Renal artery stenosis

Renal artery stenosis
Other names: Renovascular hypertension, renal hypertension[1]
Diagram of renal artery stenosis
SpecialtyNephrology
SymptomsDifficult to treat high blood pressure[2]
ComplicationsChronic kidney disease, stroke, coronary artery disease[3]
CausesAtherosclerosis, fibromuscular dysplasia[3]
Risk factorsHigh cholesterol, smoking, diabetes, high blood pressure, obesity, inactivity, family history[3]
Diagnostic methodMedical imaging[3]
Differential diagnosisMalignant hypertension, chronic glomerulonephritis, nephrosclerosis[2]
TreatmentLifestyle changes, medications, and surgery.[3]
MedicationACE inhibitors[3]
Frequency1 to 10% of people with high blood pressure[2]

Renal artery stenosis (RAS) is the narrowing of one or both of the arteries to the kidneys.[3] Early on there are typically no symptoms, while later high blood pressure or kidney problems may occur.[3] The blood pressure may be difficult to treat.[2] Complications may include chronic kidney disease, stroke, and coronary artery disease.[3]

About 90% of cases are due to atherosclerosis.[3] Other causes include fibromuscular dysplasia, vasculitis, AAA, and arterial dissection.[3][2] Risk factors for atherosclerosis include high cholesterol, smoking, diabetes, high blood pressure, obesity, inactivity, and family history.[3] Diagnosis is generally by ultrasound or CT scan.[2]

Treatment may include lifestyle changes, medications, and surgery.[3] Medications used may include ACE inhibitors.[3] Often multiple blood pressure medications; however, are required.[3] If this is not sufficient angioplasty or endarterectomy may be performed.[3]

Of the 50 million cases of high blood pressure in the United States about 0.5 to 5 million are due to RAS.[2] RAS due to atherosclerosis generally occurs in males older than 45 and females older than 55 while fibromuscular dysplasia is most common in women 25 to 50 years old.[3] The condition was first described in 1777 by Respinger.[4]

Signs and symptoms

Most cases of renal artery stenosis result in no symptoms, and the main problem is high blood pressure that cannot be controlled with medication.[5] Decreased kidney function may develop if both kidneys do not receive adequate blood flow, furthermore some people with renal artery stenosis present with episodes of flash pulmonary edema.[6]

Cause

Renal artery stenosis is most often caused by atherosclerosis which causes the renal arteries to harden and narrow due to the build-up of plaque. This is known as atherosclerotic renovascular disease. This accounts for about 90% of cases with most of the rest due to fibromuscular dysplasia.[7] Fibromuscular dysplasia is the predominant cause in young people, usually females under 40 years of age.[8]

Pathophysiology

The pathophysiology of renal artery stenosis leads to changes in the structure of the kidney that are most noticeable in the tubular tissue.[9] If the stenosis is longstanding and severe, the glomerular filtration rate in the affected kidneys never recovers and (prerenal) kidney failure is the result.

Changes include:[9]

Diagnosis

The diagnosis of renal artery stenosis can use many techniques to determine if the condition is present, a clinical prediction rule is available to guide diagnosis.[10]

Among the diagnostic techniques are:

The specific criteria for renal artery stenosis on Doppler are an acceleration time of greater than 70 milliseconds, an acceleration index of less than 300 cm/sec² and a velocity ratio of the renal artery to aorta of greater than 3.5.[17]

  • Bilateral renal artery stenosis asterisk (Absent infra-renal aorta arrow)
    Bilateral renal artery stenosis asterisk (Absent infra-renal aorta arrow)
  • Assessment of kidneys with artery stenosis taken by magnetic resonance angiography
  • Images a,b,c,d,e) (Malignant) renovascular hypertension caused by a renal artery CG (Chimney graft) occlusion
    Images a,b,c,d,e) (Malignant) renovascular hypertension caused by a renal artery CG (Chimney graft) occlusion
  • Pulmonary edema
    Pulmonary edema

Treatment

The diuretic, hydrochlorothiazide

Atherosclerosis

It is initially treated with medications, including diuretics, and medications for blood pressure control.[9] When high-grade renal artery stenosis is documented and blood pressure cannot be controlled with medication, or if kidney function deteriorates, surgery may be recommended. The most commonly used procedure is a minimally-invasive angioplasty with or without stenting. It is unclear if this approach yields better results than the use of medications alone.[18] It is a relatively safe procedure.[18] If all else fails and the kidney is thought to be worsening hypertension and revascularization with angioplasty or surgery does not work, then surgical removal of the affected kidney (nephrectomy) may improve blood pressure.[19]

Fibromuscular dysplasia

Angioplasty with or without stenting is the best option for the treatment of renal artery stenosis due to fibromuscular dysplasia.[20]

Prognosis

The prognosis of individuals with renovascular hypertension is not easy to determine. Those with atherosclerotic renal artery disease have a high risk of mortality, furthermore, those who also have renal dysfunction have a higher mortality risk. However, the majority of renovascular diseases can be improved with surgery.[21]

