given effectively long-term in patients unsuitable for corrective surgery.

Topics: Adolescent; Adult; Blood Pressure; Enalapril; Follow-Up Studies; Humans; Hypertension; Hypertension, Renovascular; Kidney; Middle Aged; Proteinuria; Renal Artery Obstruction; Renal Veins; Renin; Renin-Angiotensin System

The responses to 48 h of renal artery stenosis were compared in uninephrectomized, chronically-instrumented dogs with or without inhibition of angiotensin II (AII) formation by enalapril. Mean arterial pressure rose by an average of 29.9 mmHg (s.e.m. 3.5) in untreated dogs and by 14.5 mmHg (s.e.m. 2.8) in enalapril-treated dogs over the two days of stenosis. Renal artery stenosis reduced glomerular filtration rate (GFR) by 49% (s.e.m. 9) in untreated dogs and by 86% (s.e.m. 8) in enalapril-treated dogs. Compared to untreated dogs, enalapril-treated dogs also had lower renal artery pressure distal to the stenosis, drank less water and had larger rises in plasma K+ following renal artery stenosis. There were no differences in renal blood flow or urinary Na+ excretion in the two groups of dogs. Thus blockade of AII production did not prevent hypertension occurring in response to renal artery stenosis, but the rise in blood pressure was only about half that which occurred in normal dogs and GFR was much more severely reduced.

Topics: Angiotensin II; Animals; Blood Pressure; Body Water; Dipeptides; Dogs; Enalapril; Glomerular Filtration Rate; Heart Rate; Hypertension, Renal; Male; Renal Artery Obstruction; Renin; Sodium; Time Factors

Enalapril maleate (MK421), a new inhibitor of angiotensin converting enzyme, in single daily doses of 1.25-40 mg was assessed in five patients with hypertension and renal artery stenosis. Only small falls in plasma angiotensin II concentrations were seen at doses less than 10 mg; even with 10 and 20 mg, angiotensin II concentrations had risen again 24 hours from the last dose. During long-term treatment with 10-40 mg daily all patients achieved good blood-pressure control. No significant changes of body sodium or potassium values were seen. The drug was well tolerated with no serious side effects. These findings are evidence of the efficacy and acceptability of enalapril in the medical management of hypertension with renal artery stenosis.

Topics: Adult; Angiotensin II; Antihypertensive Agents; Dipeptides; Enalapril; Enzyme Inhibitors; Female; Humans; Hypertension, Renal; Hypertension, Renovascular; Male; Middle Aged; Renal Artery Obstruction; Renin-Angiotensin System