Multimodality Diagnosis of Mesenteric Ischemia.

Early diagnosis of mesenteric ischemia remains challenging because mesenteric ischemia presents with no key symptoms or physical findings, and no laboratory data specifically indicates intestinal tissue ischemic status before necrosis develops. While computed tomography is the standard for diagnostic imaging, there are several limitations: (1) repeated assessments are associated with increased radiation exposure and risk of renal damage; (2) the computed tomography findings can be misleading because necrosis occasionally occurs despite opacified mesenteric arteries; and (3) computed tomography is not necessarily available within the golden time of salvaging the intestines for those patients in the operating room or at a place far from the hospital. This article describes a challenge to overcome such limitations using ultrasonography and near-infrared light, including clinical studies. The former is capable of providing not only morphologic and kinetic information of the intestines but also perfusion of the mesenteric vessels in real-time without transferring the patient or exposing them to radiation. Transesophageal echocardiography enables precise assessment of mesenteric perfusion in the OR, ER, or ICU. Representative findings of mesenteric ischemia in seven aortic dissection cases are presented. Near-infrared imaging with indocyanine green helps visualize the perfusion of vessels and intestinal tissues although this application requires laparotomy. Findings in two cases (aortic aneurysm) are shown. Near-infrared spectroscopy demonstrates oxygen debt in the intestinal tissue as digital data and can be a candidate for early detection of mesenteric ischemia without laparotomy. The accuracy of these assessments has been confirmed by intraoperative inspections and postoperative course (prognosis).

Management of spontaneous isolated mesenteric artery dissection.

Spontaneous isolated mesenteric arterial dissection (SIMAD) is an uncommon subset of non-traumatic dissection of the mesenteric arteries without concurrent aortic dissection. Due to the widespread use of computer tomography angiography, SIMAD cases have been increasingly reported in the past 20 years. Common risk factors associated with SIMAD include male gender, age 50-60 years, hypertension and smoking. This review summarises the diagnostic pathway and management of SIMAD based on contemporary literature and proposes a treatment algorithm for SIMAD. The presentation of SIMAD can be divided into symptomatic and asymptomatic cases. Symptomatic patients should be carefully assessed to detect the development of complications, particularly bowel ischemia or vessel rupture. Although these complications are rare, they necessitate urgent surgical management. The vast majority of symptomatic SIMAD cases are uncomplicated and can be managed safely with conservative treatment that includes antihypertensive therapy, bowel rest, with or without antithrombotic therapy. For asymptomatic SIMAD cases, expectant management with outpatient surveillance imaging appears to be a safe strategy.

Abdominal arterial lesions associated with antiphospholipid antibodies: a comparative cross-sectional magnetic resonance angiography study.

OBJECTIVE: Case reports and small case series suggest that stenotic lesions of the renal, coeliac and mesenteric arteries may occur in the antiphospholipid syndrome (APS) resulting in clinical consequences such as hypertension and abdominal angina. The objective was to determine the prevalence of stenotic lesions in arteries arising from the middle aorta in patients with antiphospholipid antibodies (aPL) compared with healthy, hypertensive and atherosclerotic controls. METHODS: In a cross-sectional comparative radiological study using magnetic resonance angiography (MRA), we assessed five groups of subjects for the prevalence of stenotic lesions in arteries arising from the middle aorta: APS/aPL positive, healthy renal donors, patients with hypertension, patients with atherosclerosis defined radiologically and patients with systemic lupus erythematosus and vasculitis who were negative for aPL. All subjects underwent MRA in suspended respiration and images were assessed by two senior radiologists blinded to the clinical details. RESULTS: In the atherosclerosis group, vascular stenotic lesions were more prevalent (71%) than in any other group (P ≤0.000002). The prevalence of all stenotic lesions in aPL positive patients (33%) was significantly higher than in the renal donors (18%) and hypertensive patients (19%) (P ≤0.009). Renal artery stenosis was significantly more prevalent in aPL positive patients than in renal donors (P ≤0.0006) but similar to the prevalence in hypertensive patients. Coeliac and/or mesenteric lesions were significantly more common in aPL positive patients vs hypertensive patients (P ≤0.001). Stenoses did not correlate with traditional risk factors. CONCLUSION: Arterial stenotic lesions in arteries arising from the middle aorta were highly prevalent in atherosclerotic subjects and were more common in aPL-positive patients than in hypertensive patients and healthy renal donors.

