Hemodynamic Assessment of Celiaco-mesenteric Anastomosis in Patients with Pancreaticoduodenal Artery Aneurysm Concomitant with Celiac Artery Occlusion using Flow-sensitive Four-dimensional Magnetic Resonance Imaging

Presentation and management of true aneurysms of the pancreaticoduodenal arcade with concomitant celiac artery stenosis using the endovascular approach

True aneurysms of the pancreaticoduodenal artery (PDA) arcade are rare but require intervention due to the high risk of rupture. Historically, these aneurysms have been managed with open surgical methods. In this study, we describe a contemporary series of aneurysms treated using a modern approach that includes endovascular and hybrid techniques. All the patients with aneurysms of the PDA arcade in an institutional database were identified between 2008 and 2022. Patients with history of pancreatic resection were excluded. Data on demographics, presenting symptoms, imaging findings, operative approach, and outcomes were collected and reviewed. There were nine patients diagnosed with a PDA aneurysm, and all nine underwent endovascular intervention. Most were men (n = 5; 55.6%) and White (n = 7; 77.8%) and had American Society of Anesthesiologists class II or III. The median aneurysm size was 21 mm (range, 6-42 mm), and five (55.5%) were symptomatic. Of the five symptomatic cases, two presented with rupture and were treated urgently. The median time to intervention for the nonurgent cases was 30 days. All but one patient had concomitant celiac artery stenosis and two of the eight cases (25%) were due to extrinsic compression from median arcuate ligament syndrome. Both patients underwent median arcuate ligament syndrome release before endovascular intervention. Another patient required open surgical bypass before endovascular repair from the supraceliac aorta to hepatic artery using a Dacron graft to maintain hepatic perfusion. Among the eight patients with celiac axis stenosis, five (62.5%) required celiac stent placement within the same operation. Coil embolization of the aneurysm was used for all except for two patients (n = 7 of 9; 77.8%), with one patient receiving embolic plugs and another receiving an 8 × 38-mm balloon-expandable covered stent for aneurysm exclusion. The median operating room time was 134 minutes. All repairs were technically successful without any intraoperative or postoperative complications. The mean follow-up was 30 months. There was no morbidity, mortality, or unplanned secondary reinterventions within 6 months after aneurysm repair. Stent patency and aneurysm size remained stable at 2 years of follow-up. True pancreaticoduodenal artery arcade aneurysms can be safely and effectively treated using endovascular and hybrid techniques. Because many of these aneurysms have concomitant celiac artery stenosis, the use of endovascular technology allows for simultaneous treatment of both the aneurysm and the stenosis with exceptional results.

Sutton-Kadir Syndrome can be treated safely with endovascular embolisation alone

INTRODUCTION

Sutton-Kadir Syndrome (SKS) describes true inferior pancreaticoduodenal artery (IPDA) aneurysms in the setting of coeliac artery (CA) stenosis or occlusion. Although rare, SKS aneurysms can rupture and cause morbidity. Due to its rarity and lack of controlled treatment data, correct treatment for the CA lesion is currently unknown. Our aim was to assess if endovascular embolisation alone was safe and effective in treatment of SKS aneurysms, in emergent and elective settings. Secondary objectives were to describe presentation and imaging findings.

METHODS

A retrospective cohort study of patients treated at Sir Charles Gairdner Hospital between January 2014 and December 2021 was done. Data on presentation, diagnostics, aneurysm characteristics, CA lesion aetiology, treatment and outcomes were extracted from chart review.

RESULTS

Twenty-four aneurysms in 14 patients were identified. Rupture was seen in 7/15 patients. Most aneurysms (22/24) were in the IPDA or one of its anterior or posterior branches. Median arcuate ligament (MAL) compression was identified in all. There was no difference in median (IQR) maximal transverse diameter between ruptured and non-ruptured aneurysms (6 mm (9), 12 mm (6), P = 0.18). Of ruptures, 6/7 had successful endovascular embolisation and 1/7 open surgical ligation. Of non-ruptures, 6/7 had successful endovascular embolisation, 1/7 open MAL division then endovascular CA stenting and aneurysm embolisation. No recurrences or new aneurysms were detected with computed tomography or magnetic resonance angiography over a median (IQR) follow-up period of 30 (10) months in 12 patients.

CONCLUSION

Endovascular embolisation of SKS aneurysms without treatment of MAL compression is safe and effective in both the emergent and elective settings.

Laparoscopic median arcuate ligament section for median arcuate ligament compression syndrome initially detected as splenic infarction: a case report

BACKGROUND

Median arcuate ligament compression syndrome (MALS) causes upper abdominal pain and at times hemodynamic abnormalities in the pancreaticoduodenal region. Herein, we present a case of a 70 year-old man, initially diagnosed with splenic infarction and was successfully treated laparoscopically.

CASE PRESENTATION

A 70-year-old man with abdominal pain admitted to our hospital. Abdominal-enhanced computed tomography revealed a poorly contrasted area in the spleen and stenosis at the root of the celiac artery. Arterial dilatation was observed around the pancreaticoduodenal arcade, however, no obvious aneurysm formation or arterial dissection was observed. Abdominal-enhanced magnetic resonance imaging indicated the disappearance of the flow void at the root of the celiac artery. The patient had no history of atrial fibrillation and was diagnosed with splenic infarction due to median arcuate ligament compression syndrome. We performed a laparoscopic median arcuate ligament section with five ports. Intraoperative ultrasonography showed a retrograde blood flow in the common hepatic artery and the celiac artery. After releasing the compression, the antegrade blood flow from the celiac artery to the splenic artery, and the common hepatic artery were visualized using intraoperative ultrasonography. The postoperative course of the patient was uneventful, and he was discharged on postoperative day 9. Postoperative computed tomography a month after surgery revealed no residual stenosis of the celiac artery or dilation of the pancreaticoduodenal arcade. Furthermore, the poorly contrasted area of the spleen improved.

