Coil embolization of segmental arterial mediolysis of the hepatic artery

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.

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.

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.

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.

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.

Scleroderma renal crisis with coexisting segmental arterial mediolysis presenting as intraperitoneal bleeding: a case report

Background

Segmental arterial mediolysis is a rare nonarteriosclerotic and noninflammatory vascular disease that may cause intraperitoneal bleeding. Scleroderma renal crisis is a rare complication of systemic sclerosis, leading to severe hypertension and renal dysfunction. To the best of our knowledge, this is the first reported case of a patient with concurrent systemic sclerosis with scleroderma renal crisis and pathologically confirmed segmental arterial mediolysis.

Case presentation

We report a case of a 68-year-old Chinese woman diagnosed with systemic sclerosis who was found to have coexisting segmental arterial mediolysis. She presented with back pain, and massive intraperitoneal bleeding was detected by computed tomography. She underwent laparotomy, and the bleeding was found to originate from the gastroepiploic artery. The pathological examination demonstrated gastroepiploic arterial dissection caused by segmental arterial mediolysis. After surgery, she developed severe hypertension with hyperreninemia and progressive renal dysfunction. Given the risk factors of corticosteroid administration and the presence of anti-ribonucleic acid polymerase III antibody, she was diagnosed with scleroderma renal crisis. The patient was proved to have a very rare case of coexisting scleroderma renal crisis and segmental arterial mediolysis.

Conclusions

There is no known etiological connection between segmental arterial mediolysis and systemic sclerosis or scleroderma renal crisis, but it is possible that coexisting segmental arterial mediolysis and scleroderma renal crisis may have interacted to trigger the development of the other in our patient.

Stent treatment for huge aneurysm of the common hepatic artery: A case report

Objective/Background: Huge aneurysm of the visceral artery is rare and a treatment strategy for such cases has not yet been established. Here, we report a case of huge aneurysm of the common hepatic artery (44-mm diameter) successfully treated by stent placement.

Methods: A 77-year-old female patient was referred to our department due to growth of the common hepatic artery aneurysm. The cause of the aneurysm was suspected to be segmental arterial mediolysis. Due to the possibility of a spontaneous rupture, we decided to stent the common hepatic artery.

Result: We had some difficulties during the procedure, such as thrombosis of the stent, and it was necessary to insert an additional stent. The procedure was effective and the patient has been doing well without any complications at the 6-year follow-up.

Conclusion: Stenting is possible and effective in cases of huge aneurysm of the common hepatic artery.

Segmental Arterial Mediolysis: Abdominal Imaging of and Disease Course in 111 Patients

OBJECTIVE

The purpose of this study is to identify the imaging characteristics of segmental arterial mediolysis (SAM) at presentation and establish the longitudinal course of disease.

MATERIALS AND METHODS

We retrospectively identified patients with SAM at a single institution from 2000 through 2015. Diagnosis was based on published guidelines with multidisciplinary consensus. Imaging studies obtained at initial evaluation were reviewed to evaluate imaging findings and vascular territory distribution. All subsequent follow-up imaging studies were reviewed to assess for progression, stability, or regression.

RESULTS

We identified 111 patients (79 men and 32 women; median age, 51 years) who met the diagnostic criteria for SAM. Abdominal pain was the most common presentation (74%), followed by flank pain (21%). SAM most commonly affected the renal arteries (47%), superior mesenteric artery (46%), celiac trunk (46%), hepatic artery (23%), iliac arteries (18%), and splenic artery (14%). The most common imaging findings were dissection (86%), aneurysm (57%), beading or webs (28%), occlusion (19%), and a rind or wall thickening (15%). The 247 available follow-up imaging studies for 97 patients (median follow-up, 12 months) showed progression in 19 patients (20%), with either stability or regression observed in the remaining patients.

CONCLUSION

SAM most commonly affects the renal arteries, superior mesenteric artery, and celiac artery. Dissections and aneurysms are the most common imaging findings. Follow-up imaging studies show stability or regression in most patients.

Endovascular Treatment of a Splenic Aneurysm Associated With Segmental Arterial Mediolysis

Introduction

Segmental arterial mediolysis is a rare disorder characterised by disintegration of the medial layer of an arterial wall usually affecting the intra-abdominal splanchnic vessels.

Report

A case of 50 year old man who presented with sudden-onset left sided flank pain is reported. A computed tomography mesenteric angiogram showed haemorrhage and a stable left upper quadrant haematoma arising from 8 × 8 mm splenic artery aneurysm.