References

  1. ↑ "Renovascular Hypertension". www.pennmedicine.org. Archived from the original on 17 August 2022. Retrieved 21 June 2023.
  2. 1 2 3 4 5 6 7 Bokhari, MR; Bokhari, SRA (January 2020). "Renal Artery Stenosis". PMID 28613469. {{cite journal}}: Cite journal requires |journal= (help)
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 "Renal Artery Stenosis | NIDDK". National Institute of Diabetes and Digestive and Kidney Diseases. 2014. Archived from the original on 29 August 2021. Retrieved 23 January 2021.
  4. ↑ Diehm, C.; Allenberg, J.-R.; Nimura-Eckert, K.; Veith, F. J. (2013). Color Atlas of Vascular Diseases. Springer Science & Business Media. p. 111. ISBN 978-3-662-06287-6. Archived from the original on 2021-08-29. Retrieved 2021-01-23.
  5. ↑ "Renovascular hypertension: MedlinePlus Medical Encyclopedia". www.nlm.nih.gov. Archived from the original on 2016-07-05. Retrieved 2015-08-17.
  6. ↑ Messerli, Franz H.; Bangalore, Sripal; Makani, Harikrishna; Rimoldi, Stefano F.; Allemann, Yves; White, Christopher J.; Textor, Stephen; Sleight, Peter (2011-03-15). "Flash pulmonary oedema and bilateral renal artery stenosis: the Pickering Syndrome". European Heart Journal. 32 (18): 2231–5. doi:10.1093/eurheartj/ehr056. ISSN 0195-668X. PMID 21406441. Archived from the original on 2019-01-09. Retrieved 2015-08-17.
  7. ↑ "RenalArtery Stenosis" (PDF). NIH. National Institute of Health. Archived from the original (PDF) on 27 December 2016. Retrieved 1 August 2016.
  8. ↑ "Fibromuscular Dysplasia: Practice Essentials, Background, Pathophysiology". 2018-09-19. Archived from the original on 2018-12-20. Retrieved 2015-08-17. {{cite journal}}: Cite journal requires |journal= (help)
  9. 1 2 3 "Renal Artery Stenosis: Background, Pathophysiology, Etiology". 2018-12-14. Archived from the original on 2020-05-05. Retrieved 2015-08-17. {{cite journal}}: Cite journal requires |journal= (help)
  10. ↑ Steyerberg, Ewout (2008-12-16). Clinical Prediction Models: A Practical Approach to Development, Validation, and Updating. Springer Science & Business Media. ISBN 9780387772448. Archived from the original on 2020-05-22. Retrieved 2019-01-08.
  11. ↑ Granata, A.; Fiorini, F.; Andrulli, S.; Logias, F.; Gallieni, M.; Romano, G.; Sicurezza, E.; Fiore, C.E. (2009-10-12). "Doppler ultrasound and renal artery stenosis: An overview". Journal of Ultrasound. 12 (4): 133–143. doi:10.1016/j.jus.2009.09.006. ISSN 1971-3495. PMC 3567456. PMID 23397022.
  12. ↑ Protasiewicz, Marcin; Kądziela, Jacek; Początek, Karol; Poręba, Rafał; Podgórski, Maciej; Derkacz, Arkadiusz; Prejbisz, Aleksander; Mysiak, Andrzej; Januszewicz, Andrzej (2013-11-01). "Renal artery stenosis in patients with resistant hypertension". The American Journal of Cardiology. 112 (9): 1417–1420. doi:10.1016/j.amjcard.2013.06.030. ISSN 1879-1913. PMID 24135303. – via ScienceDirect (Subscription may be required or content may be available in libraries.)
  13. ↑ Talley, Nicholas Joseph; O'Connor, Simon (2013-09-20). Clinical Examination: A Systematic Guide to Physical Diagnosis. Elsevier Health Sciences. ISBN 9780729541473. Archived from the original on 2020-05-22. Retrieved 2019-01-08.
  14. ↑ Ong, Yong Yau (2005-01-01). A Clinical Approach to Medicine. World Scientific. ISBN 9789812560735. Archived from the original on 2021-08-29. Retrieved 2019-01-08.
  15. ↑ Sam, Amir H.; James T.H. Teo (2010). Rapid Medicine. Wiley-Blackwell. ISBN 978-1405183239.
  16. ↑ Attenberger, Ulrike I.; Morelli, John N.; Schoenberg, Stefan O.; Michaely, Henrik J. (2011-11-15). "Assessment of the kidneys: magnetic resonance angiography, perfusion and diffusion". Journal of Cardiovascular Magnetic Resonance. 13 (1): 70. doi:10.1186/1532-429X-13-70. ISSN 1532-429X. PMC 3228749. PMID 22085467.
  17. ↑ Granata, A.; Fiorini, F.; Andrulli, S.; Logias, F.; Gallieni, M.; Romano, G.; Sicurezza, E.; Fiore, C. E. (1 December 2009). "Doppler ultrasound and renal artery stenosis: An overview". Journal of Ultrasound. 12 (4): 133–143. doi:10.1016/j.jus.2009.09.006. ISSN 1971-3495. PMC 3567456. PMID 23397022.
  18. 1 2 Jenks, S; Yeoh, SE; Conway, BR (5 December 2014). "Balloon angioplasty, with and without stenting, versus medical therapy for hypertensive patients with renal artery stenosis". The Cochrane Database of Systematic Reviews. 12 (12): CD002944. doi:10.1002/14651858.CD002944.pub2. PMC 7138037. PMID 25478936.
  19. ↑ Fine, Richard N.; Webber, Steven A.; Harmon, William E.; Kelly, Deirdre; Olthoff, Kim M. (2009-04-08). Pediatric Solid Organ Transplantation. John Wiley & Sons. ISBN 9781444312737. Archived from the original on 2020-05-22. Retrieved 2019-01-08.
  20. ↑ Chrysant, Steven G.; Chrysant, George S. (2014-02-21). "Treatment of hypertension in patients with renal artery stenosis due to fibromuscular dysplasia of the renal arteries". Cardiovascular Diagnosis and Therapy. 4 (1): 36–43. doi:10.3978/j.issn.2223-3652.2014.02.01. PMC 3943779. PMID 24649423.
  21. ↑ Renovascular Hypertension at eMedicine

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