Diagnosis and management of fibromuscular dysplasia and segmental arterial mediolysis in gastroenterology field: A mini-review

A case of transcatheter arterial embolization for intraperitoneal hemorrhage due to giant hepatic segmental arterial mediolysis

This study aimed to demonstrate the effect of transcatheter arterial embolization (TAE) on hepatic segmental arterial mediolysis (SAM). The patient, a 68-year-old female, suddenly developed right upper abdominal pain in October 2021, which was initially relieved. However, she was rushed to a local hospital the next day when her abdominal pain recurred. An abdominal computed tomography scan suggested a ruptured hepatic aneurysm; therefore, she was transferred to our hospital and admitted on the same day. On the first day after admission, she underwent emergency catheterization and N-butyl-2-cyanoacrylate (NBCA)/lipiodol embolization for an aneurysm in the hepatic S6. A multi-detector computed tomography on hospital day 8 to probe for extrahepatic lesions revealed multiple beaded irregularities in the superior mesenteric and bilateral renal arteries. A head magnetic resonance angiography performed on the ninth day showed no aneurysms or irregularities. She did well after TAE, did not have rebleeding, and was discharged on hospital day 16. Rupture of an aneurysm associated with SAM occurs frequently in the colonic and gastroepiploic arteries, and rupture of a hepatic aneurysm is relatively rare. TAE hemostasis was able to save the patient by preventing intraperitoneal bleeding caused by hepatic segmental arterial mediolysis.

A case of subarachnoid hemorrhage caused by multiple cerebral aneurysms due to segmental arterial mediolysis

Background:

Segmental arterial mediolysis (SAM) is a condition in which an aneurysm is formed by causing lysis of the media and remodeling of blood vessels. Short-term recurrence has been reported in abdominal aortic aneurysms. Cerebral aneurysms have been suggested to form in a short period not only in the abdominal cavity but also in the intracranial arteries in SAM.

Case Description:

A 36-year-old pregnant woman at 35 weeks’ gestation developed sudden headache and disorientation. Head magnetic resonance imaging showed a small amount of subarachnoid hemorrhage in the right ambient cistern. A fusiform cerebral aneurysm was found in the periphery of the right superior cerebellar artery, and small saccular aneurysms were found in the periphery of the right posterior cerebral artery and left posterior inferior cerebral artery. After delivery of the fetus, endovascular embolization of the ruptured aneurysm was performed. However, 10-week postoperatively, she developed sudden headache. Hemorrhage was found in the fourth ventricle, and enlargement of the left posterior inferior cerebellar artery (PICA) peripheral aneurysm and disappearance of the right posterior cerebral artery peripheral aneurysm were confirmed. A ruptured aneurysm in the peripheral left PICA was removed after trapping. Intraoperatively, an unruptured thrombosed aneurysm that was not visualized by imaging was also removed. Histopathological examination showed no calcification or inflammation, rupture of the internal elastic lamina, and lack of segmentation, and SAM was diagnosed.

Conclusion:

In atypical dissecting aneurysms, SAM should be considered as a differential diagnosis. Systemic examination and short-term follow-up are also necessary.

Value of second opinion subspecialty radiology consultation in suspected abdominal medium vessel vasculitis

PURPOSE

To perform a descriptive analysis of individuals with suspected Polyarteritis nodosa (PAN) referred for second opinion imaging consultation.

METHODS

A retrospective observational cohort study was performed at a single institution. A consecutive sample was performed of individuals who underwent a second opinion CT or MR angiography subspecialty radiologist consultation between January 2008 and September 2019 for suspected abdominal medium vessel vasculitis. Demographic, clinical, and imaging data were collected. Clinical and imaging findings were reported for PAN, small vessel vasculitis, and "non-vasculitis" groups. Agreement and diagnostic accuracy between final clinical and second opinion imaging diagnoses for PAN were determined. Two-tailed t-tests with a significant p-value < 0.05 were utilized.

RESULTS

Of the 58 participants, 9 were clinically diagnosed with PAN, 11 with small vessel vasculitis (including lupus, IgA, and ANCA-associated vasculitis), and 38 with non-vasculitis diagnoses. The non-vasculitis group included 15 SAM, 3 FMD, and 1 SAM-FMD spectrum diagnoses. Higher C-reactive protein level (51 vs 17, p = 0.04) and superior mesenteric artery involvement (56% vs 21%, p = 0.04) were more common in PAN than non-vasculitis diagnoses, while arterial dissection (40% vs 0%, p = 0.02) and celiac vasculature involvement (53% vs 0%, p = 0.003) were more common in the non-vasculitis group. There was 88% agreement (51/58; Cohen's kappa 0.56); sensitivity was 67% [95%-confidence interval (CI) 30-93%] and specificity was 92% (95%-CI 80-98%).

