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Saudi Journal of Kidney Diseases and Transplantation
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Year : 2014  |  Volume : 25  |  Issue : 1  |  Page : 96-100
Renovascular hypertension: A report of 21 cases


1 Service of Internal Medicine, Tunisian Military Hospital, Tunis, Tunisia
2 Service M8, Charles Nicol Hospital, Tunis, Tunisia

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Date of Web Publication7-Jan-2014
 

   Abstract 

Renovascular hypertension (RVH) is among the most common forms of secondary hypertension. We studied 21 patients (eight male and 13 female) with RVH who were encountered during a period of 16 years. The average age of the patients was 34.75 years. Trans-renal Doppler ultrasound confirmed the diagnosis of renovascular stenosis (RAS) as the cause of RVH in 95% of the patients. Computed tomography angiography was performed in ten cases, which confirmed the diagnosis in all these cases. Magnetic resonance angiography was performed in only three patients. Renal scintigraphy was performed in 11 patients, with DTPA in nine patients and with MAG3 in two cases. Arteriography was performed in 15 cases for therapeutic end points. In two patients, we treated the arteries of both kidneys and in 19 cases we treated only one kidney artery. Percutaneous transluminal angioplasty was performed in ten cases. Renal arterial stent placement was performed in three cases in which RAS was from an atherosclerosis etiology. Surgical revascularization was performed in four cases. Nephrectomy was necessary in four cases. After interventional treatment, medical treatment using antihypertensive drugs was necessary in 17 of the patients. After treatment, three patients returned to normal kidney function, while worsening of glomerular filtration rate was noted in four patients. Some complications such as a kidney infarct after treatment, a nephrectomy, artery thrombosis, an ischemic stroke and recurrent RAS were also noted.

How to cite this article:
Labidi J, Touat D, Abdelghanim K, Ajili F, Ariba YB, Abdelhafidh NB, Louzir B, Othmani S. Renovascular hypertension: A report of 21 cases. Saudi J Kidney Dis Transpl 2014;25:96-100

How to cite this URL:
Labidi J, Touat D, Abdelghanim K, Ajili F, Ariba YB, Abdelhafidh NB, Louzir B, Othmani S. Renovascular hypertension: A report of 21 cases. Saudi J Kidney Dis Transpl [serial online] 2014 [cited 2020 Oct 30];25:96-100. Available from: https://www.sjkdt.org/text.asp?2014/25/1/96/124501

   Introduction Top


Only 5-10% of hypertension cases are due to definable causes. Renovascular hypertension (RVH) is among the most common forms of secondary hypertension. RVH is defined as an elevated blood pressure caused by renal hypoperfusion, usually due to anatomic renal artery stenosis (RAS) and activation of the renin- angiotensin system. [1] Its prevalence is estimated to range from 1-5% of all hypertensive patients in the general population, and can reach up to 30% in a highly selected population.

RVH may be caused by a heterogeneous group of conditions, but the most common is the RAS due to fibromuscular dysplasia (FMD) and atherosclerotic renovascular disease. [2]

RAS is a progressive disease leading to hypertension, renal insufficiency and end-stage renal disease. It is also independently associated with a high rate of cardiovascular and neurological events such as unstable angina, congestive heart failure, stroke and death. [2]

The aim of our study is to present our cases of RVH that have been treated in our center during a period of 16 years and their characteristics, including diagnosis and management.


   Patients and Methods Top


We retrospectively studied all cases of RVH encountered in the Military Hospital and Charles Nicolle Hospital, Tunis, Tunisia, during a period of 16 years from January 1995 through December 2011.

RVH was defined as an elevation of blood pressure due to RAS established by morpho­logical investigations and confirmed after treat­ment.

The study group included 21 consecutive hyper­tensive patients aged more than 18 years. The diagnosis of RAS origin was established or confirmed during hospitalization by the diffe­rent radiological investigations and functional correlation with the structural changes. All cases were treated by revascularization or nephrectomy, and the treatment was successful in all of them. The choice of treatment depended on its applicability and the abilities of the medical team.

The exclusion criteria included cases of RVH that were treated only medically and cases that did not respond to interventional invasive treat­ment.


   Results Top


The study included 21 patients aged between 18 and 71 years, with an average of 34.75 years. There were eight males and 13 females.

[Table 1] presents the demographics of the study group.
Table 1: Demographic characteristics.

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The history of evolution of hypertension was less than one year in eight cases, and 15 pa­tients had a family history of hypertension. Twelve patients had a personal history of athe­rosclerosis and 14 patients presented with kid­ney failure. The hypertension was "malignant" in four patients and refractory to treatment in 12 patients. Abdominal systolic-diastolic bruit was noted in seven cases [Table 2].
Table 2: Most clinical and biological abnormalities presented by the cases.

