Segmental Arterial Mediolysis: Clinical and Imaging Features at Presentation and during Follow-up

Segmental arterial mediolysis after fenestrated endovascular abdominal aortic aneurysm repair-A rare complication

Segmental arterial mediolysis (SAM) is a rare, noninflammatory, nonatherosclerotic condition that occurs commonly in mesenteric vessels. There are no known predisposing risk factors to the development of SAM. We present a case of a 67-year-old woman who presented with abdominal pain 2 days following discharge after an elective endovascular abdominal aortic intervention. Repeat imaging 2 days after readmission showed the presence of multiple new aneurysms involving the mesenteric vasculature. She underwent attempted endovascular embolization of the largest aneurysm. The postmortem and histopathologic examinations confirmed the diagnosis of SAM.

Spontaneous Subdiaphragmatic Hemorrhage From an Aneurysm of Inferior Phrenic Artery

Inferior phrenic artery (IPA) aneurysms are the rarest type of visceral aneurysms. It usually occurs secondary to trauma, surgery, or as a complication of pancreatitis. In addition, it can be a manifestation of underlying systemic pathology such as vasculitis, collagen vascular disorders, sepsis, or segmental arterial mediolysis. It can be associated with hypertension in 43% of cases. The presentation of IPA aneurysm is nonspecific with abdominal pain, melena, hematochezia, and anemia. The ruptured and actively bleeding aneurysm can lead to hemorrhagic shock, and immediate management is required with angiography and endovascular embolization with coil or gel foam or stent etc. Inaccessible locations are reached with surgical intervention, but it is associated with high morbidity and mortality. We here report a rare case of spontaneously ruptured IPA pseudoaneurysm extending from the posterior mediastinum to the subdiaphragmatic area and managed with coil and gel foam embolization.

Imaging of Visceral Vessels

The visceral vasculature is inextricably intertwined with abdominopelvic disease staging, spread, and management in routine and emergent cases. Comprehensive evaluation requires specialized imaging techniques for abnormality detection and characterization. Vascular pathology is often encountered on nondedicated routine imaging examinations, which may obscure, mimic, or confound many vascular diagnoses. This review highlights normal arterial, portal venous, and systemic venous anatomy and clinically relevant variants; diagnostic pitfalls related to image-acquisition technique and disease mimics; and characteristics of common and rare vascular diseases to empower radiologists to confidently interpret the vascular findings and avoid misdiagnosis.

Segmental Arterial Mediolysis in a Patient With Ascending Aorta Dilatation

A 70-year-old woman consulted us for dyspnea. Echocardiography revealed moderate aortic regurgitation secondary to ascending aorta dilatation. Study was completed with aortic angiography computed tomography, showing stenosis and dissection of several visceral arteries. There were no abnormal inflammatory or autoimmune markers, nor fluorine-18-fluorodeoxyglucose positron emission tomography uptake. Segmental arterial mediolysis was diagnosed.

Gallbladder hemorrhage associated with segmental arterial mediolysis: a case report

BACKGROUND

Gallbladder hemorrhage is a rare but fatal condition. The reported causes of gallbladder hemorrhage include iatrogenesis, atherosclerotic changes in the cystic arteries, acute cholecystitis or cholelithiasis, malignancy, trauma, hemophilia, pseudoaneurysm, and the use of oral anticoagulant medications. Recently, segmental arterial mediolysis (SAM) has been reported as a possible etiology of life-threatening abdominal, retroperitoneal, and intracranial hemorrhages. However, no previous reports have described the association between gallbladder hemorrhage and SAM.

CASE PRESENTATION

A 59-year-old man was transferred to our hospital complaining of upper abdominal pain and vomiting. Contrast-enhanced computed tomography revealed high-density images of the gallbladder and common bile duct. However, there were no obvious findings of gallstones, cholecystitis, tumors, or aneurysms. He was diagnosed with gallbladder hemorrhage and bile duct obstruction. We performed a laparoscopic cholecystectomy after endoscopic biliary drainage. The gross appearance of the surgically resected specimen showed 12 small (3-12 mm), slightly elevated lesions on the gallbladder mucosa. Histologically, these slightly elevated lesions consisted of dilated muscular arteries of the gallbladder wall with fibrinoid degeneration of the media and focal loss of the internal and external elastic laminae. The histopathological diagnosis was confirmed as SAM.

CONCLUSIONS

To the best of our knowledge, this is the first reported case of a gallbladder hemorrhage associated with SAM. Our case report shows that SAM can cause gallbladder hemorrhage, suggesting that SAM should be considered in the differential diagnosis of gallbladder hemorrhage.

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.

Pancreaticoduodenal Artery Aneurysm Rupture Presenting as Duodenal Obstruction Successfully Treated with Early Transcatheter Arterial Embolization: A Case Report of Suspected Segmental Arterial Mediolysis

Visceral aneurysms are a rare but important form of abdominal vascular disease. Rupture of the aneurysms leads to serious symptoms, such as acute abdomen or abdominal bleeding. However, duodenal obstruction due to arterial rupture of an aneurysm is very rare. We herein report a 50-year-old woman with suspected segmental arterial mediolysis (SAM) who was first diagnosed with acute abdomen and duodenal obstruction. Rupture of a pancreaticoduodenal artery aneurysm was confirmed, and she was treated with transcatheter arterial embolization. In cases of acute abdomen, SAM is a rare but important possibility to consider as a differential diagnosis.