CONCLUSION

Isolated celiac artery involvement and arterial dissection were more common in non-inflammatory vasculopathies than PAN. Our findings highlight the need for multidisciplinary collaboration and awareness of the diverse findings of abdominal vasculopathies.

Idiopathic Middle Meningeal Arteriovenous Fistula Associated with Segmental Arterial Mediolysis: A Case Report

Objective

Middle meningeal arteriovenous fistula (MMAVF) is typically post-traumatic or iatrogenic in origin, but it can have an idiopathic origin in rare cases. Here, we report a case of idiopathic MMAVF complicated by segmental arterial mediolysis (SAM).

Case Presentation

The patient was a 63-year-old woman admitted to our hospital with symptoms of right pulsating tinnitus for the past 2 months. She had no significant medical history. MRI and DSA revealed a right MMAVF. Selective embolization using coils was performed. Seven years later, when she underwent laparotomy for intestinal perforation, multiple aneurysms were found in the abdominal cavity. Left hemicolectomy was performed, and an aneurysm of the gastroepiploic artery was resected. Based on a pathological examination of the aneurysm, the patient was diagnosed with SAM. Coil embolization was performed to prevent rupture.

Conclusion

This case report shows that MMAVF may be associated with SAM. Fistula embolization with coils is an effective treatment of MMAVF associated with SAM. Therefore, it is important to check for systemic diseases, such as SAM when idiopathic MMAVF is detected.

Segmental Arterial Mediolysis (SAM) Leading to Chronic Renal Insufficiency

Background

Segmental arterial mediolysis (SAM) is a rare self-limiting non-atherosclerotic, non-inflammatory vasculopathy. SAM typically affects the visceral arteries of the abdomen to include the celiac, mesenteric, and renal arteries. SAM has a favorable prognosis in most cases with an asymptomatic course but can have mortality rates as high as 50% due to acute aneurysmal rupture. Very few cases of adverse long-term sequelae involving SAM have been described, and this report of chronic kidney disease represents a sentinel case illustrating that chronic disease can and does occur as a result of SAM and should be investigated for at follow-up.

Case Presentation

In this case report, we describe a case of a 45-year-old male with erectile dysfunction but without any readily identifiable risk factors for chronic kidney disease (CKD) or vasculopathy, who presented with bilateral renal infarction and parenchymal infarcts due to SAM and who subsequently developed CKD at follow-up. We conduct a mini-literature review that discusses the pathogenesis of SAM in the context of vasospastic diseases, as well as compares the outcomes of observation-only, versus medical-management, versus endovascular-interventions in patients with SAM.

Conclusion

This is the first case to our knowledge of CKD occurring as an outcome of SAM without any preceding significant comorbidity, highlighting that whereas SAM is of itself rare and typically resolves, chronic disease can linger and should be evaluated for on follow-up. Further, we argue that radiological evidence of precursor vasospastic disease may exist in several locations apart from the index lesion and thus warrants wider whole-body radiographic exploration for lesions as an opportunity to prevent chronic sequelae as illustrated in this case report from occurring. Finally, a review of published case-series suggests that disease progression is less likely to occur after endovascular-intervention compared to observation-only or medical management and the risk of intervention vs conservative management should therefore be discussed with the patient.

Mimics of vasculitis

While prompt diagnosis of vasculitis is important, recognition of vasculitis mimics is equally essential. As in the case of vasculitis, an approach to mimics based on the anatomic size of vessels can be useful. Infections can mimic vasculitis of any vessel size, including the formation of aneurysms and induction of ANCAs. Genetic disorders and vasculopathies are important considerations in large and medium vessel vasculitis. Cholesterol emboli, thrombotic conditions and calciphylaxis typically affect the medium and small vessels and, like vasculitis, can cause cutaneous, renal and CNS manifestations. Reversible cerebral vasoconstriction syndrome is important to distinguish from primary angiitis of the CNS. As an incorrect diagnosis of vasculitis can result in harmful consequences, it is imperative that the evaluation of suspected vasculitis includes consideration of mimics. We discuss the above mimics and outline a systematic and practical approach for differentiating vasculitis from its mimics.

Ileocolic arterial aneurysm associated with segmental arterial mediolysis: A case report

OBJECTIVES

Segmental arterial mediolysis is a rare disease that most commonly affects the superior mesenteric artery among abdominal arteries. However, aneurysms involving the ileocolic arterial branch of the superior mesenteric artery are extremely rare. Here, we describe the treatment of a patient with an ileocolic arterial aneurysm suspected to have occurred secondary to segmental arterial mediolysis.

METHODS

We confirmed the diagnosis of ileocolic arterial aneurysm, which showed the characteristic "string-of-beads" appearance of the distal main trunk of the superior mesenteric artery on angiography. We performed endovascular coil embolization for the aneurysm, and for both the inflow and outflow vessels. After confirming that the aneurysm was no longer visible, the treatment was completed.

RESULTS

There were no clinical findings suspicious of ischemic enteritis or intestinal necrosis after embolization. We confirmed that the ileocolic arterial aneurysm was not observed on computed tomography angiography one month after treatment.

