Renal artery stenosis diagnostic criteria: Difference between revisions
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CT angiography | CT angiography | ||
* contraindicated in patients with contrast allergy as the this procedure modality involves the ionizing radiations and iodinated contrast medium. | *contraindicated in patients with contrast allergy as the this procedure modality involves the ionizing radiations and iodinated contrast medium. | ||
* In patients having underlying renal impairment the use of iodinated contrast can lead to the development of contrast induced nephropathy, but it can be prevented with the use of hydration before doing the procedure. | *In patients having underlying renal impairment the use of iodinated contrast can lead to the development of contrast induced nephropathy, but it can be prevented with the use of hydration before doing the procedure. | ||
* The sensitivity of this procedure is extremely high with 94% and specificity varies between 60% to 90 %. | *The sensitivity of this procedure is extremely high with 94% and specificity varies between 60% to 90 %. | ||
*CTA can give the detailed resolution of even small accessory renal arteries. | |||
*It is also the diagnostic modality of choice in patients having limited capacity to hold breath and also in patients having claustrophobia. But at the same time CTA is having limited diagnostic modality as compared to MRA in detecting clinically significant Renal artery stenosis and also in patients having renal dysfunction | |||
===Magnetic Resonance Angiography=== | ===Magnetic Resonance Angiography=== | ||
Revision as of 01:23, 10 December 2020
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Renal artery stenosis Microchapters |
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Renal artery stenosis diagnostic criteria On the Web |
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American Roentgen Ray Society Images of Renal artery stenosis diagnostic criteria |
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Risk calculators and risk factors for Renal artery stenosis diagnostic criteria |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Shivam Singla, M.D.[2]
Overview
Several clinical clues aid in the suspicion of ARAS and warrant further investigation. To date, imaging is considered the optimal modality to diagnose ARAS. According to the ACC/AHA guidelines in 2013, Doppler ultrasonography, CT angiography, and MR angiography are all non-invasive techniques to diagnose ARAS. Renal angiography remains the gold standard for diagnosis of ARAS. Nonetheless, it is an invasive procedure that should be reserved to patients who are planning to perform a catheterization procedure and concede to renal angiography or to patients whose non-invasive imaging was equivocal.
Diagnosis
There are numerous tests and procedures involved in the detection of renal artery stenosis. Renal artery stenosis is best diagnosed with MRA(Magnetic resonance Imaging), Doppler ultrasound, Computed tomography, renal scintigraphy, peripheral renin levels, and renal vein sampling. Though these all modalities are used for making the diagnosis but still renal vein sampling, renal scintigraphy are not the first choice for making the diagnosis of renal artery stenosis because of their low sensitivity and specificity which is around 38-40.
The imaging modalities may be considered diagnostic if the following objectives are met:
(1) Anatomic and or Hemodynamic abnormality
(2) Anatomic consequences and complications associated with renal artery stenosis (Post stenotic dilatation of renal artery can be seen with the use of CTA and MRA, shrinkage of renal parenchyma, with kidneys being < 8 cm.
(3) Functional and cellular consequences of renal artery stenosis
(4) Renal impairment criteria related to renovascular disease should be met
Ultrasonography
Ultrasonography is readily available, secure, and inexpensive and consequently is usually the first imaging study used to detect Renal artery stenosis. Usually the results and accuracy is operator dependent and ranges in between 60-90%. This modality helps in the assessment of
- Renal functional reserve
- Renal resistive index.
A renal artery EDV >90cm/s and RRI< 75-80 represents no microvascular disease. The hemodynamic significant abnormality is concluded with the presence of spectral broadening and increased velocity on USG.
Reno aortic velocity ratio > 3.5 corresponds with 60% stenosis and RAPSV (Renal artery peak systolic velocity) greater than 150cm/s corresponds to 50% stenosis where as velocity greater than 180cm/s corresponds to 60% stenosis. According to the recent studies the sensitivity and specificity of ultrasound guided detection of renal artery stenosis is usually 85% and 92% respectively. Severe stenosis is diagnosed on USG with slowed systolic accelerations along with the decreased resistive index.
Quantitative criteria for diagnosing distal stenosis includes early peak systolic acceleration <3m/s2, an acceleration index > 4m/s2, and or greater than 5% difference in RRI between both the kidneys. Because of these waveform are difficult to interpret these criteria's are difficult to interpret.
Computed Tomographic Angiography
The three dimensional assessment of the tissue made the CT scanning as one of the important tool in the diagnosis of Renal artery stenosis.
CT angiography
- contraindicated in patients with contrast allergy as the this procedure modality involves the ionizing radiations and iodinated contrast medium.
- In patients having underlying renal impairment the use of iodinated contrast can lead to the development of contrast induced nephropathy, but it can be prevented with the use of hydration before doing the procedure.
- The sensitivity of this procedure is extremely high with 94% and specificity varies between 60% to 90 %.
- CTA can give the detailed resolution of even small accessory renal arteries.
