Integrative gene regulatory network analysis discloses key driver genes of fibromuscular dysplasia.

Fibromuscular dysplasia (FMD) is a poorly understood disease affecting 3-5% of adult females. The pathobiology of FMD involves arterial lesions of stenosis, dissection, tortuosity, dilation and aneurysm, which can lead to hypertension, stroke, myocardial infarction and even death. Currently, there are no animal models for FMD and few insights as to its pathobiology. In this study, by integrating DNA genotype and RNA sequence data from primary fibroblasts of 83 patients with FMD and 71 matched healthy controls, we inferred 18 gene regulatory co-expression networks, four of which were found to act together as an FMD-associated supernetwork in the arterial wall. After in vivo perturbation of this co-expression supernetwork by selective knockout of a top network key driver, mice developed arterial dilation, a hallmark of FMD. Molecular studies indicated that this supernetwork governs multiple aspects of vascular cell physiology and functionality, including collagen/matrix production. These studies illuminate the complex causal mechanisms of FMD and suggest a potential therapeutic avenue for this challenging 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 has led to improve our understanding 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.

Spontaneous compartment syndrome and endovascular repair of tibioperoneal trunk pseudoaneurysm in Ehlers-Danlos syndrome.

Vascular Ehlers-Danlos syndrome is caused by mutations in the COL3A1 (collagen type III alpha-1) gene, resulting in loss of integrity of arteries and hollow organs. Patients are predisposed to dissection, aneurysm, and organ rupture. The median life expectancy is ∼51 years. We have described a unique presentation of spontaneous compartment syndrome, likely secondary to ischemia reperfusion injury, in a 32-year-old man with vascular Ehlers-Danlos syndrome. The compartment syndrome was treated with four-compartment fasciotomy, and subsequent evaluation demonstrated a pseudoaneurysm of the tibioperoneal trunk. Endovascular intervention and stent graft deployment guided by intravascular ultrasound successfully excluded the pseudoaneurysm with three vessel run off preserved.

Genetic investigation of fibromuscular dysplasia identifies risk loci and shared genetics with common cardiovascular diseases.

Fibromuscular dysplasia (FMD) is an arteriopathy associated with hypertension, stroke and myocardial infarction, affecting mostly women. We report results from the first genome-wide association meta-analysis of six studies including 1556 FMD cases and 7100 controls. We find an estimate of SNP-based heritability compatible with FMD having a polygenic basis, and report four robustly associated loci (PHACTR1, LRP1, ATP2B1, and LIMA1). Transcriptome-wide association analysis in arteries identifies one additional locus (SLC24A3). We characterize open chromatin in arterial primary cells and find that FMD associated variants are located in arterial-specific regulatory elements. Target genes are broadly involved in mechanisms related to actin cytoskeleton and intracellular calcium homeostasis, central to vascular contraction. We find significant genetic overlap between FMD and more common cardiovascular diseases and traits including blood pressure, migraine, intracranial aneurysm, and coronary artery disease.

Association of Fibromuscular Dysplasia and Pulsatile Tinnitus: A Report of the US Registry for Fibromuscular Dysplasia.

Background Fibromuscular dysplasia (FMD) is a nonatherosclerotic arterial disease that has a variable presentation including pulsatile tinnitus (PT). The frequency and characteristics of PT in FMD are not well understood. The objective of this study was to evaluate the frequency of PT in FMD and compare characteristics between patients with and without PT. Methods and Results Data were queried from the US Registry for FMD from 2009 to 2020. The primary outcomes were frequency of PT among the FMD population and prevalence of baseline characteristics, signs/symptoms, and vascular bed involvement in patients with and without PT. Of 2613 patients with FMD who were included in the analysis, 972 (37.2%) reported PT. Univariable analysis and multivariable logistic regression were performed to explore factors associated with PT. Compared with those without PT, patients with PT were more likely to have involvement of the extracranial carotid artery (90.0% versus 78.6%; odds ratio, 1.49; P=0.005) and to have higher prevalence of other neurovascular signs/symptoms including headache (82.5% versus 62.7%; odds ratio, 1.82; P<0.001), dizziness (44.9% versus 22.9%; odds ratio, 2.01; P<0.001), and cervical bruit (37.5% versus 15.8%; odds ratio, 2.73; P<0.001) compared with those without PT. Conclusions PT is common among patients with FMD. Patients with FMD who present with PT have higher rates of neurovascular signs/symptoms, cervical bruit, and involvement of the extracranial carotid arteries. The coexistence of the 2 conditions should be recognized, and providers who evaluate patients with PT should be aware of FMD as a potential cause.

