Spontaneous isolated dissection and atherosclerotic plaques of superior mesenteric artery: the vastly different occurrence site suggests the opposite haemodynamic aetiology

Isolated Superior Mesenteric Artery Dissection following Blunt Trauma: A Case Report

Isolated superior mesenteric artery dissection (ISMAD) is rare, with symptoms ranging from asymptomatic to acute intestinal ischemia. Risk factors for ISMAD include hypertension, atherosclerosis, abnormal elastic fibers, and pregnancy. In the present case, blunt trauma, which has not been previously reported, was suggested as a risk factor. A 46-year-old man was brought to the emergency room after he was found unconscious after a motor vehicle collision. At presentation, he had no abdominal symptoms; however, on the fourth day of admission, he presented with severe abdominal pain and vomiting. A contrast-enhanced computed tomography scan revealed an ISMAD with associated intestinal ischemia and necrosis; hence, emergency surgery was performed. Herein, we report a case of ISMAD caused by blunt abdominal trauma.

Isolated Superior Mesenteric Artery Dissection: A Novel Etiology and a Review

Isolated superior mesenteric artery dissection (ISMAD) is a rare pathology with multifactorial etiology. The aim of this article is to provide a narrative review of the latest literature about ISMAD. Case reports, series, and recent meta-analyses were included. This review is introduced with a brief case report of a rare etiology of ISMAD, followed by a discussion of its etiology, clinical presentation, diagnosis, classification, and treatment, and we report a new cause of ISMAD, that is, blunt abdominal trauma. The etiology of ISMAD is multifactorial, consisting of anatomic, genetic, and systemic components. ISMAD is more common among middle-aged males and in East Asia. Its clinical presentation ranges from asymptomatic to mesenteric ischemia, albeit mortality remains <1%. It is diagnosed and classified mostly by computed tomography angiography, and there are five classification systems for ISMAD, though traumatic etiology may be added. The treatment of ISMAD is mostly conservative, with a success rate exceeding 90%. Endovascular stenting is second line, reserved so far for failed medical management, though its role is expanding to include earlier management of symptomatic patients, while open surgical repair is left for acute mesenteric ischemia with bowel compromise.

Management of Spontaneous Isolated Mesenteric Artery Dissection: A Systematic Review

Background and Aims:

There are increasing reports on case series on spontaneous isolated mesenteric artery dissection, that is, dissections of the superior mesenteric artery and celiac artery, mainly due to improved diagnostic capacity of high-resolution computed tomography angiography performed around the clock. A few case–control studies are now available, while randomized controlled trials are awaited.

Material and Methods:

The present systematic review based on 97 original studies offers a comprehensive overview on risk factors, management, conservative therapy, morphological modeling of dissection, and prognosis.

Results and Conclusions:

Male gender, hypertension, and smoking are risk factors for isolated mesenteric artery dissection, while the frequency of diabetes mellitus is reported to be low. Large aortomesenteric angle has also been considered to be a factor for superior mesenteric artery dissection. The overwhelming majority of patients can be conservatively treated without the need of endovascular or open operations. Conservative therapy consists of blood pressure lowering therapy, analgesics, and initial bowel rest, whereas there is no support for antithrombotic agents. Complete remodeling of the dissection after conservative therapy was found in 43% at mid-term follow-up. One absolute indication for surgery and endovascular stenting of the superior mesenteric artery is development of peritonitis due to bowel infarction, which occurs in 2.1% of superior mesenteric artery dissections and none in celiac artery dissections. The most documented end-organ infarction in celiac artery dissections is splenic infarctions, which occurs in 11.2%, and is a condition that should be treated conservatively. The frequency of ruptured pseudoaneurysm in the superior mesenteric artery and celiac artery dissection is very rare, 0.4%, and none of these patients were in shock at presentation. Endovascular therapy with covered stents should be considered in these patients.

Isolated superior mesenteric artery dissection: CTA features and clinical relevance

PURPOSE

To determine the detailed computed tomography angiography (CTA) features of isolated superior mesenteric artery dissection (ISMAD), aiming to improve the current understanding of ISMAD.