Endovascular treatment of an isolated iliac artery aneurysm associated with segmental arterial mediolysis

Segmental arterial mediolysis is a noninflammatory nonatherosclerotic vasculopathy of uncertain etiology characterized by dissection and/or aneurysm formation. It affects medium-to-large arteries, primarily the celiac, superior mesenteric, and renal arteries. Iliac involvement is rare, and its specific treatment has not been described. We detail a patient who presented with intrabdominal hemorrhage from a ruptured right colic artery aneurysm. He underwent transcatheter arterial embolization followed by right hemicolectomy. Histopathology confirmed the diagnosis of segmental arterial mediolysis. Endovascular treatment of a 3-cm iliac artery aneurysm was performed 18 months later. There was successful exclusion of the aneurysm demonstrated on computed tomography angiography at 10 years.

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.

Vaskulitis mimics

Idiopathische Vaskulitiden sind seltene entzündliche Systemerkrankungen, die nach der Chapel-Hill Konsensus-Nomenklatur nach der Größe der prädominant betroffenen Gebiete von Blutgefäßen (große, mittelgroße, kleine Gefäße und Gefäße variabler Größe) eingeteilt werden. Vaskulitis mimics sind Syndrome, die ein ähnliches klinisches Bild hervorrufen oder leicht mit einer idiopathischen Vaskulitis verwechselt werden und teils sogar ein Krankheitsbild, das klinisch und histologisch einer Vaskulitis gleicht, auslösen können. Die Zahl der Vaskulitis mimics ist groß, je nach betroffenem Gefäßgebiet kommen hereditäre Erkrankungen des Bindegewebes, genetisch bedingte Immundefekt- und Autoinflammationssyndrome, infektiöse Erkrankungen, seltene entzündliche Systemerkrankungen, Tumorerkrankungen, medikamenteninduzierte Syndrome und zahlreiche weitere infrage. In diesem Review wird eine Auswahl klassischer Imitatoren von Vaskulitiden, orientiert an der Größe der betroffenen Blutgefäße präsentiert und Konstellationen, die typische „Fallstricke“ in der klinischen Abklärung darstellen können, diskutiert.

An Unusual Presentation of Segmental Arterial Mediolysis

Segmental arterial mediolysis (SAM) is a rare nonatherosclerotic and noninflammatory disease that often affects medium to large-sized arteries. We report a case of SAM involving bilateral hepatic arteries in an elderly woman. Although her initial presentation mimicked vasculitis, the clinical course and imaging led to the diagnosis of SAM. She was treated with coil embolization and stenting of the involved hepatic vessel leading to dramatic clinical improvement. It should be differentiated from vasculitis because there is no role of steroids in the management of SAM.

Acute abdominal pain: a challenging diagnosis

We hereby describe a case of an acutely ill 41-year-old male without any medical history who presented with an acute abdomen in the emergency department. An abdominal CT showed a dissection of the coeliac trunk and infarction of the spleen. Because of a presumed diagnosis of vasculitis he was started on high dose IV steroids. However, after additional testing the diagnosis of segmental arteriolar Mediolysis (SAM) was made. In this case report we describe the presentation, diagnosis, treatment and follow-up of this patient and provide the readers with background about common differential diagnosis and criteria for diagnosing SAM.

Intraperitoneal hemorrhage due to segmental arterial mediolysis associated with cerebral vasospasm after subarachnoid hemorrhage

A man in his 50s with no significant past medical history developed subarachnoid hemorrhage due to ruptured left middle cerebral artery aneurysm. On the ninth hospital day, he had a ruptured visceral aneurysm with segmental arterial mediolysis, and we successfully treated with transarterial embolization using metallic coils.

Clinical Presentation, Imaging, and Management of Segmental Arterial Mediolysis: A Rare Vascular Disorder

Objectives  Our objective was to analyze the clinical presentation, imaging findings, and the management of segmental arterial mediolysis (SAM) in different case scenarios within our medical institution.

Materials and Methods  We retrospectively analyzed 13 cases of SAM in our institution from July 2017 to March 2020. The images from the cases were collected from picture archiving and communication system (PACS) along with other pertinent clinical information from the hospital's information system. All the patients we studied underwent contrast-enhanced computed tomography (CT) using a third-generation Siemens SOMATOM Force dual-source CT scanner. Once the dual-phase scanning was completed, the images were analyzed using the workstation's syngo.via software.

Results  Three out of the 13 cases required stent-grafting of the renal/celiac artery, and the involved branch of the superior mesenteric artery was embolized in one case. The rest of the cases were managed conservatively with antiplatelets/anticoagulants. Subsequent follow-ups of the patients were conducted and showed stabilization/regression of the initial findings without finding any evidence of worsening.

Conclusion  SAM should be considered when making a differential diagnosis of acute abdominal pain when associated with dissection or aneurysms in splanchnic arteries, and in cases of unexplained intra-abdominal hemorrhaging. The radiologist needs to be aware of this possibility to raise suspicion, alert the clinician, and guide appropriate management.

