Optimal management of renal artery fibromuscular dysplasia

Long-term outcomes of percutaneous transluminal renal artery intervention: a retrospective study at a single center

BACKGROUND

The indications, benefits, and outcomes of percutaneous transluminal renal artery intervention (PTRI) remain controversial. The study purpose was to evaluate the long-term outcomes of PTRI in clinical practice.

METHODS

A retrospective review of 217 subjects (254 renal arteries; mean age, 59.8 years) who underwent PTRI based on medical database.

RESULTS

The most common cause of renal artery stenosis was atherosclerosis in 217 (85.4%), followed by Takayasu arteritis (TA) in 23 (9.1%), fibromuscular dysplasia in five (2.0%) and others in nine (3.5%). Mean follow-up duration was 5.7 ± 3.7 years. The first restenosis rate was 7.5% (n = 19; highest in TA: n = 9, 47.4%) and second restenosis occurred in six arteries (five TAs, one fibromuscular dysplasia). Follow-up blood pressure improved from 142.0/83.5 to 122.8/73.5 mmHg (P < 0.001). There was no change within 5 years' follow-up in estimated glomerular filtration rate (P = 0.44), whereas TA changed from 69.8 ± 20.5 to 84.2 ± 17.9 mL/min/1.73 m² (P = 0.008). Progressive renal dysfunction was related to diabetes mellitus, chronic kidney disease, and peripheral artery obstructive disease on multivariate analysis with hazard ratios (95% confidence intervals) of 2.24 (1.21-4.17), 2.54 (1.33-4.84), and 3.93 (1.97-7.82), respectively.

CONCLUSIONS

PTRI was associated with a blood pressure reduction. Despite a higher rate of restenosis, patients with TA showed significant improvement in estimated glomerular filtration rate. Diabetes mellitus, chronic kidney disease, and peripheral artery obstructive disease were related with progressive renal dysfunction after PTRI.

The role of nitric oxide in renovascular hypertension: from the pathophysiology to the treatment

Renovascular hypertension is one of the most relevant causes of secondary hypertension, mostly caused by atherosclerotic renovascular stenosis or fibromuscular dysplasia. The increase in angiotensin II production, oxidative stress, and formation of peroxynitrite promotes the decrease in nitric oxide (NO) availability and the development of hypertension, renal and endothelial dysfunction, and cardiac and vascular remodeling. The NO produced by nitric oxide synthases (NOS) acts as a vasodilator; however, endothelial NOS uncoupling (eNOS) also contributes to NO reduced availability in renovascular hypertension. NO donors and NO-derived metabolites have been investigated in experimental renovascular hypertension and have shown promissory effects in attenuating blood pressure and organ damage in this condition. Therefore, understanding the role of decreased NO in the pathophysiology of renovascular hypertension promotes the study and development of NO donors and molecules that can be converted into NO (such as nitrate and nitrite), contributing for the treatment of this condition in the future.

Renovascular involvement of systemic vascular disease: a pictorial review

Like many solid organs, the kidneys are susceptible to a wide variety of systemic vascular diseases. Comprising a significant subset of these diseases are the vasculitides, broadly encompassing numerous inflammatory conditions of the blood vessels. However, many of these conditions are non-vasculitic and non-inflammatory, and differentiation of these entities is crucial to guide the initiation of proper therapy. These non-vasculitic diseases include coagulopathic conditions leading to vascular complications, hemolysis, and hematogenous processes that can affect multiple organ systems. These systemic diseases can result in both macrovascular and microvascular pathology, involving the arteries, veins, and smaller vessels, and management of these conditions can differ significantly depending upon the underlying pathophysiology. Because the clinical manifestations of these disease processes can be heterogeneous, ranging from renal dysfunction to life-threatening hemorrhage, proper recognition of these entities is essential to help guide clinicians to the correct diagnosis and prevent potentially disastrous complications. Many of these systemic vascular processes can be detected by non-invasive imaging, including computed tomography (CT) and magnetic resonance imaging (MRI), and identification of their characteristic renal manifestations by radiologists is a critical component of patient care. This review covers a variety of these diseases and their imaging manifestations, to aid in their recognition and better equip radiologists to provide vital diagnostic information that can optimize patient care.

