Renovascular hypertension due to fibromuscular dysplasia
(Portuguese PDF version)

Fábio Mesquita de Souza,1 Wagner Rodrigues Chagas,2 Márcio Avelar,3 Jonas Marques Ribas4

1. Specialist by the Brazilian Society of Angiology and Vascular Surgery, Hospital São Lucas, Governador Valadares, MG, Brazil.
2. Urologist, Hospital São Lucas, Governador Valadares, MG, Brazil.
3. Cardiologist/Hemodynamicist, Hospital São Lucas, Governador Valadares, MG, Brazil.
4. Angiologist and Vascular Surgeon, Hospital São Lucas, Governador Valadares, MG, Brazil.

Correspondence:
Fábio Mesquita de Souza
Rua Barão do Rio Branco, 681/304, Centro
CEP 35010-030 - Governador Valadares, MG, Brazil
Phone: +55 (33) 3271.6510/3272.7979
E-mail: fabiomeskita@ig.com.br

ABSTRACT

The authors report a case of renovascular hypertension due to fibromuscular dysplasia in a 34-year-old patient, female, Caucasian, sent to hospital service because of a complaint about a "buzz" in the bilateral cervical region for approximately 8 months, more intense on the left side. She also reported occasional dizziness and arterial hypertension. Diagnosis was confirmed by arteriography, which showed injuries with a "pearl necklace" appearance on internal carotid arteries, right renal artery, and external iliac arteries. This article aims at calling the attention to rare diseases, which many times are unnoticed, as well as stimulating the exercise of the differential diagnosis.

Key-words: renovascular hypertension, renal artery obstruction, fibromuscular dysplasia.

J Vasc Br 2005;4(1):101-4

Renal artery stenosis is the most common cause of secondary arterial hypertension potentially remediable. The most common causes involve arteriosclerosis and fibromuscular dysplasia. The earlier the diagnosis of renal artery stenosis, the sooner can be given therapy to cure hypertension and preserve the renal function.

The screening of renal artery stenosis is indicated if there is a suspicion of renovascular hypertension or ischemic nephropathy. It can also include laboratory exams, duplex scan, renal arteriography, renal scintigraphy, angiotomography, angioresonance.

The screening of other arteries is extremely important at the time of the diagnosis of renal dysplasia, since there usually is an association between them.

CASE REPORT

Female patient, 34 years old, Caucasian, receiving care at the Angiology and Vascular Surgery office, referred for presenting bilateral carotid murmur near the mandibular branch. The patient had already undergone a duplex scan, which showed an increased flow speed in the internal carotids, but it did not show any kind of injury.

The patient presented a history of "neck buzz", started about 8 months ago, besides occasional dizziness and discrete cephalea. She did not have complaints that would limit her daily routine.

After the physical examination was performed, the following remarkable alterations were observed:

  • Physical examination
    aPA: 180 x 120 mmHg (left upper limb);
    aPA: 160 x 110 mmHg (right upper limb);
    aAortic murmur, renal, iliac (2±4);
    aPalpable carotids, bilateral murmur near the mandibular branch (4±4);
    aRight femoral with clear fremitus and murmur (3±4)
  • Requested laboratory exams: blood cell count, C-reactive protein, blood sedimentation speed, urea, and creatinin.

It was also requested a new duplex scan for evaluation of the aortic artery and renal arteries. It was not possible to perform renal scintigraphy due to resource limitation.

Blood tests did not show alterations. The abdominal duplex scan had not identified any injury in the aortic artery or renal arteries. The aorto-renal index was bilaterally normal; the kidneys presented usual conformation; the exam of the carotid arteries was inconclusive. Considering all this, diagnostic hypotheses for the case were primary arteritis of the aorta, fibromuscular dysplasia, early atherosclerosis, and arterial hypoplasia.

An angiography of the carotid arteries, aortic arch, subclavians, abdominal, renal, and cerebral aortas concluded the diagnosis, showing injuries with stenosis, intercalated with dilations in the distal third of the internal carotid arteries (Figure 1). The distal third of the right renal artery presented the same angiographic aspect (Figure 2), as well as the external iliac arteries bilaterally (Figure 3). The other vasa that were studied presented a normal angiographic aspect.

click hereFigure 1 - Distal third of the carotid artery with a dysplastic injury and a "pearl necklace" aspect.

click hereFigure 2 - Medial and distal third of the injured right renal artery. "Pearl necklace" aspect. The left renal artery presents a normal aspect.

click hereFigure 3 - Injury in external iliac arteries. A more aggravated injury to the right.

The patient received the diagnosis of medial fibromuscular dysplasia (subtype medial fibroplasia) in the internal carotid arteries, right renal artery, external iliac artery, and hypertension due to the right renal artery secondary to stenosis.

The patient was under clinical treatment with platelet anti-aggregating and antihypertensive medication, with control of the arterial hypertension, kept at acceptable levels. There were no more episodes of dizziness, and there was a reduction of the "buzz".