A Single Center 8 Year Experience of Segmental Arterial Mediolysis Management

OBJECTIVE

Segmental Arterial Mediolysis (SAM) is a rare, poorly understood vasculopathy that involves vacuolization of the arterial wall, most commonly of the visceral arteries. There are no established therapeutic or monitoring guidelines for SAM, and intervention typically depends on patient presentation. The purpose of this study is to review the management and outcomes of patients with this rare vascular disease METHODS: Single center retrospective review of patients diagnosed with SAM between 2011 and 2019. Included were patients with radiological diagnosis of SAM. Demographic factors, past medical history, presenting symptoms, affected vessels, management, and lesion characteristics over time were collected. Demographic and periprocedural factors, and medical management strategies were compared for those who required operative intervention versus those managed non-operatively.

RESULTS

Thirty patients were included, 21 (70%) were male, mean age was 53.5 years (range: 35.7-72.2). Twenty-seven patients were managed non-operatively, 3 patients required surgical intervention. Patients who underwent operative intervention were more likely to present with pain >30 days (P < 0.05), and hemorrhage (P < 0.01). Abdominal pain was the most common presenting symptom (n = 24, 80%). Arterial dissection was the most common radiological finding at time of presentation (n = 20, 67%). The celiac artery and its branches were most often involved (n=22, 73%) followed by the superior mesenteric artery and its branches (n = 15, 50%). Non-operative management most often consisted of anti-hypertensive therapy (n = 13, 43%), antiplatelet agents (n = 17, 57%%), and lipid-lowering agents (n = 13, 43%), with 7 patients receiving all three. Six patients demonstrated confirmed resolution of lesions during surveillance imaging, with average time to resolution of 325.5 days.

CONCLUSIONS

Patients who underwent intervention for SAM presented with either mesenteric ischemia or pseudoaneurysm rupture. In patients that present without those conditions, medical management consisting of anti-hypertensives, antiplatelet agents, and lipid-lowering therapy was effective. Non operative management resulted in symptom resolution in all patients and surveillance imaging showed resolution of radiographic abnormalities in 6 patients out of 27 at less than one year.

Segmental arterial mediolysis: a rare cause of an acute abdomen

Segmental arterial mediolysis (SAM) is a nonatherosclerotic, noninflammatory and nonimmune arteriopathy of unknown aetiology. We present the case of a 43-year-old male who presented to the emergency department with abdominal pain. A computed tomography of abdomen and pelvis showed a narrow, hypodense superior mesenteric artery after the origin, raising the possibility of thrombus or vasculitis. He was commenced on rivaroxaban and steroids. He subsequently presented with an acute abdomen in a collapsed state. Repeat imaging of his abdomen and pelvis revealed an ischaemic ileal segment and caecum. He required an emergency laparotomy with resection of the ischaemic segment and formation of a double-barrelled stoma. SAM is an important diagnosis for clinicians and radiologists to be aware of, given the risks of life-threatening haemorrhage and acute organ ischaemia. This is a commonly overlooked cause of abdominal pain, where an early diagnosis with lifestyle modifications may prevent disease progression and subsequent development of life-threatening complications.

Beyond Atherosclerosis and Fibromuscular Dysplasia: Rare Causes of Renovascular Hypertension

Renovascular hypertension is one of the most common forms of secondary hypertension. Over 95% of cases of renovascular hypertension are due either to atherosclerosis of the main renal artery trunks or to fibromuscular dysplasia. These two causes of renal artery stenosis have been extensively discussed in recent reviews and consensus. The aim of the current article is to provide comprehensive and up-to-date information on the remaining causes. While these causes are rare or extremely rare, etiologic and differential diagnosis matters both for prognosis and management. Therefore, the clinician cannot ignore them. For didactic reasons, we have grouped these different entities into stenotic lesions (neurofibromatosis type 1 and other rare syndromes, dissection, arteritis, and segmental arterial mediolysis) often associated with aortic coarctation and other arterial abnormalities, and nonstenotic lesions, where hypertension is secondary to compression of adjacent arteries and changes in arterial pulsatility (aneurysm) or to the formation of a shunt, leading to kidney ischemia (arteriovenous fistula). Finally, thrombotic disorders of the renal artery may also be responsible for renovascular hypertension. Although thrombotic/embolic lesions do not represent primary vessel wall disease, they are characterized by frequent macrovascular involvement. In this review, we illustrate the most characteristic aspects of these different entities responsible for renovascular hypertension and discuss their prevalence, pathophysiology, clinical presentation, management, and prognosis.

Beyond Atherosclerosis and Fibromuscular Dysplasia: Rare Causes of Renovascular Hypertension

Renovascular hypertension is one of the most common forms of secondary hypertension. Over 95% of cases of renovascular hypertension are due either to atherosclerosis of the main renal artery trunks or to fibromuscular dysplasia. These two causes of renal artery stenosis have been extensively discussed in recent reviews and consensus. The aim of the current article is to provide comprehensive and up-to-date information on the remaining causes. While these causes are rare or extremely rare, etiologic and differential diagnosis matters both for prognosis and management. Therefore, the clinician cannot ignore them. For didactic reasons, we have grouped these different entities into stenotic lesions (neurofibromatosis type 1 and other rare syndromes, dissection, arteritis, and segmental arterial mediolysis) often associated with aortic coarctation and other arterial abnormalities, and nonstenotic lesions, where hypertension is secondary to compression of adjacent arteries and changes in arterial pulsatility (aneurysm) or to the formation of a shunt, leading to kidney ischemia (arteriovenous fistula). Finally, thrombotic disorders of the renal artery may also be responsible for renovascular hypertension. Although thrombotic/embolic lesions do not represent primary vessel wall disease, they are characterized by frequent macrovascular involvement. In this review, we illustrate the most characteristic aspects of these different entities responsible for renovascular hypertension and discuss their prevalence, pathophysiology, clinical presentation, management, and prognosis.