Insights from intravascular pressure measurement of renal artery revascularization in patients with fibromuscular dysplasia: the DYSART study

OBJECTIVE

The indication of percutaneous renal transluminal angioplasty (PTRA) in fibromuscular dysplasia (FMD) is mainly based on renal artery stenosis (RAS) due to atherosclerosis criteria, which are not specific to FMD. Consequently, the selection of patients who could benefit from this treatment and its effectiveness remain uncertain. The aims of this study were to: (1) report the effects of PTRA guided by trans-stenotic pressure measurements on hypertension 7 months after treatment; (2) assess the impact of pressure measurement to guide treatment efficacy in comparison to visual angiographic parameters; and (3) evaluate the reproducibility and accuracy of the stenosis measurement using a 4F catheter in comparison to a pressure guidewire.

METHODS

This prospective multi-centric study analyzed 24 patients with hypertension with RAS due to FMD that required PTRA. Clinical, duplex ultrasound, and angiographic indices were collected, and patients were followed up for 7 months (±1 month). Angiographic indices were measured twice both by a pressure guidewire and a 4F catheter. Assessment of procedural and clinical success of angioplasty was performed for all patients.

RESULTS

Twenty-three patients (96%) had procedural success (considered as a post-PTRA translesional systolic gradient ≤10 mmHg or reduced by at least 80%) with a significant decrease in the systolic gradient after angioplasty (26.50 mmHg; [interquartile range, 16.75-38.75] vs 0.00 [interquartile range, 0.00-2.00]; P < .01). Three patients (12%) had complications, including two renal artery dissections and one partial renal infarction. Twenty-one patients (88%) were clinical responders to angioplasty at follow-up. Visual stenosis assessment showed a poor correlation with systolic gradient measurement before and after PTRA (R from -0.05 to 0.41; P = 0.06-0.82). High correlations were found between pressure measurements made by a 4F catheter and guidewire (R from 0.64 to 0.89; P ≤ .003).

CONCLUSIONS

In patients selected by clinical indicators and duplex ultrasound, reaching a translesional systolic gradient ≤10 mmHg or reduced by at least 80% after angioplasty, promotes a high success rate for PTRA in hypertension due to FMD RAS.

Overcoming Diagnostic Dilemma and Optimizing Intervention with Optical Coherence Tomographic Guidance in an Angiographically Ambiguous Renal Artery Stenosis Due to Fibromuscular Dysplasia

With the advent of endovascular therapy, conventional angiography has replaced histology as a diagnostic gold standard for fibromuscular dysplasia (FMD). However, angiographic findings are not precisely diagnostic in isolated focal renal artery stenosis (RAS) in FMD. Optical coherence tomography (OCT) imaging by reflecting in vivo histology may improve the diagnostic accuracy in such cases. Restenosis following balloon angioplasty of RAS in FMD occurs frequently and often requires optimized reintervention. However, the role of OCT in the diagnostic evaluation of focal RAS in FMD and in optimizing the intervention is not well studied. We present a young female with resistant secondary hypertension due to bilateral focal RAS on angiography. In the absence of an angiographic string of beads appearance, the diagnoses remained uncertain. However, OCT imaging diagnosed a multifocal disease with characteristic changes of fibro-medial dysplasia, akin to its histological description in the literature. The patient underwent bilateral balloon angioplasty with good angiographic results. After one year on follow-up, relapse of uncontrolled systemic hypertension occurred due to bilateral restenosis. Despite a satisfactory repeat balloon angioplasty of the left-sided re-stenotic lesion, a significant residual pressure gradient persisted. Usage of OCT guided oversized balloon and stent safely achieved good results with complete resolution of the pressure gradient. Right renal artery stenosis required balloon angioplasty alone. She had complete resolution of hypertension without any medications at six months of follow-up. In conclusion, OCT can supplement other diagnostic modalities in providing a proper diagnosis in an angiographically ambiguous focal RAS in FMD. A persistent residual pressure gradient across the lesion despite good angiographic results may be optimized with OCT guidance during the intervention.