Discussion

The patient underwent a successful endovascular coiling procedure to exclude the aneurysm and for complete resolution of his symptoms.

•

Segmental arterial mediolysis (SAM) is a rare cause of bleeding from a splenic artery aneurysm.

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Endovascular treatment with coiling and embolisation could be a safe and effective technique to prevent rupture and complications arising from splenic artery aneurysms associated with SAM.

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Close follow-up is required in patients diagnosed with SAM.

Segmental arterial mediolysis with 5 splenic artery aneurysms. A rare finding of a rare disease: Case report and literature review

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The article represents SAM in SAA which is a rare finding in a rare disease and due to the paucity of sample of cases there is no standardization in the management.

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SAM should be suspected when multiple aneurysms are found in the same anatomic site.

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Angiography is important to detect adjacent involvement. CT angiography of brain should be done to rule out distal vascular disease.

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Endovascular option is the first choice but sometimes it is not feasible, in this case was excluded due to anatomical and configuration reasons.

Introduction

Splenic artery aneurysms (SAA) are uncommon findings. They are usually single and isolated; however they can be multiple; hence vasculopathy and segmental artery mediolysis may be considered.

Presentation of case

In our manuscript we present a case of a 54 year old multiparous lady who was discovered incidentally to have a diseased splenic artery containing five SSAs. The largest aneurysm was close to the takeoff of the vessel and the smallest was distal embedded in the splenic hilum. Endovascular option was technically not feasible. Therefore the patient underwent a complete splenic artery resection with splenectomy and the histopathologic examination was suggestive of segmental arterial mediolysis (SAM).

Discussion and conclusion

Multiple SAAs remains a rare finding of a rare disease. Complications can be crucial and high index of suspicion is important. Segmental arterial mediolysis can be considered in patients with several aneurysms on one anatomic site; Angiography is the gold standard diagnostic and therapeutic method. Complete splenic artery resection with splenectomy is the best treatment option for solitary vessel involvement.

Imaging and clinical findings in segmental arterial mediolysis (SAM)

Segmental arterial mediolysis (SAM) is an uncommon, non-atherosclerotic, non-inflammatory arteriopathy that tends to affect the medium-sized splanchnic branches of the aorta along with renal, carotid, cerebral, and coronary arteries. The clinical presentation ranges from asymptomatic to severe, life-threatening intra-abdominal hemorrhage and shock. SAM overlaps clinically and radiologically with other inflammatory vasculitides. This article describes the pathologic-radiologic correlation, imaging findings, and the management of the disease. Radiologists should be familiar with this disease entity as imaging plays a crucial role in the diagnosis.

Longitudinal Evaluation of Segmental Arterial Mediolysis in Splanchnic Arteries: Case Series and Systematic Review

BACKGROUND

Segmental arterial mediolysis (SAM) is a rare non-atherosclerotic, non-inflammatory vascular disorder varying widely in clinical course. The purpose of this study is to analyze detailing clinical and imaging manifestations over time in patients with SAM through a literature review and to suggest an optimal management strategy.

METHODS

A retrospective review of eight consecutive patients diagnosed with SAM between January, 2000 and January, 2012 was conducted. All presented with acute-onset abdominal or flank pain. Clinical features, imaging studies, and laboratory findings served as grounds for diagnosis, having excluded more common conditions (ie, fibromuscular dysplasia, collagen vascular disorders, or arteritis). CT angiography was done initially and repeated periodically (Week 1, Month 3, then yearly). Treatment was conservative, utilizing endovascular intervention as warranted by CT diagnostics. In a related systematic review, all English literature from 1976 to 2015 was screened via the PubMed database, assessing patient demographics, affected arteries, clinical presentations, and treatment methods.

FINDINGS

Ultimately, 25 arterial lesions identified in eight patients (median age, 62.8 years; range, 40-84 years) were monitored for a median period of 26 months (range, 15-57 months). At baseline, celiac axis (3/8, 37.5%), superior mesenteric (4/8, 50%), and common hepatic (2/8, 25%) arteries were involved, in addition to isolated lesions of right renal, splenic, right colic, middle colic, gastroduodenal, left gastric, right gastroepiploic, proper hepatic, right hepatic, and left hepatic arteries. Compared with prior publications, celiac axis and superior mesenteric artery were more commonly affected in cohort. Arterial dissections (n = 8), aneurysms (n = 5), stenoses or occlusions (n = 4), and a single pseudoaneurysm were documented. Despite careful conservative management, new splanchnic arterial lesions (n = 4) arose during follow-up. Considering the few available reports of new arterial lesions in the literature, newly developing pathology is a distinctive feature of our patients, four of whom eventually required endovascular interventions.