Male Sex Is Associated With Cervical Artery Dissection in Patients With Fibromuscular Dysplasia.

Background Cervical artery dissection (CeAD) is a frequent manifestation of fibromuscular dysplasia (FMD). However, risk factors for CeAD are unknown. We investigated factors associated with CeAD in the ARCADIA (Assessment of Renal and Cervical Artery Dysplasia) registry. Methods and Results The ARCADIA registry includes women or men aged ≥18 years, with a diagnosis of renal, cervical, or intracranial artery FMD, who were prospectively recruited at 16 university hospitals in France and Belgium. Diagnosis of acute or past CeAD at inclusion was established on imaging according to standard diagnostic criteria. Associations between potential determinants and CeAD were assessed by logistic regression analyses. Among 469 patients (75 men) with FMD, 65 (13.9%) had CeAD. Patients with CeAD were younger, more likely to be men, have a history of migraine, and less likely to have a history of hypertension than patients without CeAD. In the multivariable analysis, male sex (odds ratio [OR], 2.66; 95% CI, 1.34-5.25), history of migraine (OR, 1.90; 95% CI, 1.06-3.39), age ≥50 years (OR, 0.41; 95% CI, 0.23-0.73), history of hypertension (OR, 0.35; 95% CI, 0.20-0.64), and involvement of ≥3 vascular beds (OR, 2.49; 95% CI, 1.15-5.40) were significantly associated with CeAD. To validate the association between CeAD and sex, we performed a systematic review. We collected additional data on sex from 2 published studies and unpublished data from the US Registry for Fibromuscular Dysplasia and the European/International FMD Registry. In the pooled analysis (289 CeAD, 1933 patients), male sex was significantly associated with CeAD (OR, 2.04; 95% CI, 1.41-2.95; I2=0%). Conclusions In patients with FMD, male sex and multisite involvement are associated with CeAD, in addition to other previously known risk factors. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02884141.

Rare loss-of-function mutations of PTGIR are enriched in fibromuscular dysplasia.

AIMS: Fibromuscular dysplasia (FMD) and spontaneous coronary artery dissection (SCAD) are related, non-atherosclerotic arterial diseases mainly affecting middle-aged women. Little is known about their physiopathological mechanisms. We aimed to identify rare genetic causes to elucidate molecular mechanisms implicated in FMD and SCAD. METHODS AND RESULTS: We analysed 29 exomes that included familial and sporadic FMD. We identified one rare loss-of-function variant (LoF) (frequencygnomAD = 0.000075) shared by two FMD sisters in the prostaglandin I2 receptor gene (PTGIR), a key player in vascular remodelling. Follow-up was conducted by targeted or Sanger sequencing (1071 FMD and 363 SCAD patients) or lookups in exome (264 FMD) or genome sequences (480 SCAD), all independent and unrelated. It revealed four additional LoF allele carriers, in addition to several rare missense variants, among FMD patients, and two LoF allele carriers among SCAD patients, including one carrying a rare splicing mutation (c.768 + 1C>G). We used burden test to test for enrichment in patients compared to gnomAD controls, which detected a putative enrichment in FMD (PTRAPD = 8 × 10-4), but not a significant enrichment (PTRAPD = 0.12) in SCAD. The biological effects of variants on human prostaclycin receptor (hIP) signalling and protein expression were characterized using transient overexpression in human cells. We confirmed the LoFs (Q163X and P17RfsX6) and one missense (L67P), identified in one FMD and one SCAD patient, to severely impair hIP function in vitro. CONCLUSIONS: Our study shows that rare genetic mutations in PTGIR are enriched among FMD patients and found in SCAD patients, suggesting a role for prostacyclin signalling in non-atherosclerotic stenosis and dissection.