Renal Arteries Revisited: Anatomy, Pathologic Entities, and Implications for Endovascular Management

The renal arteries (RAs) are important vessels that usually arise from the abdominal aorta and supply the kidneys; thus, these arteries play a vital role in physiologic functions such as hemofiltration and blood pressure regulation. An understanding of the basis for embryologic development and the frequently variable anatomy of the RAs is necessary to fully appreciate the range of diseases and the implications for procedural planning. Hemorrhage from an RA is relatively common and is typically traumatic or spontaneous, with the latter form often seen in association with underlying tumors or arteriopathy. Accurate diagnostic evaluation of RA disease due to conditions such as atherosclerosis, fibromuscular dysplasia, vasculitis, aneurysm, arteriovenous shunt, embolic disease, and dissection is dependent on the use of multimodality imaging and is essential for selecting appropriate clinical management, with endovascular therapy having a key role in treatment. Surgical considerations include extra-anatomic renal bypass, which remains an important treatment option even in this era of endovascular therapy, and RA embolization as an adjunct to tumor surgery. A novel area of research interest is the potential role of RA denervation in the management of refractory hypertension. ^©RSNA, 2021.

Extracellular Matrix in Vascular Disease, Part 2/4: JACC Focus Seminar

Medium-sized and large arteries consist of 3 layers: the tunica intima, tunica media, and tunica adventitia. The tunica media accounts for the bulk of the vessel wall and is the chief determinant of mechanical compliance. It is primarily composed of circumferentially arranged layers of vascular smooth muscle cells that are separated by concentrically arranged elastic lamellae; a form of extracellular matrix (ECM). The tunica media is separated from the tunica intima and tunica adventitia, the innermost and outermost layers, respectively, by the internal and external elastic laminae. This second part of a 4-part JACC Focus Seminar discusses the contributions of the ECM to vascular homeostasis and pathology. Advances in genetics and proteomics approaches have fostered significant progress in our understanding of vascular ECM. This review highlights the important role of the ECM in vascular disease and the prospect of translating these discoveries into clinical disease biomarkers and potential future therapies.

Endovascular management of an unsual case of spontaneous Retroperitoneal Haemorrhage due to Fibromuscular Dysplasia

Background

Fibromuscular dysplasia (FMD) is an uncommon vascular disease that results in stenosis, dissection or aneurysmal degeneration. However, it can sometimes manifest atypically, as we show in this case.

Case presentation

A 24-year old patient with no relevant medical history with severe left hypochondrium pain. The physical examination showed blood pressure levels of 160/90 mmHg. An abdominopelvic CT evidenced left retroperitoneal haematoma associated with active bleeding and left renal artery stenosis. Given these findings, it was decided to perform an endovascular treatment. Significant stenosis was seen during the arteriography in both renal arteries, suggesting fibromuscular dysplasia and development of a collateral neovascular network responsible for the retroperitoneal haematoma. It was embolised in association with angioplasty of the left renal artery. The patient had a favourable outcome; however, high blood pressure levels persisted. A new bilateral renal angioplasty was performed, which returned blood pressure values to normal. The patient was discharged without needing antihypertensives.

Conclusions

FMD is a rare disease that can show multiple clinical presentations and need individualized treatment options. Endovascular techniques are in the first therapeutic line regarding fibromuscular dysplasia.