Rapid Formation and Rupture of Multiple Abdominal Pseudoaneurysms: A Life Threatening Case of Segmental Arterial Mediolysis

We present a 62-year-old gentleman with rapidly forming abdominal pseudoaneurysms due to segmental arterial mediolysis (SAM). With rupture of his pseudoaneurysms, he underwent angiography and successful coil embolisation. In this case, we demonstrate the potential for rapid progression of pseudoaneurysms in SAM, with the need for prompt diagnosis and urgent endovascular intervention.

Beyond Atherosclerosis and Fibromuscular Dysplasia: Rare Causes of Renovascular Hypertension

Renovascular hypertension is one of the most common forms of secondary hypertension. Over 95% of cases of renovascular hypertension are due either to atherosclerosis of the main renal artery trunks or to fibromuscular dysplasia. These two causes of renal artery stenosis have been extensively discussed in recent reviews and consensus. The aim of the current article is to provide comprehensive and up-to-date information on the remaining causes. While these causes are rare or extremely rare, etiologic and differential diagnosis matters both for prognosis and management. Therefore, the clinician cannot ignore them. For didactic reasons, we have grouped these different entities into stenotic lesions (neurofibromatosis type 1 and other rare syndromes, dissection, arteritis, and segmental arterial mediolysis) often associated with aortic coarctation and other arterial abnormalities, and nonstenotic lesions, where hypertension is secondary to compression of adjacent arteries and changes in arterial pulsatility (aneurysm) or to the formation of a shunt, leading to kidney ischemia (arteriovenous fistula). Finally, thrombotic disorders of the renal artery may also be responsible for renovascular hypertension. Although thrombotic/embolic lesions do not represent primary vessel wall disease, they are characterized by frequent macrovascular involvement. In this review, we illustrate the most characteristic aspects of these different entities responsible for renovascular hypertension and discuss their prevalence, pathophysiology, clinical presentation, management, and prognosis.

Beyond Atherosclerosis and Fibromuscular Dysplasia: Rare Causes of Renovascular Hypertension

Renovascular hypertension is one of the most common forms of secondary hypertension. Over 95% of cases of renovascular hypertension are due either to atherosclerosis of the main renal artery trunks or to fibromuscular dysplasia. These two causes of renal artery stenosis have been extensively discussed in recent reviews and consensus. The aim of the current article is to provide comprehensive and up-to-date information on the remaining causes. While these causes are rare or extremely rare, etiologic and differential diagnosis matters both for prognosis and management. Therefore, the clinician cannot ignore them. For didactic reasons, we have grouped these different entities into stenotic lesions (neurofibromatosis type 1 and other rare syndromes, dissection, arteritis, and segmental arterial mediolysis) often associated with aortic coarctation and other arterial abnormalities, and nonstenotic lesions, where hypertension is secondary to compression of adjacent arteries and changes in arterial pulsatility (aneurysm) or to the formation of a shunt, leading to kidney ischemia (arteriovenous fistula). Finally, thrombotic disorders of the renal artery may also be responsible for renovascular hypertension. Although thrombotic/embolic lesions do not represent primary vessel wall disease, they are characterized by frequent macrovascular involvement. In this review, we illustrate the most characteristic aspects of these different entities responsible for renovascular hypertension and discuss their prevalence, pathophysiology, clinical presentation, management, and prognosis.

Multiple abdominal artery dissections: how to distinguish two rare diseases

A 59-year-old woman was referred to the emergency room with acute abdominal pain. A CT scan revealed multiple dissections and microaneurysms of the superior mesenteric, the hepatic and the renal arteries. Stenting of the superior mesenteric artery was required. A non-invasive diagnostic procedure was instrumental to establish the diagnosis and guide appropriate treatment, which resulted in a rapid and sustained recovery.

A case of segmental arterial mediolysis with subarachnoid hemorrhage due to anterior cerebral artery dissection followed by internal carotid artery dissection

Background:

Segmental arterial mediolysis (SAM) causes subarachnoid hemorrhage (SAH) due to intracranial aneurysm rupture and arterial dissection. We encountered a case of SAM-related SAH due to ruptured dissection of the A1 segment of the anterior cerebral artery concomitant with internal carotid artery (ICA) dissection.

Case Description:

A 53-year-old man presented with SAH due to a ruptured right A1 dissecting aneurysm. The aneurysm was trapped; however, 7 days after the onset of SAH, he experienced right hemiparesis and aphasia. Angiography showed left ICA dissection; urgent carotid artery stenting was performed, leading to symptom improvement. Abdominal computed tomography angiography showed aneurysms of the celiac and superior mesenteric arteries. He was diagnosed with SAM based on clinical, imaging, and laboratory findings.