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All the cases of RAS were detected by ultra­sound; we noted an asymmetric kidneys axis length, which is an indirect sign of RAS, in 14 cases. Trans-renal Doppler ultrasound confirmed the diagnosis of RAS in 95% of the patients.

Computed tomography angiography (CTA) was performed in ten cases, which confirmed the diagnosis in all of them. Magnetic resonance angiography (MRA) was performed in only three patients, and RAS was revealed in all of them.

Renal scintigraphy was performed in 11 patients, with DTPA in nine patients and with MAG3 in two cases. We noted an inequality of kidney function of more than 10% between both kid­neys in eight patients, non-functional kidney in the RSA side in 10% of the cases and low glomerular filtration rate (GFR) in both kidneys in 20% of the cases. The Captopril test was per­formed in three cases, and it was positive in all of them. Arteriography was performed in 15 cases mainly for therapeutic purposes.

We treated the arteries of both kidneys in two patients, and one kidney in 19 cases. We treated 15 right and four left kidney arteries.

Percutaneous transluminal angioplasty (PTA) was performed in ten patients; the etiology of the RAS included atherosclerosis lesions in five cases, Takayasu in one case, FMD in two cases and undetermined cause in one case.

Renal arterial stent placement was performed in three cases of RAS of an atherosclerosis etiology. Surgical revascularization was per­formed in four cases; in three cases, surgical treatment was the first indication (in one case, RAS was secondary to FMD and the surgical treatment was an aorto-renal pontage using the internal saphenous vein - the aim was to treat several ostial stenoses; the second case was of atherosclerosis that received the same surgical treatment as the first one and the indication was a severe medio-troncular stenosis; the third case presented with bilateral RAS with a non­functional right kidney, and the patient was treated with right nephrectomy and an aorto- renal pontage using the internal saphenous vein; the fourth case was an atherosclerosis RAS in which the percutaneous transluminal angioplasty was not successful and required a bypass pro­cedure).

Nephrectomy was necessary in four cases, which included a case of an aneurysm with totally thrombosed kidney artery secondary to a MFD type I, a case of RAS in non-functional kidney in two cases and a case of bilateral RAS with a right non-functional kidney.

After interventional treatment, medical treat­ment using antihypertensive drugs was neces­sary in 17 of the patients; seven of them con­tinue to receive three medicines, two patients receive two medicines and nine patients receive one medicine.

After treatment, three patients regained normal kidney function and 13 of them maintained sta­ble kidney function; worsening of GFR was noted in four patients. In total, the mean of GFR was not significantly modified after treatment, and averaged 52 mL/min before treatment ver­sus 51 mL/min after treatment. [Table 3] presents the response to treatment in our cases.
Table 3: The response to treatment of our cases.

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Outcome after PTA: Kidney infarct occurred in a patient with a Takayasu bilateral RAS and resulted in nephrectomy followed by chronic hemodialysis; in another case, renal artery throm­bosis occurred and required an aorto-renal pon­tage with sympathectomy.

Outcome after surgical treatment: We noted in one case an ischemic stroke due to intraauricular thrombus migration.

Recurrence of RAS was noted in three cases who were treated with PTA. The etiology of RAS was Takayasu in one case (15 months later), FMD in another (six months later) and atherosclerosis in a third case (four months later). Hypertension was noted in all these cases, and we succeeded in normalizing hyper­tension in only two (10%) cases despite revascularization in all of them.


   Discussion Top


RVH is the most common etiology of secon­dary hypertension. The RAS seems to be a cu­rable cause of RVH in case of early treatment, otherwise it may result in renal failure.

The degree of RAS can be assessed using quantitative computerized angiography (QCA). The most accurate way to test for RAS is to X-ray the renal arteries after injecting them di­rectly with dye (intraarterial angiography), which is invasive and sometimes dangerous. Although renal arteriography is the gold stan­dard for confirmation of the diagnosis and cause of RAS, there are risks associated with pro­cedure-related complications and contrast media nephropathy. These risks are especially consi­derable in patients with a solitary kidney.

Several other non-invasive, less-dangerous tests can help diagnose RAS by showing the ana­tomy of the arteries, detecting changes in blood flow or measuring kidney function. These include CTA, MRA, ultrasonography (US), captopril renal scans (CRS) and, the simple, captopril test.

The sensitivity and specificity of MRA for the detection of hemodynamically significant ste­nosis of the main renal artery were reported to be around 90%. [3]

However, MRA is less reliable for the diagno­sis of FMD, and duplex US seems more suitable for the assessment of patients with suspected FMD. [4]

US provides anatomic and functional infor­mation in the pre-operative and post-operative assessments for potential intervention, without the risk of radiation, nephrotoxicity or nephrogenic systemic fibrosis. Doppler ultrasound's main limitation is technical failure to visualize the entire length of the main renal arteries. In the future, the use of intravenous ultrasound contrast agents and elastography could reduce the rate of technical failure.