DISCUSSION

The fibromuscular dysplasia is a non-atherosclerotic, non-inflammatory, and segmental disease of unknown cause, which affects middle-sized arteries, and seldom affects small-sized arteries.1,2 The non-inflammatory aspect of the disease explains the speed of blood sedimentation and unaltered C-reactive protein, which makes us think about a disease other than the primary arteritis of the aorta, known to be inflammatory. The stenosing injuries of the renal arteries are usually a consequence of atherosclerosis or fibromuscular dysplasia.

The fibromuscular dysplasia mainly affects the renal arteries, and it can also be found in carotid, cerebral and iliac territories. The involvement of the renal arteries is bilateral in 60% of cases.2,3

It is estimated that approximately 2% of cases of renovascular hypertension are secondary to fibromuscular dysplasia.2,3 A cooperative study on renovascular hypertension considered the fibromuscular dysplasia to be the cause of 1/3 of the renal stenosis.2,4

The incidence of fibromuscular dysplasia ranges from 8:1 to 2:1 between women and men, and this disease almost exclusively occurs in Caucasians. It is more frequently observed in young women and it rarely evolves to renal artery occlusion.5

Stanley et al., at Michigan University, found 196 patients with fibromuscular dysplasia from 1960 to 1974. 88% of them were female. The visceral and iliac arteries were occasionally involved.2,6

The medial fibromuscular dysplasia is the most frequent type, and its subtype, the medial fibroplasia, corresponds to 70-95% of dysplasias and 85% of renovascular injuries. The medial fibroplasia is shown with the classic "pearl necklace" aspect. It can be shown in three ways: asymptomatic renal artery stenosis, renovascular hypertension, and ischemic nephropathy.

The definite exam for the diagnosis of fibromuscular dysplasia is the histopathological exam. However, angiography offers a high degree of accuracy, as can be observed in this case. The histopathological exam implies in biopsy, which is an unnecessary risk, since the classic "pearl necklace" arteriographic aspect is sometimes pathognomonic of the medial fibromuscular dysplasia, subtype medial fibroplasia.

The duplex scan is the most accessible method for the diagnosis, less expensive and non-invasive, with 95% of sensitiveness and 90% of specificity in competent hands. However, it should not be considered as a substitute for arteriography. Antonica et al. observed the inapplicability of the method in 11% of cases.2,7 Angiotomography and angioresonance may also be applied, with known limitations of such methods, though.

The main objectives of the treatment of renovasular hypertension are the effective control of the arterial hypertension and the preservation of the renal function. The three therapeutic modalities include clinical treatment, angioplasty or stent graft, and surgical revascularization.8 In the described case, there was an improvement of hypertension with the clinical treatment, which will be kept until there are conditions to perform angioplasty.

The percutaneous treatment has its limitations, such as, for instance, serum creatinin higher than 3 mg/dl. The bridge surgeries have better results than percutaneous procedures. We should remember that the revascularization, surgical and percutaneous procedures are only valid when renal viability is confirmed. Otherwise, nephrectomy can be inevitable.9

The clinical treatment has been reserved for cases of technical impossibility, of high risk for the interventionist procedure and for special patients, in which the arterial pressure and the renal function are controlled by conventional clinical treatment.8

ACKNOWLEDGMENT

The Ultracor staff - diagnosis clinic by images of Governador Valadares - for the interest and effort to diagnose the case, and for the free duplex scan exams.

To Professor Dr. João Luís Sandri, for his collaboration in guiding the conduct for this case.

REFERENCES

1. Begelman SM, Olin JW. Fibromuscular dysplasia. Curr Opin Rheumatol 2000;12:41-7.

2. Maffei FHA. Displasia fibromuscular arterial. In: Maffei FHA, Lastória S, Yoshida WB. Doenças Vasculares Periféricas. 3ª ed. São Paulo: Medsi; 2002. p.1317-35.

3. Younberg SP, Sheps SG, Strong CG. Fibromuscular disease of the renal arteries. Med Clin North Am 1977;61:623-41.

4. Simon N, Franklin SS, Bleifer KH, et al. Clinical characteristics of renovascular hypertension. JAMA 1972;220:1209-18.

5. Barbey F, Matthieu C, Nseir G, Burnier M, Teta D. A young man with a renal colic. J Intern Med 2003;254:605-8.

6. Stanley JC, Gewertz BL, Bove EL, et al. Arterial fibrodysplasia: histopathologic character and current etiologic concepts. Arch Surg 1975;110:561-6.

7. Antonica G, Sabba C, Berardi E, et al. Accuracy of echo-doppler flowmetry for renal artery stenosis. J Hypertension 1991;9(Suppl 6):S240-1.

8. Silva HB, Bortolotto LA. Hipertensão renovascular: novas diretrizes no tratamento. Rev Bras Hipertens 2002;9(2):154-59.

9. Leal AJ, Borges Melo A, Alysson N, da Mota, NR, de Jesus SG. Hipertensão renovascular: revisão de literatura. Rev Paul Med 2001;15(2):31-9.

J Vasc Br - Official Publication of the Brazilian Society of Angiology and Vascular Surgery