Insight into Dunbar syndrome: color-Doppler ultrasound findings and literature review

Vascular compression syndromes in the abdomen and pelvis: a concise pictorial review

Vascular compression syndromes are a diverse group of pathologies that can manifest asymptomatically and incidentally in otherwise healthy individuals or symptomatically with a spectrum of presentations. Due to their relative rarity, these syndromes are often poorly understood and overlooked. Early identification of these syndromes can have a significant impact on subsequent clinical management. This pictorial review provides a concise summary of seven vascular compression syndromes within the abdomen and pelvis including median arcuate ligament (MAL) syndrome, superior mesenteric artery (SMA) syndrome, nutcracker syndrome (NCS), May-Thurner syndrome (MTS), ureteropelvic junction obstruction (UPJO), vascular compression of the ureter, and portal biliopathy. The demographics, pathophysiology, predisposing factors, and expected treatment for each compression syndrome are reviewed. Salient imaging features of each entity are illustrated through imaging examples using multiple modalities including ultrasound, fluoroscopy, CT, and MRI.

Ultrasound characteristics of abdominal vascular compression syndromes

Abdominal vascular compression syndrome (AVCS) is caused by the compression of abdominal blood vessels by adjacent structures or the compression of abdominal organs by neighboring blood vessels. Such compressions can result in a variety of clinical symptoms. They are not commonly seen in ultrasound practices, and their presence may have been underrecognized and underdiagnosed. This article reviews the clinical features, ultrasound characteristics, and diagnostic criteria of four types of AVCS, namely, celiac artery compression syndrome, renal vein compression syndrome, iliac vein compression syndrome, and superior mesenteric artery syndrome to increase awareness of these conditions among ultrasound practitioners. The ultrasound criteria for AVCS are primarily based on studies with small sample sizes, and therefore, it is important to exercise caution if these criteria are used.

Overview of Median Arcuate Ligament Syndrome: A Narrative Review

Median arcuate ligament syndrome (MALS) is a rare disorder caused primarily by compression of the celiac trunk by the median arcuate ligament (MAL). This disorder typically results in patients presenting with bloating, weight loss, nausea, vomiting, and abdominal pain. The MALS diagnosis is one of exclusion, as the disorder has no specific diagnostic criteria. Imaging modalities are often utilized to assist in making the diagnosis, such as ultrasound, computed tomography angiography (CTA), and magnetic resonance angiography (MRA). These imaging modalities typically reveal a stenosed celiac artery with post-stenotic dilation in patients. This disorder is usually treated by dividing the MAL, thus relieving the compression of the celiac artery. The surgery may be done through either an open approach or a minimally invasive approach, which can be either laparoscopic or robot-assisted. Most patients respond well to this treatment, though certain factors that predict a poorer response to treatment include elderly age, a history of alcohol abuse, and psychiatric illness.

Prevalence and Characteristics of Patients with Median Arcuate Ligament Syndrome in a Cohort Diagnosed with Celiac Artery Compression

BACKGROUND

Median arcuate ligament syndrome (MALS) is a frequent differential diagnosis in patients with postprandial abdominal symptoms, but diagnosis remains challenging. The aim of this study was to identify characteristics of patients who had MALS compared with non-MALS patients among a cohort of patients diagnosed with celiac artery compression (CAC).

STUDY DESIGN

An IRB-approved retrospective chart review (2000 to 2021) of patients at our institution with a discharge diagnosis of CAC was performed. Medical record review for clinical symptoms and findings consistent with MALS was performed.

RESULTS

Two hundred ninety-three patients with a diagnosis of CAC were identified; 59.7% were women, and average age was 63.9 ± 20.2 years. Sixty-nine (23.5%) patients with CAC had MALS. There were no significant differences in sex or race between MALS and non-MALS patients, but MALS patients were younger (55.7 vs 68.1, p < 0.001). There was no significant difference in gastrointestinal comorbidities between the 2 groups. Patients with MALS were less likely to have diabetes (12.5% vs 26.9%), renal disease (4.6% vs 8.2%), hypertension (41.5% vs 70.3%), mesenteric atherosclerotic disease (14% vs 61.9%), and peripheral artery disease (15.0% vs 39.7%).

CONCLUSIONS

We demonstrate a novel observation that MALS patients tend to have fewer atherosclerotic characteristics than non-MALS patients with CAC. Patients in our study with MALS were more likely to be younger, women, and presenting with epigastric pain. MALS patients had a significantly lower incidence of diabetes, hypertension, renal disease, mesenteric artery disease, and peripheral arterial disease compared with the non-MALS group. An important clinically relevant feature of MALS patients may be their lack of atherosclerotic phenotype compared with non- MALS patients with CAC.

Surgical therapy of celiac axis and superior mesenteric artery syndrome

INTRODUCTION

Compression syndromes of the celiac artery (CAS) or superior mesenteric artery (SMAS) are rare conditions that are difficult to diagnose; optimal treatment remains complex, and symptoms often persist after surgery. We aim to review the literature on surgical treatment and postoperative outcome in CAS and SMAS syndrome.