Conclusion:

In the acute phase of SAM-related SAH, cerebral ischemia could occur due to both cerebral vasospasm and intracranial or cervical artery dissection.

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.

Clinically Suspected Segmental Arterial Mediolysis of the Splanchnic Arteries: A Report of 2 Rare Cases

Case series

Patients: Female, 89-year-old • Male, 52-year-old

Final Diagnosis: Segmental arterial mediolysis

Symptoms: Abdominal pain • bleeding

Medication: —

Clinical Procedure: —

Specialty: Radiology

Natural History of Unruptured Visceral Artery Aneurysms Due to Segmental Arterial Mediolysis and Efficacy of Transcatheter Arterial Embolization: A Retrospective Multiinstitutional Study in Japan

OBJECTIVE. The purpose of this study was to clarify the natural history of unruptured visceral artery aneurysms due to segmental arterial mediolysis and the efficacy of transcatheter arterial embolization. MATERIALS AND METHODS. Patients with a pathologic or clinical diagnosis of visceral artery aneurysms due to segmental arterial mediolysis between 2005 and 2015 were enrolled. For patients with clinical diagnoses, images were collected and assessed by central radiologic review. To clarify the natural history of unruptured aneurysms, the morphologic changes were assessed. The efficacy and safety of transcatheter arterial embolization for aneurysms due to segmental arterial mediolysis were evaluated. RESULTS. Forty-five patients with 123 aneurysms due to segmental arterial mediolysis were enrolled. Among the 123 aneurysms, 70 unruptured aneurysms were evaluated for natural history. Forty-five of the 70 (64%) aneurysms had no change in morphology. Among the other 25 aneurysms, nine (13% of the 70) were reduced in size, 13 (19%) disappeared, and three (4%) were newly found at follow-up. Aneurysms of the middle colic artery were ruptured in 10 of 11 (91%) cases. Transcatheter arterial embolization was performed on 45 aneurysms and was successful in all cases but caused slight arterial injury in three cases (6.7%). CONCLUSION. At initial diagnosis, unruptured aneurysms due to segmental arterial mediolysis are likely to be stable or to resolve, but the risk of rupture of aneurysms of the middle colic artery appears high. Transcatheter arterial embolization is a useful treatment, but careful manipulation is necessary.

A Case of Segmental Arterial Mediolysis: Hemoperitoneum with Hemorrhagic Shock due to Rupture of a Visceral Artery Aneurysm Following Subarachnoid Hemorrhage

Objective

Segmental arterial mediolysis (SAM) is a non-inflammatory and non-atherosclerotic vascular disease characterized by segmental medial defect/necrosis of muscular arteries as a result of mediolysis. SAM affects the visceral and intracranial arteries, and causes arterial dissection and aneurysm. We report a case of aneurysmal subarachnoid hemorrhage (SAH) followed by hemoperitoneum due to a ruptured visceral artery aneurysm.

Case Presentation

A 54-year-old man developed SAH from a ruptured anterior communicating artery aneurysm, which was clipped on the same day. Thereafter, he was treated to prevent cerebral vasospasm. Six days after onset, he developed acute anemia and his blood pressure decreased, suggesting hemorrhagic shock. Hemoperitoneum was detected on computed tomography and abdominal angiography was performed. Irregular and stenotic arterial findings, and an unusual aneurysm with contrast stasis were found in a branch vessel from the right gastroepiploic artery. SAM was diagnosed based on the clinical course and angiographic characteristics. Endovascular treatment consisted of embolization of the visceral artery aneurysm with liquid embolic material. after embolization, the vital signs stabilized and he recovered from shock. Acute treatment for SAH was continued. Although the patient did not develop vasospasm-related sequelae, he was transferred to the rehabilitation hospital 7 weeks after onset and his modified Rankin Scale score at 3 months after onset was 2.

Conclusion

Visceral artery aneurysm associated with SAM should be considered as the cause of hemoperitoneum with hemorrhagic shock during the acute phase of SAH.

Segmental Arterial Mediolysis: An Under-Recognized Cause of Chronic Abdominal Pain

Segmental arterial mediolysis (SAM) is a non-inflammatory, non-atherosclerotic vasculopathy mostly involving the abdominal arteries. SAM was recently recognized as a more prevalent aetiology of abdominal pain than initially thought by healthcare providers. It is still a commonly missed diagnosis in patients with recurrent emergency room (ER) visits for abdominal pain. Most published case reports in the past have highlighted catastrophic sequelae such as intra-abdominal haemorrhage requiring surgical intervention. We report a case of SAM where the diagnosis was initially missed. After diagnosis, conservative medical management was offered which led to clinical improvement.

LEARNING POINTS

To recognize segmental arterial mediolysis (SAM) as a cause of chronic abdominal pain in the middle-aged and elderly population.To differentiate SAM from inflammatory vasculitis and atherosclerotic conditions.For cases with mild symptoms and haemodynamic stability, conservative management such as early lifestyle modifications, hypertension and hyperlipidaemia control and regular imaging follow-up should be offered.