CONCLUSIONS

Careful clinical observation via periodic CT angiography is required in patients with SAM, checking for newly developing lesions. The natural history of SAM should be clarified in a larger patient population.

Segmental arterial mediolysis: findings at computed tomography angiography

OBJECTIVE

To review the principal findings on computed tomography angiography for segmental arterial mediolysis, and to emphasize the points that help to differentiate it from other vasculopathies such as vasculitis. We also review the protocols for follow-up and the various treatment options.

CONCLUSION

Segmental arterial mediolysis is a rare disease that is defined as a non-atherosclerotic, non-hereditary, and non-inflammatory vasculopathy characterized by lysis of the medial layer of the arterial wall. It should be suspected in middle-aged patients with aneurysms, dissections, or spontaneous ruptures of visceral arteries of unknown etiology who do not fulfill the clinical and laboratory criteria for vasculitis. The arteries of the abdominal organs are the most commonly affected, including the arteries of the celiac trunk and the superior and inferior mesenteric arteries. Radiologically, segmental arterial mediolysis can present as arterial dilation; single or multiple, saccular or fusiform aneurysms; stenoses; or dissections.

Segmental arterial mediolysis

Segmental arterial mediolysis (SAM) is an uncommon, nonatherosclerotic, noninflammatory, large- to medium-sized arteriopathy first described in 1976. It is characterized histologically by vacuolization and lysis of the outer arterial media leading to dissecting aneurysms and vessel rupture presenting clinically with self-limiting abdominal pain or catastrophic hemorrhages in the abdomen. Patients of all ages are affected with a greater incidence at the fifth and sixth decades. There is a slight male predominance. Imaging findings overlap with inflammatory vasculitis, collagen vascular disease, and fibromuscular dysplasia. The presence of segmental dissections involving the celiac, mesenteric, and/or renal arteries is the key distinguishing features of SAM. Inflammatory markers, genetic tests for collagen vascular disorders, and hypercoagulable studies are negative. Anti-inflammatory agents and immunosuppressants are not effective. A mortality rate of 50 % has been attributed to the acute presentation with aneurysmal rupture necessitating urgent surgical or endovascular treatments; in the absence of the acute presentation, SAM is a self-limiting disease and is treated conservatively. There are no established guidelines on medical therapy, although optimal control of blood pressure is considered the main cornerstone of medical therapy. The long-term prognosis is not known.

Segmental arterial mediolysis: a systematic review of 85 cases

BACKGROUND

Segmental arterial mediolysis (SAM) is a nonatherosclerotic, noninflammatory arteriopathy of unknown etiology with life-threatening manifestations. With advances in endovascular techniques, SAM is increasingly being managed without the need for major surgery.

METHODS

A systematic review of the literature published on SAM between 1976 and 2012 was performed, focusing on arterial involvement, diagnostic imaging modalities, mortality and morbidity rates, and in particular treatment outcomes with open versus endovascular intervention.

RESULTS

Sixty-two studies reporting on 85 cases of SAM were reviewed. Sixty-nine percent of cases were diagnosed histologically (24% on autopsy). Angiography was the most common form of diagnostic imaging modality (56% of cases). Arterial involvement was largely abdominal or cranial, with splenic arterial involvement being the most prevalent (29% of cases). There was a total SAM-related mortality of 26%. Endovascular intervention, most commonly in the form of coil embolization of aneurysmal vessel(s), was successful in 88% of cases where attempted, with no reported mortality. There was a mortality rate of 9% where open surgery was attempted.

CONCLUSIONS

Catheter-based endovascular techniques can be a successful, minimally invasive treatment option in the management of this potentially life-threatening condition, and may also provide a temporary bailout measure in the acute phase before definitive surgical treatment at a later stage.