METHODS

A systematic literature review of medical literature databases on the surgical treatment of CAS and SMAS syndrome was performed from 2000 to 2022. Articles were included according to PROSPERO guidelines. The primary endpoint was the failure-to-treat rate, defined as persistence of symptoms at first follow-up.

RESULTS

Twenty-three studies on CAS (n = 548) and 11 on SMAS (n = 168) undergoing surgery were included. Failure-to-treat rate was 28% for CAS and 21% for SMAS. Intraoperative blood loss was 95 ml (0-217) and 31 ml (21-50), respectively, and conversion rate was 4% in CAS patients and 0% for SMAS. Major postoperative morbidity was 2% for each group, and mortality was described in 0% of CAS and 0.4% of SMAS patients. Median length of stay was 3 days (1-12) for CAS and 5 days (1-10) for SMAS patients. Consequently, 47% of CAS and 5% of SMAS patients underwent subsequent interventions for persisting symptoms.

CONCLUSION

Failure of surgical treatment was observed in up to every forth patient with a high rate of subsequent interventions. A thorough preoperative work-up with a careful patient selection is of paramount importance. Nevertheless, the surgical procedure was associated with a beneficial risk profile and can be performed minimally invasive.

The Ultrasound Findings in a Rare Case of Nutcracker Syndrome, Wilkie's Syndrome, and Dunbar Syndrome Combination

Vascular compression syndromes represent a group of rare and poorly understood diseases. Dunbar syndrome (DS) is caused by the median arcuate ligament of diaphragm originating lower than normal and causing compression of celiac artery. The Nutcracker is caused by the superior mesenteric artery (SMA) originating from aorta at an acute angle causing a restriction of aortomesenteric space that is traversed by the left renal vein and duodenum; if the compression involves only the left renal vein and becomes symptomatic it is called Nutcracker syndrome; if the symptomatic compression involves only the duodenum it is called Wilkie's syndrome or SMA syndrome. The knowledge of these rare pathologies is essential to reduce the false negatives which still remain very high; it is, therefore, necessary to promote greater knowledge as the lack of diagnosis can be very dangerous for the patient's health. We describe a rare case of a combination of DS, Nutcracker, and SMA or Wilkie's syndrome in a young patient.

Systematic hybrid laparoscopic and endovascular treatment of median arcuate ligament syndrome: A single-center experience

Background

Median arcuate ligament syndrome (MALS) is caused by celiac trunk (CT) compression by the median arcuate ligament. Clinically, this pathology varies from postprandial pain (Dunbar syndrome) to a life-threatening hemorrhage because of a rupture of a gastroduodenal artery aneurysm (GAA). Due to the low prevalence of this disease, there is no standard management for MALS.

Material and method

This was a single-center, retrospective study of 13 patients. Two groups were identified on the basis of the initial clinical presentation: those operated for a GAA rupture (bleeding group-BG) and those operated electively for Dunbar syndrome (Dunbar syndrome group-DG). The primary endpoint was 30-day postoperative complications of a systematic laparoscopic release of the median arcuate ligament and stenting during the same procedure.

Results

Seven patients (54%) underwent elective surgery. Six patients (46%) underwent semiurgent repair under elective conditions post-embolization for GAA bleeding. The total operative time was longer in the BG (p = 0.06). Two patients in the BG suffered early major complications and needed reintervention, and those in the DG had a lower comprehensive complication index. No mortality was reported at 30 days. Overall median length of stay was 5 days (IQR: 3.5-15.3). Patients in the DG had a significantly shorter length of stay (p = 0.02). At 6 months, the primary and secondary CT stent patencies were 82% and 100%, respectively. There were no high-flow GAA recurrences.

Conclusions

A combined approach of laparoscopic release of the median arcuate ligament and stenting during the same procedure is feasible and safe, and this approach must be systematically discussed in symptomatic patients.

Vascular compression syndromes: a pictorial review

Vascular compression syndromes include a group of rare vascular changes due to extrinsic compression of veins or arteries by surrounding structures. These pathologies are often underestimated due to their rarity, clinicians’ poor level of knowledge, and the non-specificity of their symptoms. The best known are Eagle syndrome, thoracic outlet syndrome, nutcracker syndrome, May-Thurner syndrome, Dunbar syndrome, and popliteal entrapment syndrome. This work summarizes the main ultrasonographic characteristics, symptoms, and treatments of choice for these syndromes. Knowledge of these conditions’ characteristic signs is essential for the differential diagnosis. Failure to diagnose these rare diseases can expose patients to serious complications and risks to their health.