MATERIALS AND METHODS

We retrospectively analyzed 57 patients with confirmed diagnoses of ISMAD with CTA from June 2011 to June 2018 in our hospital. The superior mesenteric artery (SMA) angle, entry site of dissection, and features of both false and true lumen were analyzed individually.

RESULTS

In general, middle-aged men with atherosclerosis (42.1%), hypertension (35.3%), or long-term smoking (33.3%) were the main populations. 80.7% of patients can be discharged successfully after conservative treatment. 87% of patients had a right (or almost right) SMA angle, and the entry site of dissection in 90% of patients occurred in the curved segment of the SMA. As a polymorphic disease, we can use the coded CTA features to delineate individual cases, including cases beyond the presenting classification systems. The diameter of the true lumen is the only different CTA feature between the conservative treatment group and the interventional treatment group (p = 0.000). The re-entry site (p = 0.501), thrombosis in the false lumen (p = 0.135), the distance between the entry site of dissection and SMA root (p = 0.133), and SMA branch involvement (p = 0.322) had no difference between the 2 groups.

CONCLUSIONS

Based on CTA analysis, the bending area, especially in the SMA with right or nearly right SMA angle, is the most vulnerable anatomical region for the occurrence of ISMAD. The diameter of true lumen is the determined CTA feature for the decision of treatment. CTA should be recommended as a standardized diagnostic and classification tool for ISMAD.

Long-term outcomes of conservative treatment and endovascular treatment in patients with symptomatic spontaneous isolated superior mesenteric artery dissection: a single-center experience

BACKGROUND

Spontaneous isolated superior mesenteric artery dissection (SISMAD) is a rare vascular disorder, and the treatment strategies remain controversial. This study aimed to compare outcomes of conservative and endovascular treatments in symptomatic patients with SISMAD.

METHODS

Forty-two consecutive SISMAD patients who were admitted to a single center between October 2009 and May 2018 were enrolled in this study. Based on their symptoms, 15 had conservative treatment, and 27 had endovascular treatment. The baseline characteristics, treatments, and follow-up results of the conservative group and endovascular group were analysed.

RESULTS

The rates of symptom relief were 93.3% in the conservative group and 96.3% in the endovascular group. The procedure-related complications in the endovascular group included one case of pseudoaneurysm formation in the left brachial artery. During the follow-up period (median 28.5 months), a higher proportion of patients in the conservative group had symptom recurrence (42.9% in the conservative group versus 4.8% in the endovascular group, p < 0.001). Four patients in the conservative group and one patient in the endovascular group had additional endovascular intervention during follow-up. Compared with the conservative group, patients in the endovascular group had statistically significantly longer symptom-free survival (p = 0.014) and a higher rate of superior mesenteric artery (SMA) remodeling (p < 0.001).

CONCLUSIONS

For symptomatic SISMAD, endovascularly treated patients had a lower rate of symptom recurrence and a higher rate of SMA remodeling in the long term. Prospective, multi-center studies are needed to confirm the long-term outcomes of both treatments.

The role of aortomesenteric angle in occurrence of spontaneous isolated superior mesenteric artery dissection

BACKGROUND

This study investigated whether anatomical factors affect the occurrence of SISMAD by measuring the aortomesenteric angle (AMA).

METHODS

The study population is comprised of 3 distinct population; Korean SISMAD patients, two control groups from a medical checkup database of 4997 Korean and 317 Caucasian patients from 2011 to 2016. The patient group (PG) included 26 symptomatic patients and 19 Korean diagnosed with SISMAD during medical checkup. The control group was selected based on propensity score similarities calculated by using the following covariates: sex, age, body mass index, drinking, smoking, hypertension, diabetes, and cancer. We compared PG with equal numbers of two control groups comprised of Koreans (KG) and Caucasians (FG), respectively.

RESULTS

The mean (SD) AMA was 74.9o (17.5) (range, 45.9-110.9o) in the PG, 56.8o (19.5 (range, 10.2o -91.9o) in the FG, and 62.4o (19.1) (range, 25.4-110.8o) in the KG. A significant difference was observed between PG and the two control groups (P<0.001). The AMA in the FG was significantly more acute than the AMA in Korean patients including those in the PG and KG (P=0.001).

CONCLUSIONS

Large AMA is considered to be an important etiologic factor in SISMAD.