Segmental arterial mediolysis: a systematic review of 85 cases

Segmental arterial mediolysis leading to spontaneous rupture of splenic artery and fatal hemorrhage in pregnancy

We report an unexpected death of a 22-year-old primigravida who was admitted to the hospital with sudden abdominal pain two days before a scheduled delivery. During an emergency caesarean section due to intrauterine asphyxia, intraabdominal bleeding was observed with no apparent source of bleeding. Newly formed blood clots in the subdiaphragmatic space and arterial bleeding near the splenic hilum required a surgery on the next day. Hemorrhagic shock led to multiple organ failure on the fourth day of admission. The autopsy revealed ruptured splenic artery at the pancreatic tail and near the splenic hilum. Microscopically, different stages of segmental arterial mediolysis were observed in partially thinned and aneurysmatic artery.

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.

A review of histopathologic and radiologic features of non-atherosclerotic pathologies of the extracranial carotid arteries

Diseases of the carotid arteries can be classified into different categories based on their origin. Atherosclerotic carotid disease remains the most encountered arterial wall pathology. However, other less-common non-atherosclerotic diseases can have detrimental clinical consequences if not appropriately recognized. The underlying histological features of each disease process may result in imaging findings that possess features that are obvious of the disease. However, some carotid disease processes may have histological characteristics that manifest as non-specific radiologic findings. The purpose of this manuscript is to review various non-atherosclerotic causes of carotid artery disease as well as their histologic-radiologic characteristics to aid in the appropriate recognition of these less-commonly encountered pathologies.

A case of rectal cancer complicated with segmental arterial mediolysis (SAM) safely treated with curative resection - A case report

INTRODUCTION

Recent advances in diagnostic imaging techniques have led to an increasing number of case reports of segmental arterial mediolysis (SAM). However, reports of abnormalities associated with SAM of abdominal organs, including the bowel, are limited. SAM, a rare vascular disease that causes spontaneous intra-abdominal bleeding, including shock and intestinal ischemia, has been reported to be associated with high mortality, but it has not been reported to coexist with rectal cancer.

CASE PRESENTATION

A 74 year-old male was referred to our hospital with a rectal cancer and he was admitted for further examination. Computed tomography angiography (CTA) revealed dissection and aneurysm in the celiac artery, superior mesenteric artery (SMA), and the inferior mesenteric artery were dilated, leading to a diagnosis of SAM.

CLINICAL DISCUSSION

Surgery for rectal cancer requires cutting the inferior mesenteric artery. The risk of bleeding during surgery increases when SAM is associated with the inferior mesenteric artery. The radical surgery for rectal cancer was executed without complications, including significant bleeding. This was achieved through careful management of SAM, meticulous control of blood pressure throughout the surgical procedure, and the delicate treatment of the SMA. A pathological diagnosis of the resected inferior mesenteric artery at the time of radical surgery was performed, and a definitive diagnosis of SAM was made.

CONCLUSION

We present a first known case in which high anterior resection was successfully performed for rectal cancer complicated by SAM. The relationship between cancer and SAM is unclear and further case accumulation is needed.

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.

Rheumatic masqueraders: mimics of primary vasculitis - a case-based review

INTRODUCTION

Vasculitis conditions are often serious and sometimes fatal diseases, therefore it is paramount to diagnose correctly and treat appropriately. Mimics of primary vasculitis can include either non-inflammatory syndromes or secondary vasculitis where the underlying etiology of the vasculitis is being driven by infection, malignancy, drug-effect or other.

AREAS COVERED

This review comprises six individual cases of vasculitis mimics. Each case is presented and the clinical, radiographic, and histological features that distinguish the case from primary vasculitis are highlighted. Key mimics in large, medium and small vessel vasculitis are outlined.

EXPERT OPINION

The diagnosis of vasculitis requires a comprehensive assessment of clinical, radiographic, and histologic features. Clinicians should be familiar with mimics of primary vasculitis conditions. In the case of non-inflammatory mimics, it is important to differentiate from primary vasculitides in order to avoid unnecessary and potentially harmful immunosuppression. For cases of secondary vasculitis, identification of the correct etiologic cause is critical because treatment of the underlying stimulus is necessary for successful management and outcomes.

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.