Automated Detection and Diameter Estimation for Mouse Mesenteric Artery Using Semantic Segmentation.

BACKGROUND: Pressurized myography is useful for the assessment of small artery structures and function. However, this procedure requires technical expertise for sample preparation and effort to choose an appropriate sized artery. In this study, we developed an automatic artery/vein differentiation and a size measurement system utilizing machine learning algorithms. METHODS AND RESULTS: We used 654 independent mouse mesenteric artery images for model training. The model yielded an Intersection-over-Union of 0.744 ± 0.031 and a Dice coefficient of 0.881 ± 0.016. The vessel size and lumen size calculated from the predicted vessel contours demonstrated a strong linear correlation with manually determined vessel sizes (R = 0.722 ± 0.048, p < 0.001 for vessel size and R = 0.908 ± 0.027, p < 0.001 for lumen size). Last, we assessed the relation between the vessel size before and after dissection using a pressurized myography system. We observed a strong positive correlation between the wall/lumen ratio before dissection and the lumen expansion ratio (R = 0.832, p < 0.01). Using multivariate binary logistic regression, 2 models estimating whether the vessel met the size criteria (lumen size of 160-240 µm) were generated with an area under the receiver operating characteristic curve of 0.761 for the upper limit and 0.747 for the lower limit. CONCLUSION: The U-Net-based image analysis method could streamline the experimental approach.

Early risk stratification of patients with suspected chronic mesenteric ischaemia using a symptom and mesenteric artery calcium score based score chart.

BACKGROUND: The mesenteric artery calcium score (MACS) identifies patients with possible chronic mesenteric ischaemia (CMI) using standard computed tomography (CT) imaging. The MACS does not necessitate a dedicated computed tomography angiography (CTA) which is required for evaluation of mesenteric artery patency. This study aimed to test the use of a symptom and MACS based score chart to facilitate the selection of patients with a low probability of CMI, in whom further diagnostic workup can be omitted, and to validate the CTA-based score chart proposed by van Dijk et al. which guides treatment decisions in patients with suspected CMI. METHODS: This retrospective study included consecutive patients with suspected CMI. The Agatston definition was used to calculate the MACS. Multivariable logistic regression analysis was used to create a MACS score chart, which was applied in all patients to determine its discriminative ability. The score chart by van Dijk et al. was validated in this independent external patient series. RESULTS: Hundred-ninety-two patients were included, of whom 49 had CMI. The MACS score chart composed of the variables weight loss, postprandial abdominal pain, history of cardiovascular disease, and MACS, showed an excellent discriminative ability (area under the curve [AUC] 0.87). CMI risks were 2.1% in the low-risk group (0-4 points) and 39.1% in the increased risk group (5-10 points); sensitivity (97.8%) and negative predictive value (NPV; 97.9%) were high. The CTA-based score chart by van Dijk et al. showed an excellent discriminative ability (AUC 0.89). CONCLUSION: The MACS score chart shows promise for early risk stratification of patients with suspected CMI based on a near-perfect NPV. It is complementary to the CTA-based score chart by van Dijk et al., which showed excellent external validity and is well suited to guide subsequent (invasive) treatment decisions in patients with suspected CMI.

Retrograde Open Mesenteric Stenting for Acute and Chronic Mesenteric Ischaemia: Results from an Intestinal Stroke Centre.