Acute remodeling of an adjoining aneurysm after endovascular treatment of a ruptured splanchnic arterial aneurysm: a case of clinically diagnosed segmental arterial mediolysis

A 61-year-old woman with multiple splanchnic arterial aneurysms (SAAs) was transferred to our hospital in a state of shock. She underwent coil embolization under the diagnosis of ruptured pancreaticoduodenal artery aneurysm. Follow-up computed tomography performed 2 weeks later showed rapid enlargement of a gastric artery aneurysm, and she underwent an additional embolization. Atherosclerotic, inflammatory or hereditary causes were excluded, and the patient was clinically diagnosed with segmental arterial mediolysis accompanied by multiple SAAs, one of which showed acute remodeling after endovascular treatment.

Segmental arterial mediolysis: report of 2 cases and review of the literature

Segmental arterial mediolysis (SAM) is an idiopathic noninflammatory vasculopathy involving small to medium arteries, usually in the abdomen, although arteries in the cerebral and coronary circulations also may be affected. Some cases present as abdominal apoplexy due to aneurysmal rupture, but ischemia and infarction also occur. Not uncommonly, SAM may be misdiagnosed as a systemic necrotizing vasculitis. We present 2 patients with bilateral renal infarctions, cerebral arterial dissections, and visceral artery microaneurysms. Both were diagnosed initially as polyarteritis nodosa. The diagnosis was changed to SAM, in one case based on clinical and radiologic features, and in the other, on an open wedge kidney biopsy. We discuss the differential diagnosis and review the literature on SAM.

Segmental arterial mediolysis

Segmental arterial mediolysis (SAM) is a nonatherosclerotic, noninflammatory arteriopathy, which is characterized by dissecting aneurysms resulting from lysis of the outer media of the arterial wall. The most common presentation is abdominal pain and hemorrhage in the elderly. Computed tomography (CT) and angiography imaging findings overlap with various vasculitides and include segmental changes of aneurysm and stenosis. A key distinguishing feature is the presence of dissections, the principle morphologic expression of SAM. Differentiation and exclusion of an inflammatory arteritis is crucial in appropriate management, as immunosuppressants generally used for treatment of vasculitis may be ineffective or even worsen the vasculopathy. Although the disease can be self-limiting without treatment or with conservative medical therapy, the acute process carries a 50% mortality rate and may necessitate urgent surgical and/or endovascular therapy. Prompt recognition and diagnosis are therefore of utmost importance in appropriate management of this rare entity.

Spontaneous dissection with rupture of the superior mesenteric artery from segmental arterial mediolysis

Spontaneous dissection of the superior mesenteric artery (SMA) is rare. We report a case of rupture of the SMA after spontaneous dissection in a 51-year-old male who presented with acute onset of abdominal pain and hypotension. The patient was initially treated with intravenous fluid resuscitation and endovascular intervention followed by open surgery. No identifiable cause for dissection was found. The patient was diagnosed as having segmental arterial mediolysis (SAM). The patients' presentation, treatment, outcome, and all relevant imaging, pathologic, and laboratory studies were reviewed. The relevant features of the case and SAM are presented herein. In addition, a review of all available published literature on SAM to date is presented.

Aneurysms of the renal arteries associated with segmental arterial mediolysis in a case of polyarteritis nodosa

This is the first report of segmental arterial mediolysis (SAM) accompanied with polyarteritis nodosa (PN), and manifesting aneurysms of the renal arteries. A 73-year-old woman was admitted to hospital because of a high fever. Laboratory tests showed leukocytosis with increased CRP level in the serum. Myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPO-ANCA) and proteinase 3 (PR3)-ANCA were negative. There were no signs indicating infection or malignancy. After admission renal function rapidly deteriorated. Treatment was then started with daily oral prednisolone and hemodialysis. On the 40th day of hospitalization the patient suddenly became comatose. Cranial CT showed a subarachnoid hemorrhage. The patient died and an autopsy was performed. The pathological findings showed necrotizing vasculitis of the small arteries in various organs, but not associated with that of arterioles or renal glomerular lesions, indicating PN. Unexpectedly, the segmental arteries of the bilateral kidneys showed vascular lesions of dissecting aneurysms, indicating SAM. This case indicates that SAM is one of the causes of aneurysms in PN and is clinically important when the clinical course of PN patients rapidly advances.

Transcatheter arterial embolization for segmental arterial mediolysis

PURPOSE

To report outcomes of transcatheter arterial embolization for segmental arterial mediolysis (SAM), a vascular disorder characterized by angiographically documented fusiform aneurysms separated by areas of normal appearing vessel in the celiac or mesenteric arteries.