CONCLUSIONS

While development of an ileocolic arterial aneurysm associated with segmental arterial mediolysis is very rare, it is at a high risk of sudden rupture. Therefore, coil embolization is a useful intervention in such patients and can be implemented based on the size and morphology of the aneurysm.

Spontaneous visceral artery dissections in otherwise normal arteries: Clinical features, management, and outcomes compared with fibromuscular dysplasia

OBJECTIVE

Visceral artery dissection with otherwise normal-appearing arteries (VADNA), diagnosed on imaging and suggestive of segmental arterial mediolysis, is a poorly understood disease entity. Study objectives were to define the clinical features, management, and outcomes of patients with VADNA compared with patients with fibromuscular dysplasia (FMD).

METHODS

In this single-center retrospective cohort study, consecutive patients with a diagnosis of VADNA or FMD evaluated in the Mayo Clinic Gonda Vascular Center (January 1, 2000-April 1, 2017) were identified. Patient demographics, symptom presentation, management, composite adverse arterial events (recurrent arterial dissection, stroke or transient ischemic attack, myocardial infarction, mesenteric or renal infarction, or need for revascularization), and overall survival were compared between VADNA and FMD patients.

RESULTS

There were 103 VADNA patients (age [mean ± standard deviation], 51.7 ± 11.0 years; 27.9% female) and 248 FMD controls (49.8 ± 8.9 years; 81.8% female) identified. The most common symptom for VADNA patients was abdominal or flank pain (80.6%). For FMD, chest pain, headache, and dizziness were more frequent presenting complaints. The median follow-up was longer for VADNA patients (42 months; interquartile range, 9-76 months) compared with FMD patients (19 months; interquartile range, 0.6-52 months; P < .001). During this time interval, there were twofold more composite arterial events in the VADNA group compared with the FMD group (17% vs 8.1%; P = .01). This difference was primarily driven by recurrent dissections. All-cause mortality was low and similar for both groups (3.8% vs 0.4%; P = .10).

CONCLUSIONS

VADNA patients carry a higher risk of recurrent arterial events compared with those with FMD. This difference was primarily driven by recurrent dissections.

Ischemic Colitis due to Fibromuscular Dysplasia Limited to the Inferior Mesenteric Artery: A Case Report

섬유근형성이상은 주로 신동맥, 경동맥의 협착이나 동맥류 형성을 유발하는 비죽상경화, 비염증성 동맥 질환으로, 드물게 내장동맥을 침범하며 다양한 양상으로 나타날 수 있다. 저자들은 66세 남자에서 하장간막동맥을 단독으로 침범한 섬유근형성이상으로 인해 좌결장동맥과 상직장동맥의 동맥류 및 허혈성 대장염으로 발현된 증례를 경험하여 보고하고자 한다.

Rare Mesenteric Arterial Diseases: Fibromuscular Dysplasia and Segmental Arterial Mediolysis and Literature Review

Fibromuscular dysplasia (FMD) and segmental arterial mediolysis (SAM) are noninflammatory, nonatherosclerotic arterial diseases that cause aneurysm, occlusion, and thromboses. These diseases are rarely seen in mesenteric arterial lesions; however, as they can be lethal if appropriate management is not provided, the accumulation of clinical information from cases is essential. We herein report the cases of a 57-year-old man diagnosed with FMD and a 63-year-old man diagnosed with SAM. We conclude that an early diagnosis with imaging modalities and clinical information followed by the appropriate treatment improves the prognosis of these arterial diseases.

Coronary Artery Involvement in Segmental Arterial Mediolysis: A Case Report

Segmental arterial mediolysis (SAM) is an increasingly recognized disorder affecting small- to medium-sized muscular arteries. A patient with SAM involving the visceral arteries who was also found to have multivessel coronary artery involvement is described. The patient underwent a battery of biochemical, imaging, and genetic tests to exclude other vasculitides and connective tissue disorders. The aim is to shed light on the potential for SAM to affect the coronary arteries and recommend screening of the coronary arteries of patients with SAM. © RSNA, 2019.

Segmental Arterial Mediolysis with Preceding Symptoms Resembling Viral Infection Hampers the Differentiation from Polyarteritis Nodosa

A middle-aged man presented with a fever, arthralgia, gastrointestinal symptoms, headache, and rash. After two weeks, the patient suddenly complained of severe abdominal pain, and computed tomography revealed aneurysms in the hepatic and splenic arteries, which increased in size progressively. Given the elevated levels of inflammatory markers and orchitis, polyarteritis nodosa (PN) was initially suspected. Catheter embolization for the ruptured hepatic aneurysm and splenectomy for the large splenic ones were performed, and the pathological finding was consistent with segmental arterial mediolysis (SAM). Changes in inflammatory marker levels and aneurysmal size are also informative to differentiate SAM from PN.