Effect of vorapaxar on cardiovascular and limb outcomes in patients with peripheral artery disease with and without coronary artery disease: Analysis from the TRA 2°P-TIMI 50 trial.

Intensive antithrombotic therapy reduces major adverse cardiovascular events (MACE) and major adverse limb events (MALE) in patients with peripheral artery disease (PAD). Recent studies have suggested heterogeneity in risk and benefit in those with and without concomitant coronary artery disease (CAD) and peripheral revascularization. We evaluated the risk of MACE and MALE in patients with PAD stratified by history of concomitant CAD and prior peripheral revascularization and whether the efficacy and safety of vorapaxar were similar in these subgroups. The TRA 2°P-TIMI 50 trial randomized 26,449 patients with prior MI, ischemic stroke, or PAD to vorapaxar or placebo. This analysis examined the effect of vorapaxar in a broad population of 6136 patients with PAD. Overall, vorapaxar significantly reduced MACE (HR 0.85, 95% CI 0.73, 0.99; p = 0.034) and MALE (HR 0.70, 95% CI 0.53, 0.92; p = 0.011) in patients with PAD. The absolute risk reduction (ARR) for MACE was greater in patients with PAD and CAD versus those with PAD alone (-2.2% vs 0.1%: number needed to treat (NNT) 45 vs 1000). Conversely, the ARR for MALE was higher in those with prior lower extremity revascularization (2.5% vs 0.2%: NNT 40 vs 500). Vorapaxar increased major bleeding (HR 1.39, 95% CI 1.12, 1.71; p = 0.003). The net clinical outcome in all patients with PAD was reduced with vorapaxar (HR 0.82, 95% CI 0.72, 0.94; p = 0.004), with benefits driven by reductions in MACE for those with CAD and by reductions in MALE for those with prior peripheral revascularization. Among patients with PAD, vorapaxar resulted in a net clinical benefit; however, the drivers of benefit were heterogeneous, with greater reductions in MACE in those with concomitant CAD and greater reductions in MALE in those with prior lower extremity revascularization, and unclear benefit in patients with neither. These clinical characteristics may be useful in identifying the subgroups of patients with PAD most likely to benefit from potent antithrombotic therapies. ClinicalTrials.gov Identifier: NCT00526474.

A plasma proteogenomic signature for fibromuscular dysplasia.

AIMS: Fibromuscular dysplasia (FMD) is a poorly understood disease that predominantly affects women during middle-life, with features that include stenosis, aneurysm, and dissection of medium-large arteries. Recently, plasma proteomics has emerged as an important means to understand cardiovascular diseases. Our objectives were: (i) to characterize plasma proteins and determine if any exhibit differential abundance in FMD subjects vs. matched healthy controls and (ii) to leverage these protein data to conduct systems analyses to provide biologic insights on FMD, and explore if this could be developed into a blood-based FMD test. METHODS AND RESULTS: Females with 'multifocal' FMD and matched healthy controls underwent clinical phenotyping, dermal biopsy, and blood draw. Using dual-capture proximity extension assay and nuclear magnetic resonance-spectroscopy, we evaluated plasma levels of 981 proteins and 31 lipid sub-classes, respectively. In a discovery cohort (Ncases = 90, Ncontrols = 100), we identified 105 proteins and 16 lipid sub-classes (predominantly triglycerides and fatty acids) with differential plasma abundance in FMD cases vs. controls. In an independent cohort (Ncases = 23, Ncontrols = 28), we successfully validated 37 plasma proteins and 10 lipid sub-classes with differential abundance. Among these, 5/37 proteins exhibited genetic control and Bayesian analyses identified 3 of these as potential upstream drivers of FMD. In a 3rd cohort (Ncases = 506, Ncontrols = 876) the genetic locus of one of these upstream disease drivers, CD2-associated protein (CD2AP), was independently validated as being associated with risk of having FMD (odds ratios = 1.36; P = 0.0003). Immune-fluorescence staining identified that CD2AP is expressed by the endothelium of medium-large arteries. Finally, machine learning trained on the discovery cohort was used to develop a test for FMD. When independently applied to the validation cohort, the test showed a c-statistic of 0.73 and sensitivity of 78.3%. CONCLUSION: FMD exhibits a plasma proteogenomic and lipid signature that includes potential causative disease drivers, and which holds promise for developing a blood-based test for this disease.

