[Fibromuscular dysplasia of the renal arteries]. / La dysplasie fibromusculaire des artères rénales.

Fibromuscular dysplasia is a non-atherosclerotic, non-inflammatory vascular disease that primary involves medium-sized and small arteries, most commonly the renal and carotid arteries. Dysplasic stenoses can be classified by angiography into three main subtypes, multifocal (multiple contiguous stenoses with the "string of beads" appearance), unifocal (single stenosis in a given renal artery), or tubular. The multifocal subtype is the most frequent and is usually associated with medial dysplasia, whereas unifocal and tubular stenoses are associated with intimal and perimedial dysplasia, respectively. Renovascular hypertension, mainly in women aged 30 to 50 years, is the most common manifestation of renal artery fibromuscular dysplasia. Its prevalence in hypertensive patients is estimated to less than 1 percent. The true prevalence of the disease is probably higher, however, because many cases can go undetected in normotensive or asymptomatic hypertensive patients. The first line treatment is percutaneous transluminal angioplasty that usually allows blood pressure improvement or normalization. Stenosis progression is slow and rarely leads to ischemic renal failure. Recognition of renal artery fibromuscular dysplasia should lead to screening for associated carotid artery lesions. Fibromuscular dysplasia can be a familial disease.

[Genetic study of renal artery fibromuscular dysplasia]. / Etude génétique de la dysplasie fibromusculaire des artères rénales.

The aim of this study was to conduct a formal pedigree analysis of the involvement of the elastin gene in families. From 140 subjects with renal FMD documented on angiography, family cases with documented renal artery fibromuscular dysplasia (FMD) and to test pedigrees were constructed and familial cases defined by angiographic evidence of FMD in at least one sibling. Familial screening was made either by echodoppler for asymptomatic subjects or by digital intravenous angiography for hypertensive subjects. Linkage analysis at the elastin gene locus was performed in these families with two polymorphic markers: one diallelic RFLP located in exon 16 and one multiallelic CA repeat located in intron 17 of the elastin gene. Fourteen pedigrees (10%) were obtained including nine sibling pairs, four trios and one vertical transmission from a father to his daughter. Most affected subjects were females (84%) but familial cases were more frequently bilateral than sporadic cases (80% vs 49%, p = 0.07). Pedigrees analysis was compatible with an autosomal dominant mode of inheritance and suggested in these families an age and sex-dependent incomplete penetrance model. Linkage analysis resulted in a maximum two-point lod score of 0.06 at theta = 0.20 using the dinucleotide CA repeat. Analysis of the diallelic marker revealed similar frequencies in affected and non affected subjects. This study highlights the role of genetics factors in approximately 10% of FMD cases. The elastin gene does not seem to be involved in the pathogenesis of FMD.

[Reversible left intraventricular obstruction after treatment of pheochromocytoma and hyperthyroidism]. / Obstruction intraventriculaire gauche réversible après traitement d'un phéochromocytome et d'une hyperthyroïdie.

The authors report an original case of the association of three pathologies: pheochromocytoma, hyperthyroidism and cardiomyopathy with left ventricular outflow tract obstruction. This type of cardiac disease has occasionally been described in cases of pheochromocytoma and are usually induced by the endocrine disturbance because they regress with treatment of the pheochromocytoma. The associated hyperthyroidism observed in this case is very rare and may have increased the left ventricular pressure gradient. Medical treatment before surgery of the pheochromocytoma was unusual in that a triple therapy was used including betablockers, classically contra-indicated in pheochromocytoma alone. In this case, it provided excellent control of the blood pressure and decreased the left ventricular obstruction during the perioperative period.

Possible familial origin of multifocal renal artery fibromuscular dysplasia.

OBJECTIVE: To describe phenotypes and estimate the prevalence of familial cases of renal artery fibromuscular dysplasia (FMD). PATIENTS AND SETTING: One hundred and four unrelated hypertensive patients (94 women) with renal artery fibromuscular dysplasia documented on angiography and classified as having multifocal or unifocal lesions. Familial cases were defined as those with angiographic evidence of renal artery FMD in at least one sibling. RESULTS: Eighty-one patients had multifocal and 16 had unifocal FMD. Both types of stenosis were present in seven patients. Fifty-four patients had bilateral FMD, including the seven patients with both unifocal and multifocal lesions. The 16 patients with unifocal FMD were younger, more likely to be men, and more commonly had unilateral stenoses, stenoses exceeding 75% and a small ischemic kidney than the 81 patients with multifocal lesions. Eleven cases were identified as familial on the basis of FMD having been documented in at least one sibling (eight sibling pairs and three trios). All probands were women and exhibited multifocal lesions. FMD was more often bilateral in familial than it was in apparently sporadic cases. CONCLUSIONS: Multifocal FMD was mostly found in women and unifocal FMD in young men with more severe stenosis and kidney ischemia. The documented prevalence of familial cases was 11% in this series, the true prevalence being probably higher because only a few siblings were examined by angiography. Familial cases all exhibited the multifocal type and were more commonly bilateral than were sporadic cases.

[Non-surgical treatments of renal artery stenoses]. / Traitements non chirurgicaux des sténoses de l'artère rénale.

Management of patients with renal artery stenoses is aimed at normalizing or reducing blood pressure and correcting or preventing reduced glomerular filtration. The results of renal revascularization have been documented mainly in retrospective, uncontrolled reports in which blood pressure improvement was overestimated due to the placebo effect and optimization of drug treatment, the latter being frequently required despite adequate revascularization. In an overview of 10 series reporting blood pressure outcome following percutaneous angioplasty, cure rates were 50% in patients with fibrodysplastic stenosis but only 19% in those with atherosclerotic stenosis. The literature on revascularization of atherosclerotic stenosis with progressive renal failure shows that 55% of patients have improved renal function following surgery and 41% following angioplasty. Mortality is 6 and 5% respectively. The first controlled trials comparing revascularization to medical treatment in renal artery stenosis have recently been published. In a prospective randomized trial, Weibull et al. compared percutaneous angioplasty and surgery in 58 patients with unilateral atherosclerotic stenosis. Although 17% of the patients initially treated with angioplasty required subsequent surgery, blood pressure, renal function and renal artery patency rate did not differ between angioplasty and surgery 24 months after treatment. A Scottish group reported a prospective randomized trial of percutaneous angioplasty vs. medical therapy in patients with bilateral or unilateral atherosclerotic stenosis. In the bilateral group (n = 28), the drop in systolic pressure was significantly larger following angioplasty than following medical therapy, but diastolic pressure and creatinine did not differ after 24 months. In the unilateral group (n = 27), there were no differences in blood pressure or creatinine levels following angioplasty or medical therapy. Several randomized trials comparing angioplasty and conservative treatment or angioplasty and stent placement in patients with renal artery stenosis and normal or reduced renal function are currently underway. They should provide additional information regarding the risk/benefit ratio of these procedures.