OBJECTIVE: To report the intra-operative adverse events (IOAEs) and the initial and one year outcomes of retrograde open mesenteric stenting (ROMS) using balloon expandable covered stents for acute and chronic mesenteric ischaemia. METHODS: Clinical data and outcomes of all consecutive patients treated with ROMS for acute and chronic mesenteric ischaemia at an intestinal stroke centre between November 2012 and September 2019 were reviewed. ROMS was performed using balloon expandable covered stents. Endpoints included IOAEs, in hospital mortality, post-operative complications, and re-interventions. One year overall survival, freedom from re-intervention, primary patency and assisted primary patency rates were analysed using the Kaplan-Meier time to event method. RESULTS: During the study period, 379 patients were referred to the centre for acute or chronic mesenteric ischaemia. Thirty-seven patients who underwent the ROMS procedure were included. All the patients had severe atherosclerotic mesenteric lesions. The ROMS technical success rate was 89% in this cohort. The rate of IOAEs was 19% and included four cases of retrograde recanalisation failure. All ROMS failures occurred in patients presenting with flush superior mesenteric artery occlusion and they were treated by mesenteric bypass. Ten patients (27%) underwent bowel resection, four of which resulted in a short bowel syndrome (11%). The in hospital mortality rate was 27%. Post-operative complications and re-intervention rates were 67% (n = 25) and 32% (n = 12), respectively. The median follow up was 20.2 months (interquartile range 29). The estimated one year overall survival for the cohort was 70.1% (95% confidence interval [CI] 52.5% - 82.2%). The estimated freedom from re-intervention at one year was 61.1% (95% CI 42.3 - 75.4). The one year primary patency and assisted primary patency rates were 84.54% (95% CI 63.34 - 94) and 92.4% (95% CI 72.8 - 98), respectively. CONCLUSION: ROMS procedures offer acceptable one year outcomes for mesenteric ischaemia but are associated with frequent stent related complications. Precise pre-operative planning, high quality imaging, and meticulous stent placement techniques may limit the occurrence of such events.

Chronic mesenteric ischemia: Diagnosis and management.

Chronic mesenteric ischemia (CMI) is an uncommon, potentially underdiagnosed clinical condition. Although there is a high prevalence of mesenteric artery stenoses (MAS), an abundant collateral network in the mesenteric circulation mitigates occurrence of ischemia. The most common etiology of CMI is atherosclerosis. CMI is a clinical diagnosis, based upon typical and atypical symptoms and consistent anatomic findings. Typical symptoms of CMI are postprandial abdominal pain, unintended weight loss and food avoidance. The main modalities to diagnose MAS are duplex ultrasound, CT angiography or MR angiography, although high resolution CTA is preferred. Endovascular therapy with balloon expandable stents has become the preferred treatment for MAS.

Fibromuscular dysplasia of mesenteric arteries: a rare cause of multiple bowel resections-a case report and literature review.

BACKGROUND: Fibromuscular dysplasia (FMD) is a type of unexplained nonatherosclerotic vascular disease that usually involves the renal and internal carotid arteries and rarely involves the mesenteric artery. Mesenteric artery FMD is difficult to distinguish from Crohn's disease (CD) and Behcet's disease (BD) solely based on symptoms. Patients with mesenteric artery FMD can present with an acute abdomen, but case reports of patients who have a long medical history and undergo multiple bowel resections are extremely rare. CASE PRESENTATION: The patient was a 45-year-old woman with an 11-year history of intermittent lower abdominal pain and fever. At the age of 34 years, she underwent right hemicolectomy and appendectomy due to an acute abdomen. She suffered from oral ulcers between 34 and 36 years old. A clinical diagnosis of presumed CD was made by the age of 41, and she was treated with mesalazine; however, the effect was poor. At the age of 42, she came to our centre, and based on her atypical symptoms and examination results, we thought she had CD. Hence, she was treated with glucocorticoids for 3 years. However, when she was 45, due to steroid dependence, thalidomide tablets were added. Unfortunately, she suffered from another episode of intestinal obstruction. Therefore, she underwent enterectomy. The postoperative histopathological diagnosis was mesenteric artery FMD. She no longer underwent pharmacotherapy after the surgery. Although she did not have any of her previous symptoms and postoperative colonoscopy showed no signs of recurrence, splenomegaly and abnormal routine blood results were still present. CONCLUSIONS: Patients with mesenteric artery FMD can present with an acute abdomen. In addition, the symptoms and endoscopic manifestations of mesenteric artery FMD may appear similar to CD and BD. Hence, it is difficult to make a clear clinical diagnosis and proceed with treatment. Mesenteric artery FMD often requires surgical pathology to confirm its diagnosis. For patients who suffer from this disorder, surgery may be the best choice to improve the patient's quality of life.

Evaluation of mesenteric artery disease in patients with severe aortic valve stenosis.