ACR Appropriateness Criteria® Nonatherosclerotic Peripheral Arterial Disease

A broad range of nonatherosclerotic diseases affect the peripheral arteries. The appropriate initial diagnostic imaging studies vary, depending upon the clinical presentation and suspicion of disease. Accurate vascular imaging relies upon visualization of the vessel lumen, vessel wall, and surrounding soft-tissue structures, with some modalities also offering the ability to characterize blood flow direction and velocity. Furthermore, nonvascular findings are often paramount in supporting a suspected clinical syndrome or guiding surgical management. The scenarios discussed in this document include the initial evaluation of suspected popliteal entrapment syndrome, external iliac artery endofibrosis, lower-extremity inflammatory vasculitides, dissection or connective tissue disease, noninflammatory vascular disease, and vascular trauma. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Case Report: Segmental Arterial Mediolysis, a Rare Cause of Hypertension

Rationale:

The differential diagnosis for hypertension with elevated plasma renin is broad. This case illustrates one of the rarer, and therefore underrecognized, causes of high renin hypertension.

Presenting concerns of the patient:

A 41-year-old man with a medical history significant for multiple ischemic strokes and dyslipidemia presented for assessment of decreased renal function and resistant hypertension. His initial workup for secondary causes of hypertension was remarkable for an elevated plasma renin and normal aldosterone. Further investigation with computed tomography (CT) angiography was performed, which demonstrated multiple bilateral renal aneurysms and infarcts.

Diagnoses:

After ruling out other potential causes of bilateral renal aneurysms and infarcts, a diagnosis of segmental arterial mediolysis (SAM) was made.

Interventions:

Optimization of antihypertensive regimen, counseling regarding regular home blood pressure monitoring, and smoking cessation.

Outcomes:

The patient achieved excellent blood pressure control, stable renal function, and had no further strokes or other vascular events.

Teaching points:

Our case demonstrates the importance of considering SAM in the diagnosis of hypertension with elevated plasma renin and as a vasculitis mimic. It also highlights the importance of considering renal vascular imaging in the workup of resistant hypertension.

Left omental artery bleeding in two patients with segmental arterial mediolysis successfully isolated with coil embolization

Background

Segmental arterial mediolysis (SAM) is a rare, nonatherosclerotic, noninflammatory arteriopathy of unknown etiology, rarely involving omental artery (OA). No case reports have described left OA bleeding successfully treated with transarterial embolization (TAE) with coils. This report describes two cases of SAM-affected left OA bleeding successfully embolized using isolation technique with coils, recognizing the potential for the greater omentum to have arterial collateral network between OAs.

Case presentation

Case 1.

A 55-year-old male with no significant past medical history presented with an acute abdomen. Contrast-enhanced computed tomography (CT) revealed possible hemorrhagic ascites involving the left portion of the greater omentum and dilated, stenotic change of the left OA with a possible hematoma. SAM-associated left OA bleeding was suspected. Given its acute-angled branching from a splenic artery or branch and long, tortuous catheter-trajectory, we used a triaxial catheter system. Left OA angiography revealed the proximal dilated, stenotic change and a distal pseudoaneurysm. Isolation was successfully performed with coils. Because he had no abdominal pain or progressive anemia, he was discharged on hospital day 5. Neither recurrence nor new SAM-associated findings were observed during two-years of follow-up.

Case 2.

A 60-year-old-man with no significant past medical history presented with an acute abdomen. CT revealed similar finding as Case 1. SAM-associated left OA bleeding was suspected. Left OA angiography revealed proximal dilated, stenotic change with distal occlusion. Despite having no signs of active bleeding, review of the CT and angiography findings suggested the left OA as the bleeding site. Given proximal embolization at this point could lead to incomplete hemostasis or rebleeding via the arterial collateral network between OAs, an attempt was made to navigate the microcatheter into the distal side beyond the occlusion. Distal left OA angiography confirmed that the distal OA over the occlusion was intact and directly communicated with a right OA arising from right gastroepiploic artery. The SAM-associated lesion was successfully isolated with coils. Because he had no abdominal pain or progressive anemia, he was transported to another hospital on hospital day 3. Neither recurrence nor new SAM-associated findings were observed during two-years follow-up.

Conclusion

SAM can involve left OA and be controlled using an isolation technique with coils.

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.

Segmental arterial mediolysis: a commonly overlooked aetiology of acute abdominal pain

Segmental arterial mediolysis (SAM) is an uncommon condition and commonly missed diagnostic aetiology of acute abdominal pain, initially described in 1976. SAM is a non-inflammatory, non-atherosclerotic vasculopathy mostly involving the abdominal arteries with notable asymmetric involvement of the walls of the mesenteric arteries and their branches. Clinical presentation ranges from postprandial abdominal discomfort suggestive of mesenteric ischaemia to intra-abdominal bleeding. Pathophysiological explanation and prognosis of these cases are not well understood and therefore no clear guidelines for management exist. In this case report, we emphasise the imaging modalities used to reach the diagnosis and the management options available.

Natural history and management outcomes of segmental arterial mediolysis

BACKGROUND

Segmental arterial mediolysis (SAM) is a poorly understood, nonatherosclerotic, noninflammatory disease resulting from arterial medial degeneration. Patients may present with aneurysm, dissection, stenosis, or bleeding from visceral or renal arteries. Treatment algorithms are poorly characterized.

METHODS

A retrospective review of all patients diagnosed with SAM was performed at our institution. Patients were identified by established criteria that include clinical presentation in combination with radiographic and serologic findings. Demographics, presenting symptoms, diagnostic evaluation, management, and outcomes were reviewed.