Transarterial embolization for ruptured pancreaticoduodenal artery aneurysm due to segmental arterial mediolysis combined with median arcuate ligament syndrome: a case report

A 75-year-old female with a history of Parkinson's disease treatment and hypertension presented at the emergency section with sudden onset of right abdominal pain. Contrast-enhanced computed tomography revealed beaded irregular stenosis and dilation of the superior mesenteric artery (SMA) and an aneurysm in the branch of the pancreaticoduodenal artery (PDA) that communicates with the common hepatic artery and SMA. Additionally, a hematoma had formed in the retroperitoneal space, and extravasation of contrast medium from the pancreaticoduodenal artery aneurysm (PDAA) into the hematoma was observed. The celiac artery (CA) was compressed by the median arcuate ligament; stenosis of the CA at its origin and dilation on the distal side were observed. Based on the imaging findings, it was diagnosed that PDAA was ruptured, SMA developed segmental arterial mediolysis (SAM), and CA developed median arcuate ligament syndrome (MALS). The ruptured PDAA was thought to be caused by SAM combined with MALS. Transcatheter arterial embolization (TAE) was performed for the ruptured PDAA. To the best of our knowledge, there have been no reports of TAE for a ruptured PDAA caused by SAM and MALS. After TAE, the PDAA did not re-rupture.

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.

Hepatic segmental arterial mediolysis: A case report and brief literature review

Key Clinical message

When evaluating patients with abdominal pain, it is important to consider SAM in the differential diagnosis, along with vasculitis, fibromuscular dysplasia (FMD), atherosclerosis, mycotic aneurysms, and cystic medial degeneration.

Abstract

Segmental arterial mediolysis (SAM) is a rare arteriopathy which is an under-recognized and commonly missed diagnosis of abdominal pain. We report a case of a 58-year-old female who presented with abdominal pain and was misdiagnosed with a urinary tract infection. The diagnosis was made with CTA and managed with embolization. Despite appropriate intervention and close hospital monitoring, further complications were inevitable. We conclude that though literature has shown better prognosis and even complete resolution after medical and/or surgical intervention, close follow up and monitoring is needed to avoid unexpected complications.

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.

Mesenteric Artery Dissection and Wall-Thickening, Case Study and General Review

Mesenteric artery dissection (D) and wall-thickening (WT) are rare vasculopathies that can lead to serious complications. This is a single center analysis of all patients evaluated for mesenteric arterial (celiac, superior (SMA) and/or inferior mesenteric (IMA)) D and/or WT from January 1, 2000, to January 31, 2020 at our hospital. Among the 101 included patients, the average age was 55.6 ± 13.6 years, mostly affecting men (62%). There were 20 celiac artery D, 8 WT, 15 D with WT, 15 SMA D, 7 WT, 8 D with WT, one IMA D, two WT, and 25 with multiple arterial involvement. Primary etiologies included segmental arterial mediolysis (SAM) (n = 17), isolated D (n = 17), localized vasculitis of the gastrointestinal tract (LVGT) (n = 16), fibromuscular dysplasia (FMD) (n = 13), extension of thoracoabdominal aortic D (n = 12), and trauma (n = 12). Most (71%) patients presented with abdominal pain. Hypertension (55%), hyperlipidemia (33%) and tobacco use (31%) were prevalent. Management included conservative (22%), medical (47%), endovascular (19%), and/or open repair (12%) with high in-hospital survival (98%) and symptom relief (73%). Our paper complements the scarce literature addressing the diagnosis and management of rare mesenteric vasculopathies. Most patients improved with conservative management, reserving endovascular or surgical interventions for symptomatic patients with more complicated presentations.

Intra-abdominal Bleeding due to Segmental Arterial Mediolysis and Coexisting Pulmonary Thromboembolism: a Case Report