Renal Artery Stenosis As Etiology of Recurrent Flash Pulmonary Edema and Role of Imaging in Timely Diagnosis and Management

Renal hypoperfusion from renal artery stenosis (RAS) activates the renin-angiotensin system, which in turn causes volume overload and hypertension. Atherosclerosis and fibromuscular dysplasia are the most common causes of renal artery stenosis. Recurrent flash pulmonary edema, also known as Pickering syndrome, is commonly associated with bilateral renal artery stenosis. There should be a high index of clinical suspicion for renal artery stenosis in the setting of recurrent flash pulmonary edema and severe hypertension in patients with atherosclerotic disease. Duplex ultrasonography is commonly recommended as the best initial test for the detection of renal artery stenosis. Computed tomography (CT) angiography (CTA) or magnetic resonance (MR) angiography (MRA) are useful diagnostic imaging studies for the detection of renal artery stenosis in patients where duplex ultrasonography is difficult. If duplex ultrasound, CTA, and MRA are indeterminate or pose a risk of significant renal impairment, renal angiography is useful for a definitive diagnosis of RAS. The focus of medical management for RAS relies on controlling renovascular hypertension and aggressive lifestyle modification with control of atherosclerotic disease risk factors. The restoration of renal artery patency by revascularization in the setting of RAS due to atherosclerosis may help in the management of hypertension and minimize renal dysfunction.

Long-term outcomes and determinants of stenosis recurrence after renal artery angioplasty in hypertensive patients with renovascular disease

INTRODUCTION

Restenosis (RS) following percutaneous angioplasty (PTA) of renal artery stenosis (RAS) might have an unfavourable impact on renal function and blood pressure (BP) outcomes.

AIM

To evaluate the prevalence and predictors of RS in patients treated with PTA for RAS, and the relationship between BP and renal function (RF) changes with RS.

MATERIAL AND METHODS

We analysed freedom from RS in 210 patients (age 64.6 ±12.8 years; range: 20-85), who underwent 248 successful stent-assisted PTAs in RAS. The change in levels of serum creatinine (SCC), estimated glomerular filtration rate (eGFR), systolic/diastolic BPs (SBP/DBP) were analysed prior to PTA, at 6-, 12-month, and final follow-up visits, and whenever RS was diagnosed.

RESULTS

RS was identified in 30 (14.3%) patients, and there were 36 (14.5%) lesions. The Kaplan-Meier RS-free survival curves in fibromuscular dysplasia, atherosclerosis, and vasculitis at 1 and 7 years were: 100% and 100%; 95.6 and 83.9%; and 71.4 and 39.7%, respectively. Patients with RS, as compared to RS-free patients, presented with less pronounced changes in respect with: SBP (1.4 ±17.6 vs. -15.8 ±25.8 mm Hg; p = 0.01), DBP (2.64 ±10.1 vs. -6.5 ±14.1 mm Hg; p = 0.002), SCC (22.4 ±55.2 vs. -3.6 ±43.9 µmol/l; p = 0.002), and eGFR (-1.85 ±18 vs. -5.34 ±19.5 mm Hg; p = 0.045). In multivariate Cox regression analysis, independent predictors of RS occurred: lack of BP decrease (HR = 4.19, 95% CI: 1.67-10.3; p = 0.002), eGFR increase < 0.17 ml/min/1.73 m2 (HR = 2.93, 95% CI: 1.08-7.91; p = 0.033), stent diameter ≤ 5 mm (HR = 2.76, 95% CI: 1.09-6.97; p = 0.031), and vasculitis (HR = 5.61, 95% CI: 1.83-17.2; p = 0.003). RS was treated in 24 patients with RS recurrence in 20%.

CONCLUSIONS

The RS rate differs depending on RAS aetiology. Lack of SBP/DBP and eGFR improvement, vasculitis, and stent diameter are associated with RS risk. Repeated PTA is effective, but recurrent RS occurs in 20% of cases.