RESULTS

There were 117 patients diagnosed with SAM between 2000 and 2016; 67.5% (n = 79) were male. Mean age was 52.7 years (range, 23.4-90 years); 69.2% (n = 81) presented with acute abdominal pain, 22.2% (n = 26) with flank pain, and 19.7% (n = 23) with back pain; 15.4% (n = 18) had abdominal pain longer than 30 days; 13.7% (n = 16) had acute hypertension, and 5.1% (n = 6) were hypotensive; 10.3% (n = 12) were asymptomatic. There were 93 (79.5%) dissections and 61 (52.1%) aneurysms. Hemorrhage was seen in 10 (8.5%). The celiac axis was affected in 54.7% (n = 64), renal arteries in 49.6% (n = 5 8), superior mesenteric artery in 43.6% (n = 51), and inferior mesenteric artery in 2.6% (n = 3). After diagnosis of SAM, aspirin was prescribed in 60.7% (n = 71). Statins were prescribed in 29.9% (n = 35). Antihypertensive medications were prescribed in 65% (n = 76), including beta blockers in 42.7% (n = 50); 40.2% (n = 47) of patients were prescribed anticoagulation. Interventions were performed in 26 (22%) patients; 13 had endovascular intervention only, 9 open surgery only, and 4 open and endovascular interventions. Of the 17 patients undergoing endovascular intervention, 19 procedures were performed, most commonly embolization (78.9% [n = 15]), followed by stenting (10.5% [n = 2]). Of the 13 patients undergoing open surgery, 14 procedures were performed, including arterial bypass (50% [n = 7]) and splenectomy with aneurysm ligation (15.4% [n = 2]). Other surgery involved thrombectomy (21.4% [n = 3]) and angioplasty (14.3% [n = 2]). Only 11.5% (n = 3) experienced a perioperative complication, including one hematoma, one abscess, and one death secondary to ongoing hemorrhage. Follow-up imaging was performed in 96.6% (n = 112). Mean follow-up was 1258 days (range, 2-5017 days). Of these, 27.7% (n = 31) had regression, 43.8% (n = 49) stability, and 28.6% (n = 32) progression. Average time between initial diagnosis and progression was 666 days.

CONCLUSIONS

SAM is an uncommon disease that may require intervention; it is therefore important that the vascular surgery community be aware of this disease. Follow-up imaging is required to monitor for disease progression.

Peripheral Vascular Imaging Focusing on Nonatherosclerotic Disease

A variety of nonatherosclerotic diseases affect the arteries of the pelvis and lower extremities. Chronic repetitive traumatic conditions, such as popliteal entrapment and external iliac artery fibroelastosis, vasculitis and connective tissue diseases, and noninflammatory vascular diseases, are a few of the more commonly encountered nonatherosclerotic peripheral vascular diseases. Ultrasound, computed tomography angiography, and magnetic resonance angiography are essential in the initial assessment and management of patients with peripheral vascular disease.

Practical approach to vasculitides in adults: an overview of clinical conditions that can mimic vasculitides closely

Primary systemic vasculitides are rare diseases affecting blood vessel walls. The type and patterns of distribution of the organs affected usually reflect the size of the vessels predominantly involved, and the patterns of clinical manifestations are generally useful to reach a specific diagnosis. However, presenting symptoms may lack adequate specificity for a prompt diagnosis, leading to a diagnostic (and therapeutic) delay, often causing irreversible damage to the affected organs. Due to their rarity and variable clinical presentation, the diagnosis of primary vasculitides could be challenging for physicians. Vasculitis mimickers, i.e. the clinical conditions that could be likely mistaken for vasculitides, need to be carefully ruled out, especially before starting the immunosuppressive therapy. We present here a practical approach to the diagnosis of primary systemic vasculitides involving large, medium and small size vessels, and reviewed most of the conditions that could mimic primary systemic vasculitides.

Segmental arterial mediolysis (SAM): Systematic review and analysis of 143 cases

Segmental arterial mediolysis (SAM) is a rare but serious nonatherosclerotic, noninflammatory vasculopathy of unknown etiology that often results in dissection, aneurysm, occlusion, or stenosis of, primarily, the abdominal arteries. Current literature lacks consensus on diagnostic criteria and management options for SAM. This review summarizes 143 cases and aims to advance appropriate recognition and management of SAM. Literature review of all relevant SAM case studies from 2005 to 2018 yielded 126 individual SAM cases from 66 reports. We identified 17 additional SAM cases from our center, bringing our analysis to 143 patients. Patients with SAM were most commonly men (68%) in their 60s. Hypertension (43%), tobacco use (12%), and hyperlipidemia (12%) were common comorbidities. Abdominal pain (80%) and intraabdominal bleeding (50%) were the most common presenting symptoms. Computed tomography was the most frequently used imaging method (78%), and histology was available in 44% of cases. The most commonly affected vessels were the superior mesenteric (53%), hepatic (45%), celiac (36%), renal (26%), and splenic (25%) arteries with aneurysm (76%), dissection (61%), and arterial rupture (46%). Treatments included coil embolization (28%), abdominal organ surgery (24%), open arterial repair (21%), and medical management (20%). Case-specific treatment modalities yielded symptom relief in the vast majority (91%) of patients, with a mortality rate of 7%.