The aim of this study is to evaluate the mesenteric artery stenosis (MAS) in routinely performed CT angiography (CTA) of patients with severe aortic stenosis (AS) planned for transcatheter aortic valve implantation (TAVI) before the procedure. Patients with AS (AS group) who routinely underwent CTA before the TAVI procedure due to severe AS and patients who had CTA for other indications (control group) were retrospectively and sequentially scanned. The demographic characteristics of the patients in both groups were similar. Calcification and stenosis in the mesenteric arteries were recorded according to the localization of celiac truncus, superior mesenteric artery (SMA) and inferior mesenteric artery (IMA). Class 0-3 classification was used for calcification score. Stenoses with a stenosis degree ≥50% were considered as significant. A total of 184 patients, 73 patients with severe AS and 111 control groups, were included in the study. SMA and IMA calcification scores of patients with AS were significantly higher than the control group (p=0.035 for SMA and p=0.020 for IMA). In addition, the rate of patients with significant MAS in at least 1 artery (45.2% vs 22.5%, p=0.001) and the rate of patients with significant stenosis in multiple arteries were also significantly higher in the AS group (8.2% vs 1.8%, p=0.037). According to the study results, patients with AS are at a higher risk for MAS. Chronic mesenteric ischemia should be kept in mind in patients with AS who have symptoms such as non-specific abdominal pain and weight loss.

Daikenchuto increases blood flow in the superior mesenteric artery in humans: A comparison study between four-dimensional phase-contrast vastly undersampled isotropic projection reconstruction magnetic resonance imaging and Doppler ultrasound.

Respiratory-gated four-dimensional phase-contrast vastly undersampled isotropic projection reconstruction (4D PC-VIPR) is magnetic resonance (MR) imaging technique that enables analysis of vascular morphology and hemodynamics in a single examination using cardiac phase resolved 3D phase-contrast magnetic resonance imaging. The present study aimed to assess the usefulness of 4D PC-VIPR for the superior mesenteric artery (SMA) flowmetry before and after flow increase was induced by the herbal medicine Daikenchuto (TJ-100) by comparing it with Doppler ultrasound (DUS) as a current standard. Twenty healthy volunteers were enrolled in this prospective single-arm study. The peak cross-sectionally averaged velocity was measured by 4D PC-VIPR, peak velocity was measured by DUS, and flow volume (FV) of SMA and aorta were measured by 4D PC-VIPR and DUS 25 min before and after the peroral administration of TJ-100. The peak cross-sectionally averaged velocity, peak velocity, and FV of SMA measured by 4D PC-VIPR and DUS significantly increased after administration of TJ-100 (4D PC-VIPR: the peak cross-sectionally averaged velocity; p = 0.004, FV; p = 0.035, DUS: the peak velocity; p = 0.003, FV; p = 0.010). Furthermore, 4D PC-VIPR can analyze multiple blood vessels simultaneously. The ratio of the SMA FV to the aorta, before and after oral administration on the 4D PC-VIPR test also increased (p = 0.015). The rate of change assessed by 4D PC-VIPR and DUS were significantly correlated (the peak cross-sectionally averaged velocity and peak velocity: r = 0.650; p = 0.005, FV: r = 0.659; p = 0.004). Retrospective 4D PC-VIPR was a useful modality for morphological and hemodynamic analysis of SMA.

Surface anatomy and lumbar lordosis angle.

Awareness of the anatomical variations in abdominal surface anatomy with emphasis on relation to the abdominal planes may facilitate anatomical education and physical examination and inconvenience surgical intervention by giving surgeons more insight in surgical planning and training. This study was designed to verify whether the anatomical planes promote to the comprehension of surface anatomy and how the lumbar lordosis angle affects the vertebral level of the bifurcation of great vessels. This retrospective study was performed using computed tomography angiography images of 155 patients ranging from 18 up to 82 years. The vertebral levels of the celiac truncus, superior mesenteric artery, portal vein confluence, right and left renal arteries were within the transpyloric plane in 60%, 70%, 56.1% and 48.3-36.2% of patients, respectively. The inferior mesenteric artery was below the subcostal plane in 58% of patients. The aortic bifurcation (AB) was mostly corresponded to the level of L4 and was located within the umbilical plane in 73.1% of patients. The level of the inferior vena cava (IVC) confluence was within the supracristal plane in 54% of patients. We measured the mean value of the AB, IVC and lumbar lordosis angles as 39.54°, 58.05° and 54.26°, respectively. The AB and IVC levels showed a downward shift with decreasing lumbar lordosis angle. Precise knowledge of these relationships is crucial in clinical practice and surgical approaches to the anterior lumbosacral spine for safer and effective surgery.