CASE REPORTS

Four patients (3 men; median age 70 years, range 57-77) had a presumptive diagnosis of SAM; the possibility of vasculitis was ruled out based on clinical and laboratory findings. Three patients were symptomatic, with aneurysm rupture; the fourth patient was diagnosed incidentally. Coil embolization was used in 3 cases and N-butyl cyanoacrylate in the other. There was no re-rupture. One patient developed a focal dissection of the superior mesenteric artery 9 months after middle colic artery embolization. Another patient died of perforation of the lower gastrointestinal tract 3 months after treatment, but the cause was unknown; mesenteric ischemia from embolization and arteriopathy could not be ruled out.

CONCLUSION

Transcatheter embolization is useful for SAM. However, it is likely that the morphology associated with SAM transforms rapidly, so patients undergoing mesenteric artery embolization should be monitored at short intervals.

Successful treatment tailored to each splanchnic arterial lesion due to segmental arterial mediolysis (SAM): report of a case

Segmental arterial mediolysis (SAM) is a rare condition characterized by splanchnic arterial catastrophe caused by mediolysis. We report a 59-year-old man with a ruptured splenic arterial aneurysm who was successfully treated by coil embolization. He underwent additional resection of large gastroepiploic and residual splenic aneurysms. Pathological examination showed mediolysis and tearing, compatible with SAM. Furthermore, he developed acute dissection of the superior mesenteric artery (SMA) one and a half years later, demonstrated by computed tomography. This report demonstrates that SAM is characterized by multiple lesions of the splanchnic arteries at different times, and requires treatment suited to the lesions, including careful long-term observation.

Segmental arterial mediolysis with accompanying venous angiopathy: a clinical pathologic review, report of 3 new cases, and comments on the role of endothelin-1 in its pathogenesis

The authors review 20 cases of segmental arterial mediolysis (SAM) including 3 newly reported cases. SAM developed in areas of vascular distention in 2 of the latter cases: 1 in utero in the heart of a recipient of a twin transfusion syndrome and the other in the jejunum secondary to partial venous obstruction. In the third case, it occurred in a patient with Raynaud disease. Characterizing SAM are injurious and reparative lesions that occur in the media and/or at the adventitial medial junction. Four distinctive alterations are recognized: (1) mediolysis, (2) a tearing separation of the outer media from adventitia, (3) arterial gaps, and (4) a florid reparative response that replaces zones of mediolysis and fills areas of medial adventitial separation. The repair can transform SAM into lesions indistinguishable from common types of fibromuscular dysplasia (FMD.) A venous angiopathy involving large and medium-sized veins accompanies SAM. It features medial muscle vacuolar change with lysis leading to apparent separation of residual muscle bundles. Immunostaining shows endothelin-1 (ET-1) decorating adventitial capillaries in SAM and neighboring arteries, in capillaries of adjoining tissues, and outlining smooth muscle cell membranes in adjacent veins including those of the venous angiopathy. The significance of these changes is uncertain. Vasospasm is believed to cause SAM, but ET-1 is not the direct pressor agent responsible for this condition. The reason(s) for synthesis and release of ET-1 in SAM are still hypothetical, but local perturbations in vascular tone may be an important factor. ET-1 may be indirectly play a role in SAM by cross-talking and potentiating the activities of other vasoconstrictors such as norepinephrine and by orchestrating its reparative phase.

A case report of segmental arterial mediolysis

We report a case of 58-year-old woman with a ruptured dissecting aneurysm of the middle colic artery (MCA). Her initial manifestation was sudden and severe right-sided abdominal pain, followed by hemorrhagic shock and acute anemia. Abdominal CT showed a right retroperitoneal hemorrhage. Emergency catheter angiography and therapeutic coil embolization of the middle colic artery were performed and micro aneurysms were enhanced in the jejunal branch. Immunological tests showed nothing abnormal. Follow-up angiography after 3 months showed that the micro aneurysms had disappeared. The patient was diagnosed as having segmental arterial mediolysis (SAM), because no definitive evidence of atherosclerosis and polyarteritis nodosa were observed. SAM is a rare disease of unknown etiology. The arterial lesions developing in elderly patients are characterized by segmental lysis of the abdominal splanchnic arteries resulting in aneurysms, and acute bleeding in a skip pattern. Multiple aneurysms and abdominal pain due to the rupture of these lesions in SAM resemble the clinical findings in polyarteritis nodosa. Differential diagnosis of the two diseases is important because steroid therapy is not beneficial for SAM.