Segmental Arterial Mediolysis: A Case Study and Review of the Literature in Accurate Diagnosis and Management

Segmental arterial mediolysis (SAM) is a rare noninflammatory, nonarteriosclerotic arteriopathy of an unknown etiology. It most commonly affects the medium-sized vessels of the abdomen and is characterized by the disruption of the arterial medial layer. Although histological confirmation remains the gold standard in diagnosis, the use of computed tomography angiography (CTA) has greatly aided the diagnosis and surveillance of SAM. Given its rarity and angiographic similarities to other vasculopathies, the diagnosis of SAM can be challenging and is often missed. We describe the case of a 46-year-old male patient who presented to our institution with abdominal pain and multiple foci of intra-abdominal arterial dissections on CTA. We report the acute management via endovascular intervention and review the literature with respect to the diagnosis and management of this rare condition. SAM remains an uncommon yet significant disease process requiring prompt and accurate diagnosis. Initiation of immediate treatment is crucial, given the knowledge gap about its natural progression.

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

This article reports the case of a 51-year-old woman in whom brain MRI to follow up multiple sclerosis incidentally discovered an intramural hematoma in the extracranial internal carotid artery. MR angiography of the supra-aortic trunks and CT angiography of the aorta showed arterial dilations, aneurysms, dissections, and intramural hematomas in the internal carotid arteries, vertebral arteries, and arteries in the splanchnic territory. These findings raised suspicion of segmental arterial mediolysis. After 6 months of treatment with antiplatelet drugs, the arterial involvement resolved. Segmental arterial mediolysis is an uncommon disease; low clinical suspicion and radiologists' lack of knowledge about this entity mean that it can go undetected or be confused with other vasculitides. This report describes the most relevant pathophysiological findings and correlates them with the imaging findings.

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.

Unexpected intraabdominal hemorrhage due to segmental arterial mediolysis following subarachnoid hemorrhage: A case of ruptured intracranial and intraabdominal aneurysms

Background:

Segmental arterial mediolysis (SAM) is an uncommon vascular disease, which manifests as catastrophic intraabdominal hemorrhage caused by rupture of visceral dissecting aneurysms in most cases. The etiology of SAM is still unclear, but SAM may be a vasospastic disorder and the responsible pressor agent is norepinephrine. Recently, abdominal SAM coexisting with intracranial dissecting aneurysms has been reported, but the relationship between intraabdominal and intracranial aneurysms in SAM remains unclear, as no cases of concomitant abdominal SAM and ruptured intracranial saccular aneurysm have been reported.

Case Description:

A 49-year-old woman underwent emergent clipping for a ruptured saccular aneurysm at the left C1 portion of the internal carotid artery. Intraoperatively, norepinephrine was continuously administered intravenously under general anesthesia. Four days after the subarachnoid hemorrhage (SAH), the patient suddenly developed shock due to massive hematoma in the abdominal cavity. Imaging showed multiple aneurysms involving the splenic artery, gastroduodenal artery, common hepatic artery, and superior mesenteric artery. Coil embolization of the splenic artery was performed immediately to prevent bleeding. Subsequent treatment for cerebral vasospasm following SAH was performed with prevention of hypertension, and the patient recovered with left temporal lobe infarction. The diagnosis was abdominal SAM based on the clinical, imaging, and laboratory findings.

Conclusion:

Norepinephrine release induced by SAH and/or iatrogenic administration of norepinephrine may have promoted abdominal SAM in this case. Abdominal SAM may occur subsequent to rupture of ordinary saccular aneurysm, and may provoke catastrophic abdominal hemorrhage in the spasm stage after SAH.

Segmental Arterial Mediolysis of Omental Arteries with Haemoperitoneum: Case Report with Embolization of the Left Omental Artery and Brief Review of Literature

Segmental arterial mediolysis of an omental artery is an exceptionally rare condition. A 69-year-old man presented with haemoperitoneum six days after being hospitalized due to pneumogenic sepsis. Computed tomography of the abdomen showed a short segment dilatation of an omental artery in the left upper abdomen, compatible with segmental arterial mediolysis. Angiographic examination revealed alterations of omental branches of the right gastroepiploic artery and an aneurysm of the left omental artery, both characteristic of segmental arterial mediolysis. Embolization of the left omental artery with use of N-butyl-2-cyanoacrylate was performed. The postinterventional course was uneventful with increase of haemoglobin levels and without symptoms of omental infarction. Transcatheter embolization in the setting of haemoperitoneum due to segmental arterial mediolysis of an omental branch is technically feasible and a valuable alternative to emergency operation.

Segmental arterial mediolysis presenting as spontaneous bilateral renal artery dissection

The commonest site of primary dissection involving the visceral vessels is renal arteries; however, spontaneous bilateral renal artery dissection is an extremely rare entity. Spontaneous renal artery dissection (SRAD) is rarely a cause of renovascular hypertension. Segmental arterial mediolysis is a rare arteriopathy of unknown etiology which is a nonatherosclerotic and noninflammatory condition. We report a case of a 51-year-old male patient with spontaneous dissection of bilateral renal arteries with clinical, laboratory, and angiographic findings consistent with segmental artery mediolysis. Early diagnosis and treatment of this condition will decrease morbidity and mortality.