Spontaneous isolated dissection of the superior mesenteric artery and aneurysm formation resulting from segmental arterial mediolysis: a case report. Diagn Pathol. 2017;12:74. [PMID: 29037200 PMCID: PMC5644139 DOI: 10.1186/s13000-017-0664-x]

Segmental arterial mediolysis: a rare cause of an acute abdomen

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

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.

Experience of managing superior mesenteric artery aneurysm and its midterm follow-up results with 18 cases

OBJECTIVES

To characterize the clinical features, treatment, and prognosis of superior mesenteric artery aneurysms and provide evidence for clinical decision-making.

METHODS

We retrospectively reviewed the diagnosis and treatment of 18 cases of superior mesenteric artery aneurysm admitted to our center from 2003 to 2020, including demographic data, risk factors, clinical manifestations, diagnosis, treatment strategies, and follow-up results.

RESULTS

The average age of the patients was 49.1 years, and males accounted 83.3%. The development of the disease was associated with infection, hypertension, pancreatitis, and trauma, but no significant associations with atherosclerosis were noted by our results. Nine patients were diagnosed with true aneurysm, seven patients with pseudoaneurysm, and two patients with dissecting aneurysm. Rupture of aneurysm occurred in three patients (16.7%), and one of them died before surgery. The surgery success rate was 94.1%, and open surgery was performed on nine patients, endovascular surgery on three patients, and conservative treatment on three patients. The follow-up rate was 77.8% (14/18), and the average follow-up time was 48.2 months. The mortality and reintervention rate during follow-up was 0. The two-year patency rate of artificial vessels and covered stents was 50%.

CONCLUSION

The clinical manifestations and features of superior mesenteric artery aneurysms vary between patients. Careful evaluation of vascular anatomy and personalized treatment strategy are critical in the management of superior mesenteric artery aneurysms. Midterm follow-up results of superior mesenteric artery aneurysms are satisfactory.

Presentation and Management of Rare Saccular Superior Mesenteric Artery Trunk and Branch Aneurysms

Superior mesenteric artery (SMA) aneurysm is caused by degeneration of the visceral arteries. Although a rarely encountered entity, it requires timely management owing to the high mortality rate associated with rupture, particularly when the aneurysm is saccular in nature. As such, urgent treatment is generally indicated. We present five cases of SMA aneurysm arising from the main trunk or branches of the SMA.

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.

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.

Factors Associated with Failed Conservative Management in Symptomatic Isolated Mesenteric Artery Dissection

OBJECTIVE

The aim of this study was to assess factors associated with conservative management failure in patients with symptomatic isolated mesenteric artery dissection.

METHODS

Patients with symptomatic isolated mesenteric artery dissection who underwent conservative therapy as first line treatment between February 2010 and May 2018 were included in this retrospective study. Conservative management failure was defined as the persistence or aggravation of symptoms and signs, increasing aneurysmal dilation, or new appearance of a dissecting aneurysm after conservative management. Univariable and multivariable analyses were performed to identify risk factors for failure of conservative management.

RESULTS

A total of 123 patients (115 men, 8 women, mean age, 53.7 ± 6.1 years) were included in this study. Conservative management was successful in 89 (72.4%) patients but failed in the remaining 34 (27.6%) patients. Of the 89 for whom conservative management was successful, all of the symptoms were eliminated (n = 81) or relieved (n = 8) within 3.8 ± 0.7 days after conservative management. All of the 34 patients in whom conservative management failed underwent successful endovascular stenting. Failure of conservative management was associated with type II IMADs as defined by the Sakamoto classification (meaning that there is an entry tear, but no re-entry, and still no thrombosis of false lumen, odds ratio: 33.76; 95% confidence interval 8.65-131.85; p < .001) and with ≥90% luminal stenosis (odds ratio 40.70; 95% confidence interval: 3.76-440.07; p < .01).

CONCLUSIONS

Conservative management can be used successfully in most patients with symptomatic isolated mesenteric artery dissection. Risk factors for failed conservative treatment were type II IMADs and degree of luminal stenosis ≥90%.

Acute Dissection of the Middle Colic Artery Immediately after Endovascular Abdominal Aortic Aneurysm Repair: A Case Report

A 78-year-old man underwent endovascular abdominal aortic aneurysm repair (EVAR) for a true aortic aneurysm. He developed sudden abdominal pain 4 hr after EVAR. Angiography revealed a dissected aneurysm of the middle colic artery (MCA). Despite conservative treatment, follow-up computed tomography revealed an expanded aneurysm of the MCA. We therefore performed coil embolization of the dissected MCA to prevent a rupture of the aneurysm. There has never been a reported case of acute dissection of the MCA immediately after EVAR that was not caused by catheters. In this report, we discuss the possible underlying mechanisms and the optimal therapeutic strategy for this rare complication.

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

The vascular diseases including aneurysm, occlusion, and thromboses in the mesenteric lesions could cause severe symptoms and appropriate diagnosis and treatment are essential for managing patients. With the development and improvement of imaging modalities, diagnostic frequency of these vascular diseases in abdominal lesions is increasing even with the small changes in the vasculatures. Among various vascular diseases, fibromuscular dysplasia (FMD) and segmental arterial mediolysis (SAM) are noninflammatory, nonatherosclerotic arterial diseases which need to be diagnosed urgently because these diseases could affect various organs and be lethal if the appropriate management is not provided. However, because FMD and SAM are rare, the cause, prevalence, clinical characteristics including the symptoms, findings in the imaging studies, pathological findings, management, and prognoses have not been systematically summarized. Therefore, there have been neither standard diagnostic criteria nor therapeutic methodologies established, to date. To systematically summarize the information and to compare these disease entities, we have summarized the characteristics of FMD and SAM in the gastroenterological regions by reviewing the cases reported thus far. The information summarized will be helpful for physicians treating these patients in an emergency care unit and for the differential diagnosis of other diseases showing severe abdominal pain.