Renal stenosis

A 57-year-old woman is admitted to the hospital for CHF. Losartan was started, and 2 days later her renal function began declining rapidly over the ensuing few days. PMH Asthma, AV block, CHF, diabetes, and bilateral renal stenosis. Why are ARBs contraindicated in this patient ... 

A Both ACE inhibitors and ARBs are contraindicated in patients with bilateral renal stenosis. Patients with bilateral renal stenosis have decreased blood flow to the glomerulus. When given ACE inhibitors or ARBs, the effects of angiotensin II are reduced, which leads to vasodilatation of the efferent arterioles. This will result in a decrease in pressure and glomerular filtration rate and a worsening of the renal function. 

The mortality rate at 24 months was 86% however, none of these deaths were complications from aneurysms. The majority of the endoleaks found in follow-ups were type II. There was one example of a type III endoleak resulting from the fenestration. However, this fenestration had not been stented due to renal stenosis and a resulting inability to catheterize. The four incidences of renal artery occlusion found in follow-ups did not result in a need for hemodialysis. Overall there was a decrease in renal artery performance in 10% of patients (Ricco, 2010 Amiot 2010). 

Despite their clear benefits, ACE inhibitors are still underutilized in HF. One reason is undue concern or confusion regarding absolute versus relative contraindications for their use. Absolute contraindications include a history of angioedema, bilateral renal artery stenosis, and pregnancy. Relative contraindications include unilateral renal artery stenosis, renal insufficiency, hypotension, hyperkalemia, and cough. Relative contraindications provide a warning that close monitoring is required, but they do not necessarily preclude their use. 

There have been many sporadic reports that lipo-PGEj is effective in fulminant hepatitis, neuralgia associated with herpes zoster, multiple spinal canal stenosis, cerebral infarction, myocardial infarction, chronic renal failure, and bed sores as well as for its registered indications. 

The answer is d. (Hardman, p 7502) The most consistent of the toxicides of ACT inhibitors is impairment of renal function, as evidenced by proteinuria. Elevations of blood urea nitrogen (BUN) and creatinine occur frequently, especially when stenosis of the renal artery or severe heart failure exists Hyperkalemia also may occur These drugs are to be used very cautiously where prior renal failure is present and in the elderly Other toxicides include persistent dry cough, neutropenia, and angioedema. Hepatic toxicity has not been reported... 

Patients with renal artery stenosis may have an abdominal systolic-diastolic bruit. 

Acute renal failure is a rare but serious side effect of ACE inhibitors preexisting kidney disease increases the risk. Bilateral renal artery stenosis or unilateral stenosis of a solitary functioning kidney renders patients dependent on the vasoconstrictive effect of angiotensin II on efferent arterioles, making these patients particularly susceptible to acute renal failure. 

ACE inhibitors, ARBs, and direct renin inhibitors are contraindicated in sexually active girls because of potential teratogenic effect and in those who might have bilateral renal artery stenosis or unilateral stenosis in a solitary kidney. 

Isolated renal hypoperfusion Bilateral renal artery stenosis (unilateral renal artery stenosis in solitary kidney) Emboli Cholesterol Thrombotic Medications Cyclosporine Angiotensin-converting enzyme inhibitors Nonsteroidal antiinflammatory drugs Radiocontrast media... 

Undesired effects. The magnitude of the antihypertensive effect of ACE inhibitors depends on the functional state of the RAA system. When the latter has been activated by loss of electrolytes and water (resulting from treatment with diuretic drugs), cardiac failure, or renal arterial stenosis, administration of ACE inhibitors may initially cause an excessive fall in blood pressure. In renal arterial stenosis, the RAA system may be needed for maintaining renal function and ACE inhibitors may precipitate renal failure. Dry cough is a fairly frequent side effect, possibly caused by reduced inactivation of kinins in the bronchial mucosa. Rarely, disturbances of taste sensation, exanthema, neutropenia, proteinuria, and angioneurotic edema may occur. In most cases, ACE inhibitors are well tolerated and effective. Newer analogues include lisinopril, perindo-pril, ramipril, quinapril, fosinopril, benazepril, cilazapril, and trandolapril. 

Renal function impairment Some hypertensive patients with renal disease, particularly those with severe renal artery stenosis, have developed increases in BUN and serum creatinine after reduction of BP. 

The main side effects of ACE-inhibitors are cough, hypotension and angioneurotic edema, hypokalemia. Contraindications are stenosis of the renal arteries, kidney transplantation and pregnancy. 

Left ventricular dysfunction Post-myocardial infarction Non-diabetic nephropathy Type 1 diabetic nephropathy Type 2 diabetes mellitus Proteinuria Hyperkalaemia Bilateral renal artery stenosis disease... 

ARBs Type 2 diabetic nephropathy Type 2 diabetic microalbuminuria Proteinuria Left ventricular hypertrophy ACE-I cough or intolerance Pregnancy Hyperkalaemia Bilateral renal artery stenosis ... 

Unlabeled Uses Diagnosis of anatomic renal artery stenosis, hypertensive crisis, rheumatoid arthritis... 

Unlabeled Uses Diabetic nephropathy, hypertension due to scleroderma renal crisis, hypertensive crisis, idiopathic edema, renal artery stenosis, rheumatoid arthritis, post Ml for prevention of ventricular failure... 

Contraindications Bilateral renal artery stenosis, hyperaldosteronism... 

Contraindications Bilateral renal artery stenosis, biliary cirrhosis or obstruction, primary hyperaldosteronism, severe hepatic insufficiency... 

Contraindications Bilateral renal artery stenosis, history of angioedema from previous treafmenf wifh ACE inhibitors... 

A reduction of renin-angiotensin-aldosterone activity is therapeutically beneficial in patients with hypertension, heart failure or renal artery stenosis. 

Severe hypotension can occur after initial doses of any ACE inhibitor in patients who are hypovolemic as a result of diuretics, salt restriction, or gastrointestinal fluid loss. Other adverse effects common to all ACE inhibitors include acute renal failure (particularly in patients with bilateral renal artery stenosis or stenosis of the renal artery of a solitary kidney), hyperkalemia, dry cough sometimes accompanied by wheezing, and angioedema. Hyperkalemia is more likely to occur in patients with renal insufficiency or diabetes. Bradykinin and substance P seem to be responsible for the cough and angioedema seen with ACE inhibition. 

Enalapril may cause anemia. It has been used successfully in low doses for posttransplant polycythemia. ACE inhibitors may precipitate renal failure in patients with renal transplant artery stenosis. A rapid rise in serum creatinine after initiation of ACE inhibitor therapy may indicate renal transplant artery stenosis. 

A 64-year-old man with type II diabetes, hypertension, and bilateral renal artery stenosis presented with confusion and dysarthria related to profound hypoglycemia (2.2 mmol/1). He was taking naproxen 500 mg bd, ramipril 2.5 mg/day, glibenclamide 2.5 mg bd, metformin 850 mg bd, a thiazide diuretic, terazosin, ranitidine, paracetamol, and codeine. His plasma creatinine concentration, previously 185 pmol/1, was 362 pmol/1 and it fell to 210 imol/l after the withdrawal of ramipril and naproxen. 

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