Optimal Treatment of Uncomplicated Type B Aortic Dissection: JACC Review Topic of the Week.

Historically, the gold standard for treating acute uncomplicated type B aortic dissection (TBAD) has been aggressive medical therapy to achieve optimal heart rate and blood pressure control. However, recent data have demonstrated that a significant proportion of patients with medically managed acute uncomplicated TBAD have late aorta-related complications, such as aneurysmal degeneration, that increase mortality and often necessitate surgical intervention. In this review, the authors review existing literature on uncomplicated TBAD and highlight contemporary surgical and medical strategies to manage this condition. Looking ahead, efforts are underway to identify and characterize a high-risk subgroup of acute uncomplicated TBAD patients who may benefit from early intervention.

First International Consensus on the diagnosis and management of fibromuscular dysplasia.

This article is a comprehensive document on the diagnosis and management of fibromuscular dysplasia (FMD), which was commissioned by the working group 'Hypertension and the Kidney' of the European Society of Hypertension (ESH) and the Society for Vascular Medicine (SVM). This document updates previous consensus documents/scientific statements on FMD published in 2014 with full harmonization of the position of European and US experts. In addition to practical consensus-based clinical recommendations, including a consensus protocol for catheter-based angiography and percutaneous angioplasty for renal FMD, the document also includes the first analysis of the European/International FMD Registry and provides updated data from the US Registry for FMD. Finally, it provides insights on ongoing research programs and proposes future research directions for understanding this multifaceted arterial disease.

Association of the PHACTR1/EDN1 Genetic Locus With Spontaneous Coronary Artery Dissection.

BACKGROUND: Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of acute coronary syndromes (ACS) afflicting predominantly younger to middle-aged women. Observational studies have reported a high prevalence of extracoronary vascular anomalies, especially fibromuscular dysplasia (FMD) and a low prevalence of coincidental cases of atherosclerosis. PHACTR1/EDN1 is a genetic risk locus for several vascular diseases, including FMD and coronary artery disease, with the putative causal noncoding variant at the rs9349379 locus acting as a potential enhancer for the endothelin-1 (EDN1) gene. OBJECTIVES: This study sought to test the association between the rs9349379 genotype and SCAD. METHODS: Results from case control studies from France, United Kingdom, United States, and Australia were analyzed to test the association with SCAD risk, including age at first event, pregnancy-associated SCAD (P-SCAD), and recurrent SCAD. RESULTS: The previously reported risk allele for FMD (rs9349379-A) was associated with a higher risk of SCAD in all studies. In a meta-analysis of 1,055 SCAD patients and 7,190 controls, the odds ratio (OR) was 1.67 (95% confidence interval [CI]: 1.50 to 1.86) per copy of rs9349379-A. In a subset of 491 SCAD patients, the OR estimate was found to be higher for the association with SCAD in patients without FMD (OR: 1.89; 95% CI: 1.53 to 2.33) than in SCAD cases with FMD (OR: 1.60; 95% CI: 1.28 to 1.99). There was no effect of genotype on age at first event, P-SCAD, or recurrence. CONCLUSIONS: The first genetic risk factor for SCAD was identified in the largest study conducted to date for this condition. This genetic link may contribute to the clinical overlap between SCAD and FMD.

First international consensus on the diagnosis and management of fibromuscular dysplasia.

This article is a comprehensive document on the diagnosis and management of fibromuscular dysplasia (FMD) which was commissioned by the Working Group 'Hypertension and the Kidney' of the European Society of Hypertension (ESH) and the Society for Vascular Medicine (SVM). This document updates previous consensus documents/scientific statements on FMD published in 2014 with full harmonization of the position of European and US experts. In addition to practical consensus-based clinical recommendations, including a consensus protocol for catheter-based angiography and percutaneous angioplasty for renal FMD, the document also includes the first analysis of the European/International FMD Registry and provides updated data from the US Registry for FMD. Finally, it provides insights on ongoing research programs and proposes future research directions for understanding this multifaceted arterial disease.