Segmental Arterial Mediolysis: CTA Findings at Presentation and Follow-Up

OBJECTIVE

Segmental arterial mediolysis is a rare noninflammatory vascular disease of the abdominal splanchnic arteries. The purpose of our study was to retrospectively describe the CT angiography (CTA) findings of this disease and the evolution of those findings over time in five patients.

CONCLUSION

Comparison of CTA and digital subtraction angiography suggests that CTA is useful to diagnose symptomatic segmental arterial mediolysis. Midterm CTA follow-up (median, 3 years) indicates that segmental arterial mediolysis lesions may resolve or remain unchanged.

Reconstructive surgery for segmental arterial mediolysis involving both the internal carotid artery and visceral arteries

Segmental arterial mediolysis (SAM) is a rare, nonatherosclerotic, noninflammatory arteriopathy. A 52-year-old man with sudden hemiparesis of the right side was found to have an aneurysm of the left internal carotid artery and concomitant multiple aneurysms of the extrahepatic, celiac, and superior mesenteric arteries. Reconstructive operations using autologous vein graft were performed to treat the aneurysms. The histopathology analyses of resected arterial and aneurysmal specimens showed characteristics consistent with SAM. To our knowledge, a successfully treated case of SAM affecting both the carotid artery and visceral arteries has not previously been described.

Pulmonale segmentale mediolytische Arteriopathie

Segmental mediolytic arteriopathy (SMA) is defined as non-inflammatory arteriopathy with mediolysis due to segmental loss of media and consecutive formation of vascular gaps. Up to now, less than 40 cases of visceral and cerebral SMA and, to our knowledge, only one case of pulmonary SMA have been reported. We present the history of a 21 year old female patient, admitted to hospital with hemoptysis, but without other symptoms. Apart from two lesions in the sixth and tenth pulmonary segment, documented by CT and interpreted as colliquations, there were no other clinical and laboratory findings. Repeated bronchoscopy supplied no further information. Histomorphology of the resected lesion revealed SMA without evidence of vasculitis. Wegener's disease could be excluded. The aetiology of the disease is still unknown. Acute vasospasm (due to inappropriate reactions to catecholamine or endothelial dysfunction), as well as SMA as a precursor or subtype of fibromuscular dysplasia, are two theories still under discussion.

Segmental Arterial Mediolysis: Angioplasty of Bilateral Renal Artery Stenoses with 2-Year Imaging Follow-up

Segmental arterial mediolysis (SAM) is a rare condition caused by loss of muscular elements in the walls of medium-sized, usually visceral, arteries. This causes dissection, occlusion, aneurysm formation, and rupture. The clinical presentation is usually catastrophic as a result of vascular occlusion or rupture. Herein an unusual case of renovascular hypertension resulting from SAM is reported, which was successfully treated with balloon angioplasty.

Coil embolization of multiple hepatic artery aneurysms in a patient with undiagnosed polyarteritis nodosa

Hepatic aneurysms are a rare sequela of vascular abnormalities in the liver, including trauma, infection, necrotizing vasculitis such as polyarteritis nodosa (PAN), and iatrogenic and arterial mediolysis. Presentation with intra-abdominal hemorrhage is associated with a high mortality rate. We describe life-saving transcatheter coil embolization of multiple isolated ruptured hepatic pseudoaneurysms in a patient with no history or clinical findings of PAN. We present angiographic findings and intra-arterial transcatheter embolization techniques in the treatment of ruptured large hepatic artery aneurysms. Endovascular specialists should recognize that PAN could present with classic angiographic findings and, in some cases, as life-threatening ruptured isolated hepatic artery aneurysms as its first presentation.

Mesenteric arteriographic findings in a patient with strongyloides stercoralis hyperinfection

The authors present a case of a Latin American patient with systemic lupus erythematosus who was referred for a mesenteric arteriogram because of acute lower gastrointestinal bleeding. Multiple segments of dilation alternating with stenosis or spasm were noted in the superior mesenteric artery/inferior mesenteric artery distributions. At the time, these irregularities were thought to be representative of lupus vasculitis. Despite appropriate treatment for vasculitis, the patient continued to have bleeding episodes and ultimately died of multiple organ failure. Autopsy demonstrated no evidence of vasculitis, but did demonstrate the unexpected finding of Strongyloides stercoralis hyperinfection with vessel invasion.