A man with the rare simultaneous combination of three abdominal vascular compression syndromes: median arcuate ligament syndrome, superior mesenteric artery syndrome, and nutcracker syndrome

Median arcuate ligament syndrome and superior mesenteric artery syndrome are well-known abdominal compression syndromes, the coexistence of which is rarely described in literature. In addition, due to the common pathogenesis, anterior nutcracker syndrome may occur simultaneously to superior mesenteric artery syndrome. To our knowledge, this is the first case reporting combination of these 3 syndromes detected with ultrasound, Computed Tomography and upper gastrointestinal fluoroscopic exam. A 69-year-old man came to our attention for rapid weight loss, postprandial epigastric pain and recurrent vomiting for at least 6 months. Doppler ultrasound showed both celiac artery and left renal vein stenosis with simultaneous left varicocele. Computed tomography showed a reduction of aortomesenteric space causing both left renal vein and duodenal stenosis, this latter confirmed by upper gastrointestinal fluoroscopic exam. The diagnosis of these three vascular compression syndromes (MALS, SMAS, and anterior NCS) has been formulated, based on clinical and imaging findings. We assumed that the postprandial crises caused by median arcuate ligament syndrome may induce a reduction of meals consumption and progressive weight loss which can be a cause of anterior nutcracker syndrome and superior mesenteric artery syndrome onset. Doppler ultrasound, in expert hands, allows to accurately diagnosing these syndromes which are often underestimated. Failure to recognize it and inadequate treatment could have serious consequences for patients' health.

Large Bowel Ischemia/Infarction: How to Recognize It and Make Differential Diagnosis? A Review

Ischemic colitis represents the most frequent form of intestinal ischemia occurring when there is an acute impairment or chronic reduction in the colonic blood supply, resulting in mucosal ulceration, inflammation, hemorrhage and ischemic necrosis of variable severity. The clinical presentation is variable and nonspecific, so it is often misdiagnosed. The most common etiology is hypoperfusion, almost always associated with generalized atherosclerotic disease. The severity ranges from localized and transient ischemia to transmural necrosis of the bowel wall, becoming a surgical emergency, with significant associated morbidity and mortality. The diagnosis is based on clinical, laboratory suspicion and radiological, endoscopic and histopathological findings. Among the radiological tests, enhanced-CT is the diagnostic investigation of choice. It allows us to make the diagnosis in an appropriate clinical setting, and to define the entity of the ischemia. MR may be adopted in the follow-up in patients with iodine allergy or renal dysfunctions, or younger patients who should avoid radiological exposure. In the majority of cases, supportive therapy is the only required treatment. In this article we review the pathophysiology and the imaging findings of ischemic colitis.

The role of ultrasound imaging in vascular compression syndromes

Vascular compression syndromes are rare alterations that have in common the compression of an arterial and/or venous vessel by contiguous structures and can be congenital or acquired. The best known are the Thoracic Outlet Syndrome, Nutcracker Syndrome, May–Thurner Syndrome, and Dunbar Syndrome. The incidence of these pathologies is certainly underestimated due to the non-specific clinical signs and their frequent asymptomaticity. Being a first-level method, Ultrasound plays a very important role in identifying these alterations, almost always allowing a complete diagnostic classification. If in expert hands, this method can significantly contribute to the reduction of false negatives, especially in the asymptomatic population, where the finding of the aforementioned pathologies often happens randomly following routine checks. In this review, we briefly discuss the best known vascular changes, the corresponding ultrasound anatomy, and typical ultrasound patterns.

The Role of Ultrasound in Dunbar Syndrome: Lessons Based on a Case Report

Patient: Male, 55-year-old

Final Diagnosis: Dunbar syndrome

Symptoms: Epigastric pain • weight loss

Medication: —

Clinical Procedure: None

Specialty: Gastroenterology and Hepatology • Radiology

A new comprehensive ultrasonic diagnostic method for celiac artery compression syndrome that hybridizes "arterial compression hook sign" and peak systolic velocity

PURPOSE

Diagnosing celiac artery compression syndrome (CACS) is based on an imaging finding of celiac artery compression (CAC), but the diagnostic criteria are inconsistent. The study aim was to devise an ultrasonographic screening method to effectively diagnose CAC in occult CACS.

METHODS

The subjects were 61 patients with suspected CACS who underwent ultrasonography at our hospital from May 2017 to December 2019 and were divided into the following two groups: the "arterial compression hook sign"-positive group (n = 15, mean age: 26.6 ± 16.4 years, six males, nine females) and -negative group (n = 41, mean age: 32.5 ± 18.6 years, 12 males, 34 females). We used B-mode and advanced dynamic flow to detect arterial compression hook sign and pulse Doppler to measure expiration peak systolic velocity (EPSV) and inspiration PSV (IPSV).

RESULTS

The EPSV was significantly higher in the arterial compression hook sign-positive group (304.7 ± 47.4 cm/s) than in the -negative groups (158.2 ± 38.7 cm/s), (p < 0.001). Receiver operating characteristic curve analysis was performed to calculate the EPSV cutoff value for presence of CAC, which was 226 cm/s (sensitivity: 0.957, specificity: 1.000, AUC: 0.997, 95% confidence interval: 0.99-1). The IPSV was lower in the positive group than in the negative group in all cases (EPSV - IPSV range: 68-199 cm/s).

CONCLUSION

Our results showed that if arterial compression hook sign determined by B-mode ultrasound, EPSV > 226 cm/s, and IPSV decreases by ≥ 68 cm/s, then CAC can be detected with high specificity.