 Segmental arterial mediolysis (SAM) is a rare but important cause of abdominal haemorrhage and is usually treated with endovascular management. Surgical or conservative management can be performed depending on the patient’s situation. Since the course of conservative treatment is not well described in the existing literature, it must be used with caution. We describe the case of a 52-year-old man who was transferred to the emergency department because of abdominal pain, diarrhoea, and haematemesis. On arrival, he was haemodynamically unstable, with a blood pressure of 70/40 mmHg. After he was transfused and stabilised in the emergency department, contrast-enhanced computed tomography (CECT) revealed a haematoma around the transverse colon and ascites, without any evident extravasation. The peripheral branch of the middle colic artery (MCA) showed irregular calibre, suggesting SAM. Since the patient remained stable, we initially chose conservative management. However, a CECT scan performed on the third day of hospitalisation showed coexisting pulmonary thromboembolism (PTE). Because of the need for anticoagulation therapy, we performed open surgery. The pathological examination was consistent with SAM. Anticoagulation therapy was initiated the next day. A CECT scan performed on a postoperative day (POD) 13 showed no PTE. Although the patient defecated haemorrhagic stool and experienced hematemesis on PODs 19 and 23, respectively, colonoscopy, esophagogastroduodenoscopy, and repeated CECT scans revealed no evidence of rebleeding, and no recurrence was observed. Open surgery produced a relatively good postoperative course for the patient. Endovascular management, however, remains a reasonable first approach, considering its reportedly excellent outcomes.

Splenic Artery Pseudoaneurysms: The Role of ce-CT for Diagnosis and Treatment Planning

Splenic artery pseudoaneurysm (PSA) is a contained vascular wall lesion associated with a high mortality rate, generally related to pancreatitis, trauma, malignancy, iatrogenic injury, and segmental arterial mediolysis. Computed tomography angiography allows us to visualize the vascular anatomy, differentiate a PSA from an aneurysm, and provide adequate information for endovascular/surgical treatment. The present review reports on the main state-of-the-art splenic artery PSA diagnosis, differentiating between the pros and cons of the imaging methods and about the endovascular treatment.

Concurrent Takayasu Arteritis and Vascular Ehlers–Danlos Syndrome: A Case Report

Takayasu arteritis (TAK) is a rare primary systemic inflammatory vasculopathy. It is classified as a large-vessel vasculitis and is known to cause inflammatory aneurysms and vascular stenosis. Vascular Ehlers–Danlos syndrome (vEDS) is an autosomal dominant condition known to cause multiple aneurysms and arterial dissection at a young age owing to a mutation in the gene for type III collagen, COL3A1. Here, we present a case of TAK associated with vEDS with the development of multi-organ infarction of the brain, kidney, and spleen owing to multiple arterial aneurysms and stenosis of the internal carotid artery. The patient was successfully treated using anti-inflammatory agents, glucocorticoids, and tocilizumab with the addition of interventional radiology. In our case, a high inflammatory response led to vasculitis being the main cause of the disease with concurrent vEDS. When patients develop multiple aneurysms, stenosis, and dissections leading to multiple organ infarctions, a systemic differential diagnosis to consider concurrent vasculitis syndrome and non-inflammatory vasculopathy, including hereditary disorders, is important even with time constraints.

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.

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.

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.

Fatal hemorrhage after tonsillectomy

This is the first report of a segmental mediolysis occurring in arterioles, affecting the neck/tonsillar region and leading to a fatal hemorrhage after a tonsillectomy in a 20-year-old woman. Arteriolar mediolysis could be observed in tissue layers about 2 cm distant from the tonsillectomy region. Reparative changes were observed in the carotid and small neck arteries as well as in only one intramyocardial arteriole; however, no other vascular regions typically reported in segmental mediolysis arteriopathy were affected and aneurysm formation was not observed. No family history of vascular disease or hypertension was known. Pathophysiologically, previously reported reasons for post-tonsillectomy bleeding could be excluded. Segmental mediolysis may represent a wider spectrum of affected arteriolar vessels besides the reported small and medium sized arteries leading to aneurysms, which impedes radiographic diagnosis.

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

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.

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.

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.

Biphasic clinical course of a ruptured right gastric artery aneurysm caused by segmental arterial mediolysis: a case report

BACKGROUND

Gastric artery aneurysms are rarely caused by segmental arterial mediolysis (SAM), a condition that often involves multiple vessels. The clinical course of SAM after vessel rupture may vary depending on the involved vessels. For example, the "double-rupture phenomenon" observed following the rupture of the splenic artery aneurysm manifests as a biphasic and relatively slow clinical course. Even in cases of rupture of gastric artery aneurysm, the double-rupture phenomenon has only been reported in two cases so far. However, the rupture was not caused by SAM in either case. Herein, we present the apparent first case of a right gastric artery (RGA) aneurysm rupture caused by SAM that presented with a biphasic clinical course, possibly due to the double-rupture phenomenon.