For CRS and the captopril test, patients are given captopril, a drug that affects blood flow to the kidneys. The CRS scans show how well a radioactive substance injected into a vein is picked up in the kidney after the administration of captopril. The simple captopril test uses a blood sample to measure a substance (renin) released by the kidneys when blood flow to the kidney is low. Captopril-induced reduction of glomerular filtration in the renogram provides clear evidence of functionally significant ste­nosis in a renal artery with a sensitivity and specificity in excess of 90%, and is regarded as the most reliable functional diagnosis of RVH. [5]

Dondi et al reported that captopril renography is a strong predictor of the success of blood pressure control by renal artery revascularization in patients with suspected RVH, with a positive predictive value of 97% (32 of 33 cases). [6] Setaro et al also reported that scintigraphic ab­normalities induced by captopril were strongly associated with a cure or improvement in blood pressure control following revascularization or nephrectomy (16 of 19 cases). [7] Captopril renography thus seems to be an effective technique for the identification of RVH, which would benefit from renal artery revascularization.

In our patients, the blood pressure was nor­malized in the short term by PTA, and this result was consistent with expectations based on the captopril-induced scintigraphic changes.

Percutaneous revascularization of RAS involves conventional balloon angioplasty, with or with­out stenting. The procedure is successful in 82- 100% of patients, and stenosis recurs in 10- 11%. Hypertension is more likely to be cured after revascularization in patients with FMD than in those with atherosclerotic RAS, [8] and it is also feasible in patients with a solitary kid­ney, with 91.7% of the patients benefiting from PTA after a mean follow-up of 32.5 months. [9] Furthermore, for patients with both atheroscle­rosis and FMD, those with outcomes classified as treatment failures were older and had under­gone treatment for hypertension for a longer pe­riod than those classified as cured. [10] Our pa­tients were cured of hypertension immediately after PTA because the RAS was due to FMD, the patients were young and diagnosis and in­tervention were comparatively early. Neverthe­less, long-term follow-up is essential in these cases.

 
   References Top

1.Taylor AT Jr, Fletcher JW, Nally JV Jr, et al. Procedure guideline for diagnosis of renovascular hypertension. J Nucl Med 1998;39:1297-302.  Back to cited text no. 1
[PUBMED]    
2.La Batide Alanore A, Perdu J, Plouin PF. Fibro-muscular dysplasia. Presse Med 2007;36:1016-23.  Back to cited text no. 2
[PUBMED]    
3.Leung DA, Hoffmann U, Pfammatter T, et al. Magnetic resonance angiography versus duplex sonography for diagnosing renovascular disease. Hypertension 1999;33:726-31.  Back to cited text no. 3
[PUBMED]    
4.Silverman JM, Friedman ML, Van Allan RJ. Detection of main renal artery stenosis using phase-contrast cine MR angiography. Am J Roentgenol 1996;166:1131-7.  Back to cited text no. 4
    
5.Nally JV, Barton DP. Contemporary approach to diagnosis and evaluation of renovascular hypertension. Urol Clin North Am 2001;28:781-91.  Back to cited text no. 5
[PUBMED]    
6.Dondi M, Fanti S, De Fabritiis A, et al. Prognostic value of captopril renal scintigraphy in renovascular hypertension. J Nucl Med 1992;33:2040-4.  Back to cited text no. 6
[PUBMED]    
7.Setaro JF, Chen CC, Hoffer PB, Black HR. Captopril renography in the diagnosis of renal artery stenosis and the prediction of improvement with revascularization. The Yale Vascular Center experience. Am J Hypertens 1991;4:698-705s.  Back to cited text no. 7
    
8.Safian RD, Textor SC. Renal-artery stenosis. N Engl J Med 2001;344:431-42.  Back to cited text no. 8
[PUBMED]    
9.Dworkin LD, Cooper CJ. Clinical practice. Renal-artery stenosis. N Engl J Med 2009;361:1972-8.  Back to cited text no. 9
[PUBMED]    
10.Bonelli FS, McKusick MA, Textor SC, et al. Renal artery angioplasty: Technical results and clinical outcome in 320 patients. Mayo Clin Proc 1995;70:1041-52.  Back to cited text no. 10
[PUBMED]    

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Correspondence Address:
Jannet Labidi
Service of Internal Medicine, Tunisian Military Hospital, Tunis
Tunisia
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DOI: 10.4103/1319-2442.124501

PMID: 24434389

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    Abstract
   Introduction
   Patients and Methods
   Results
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    References
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