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Renal artery stenosis
Classification and external resources

Renal artery is #3
ICD-9 440.1
DiseasesDB 11255
MedlinePlus 001273
eMedicine med/2001
MeSH D012078

Renal artery stenosis is the narrowing of the renal artery, most often caused by atherosclerosis or fibromuscular dysplasia. This narrowing of the renal artery can impede blood flow to the target kidney. Hypertension and atrophy of the affected kidney may result from renal artery stenosis, ultimately leading to renal failure if not treated.

Contents

Signs and symptoms

Most cases of renal artery stenosis are asymptomatic, and the main problem is high blood pressure that cannot be controlled with medication. Deterioration in renal function may develop if both kidneys are poorly supplied, or when treatment with an ACE inhibitor is initiated. Some patients present with episodes of flash pulmonary edema (sudden left ventricular heart failure).[1]

Diagnosis

A clinical prediction rule is available to guide diagnosis.[3]

Etiology

Atherosclerosis is the predominant cause of renal artery stenosis in the majority of patients, usually those with a sudden onset of hypertension at age 50 or older. Fibromuscular dysplasia is the predominant cause in young patients, usually females under 40 years of age. A variety of other causes exist. These include arteritis, renal artery aneurysm, extrinsic compression (e.g., neoplasms), neurofibromatosis, and fibrous bands.

Pathophysiology

The macula densa of the kidney senses a decreased systemic blood pressure owing to the reduced blood flow through the narrowed artery. The response of the kidney to this perceived decreased blood pressure is activation of the renin-angiotension aldosterone system, which normally counteracts low blood pressure but in this case leads to hypertension (high arterial blood pressure). The decreased perfusion pressure (caused by the stenosis) leads to decreased blood flow (hypoperfusion) to the kidney and a decrease in the GFR. If the stenosis is longstanding and severe the GFR in the affected kidneys never increases again and (prerenal) renal failure is the result.

Treatment

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Atherosclerotic renal artery stenosis

It is initially treated with medications. These include statins, antiplatelet agents and drugs for control of blood pressure. When high-grade renal artery stenosis is documented and blood pressure cannot be controlled with medication, or if renal function deteriorates, invasive procedure may be resorted to. The most commonly used invasive procedure is angioplasty with or without stenting. A 2003 meta-analysis found that angioplasty was safe and effective in this context.[4] There are ongoing clinical trials to compare medical management and angioplasty with stenting to medical management alone. These include CORAL and ASTRAL, both scheduled to report results in 2010. In addition to angioplasty, surgical resection and anastomosis are a rarely used option.

Fibromuscular dysplasia

Angioplasty with or without stenting is the best option for the treatment of renal artery stenosis due to fibromuscular dysplasia.

See also

References

  1. ^ Pickering TG, Herman L, Devereux RB, et al. (1988). "Recurrent pulmonary oedema in hypertension due to bilateral renal artery stenosis: treatment by angioplasty or surgical revascularisation". Lancet 2 (8610): 551–2. doi:10.1016/S0140-6736(88)92668-2. PMID 2900930.  
  2. ^ Roccatello D, Picciotto G (1997). "Captopril-enhanced scintigraphy using the method of the expected renogram: improved detection of patients with renin-dependent hypertension due to functionally significant renal artery stenosis" (PDF). Nephrol. Dial. Transplant. 12 (10): 2081–6. doi:10.1093/ndt/12.10.2081. PMID 9351069. http://ndt.oxfordjournals.org/cgi/reprint/12/10/2081.pdf.  
  3. ^ Krijnen P, van Jaarsveld BC, Steyerberg EW, Man in 't Veld AJ, Schalekamp MA, Habbema JD (1998). "A clinical prediction rule for renal artery stenosis". Ann. Intern. Med. 129 (9): 705–11. PMID 9841602.  
  4. ^ Nordmann AJ, Woo K, Parkes R, Logan AG (2003). "Balloon angioplasty or medical therapy for hypertensive patients with atherosclerotic renal artery stenosis? A meta-analysis of randomized controlled trials". Am. J. Med. 114 (1): 44–50. doi:10.1016/S0002-9343(02)01396-7. PMID 12557864.  

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