CASE PRESENTATION

A 54-year-old woman was transferred to the emergency department with severe abdominal pain and a cold sweat for a duration of 3 h. She had developed mild abdominal pain and nausea 3 days earlier. Her vital signs were stable. Physical examination revealed tenderness in the epigastric area. Abdominal contrast-enhanced computed tomography revealed an RGA aneurysm with contrast media extravasation. A diagnosis of hemoperitoneum following a ruptured RGA aneurysm was made, and the patient underwent angiography. However, this modality did not reveal any extravasation from the RGA due to an interruption in the peripheral branch of the artery. Nevertheless, to prevent major bleeding, we performed coil embolization at the point of interruption in the RGA, which we suspected to be a ruptured aneurysm. A distal gastrectomy with Roux-en-Y reconstruction for aneurysm resection was performed the following day. There were no postoperative complications, and the patient was discharged 17 days after surgery. Histologically, the RGA demonstrated multiple vacuoles in the medial muscle layer, which were characteristic of SAM.

CONCLUSIONS

An RGA aneurysm rupture should be considered a differential diagnosis in patients presenting with hemoperitoneum with a slow or biphasic clinical course.

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.

Omental apoplexy: Unravelling the mystery

INTRODUCTION

To describe cases omental haemorrhage and to review the literature on this topic.

METHODS

We describe three cases of spontaneous omental haemorrhage and discuss various management strategies, in an attempt to provide direction for similar cases in the future.

RESULTS

A number of case reports of spontaneous or idiopathic omental haemorrhage exist in the literature. These cases are often attributed to an underlying vasculopathy, such as segmental arterial mediolysis (SAM). Appropriate resuscitation is paramount for best outcome. Severe bleeding may require surgery or transcatheter arterial embolisation, which is best performed early if required. Endovascular management using selective catheterisation of the bleeding vessel and embolisation is a minimally invasive alternative to emergent operative intervention. In the three cases we present, endovascular embolisation was performed in two patients, and surgical ligation in a third. Segmental arterial mediolysis is considered the likely aetiology in at least 2 of the 3 cases, based on imaging findings. No further episodes of haemorrhage occurred at follow-up (ranging from 6 months to 2 years).

CONCLUSIONS

Acute omental haemorrhage is a rare condition; however, it may be associated with significant morbidity and mortality. CT angiography is the imaging of choice. Management strategies include both endovascular and surgical intervention.

A Review of Primary Vasculitis Mimickers Based on the Chapel Hill Consensus Classification

Primary systemic vasculitides are rare diseases that may manifest similarly to more commonly encountered conditions. Depending on the size of the vessel affected (large vessel, medium vessel, or small vessel), different vasculitis mimics must be considered. Establishing the right diagnosis of a vasculitis mimic will prevent unnecessary immunosuppressive therapy.

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%.

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.

Hybrid Surgery for Multiple Visceral Artery Aneurysms: A Case Report

BACKGROUND

We present a case with multiple visceral artery aneurysms that were treated with a hybrid approach involving both surgical and endovascular treatment.

CASE REPORT

The patient was a 48-year-old female. She was diagnosed with multiple visceral artery aneurysms including 2 splenic artery aneurysms, celiac artery aneurysm, and bilateral renal artery aneurysms during an examination for loss of appetite. With regard to 2 splenic artery aneurysms, the proximal aneurysm was treated surgically, whereas the peripheral aneurysm that was located deeply in the abdomen was treated with coil embolization. The celiac artery aneurysm located at the bifurcation of the common hepatic artery and splenic artery, an intracranial aneurysm clip was used. The left and right renal aneurysms were resected and renal arteries were reconstructed surgically. The postoperative course was uneventful. The pathological diagnosis of all aneurysms was segmental arterial mediolysis. The reconstructed vessels were patent without stenosis or recurrence at 1 year after the operation.

CONCLUSIONS

Hybrid treatment involving surgical resection, endovascular coil embolization, and obliteration with clips was useful in the treatment of multiple visceral artery aneurysms.

[Vasculitis mimics]

Vasculitis mimics need to be differentiated from primary and secondary vasculitides as described in the Chapel Hill nomenclature. The clinical symptomatology resembles that of vasculitis of small and medium, rarely also large vessels and hence imitates the classical vasculitic disorders. Pathogenetically, the causes are partly genetic mutations, embolization syndromes, infections and substance abuse. Also, B‑cell lymphomas can mimic vasculitis. The present manuscript summarizes the vasculitis mimics.

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.