- It is also the diagnostic modality of choice in patients having limited capacity to hold breath and also in patients having claustrophobia. But at the same time CTA is having limited diagnostic modality as compared to MRA in detecting clinically significant Renal artery stenosis and also in patients having renal dysfunction
Magnetic Resonance Angiography
Magnetic resonance angiography has a reported sensitivity and specificity of 90% to 100%55,56 and does not require use of iodinated contrast or radiation. Gadolinium-based contrast medium should be avoided in patients with moderate to end-stage renal failure because of the risk of nephrogenic systemic fibrosis. Additionally, MRA should not be used in patients with certain implanted devices (ie, pacemakers, defibrillators, cochlear implants, and spinal cord stimulators) or in claustrophobic patients. Unlike CTA, MRA has no calcification artifact, neither iodinated contrast medium nor radiation is used, and contrast reaction rates are lower.1
Angiography
Invasive renal arteriography is helpful in evaluating ARAS. In addition to assessing the severity of ARAS, angiography can detect intrarenal vascular abnormalities and anatomic abnormalities of the kidneys, renal arteries, and aorta. Digital subtraction angiography improves contrast resolution and may decrease the volume of contrast needed to as little as 15 mL. However, because renal angiography is invasive, there are risks associated with arterial puncture and manipulation of the catheter/wire, which can result in arterial trauma, spasm, or thromboembolic phenomenon.58 In patients with renal impairment or contrast allergy, carbon dioxide can be used as a non nephrotoxic contrast agent.
The early work by White et al59 established that there is substantial intra- and interobserver variability in the visual estimation of coronary stenosis, which likely also applies to the visual estimation of ARAS. Therefore, relying solely on angiography to visually estimate the severity of ARAS is suboptimal, and adjunctive tools should be used to determine whether renal ischemia is present.
Translesional pressure gradients can be measured across areas of stenosis to determine hemodynamic significance (if there is doubt) before performing therapeutic procedures such as percutaneous transluminal renal angioplasty (PTRA) or stenting. In a small case series, Mangiacapra et al60 measured translesional pressure gradients using papaverine and dopamine to induce renal hyperemia in 53 consecutive patients before PTRA. They found that patients with the most substantial improvement in hypertension were those with a translesional gradient greater than 20 mm Hg (corresponding to a distal-proximal pressure ratio of 0.79 as the optimal cutoff). De Bruyne et al61 demonstrated that stenosis with a distal to proximal renal artery pressure decrease greater than 10% were associated with increased renin production, suggesting that measurement of translesional pressure gradients might help identify hemodynamically significant ARAS.
Diagnosis
Indications for Work-Up
According to the 2013 ACC/AHA Guidelines for the Management of PAD[1], diagnostic work-up for renal artery stenosis is indicated in the following conditions:
Class I Recommendations[1]
- Hypertension of any stage before the age of 30
- Stage II hypertension (severe hypertension systolic blood pressure > 180 mm Hg or diastolic blood pressure > 120 mm Hg) in patients older than 55 years. If only mild hypertension is present, then renal artery stenosis is the underlying cause in only 1% of patients [2], but if the blood pressure is markedly elevated, then the risk of renal artery stenosis goes up 10 to 50 fold.
- Accelerated condition of previously controlled hypertension
- Resistant hypertension
- Malignant hypertension
- New azotemia (50% rise in creatinine that is sustained) within one week after administration of an Angiotensin Converting Enzyme (ACE)inhibitor or ARB
- Unexplained atrophic kidney or asymmetric kidneys that differ by > 1.5 cm. If the kidney is < 9 cm in size, there is a 75% chance that renal artery stenosis is present.
- Severe hypertension, impaired renal function, and recurrent flash pulmonary edema
Class IIa Recommendations[1]
- Unexplained renal failure including patients starting renal replacement therapy
Class IIb Recommendations[1]
- Presence of multi vessel CAD and no clinical clues of ARAS or PAD
- Unexplained CHF or refractory angina
Other Indications
- Severe hypertension in the presence of polyvascular disease (coronary artery disease or peripheral arterial disease)
- A unilateral systolic-diastolic abdominal bruit. Although a bruit is infrequent in documented renal artery stenosis (the sensitivity is only 40% percent) if it is auscultated, it is associated with a very high specificity of 99%.[3]
- The association of race with renal artery stenosis is not clear. Reports that it is observed more often in white patients may be due to reporting bias.[4]
Diagnostic Methods[1]
The best technique to diagnose atherosclerotic renal artery stenosis (ARAS) is by imaging. Assessment of both the main and the accessory renal arteries bilaterally is important for diagnostic purposes. Further evaluation should include the anatomic location of the stenosis, severity of stenosis, associated perirenal and perivascular pathologies, such as aneurysms or masses.[1] Duplex ultrasonography, computer tomographic angiography (CTA), magnetic resonance angiography (MRA), and catheter angiography are 4 techniques that are currently recommended for the diagnosis of ARAS.[1] In contrast, neither selective renal vein renin studies, captopril renal scintigraphy, plasma renin activity nor the captopril test are recommended anymore.[1]