A refractory hypertensive patient with fibromuscular dysplasia and multicystic dysplastic kidney

The case of a 16-year-old male patient with left renal artery stenosis due to fibromuscular dysplasia (FMD) and an atrophic kidney due to a right multicystic dysplastic kidney (MCDK) who presented with refractory hypertension is reported. On continuous Doppler imaging, the peak systolic velocity (PSV) at the stenotic site of the left renal artery was 404 cm/s. The FMD formed a "string-of-beads" appearance on computed tomographic angiography (CTA) and renal artery angiography. Percutaneous transluminal renal angioplasty (PTRA) with a balloon catheter was performed, after which the left renal artery returned to near normal, and his blood pressure decreased to within the normal range. In this case, the main cause of refractory hypertension was considered to have been renal artery stenosis due to left FMD.

Endovascular Treatment of Renal Artery Stenosis due to Fibromuscular Dysplasia - Is Stent Implantation Underused in this Circumstance?

Fibromuscular dysplasia (FMD) is a nonatherosclerotic and noninflammatory arterial disease that commonly affects the renal and carotid arteries. The primary target in treating patients with renal artery FMD is the control of blood pressure in order to prevent end-organ damage, which can be caused by poorly controlled hypertension. Invasive endovascular treatment should be taken into consideration both when hypertension cannot be controlled with medication. According to current opinion, hypertension attributed to renal artery FMD is often successfully treated solely with percutaneous renal balloon angioplasty (PRBA), with no requirement for stent implantation under most circumstances. However, an FMD recurrence after PRBA occurs frequently in these patients.

Resistant Hypertension due to Fibromuscular Dysplasia in a Young Male: A Rare Case Report

Fibromuscular Dysplasia (FMD) is a sporadic non-atherosclerotic disease. FMD has been established in nearly every arterial bed. However, the most frequent arteries affected are the renal and carotid arteries. Disease presentation may vary broadly, depending upon the arterial bed complication and the severity of illness. Hypertension, particularly resistant type, headache and dizziness are the most common presentations. String of beads appearance in angiographic views due to post-stenotic aneurysms is the characteristic view. It is most commonly described in young aged females; but in rare male cases has also been reported. Moreover, balloon angioplasty is standard and effective therapy for FMD. We present a young 28-year-old man who was referred for evaluation of resistant hypertension for nearly 3 years without comprehensive workup. The patient underwent renal artery angiography which confirmed beading narrowing of the right renal artery with significant stenosis at mid portion compatible with FMD; and balloon angioplasty was done. This case highlights that FMD should be kept in mind as a rare cause of resistant hypertension in young males; although it is most common in young females.

Successful cutting balloon angioplasty in a child with resistant renal artery stenosis

Background

Although renovascular hypertension is a rare disease, it is associated with 5–10 % of cases of childhood hypertension. It is a potentially treatable cause of hypertension, and is often caused by renal artery stenosis (RAS). The most common cause of RAS in children is fibromuscular dysplasia (FMD). The options for treating RAS depend on the location, severity and abnormality underlying the condition.

Case presentation

A previously healthy 7-year-old Korean boy presented to our clinic with hypertension and headache. Renal ultrasonography and multi-detector computed tomography (MDCT) showed severe focal stenosis at the middle portion of the left renal artery (LRA) and multiple collateral vessels. Percutaneous balloon angioplasty was performed as an initial treatment, but yielded unsatisfactory results. The presence of intimal-type FMD was suspected based on his clinical features, angiographic appearance, and resistance to percutaneous transluminal renal angioplasty. Thereafter, his blood pressure was normalized using antihypertensive medication. Follow-up multi-detector computed tomography at 11 years of age showed persistent severe stenosis of the LRA. After unsuccessful attempts to perform balloon angioplasty, 3.5-mm cutting balloon angioplasty (CBA) was performed and yielded satisfactory results. He was discharged without any medication. At 1 year and 6 months after the intervention, he has been normotensive and had not required any antihypertensive medication.

Conclusion

The author describes a case of resistant RAS that was detected on MDCT and successfully treated using percutaneous (CBA). Although cutting balloon angioplasty is useful in many clinical conditions, including the current case, clinicians should carefully consider the associated risk of arterial disruption and pseudoaneurysm formation.