Outcomes and radiographic findings of symptomatic isolated mesenteric artery dissection with conservative management.

OBJECTIVES: The aim of this study was to evaluate the computed tomography follow-up outcomes and radiographic findings of symptomatic isolated mesenteric artery dissection (IMAD) after conservative management. METHODS: In this retrospective study, 130 consecutive patients with symptomatic IMAD from three institutions were enrolled from January 2011 to December 2019. The general epidemiological data, clinical manifestations, first-episode symptoms, imaging findings, and treatment strategy selection were analyzed from the medical records. RESULTS: Among 130 patients diagnosed with symptomatic IMAD, positive remodeling of the SMA was achieved in 75.38% (98/130), and negative remodeling of the SMA was achieved in 24.62% (32/130). In the positive remodeling group, complete remodeling was achieved 39.23% (51/130) (type I 6 patients, type IIa 10 patients, type IIb 35 patients), in which type IIb was the most (p = 0.004). Moreover, of the 32 patients in whom negative remodeling of the SMA was achieved, significant differences were observed between the type IIa with respect to dissecting aneurysm formation (p = 0.04).Of the seven factors analyzed with a logistic regression model identified three factors significantly associated with negative remodeling: length of dissection (Waldχ2 13.331; OR 6.945; 95% CI 2.762-10.498; p = 0.014), true lumen residual diameter (TLRD) (Waldχ2 9.626; OR 7.85; 95% CI 1.892-19.063; p = 0.022), and branch involvement (Waldχ2 11.812; OR 7.247; 95% CI 1.245-14.830; p = 0.011). CONCLUSION: The prognosis of most symptomatic IMAD has a tendency to positive remodeling after conservative management, in which the initial type IIb classification is common. In contrast, risk factors for negative remodeling were type IIa, length of dissection, TLRD, and branch involvement. Patients with these morphological characteristics may not benefit from conservative management.

Spontaneous Rupture of Mesenteric Vasculature Associated with Fibromuscular Dysplasia in a 28-Year-Old Male.

Spontaneous rupture of mesenteric vasculature associated with fibromuscular dysplasia is an unreported phenomenon. We describe a case in a 28-year-old male with a history of chronic abdominal pain who presented to our facility in hemorrhagic shock secondary to a ruptured transverse mesocolon middle colic aneurysm status postemergent transverse colectomy. He was found to have chronic vertebral, renovisceral, and iliac aneurysms as well as acute superior and inferior mesenteric artery dissection and chronic bilateral vertebral artery dissections. He subsequently developed disseminated intravascular coagulopathy, resulting in saddle pulmonary embolus as well as right renal artery and splenic artery thrombosis. Ultimately, the patient expired.

Peritoneal dialysis-related peritonitis complicated with nonocclusive mesenteric ischemia.

Peritoneal dialysis (PD)-related peritonitis is a common complication of PD. Nonocclusive mesenteric ischemia (NOMI) is a rare complication of PD-related peritonitis, has a high mortality rate, and therefore should be detected early once it occurs. We describe a case of a 70-year-old woman on PD presented with moderate abdominal pain and low blood pressure, which contributed to the early diagnosis of PD-related peritonitis complicated with NOMI. Increased white cell count of 7150/µL (neutrophil, 84%) in dialysate effluent was diagnostic of PD-related peritonitis, which was later found to be caused by Pseudomonas putida. Computed tomography with contrast performed after administering crystalloids revealed hepatic portal venous gas, pneumatosis intestinalis in the ascending colon, and normal enhancement of the bowel wall and mesenteric arteries, which suggested a reperfusion of the previously ischemic ascending colon. Colonoscopy on hospital day seventeen revealed mucosal hemorrhage and ulcers in the entire right colon and the terminal ileum while the remaining colon was normal. These findings are compatible with the consequence of NOMI. Increased peak systolic velocity of the superior mesenteric artery (SMA) implied its stenosis. Past studies show that ischemia of the colon in patients with chronic kidney disease commonly occurs in the right colon. Arteriosclerosis of the SMA due to the long history of chronic kidney disease and diabetes might have caused its vulnerability to low blood pressure. Abdominal complications including NOMI should be screened for when a patient presents with low blood pressure and strong abdominal pain. This is the first case report that shows colonoscopy images of the colonic ulcers post-NOMI and PD-related peritonitis.