Duplex Ultrasonography
Diagnosis by Duplex ultrasonography is considered class I recommendation. It may be used as an initial screening tool for diagnosis of ARAS. Ultrasonography might not be very accurate in obese patients or those with intestinal gas.[1]
Computed Tomographic Angiography
Diagnosis by CT angiography is considered class I recommendation. It provides higher spacial resolution compared to magnetic resonanc angiography (MRA). CT angiography may be used in patients with normal renal function to avoid contrast-induced nephropathy in patients with impaired renal function. Presence of previous stents or metallic objects are considered a contraindication for the use of CTA.[1]
Magnetic Resonance Angiography
Diagnosis by MRA is considered class I recommendation. Gadolinium-based MRA has less nephrotoxic characterstics with good visualization of the renal arteries and perirenal pathologies. Presence of previous stents or metallic objects are considered a contraindication for the use of MRA.[1]
Catheter Angiography
Catheter angiography is considered class I recommendation. It is the gold standard for the diagnosis of ARAS. Renal angiography may be used only if previous tests are equivocal and clinical suspicion is high or if the patient is already undergoing another catheterization process and consents to renal angiography. Generally, it is associated with a low frequency of adverse events.[1]
Management of Patients With Peripheral Artery Disease (Compilation of 2005 and 2011 ACCF/AHA Guideline Recommendations) : A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines[5]
Clinical Clues to the Diagnosis of RAS (DO NOT EDIT)[1]
| Class I |
| "1.Onset of hypertension before the age of 30 years or severe hypertension after the age of 55. (Level of Evidence: B)" |
| "2.Accelerated, resistant, or malignant hypertension. (Level of Evidence: C)" |
| "3.Development of new azotemia or worsening renal function after administration of an ACE inhibitor or ARB agent . (Level of Evidence: B)" |
| "4.Unexplained atrophic kidney or size discrepancy between kidneys of greater than 1.5 cm. (Level of Evidence: B)" |
| "5.Sudden, unexplained pulmonary edema. (Level of Evidence: B)" |
| Class IIa |
| "1.Unexplained renal dysfunction, including individuals starting renal replacement therapy. (Level of Evidence: B)" |
| Class IIb |
| "1.Multi-vessel coronary artery disease. (Level of Evidence: B)" |
| "2.Unexplained congestive heart failure. (Level of Evidence: C)" |
| "3.Refractory angina. (Level of Evidence: C)" |
Diagnostic Methods (DO NOT EDIT)[1]
| Class I |
| "1. Duplex ultrasonography is recommended as a screening test to establish the diagnosis of RAS. (Level of Evidence: B)" |
| "2. Computed tomographic angiography (in individuals with normal renal function) is recommended as a screening test to establish the diagnosis of RAS. (Level of Evidence: B)" |
| "3. Magnetic resonance angiography is recommended as a screening test to establish the diagnosis of RAS. (Level of Evidence: B)" |
| "4. When the clinical index of suspicion is high and the results of noninvasive tests are inconclusive, catheter angiography is recommended as a diagnostic test to establish the diagnosis of RAS. (Level of Evidence: B)" |
| Class III |
| "1. Captopril renal scintigraphy is not recommended as a screening test to establish the diagnosis of RAS. (Level of Evidence: C)" |
| "2. Selective renal vein renin measurements are not recommended as a useful screening test to establish the diagnosis of RAS. (Level of Evidence: B)" |
| "3. Plasma renin activity is not recommended as a useful screening test to establish the diagnosis of RAS. (Level of Evidence: B)" |
| "4. The captopril test (measurement of plasma renin activity after captopril administration) is not recommended as a useful screening test to establish the diagnosis of RAS. (Level of Evidence: B)" |
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 Anderson JL, Halperin JL, Albert NM, Bozkurt B, Brindis RG, Curtis LH; et al. (2013). "Management of patients with peripheral artery disease (compilation of 2005 and 2011 ACCF/AHA guideline recommendations): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines". Circulation. 127 (13): 1425–43. doi:10.1161/CIR.0b013e31828b82aa. PMID 23457117.
- ↑ Lewin A, Blaufox MD, Castle H, Entwisle G, Langford H (1985). "Apparent prevalence of curable hypertension in the Hypertension Detection and Follow-up Program". Arch Intern Med. 145 (3): 424–7. PMID 3872106.
- ↑ Turnbull JM (1995). "The rational clinical examination. Is listening for abdominal bruits useful in the evaluation of hypertension?". JAMA. 274 (16): 1299–301. PMID 7563536.
- ↑ Svetkey LP, Kadir S, Dunnick NR, Smith SR, Dunham CB, Lambert M; et al. (1991). "Similar prevalence of renovascular hypertension in selected blacks and whites". Hypertension. 17 (5): 678–83. PMID 2022411.
- ↑ Rooke TW, Hirsch AT, Misra S, Sidawy AN, Beckman JA, Findeiss L; et al. (2013). "Management of patients with peripheral artery disease (compilation of 2005 and 2011 ACCF/AHA Guideline Recommendations): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines". J Am Coll Cardiol. 61 (14): 1555–70. doi:10.1016/j.jacc.2013.01.004. PMC 4492473. PMID 23473760.