Dissecting visceral fibromuscular dysplasia reveals a new vascular phenotype of the disease: a report from the ARCADIA-POL study

Evidence for routine brain-to-pelvis imaging and antiplatelet therapy in patients diagnosed with fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is a disease of the musculature of arterial walls leading to stenoses, aneurysms, and dissections. The purpose of this report was to summarize the evidence for (1) one-time routine imaging from brain-to-pelvis and (2) lifelong antiplatelet therapy, for example, aspirin, for patients diagnosed with FMD as suggested by an international consensus report from 2019. PubMed was systematically searched, and the evidence providing a basis for the current consensus points, as well as articles published since, were reviewed. In four registries evaluating patients with FMD, the prevalence of multivessel involvement, aneurysms, and dissections was reported to be 43.5%-66.3%, 21.6%-30.6%, and 5.6%-28.1%, respectively. Any antiplatelet drug was used in 72.9% of patients, and aspirin was prescribed in up to 70.2% of patients. Based on the high prevalence of vascular manifestations, their associated morbidity, and the potential for endovascular or surgical intervention, the suggestion of one-time brain-to-pelvis screening with computed tomography angiography or magnetic resonance angiography is well supported. Contrarily, the evidence to support the consensus statement of lifelong antiplatelet therapy to all patients in the absence of contraindications is more uncertain since a beneficial effect has not been demonstrated specifically in patients with fibromuscular dysplasia. Therefore, until the efficacy and safety of primary thromboprophylaxis have been demonstrated in this patient group specifically, it may be equally appropriate to only use antiplatelet agents in patients with a clear indication after individual evaluation according to risk factors for thrombotic and thromboembolic complications.

Differentiating between segmental arterial mediolysis and other arterial vasculopathies to establish an early diagnosis - a systematic literature review and proposal of new diagnostic criteria

Segmental arterial mediolysis (SAM) is a rare vascular disease, characterized by acute but transient vulnerability of the wall of medium-sized arteries. The most characteristic feature of SAM is its biphasic course: an injurious phase marked by acute weakness of the arterial wall leading to acute dissection and/or hemorrhage, followed by a reparative phase in which granulation tissue and fibrosis restore the injured arterial wall. Residual stenosis, aneurysms, and/or arterial wall irregularities may remain visible on future imaging studies. Differentiating between SAM and other arterial vasculopathies is difficult due to its similarities with many other vascular diseases, such as vasculitis, fibromuscular dysplasia, inherited connective tissue disorders, and isolated visceral artery dissection. In this systematic review, we provide an overview on SAM, with an emphasis on the differential diagnosis and diagnostic work-up. We propose new diagnostic criteria to help establish a prompt diagnosis of SAM, illustrated by case examples from our multidisciplinary vascular clinic.

High prevalence of extrarenal artery involvement in children with fibromuscular dysplasia - a single-center experience

BACKGROUND

Although the clinical presentation of fibromuscular dysplasia (FMD) and its generalized character has been previously described in adults, data on FMD in children are limited.

METHOD

In this study, we aimed to assess visceral artery involvement in pediatric FMD patients with documented renal artery stenosis (RAS) and renovascular hypertension (RVH) in comparison with healthy individuals. We retrospectively analyzed the results of angiographic studies of 16 patients with a median age of 13.9 years (10 girls) in comparison with 16 age- and sex-matched healthy controls.

RESULTS

Out of the 16 FMD patients, 10 (63%) had stenotic lesions identifiable only in renal arteries, whereas six (37%) had additional stenoses in other vascular beds - in the celiac trunk (four patients), superior mesenteric artery (four patients), inferior mesenteric artery (one patient), splenic artery (one patient), common hepatic artery (three patients), and abdominal aorta (one patient). The comparison of ostial diameters of vessels, in which no periostial narrowing, stents, or occlusions were found, revealed that patients with FMD had a significantly smaller diameter of the celiac trunk (P = 0.017), splenic arteries (P = 0.007), and common hepatic artery (P = 0.026) than their age- and sex-matched healthy peers.

CONCLUSION

We found that 69% of children with RVH caused by FMD had clinically silent stenoses or tortuosity of visceral arteries. The results of our study suggest that pediatric FMD is a generalized arterial condition, and the patients may need screening for both renal as well as nonrenal manifestations of the disease.

Current progress in clinical, molecular, and genetic aspects of adult fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is a non-atherosclerotic vascular disease that may involve medium-sized muscular arteries throughout the body. The majority of FMD patients are women. Although a variety of genetic, mechanical, and hormonal factors play a role in the pathogenesis of FMD, overall, its cause remains poorly understood. It is probable that the pathogenesis of FMD is linked to a combination of genetic and environmental factors. Extensive studies have correlated the arterial lesions of FMD to histopathological findings of arterial fibrosis, cellular hyperplasia, and distortion of the abnormal architecture of the arterial wall. More recently, the vascular phenotype of lesions associated with FMD has been expanded to include arterial aneurysms, dissections, and tortuosity. However, in the absence of a string of beads or focal stenosis, these lesions do not suffice to establish the diagnosis. While FMD most commonly involves renal and cerebrovascular arteries, involvement of most arteries throughout the body has been reported. Increasing evidence highlights that FMD is a systemic arterial disease and that subclinical alterations can be found in non-affected arterial segments. Recent significant progress in FMD-related research which has led to improved understandings of the disease's clinical manifestations, natural history, epidemiology, and genetics. Ongoing work continues to focus on FMD genetics and proteomics, physiological effects of FMD on cardiovascular structure and function, and novel imaging modalities and blood-based biomarkers that can be used to identify subclinical FMD. It is also hoped that the next decade will bring the development of multi-centred and potentially international clinical trials to provide comparative effectiveness data to inform the optimal management of patients with FMD.