CONCLUSIONS

Reports indicate that hemodynamic changes in the abdominal visceral arteries due to median arcuate ligament compression are related to the formation of pancreaticoduodenal aneurysms. In this case, median arcuate ligament compression syndrome caused splenic infarction by reducing blood flow to the splenic artery.

Superior mesenteric aneurysm associated with median arcuate ligament syndrome and a single celiacomesenteric trunk

Median arcuate ligament syndrome (MALS) is known to promote arterial collateral circulation development from mesenteric vessel compression and can lead to the development of visceral aneurysms. These aneurysms are often diagnosed at the time of rupture and pose a significant morality risk without appropriate intervention. A celiacomesenteric trunk is a rare anatomic variant in which the celiac artery and superior mesenteric artery share a common origin and has been postulated as a risk factor for developing MALS. In this report, we present a novel case of MALS in a patient with a celiacomesenteric trunk and a superior mesenteric artery aneurysm.

Ruptured Pancreaticoduodenal Artery Aneurysm in a Patient With Celiac Artery Dissection: A Case Report

Unlike other visceral artery aneurysms, pancreaticoduodenal artery aneurysms (PDAAs) should be treated regardless of their size. There are no reports on PDAA associated with celiac artery (CA) dissection. We, here, report the case of a patient with a ruptured PDAA with concomitant CA dissection. A 44-year-old Korean man presented to the emergency room of another hospital 29 days ago due to a sudden onset of abdominal pain. Contrast-enhanced abdominal computed tomography (CT) revealed a large right retroperitoneal hematoma and CA dissection. Subsequently, aortography revealed no specific bleeding focus. He underwent conservative treatment for 16 days, including a transfusion, and then was referred to us. His abdominal CT angiography revealed a diminishing retroperitoneal hematoma, a 7 mm × 8 mm PDAA at the anterior inferior pancreaticoduodenal artery aneurysm (PDA), and CA dissection. Selective celiac angiography revealed sluggish and diminished blood flow to the true lumen of the CA, and the hepatic, gastroduodenal, and splenic arteries were supplied by collaterals arising from the superior mesenteric artery (SMA). We performed elective coil embolization of the anterior PDA using the right femoral approach.We believe that postprocedural surveillance is required after CA dissection because of the potential risk of recurrent PDAA. Additionally, we suggest that hidden PDAA rupture should be considered for spontaneous retroperitoneal bleeding.

Obstructive jaundice as a rare complication of multiple pancreaticoduodenal artery aneurysms due to median arcuate ligament syndrome: a case report and review of the literature

BACKGROUND

Obstructive jaundice has various causes, and one of the rarest is pancreaticoduodenal artery aneurysm (PDAA), which is often associated with celiac axis stenosis caused by median arcuate ligament syndrome (MALS).

CASE PRESENTATION

The patient was a 77-year-old Azeri woman who presented with progressive jaundice, vague abdominal pain, and abdominal distension from 6 months ago. The intra- and extrahepatic bile ducts were dilated, the liver's margin was slightly irregular, and the echogenicity of the liver was mildly heterogeneous in the initial ultrasound exam. A huge cystic mass with peripheral calcification and compressive effect on the common bile duct (CBD) was also seen near the pancreatic head, which was connected to the superior mesenteric artery (SMA) and had internal turbulent blood flow on color Doppler ultrasound. According to the computed tomography angiography (CTA) findings, the huge mass of the pancreatic head was diagnosed as a true aneurysm of the pancreaticoduodenal artery caused by MALS. Two similar smaller aneurysms were also present at the huge aneurysm's superior margin. Due to impending rupture signs in the huge aneurysm, the severe compression effect of this aneurysm on CBD, and the patient's family will surgery was chosen for the patient to resect the aneurysms, but unfortunately, the patient died on the first day after the operation due to hemorrhagic shock.

CONCLUSION

In unexpected obstructive jaundice due to a mass with vascular origin in the head of the pancreas, PDAA should be considered, and celiac trunk should be evaluated because the main reason for PDAA is celiac trunk stenosis or occlusion by atherosclerosis or MALS. The treatment method chosen (including transarterial embolization, open surgery, or combined method) depends on the patient's clinical status and radiological findings, but transarterial embolization would be safer and should be used as a first-line method.

Pre-Operative Four Dimensional Flow Sensitive Magnetic Resonance Imaging Assessment of Aortic Side Branches as a Method to Predict Risk of Type II Endoleak Resulting in Sac Enlargement After EVAR

OBJECTIVE

To predict sac enlargement with type II endoleak (ELII) before endovascular aneurysm repair (EVAR) using four dimensional flow sensitive magnetic resonance imaging (4D flow MRI).

METHODS

A single centre retrospective analysis of prospectively collected data was conducted. Patients with an abdominal aortic aneurysm (AAA) who underwent EVAR between 2013 and 2019 were included. Aortic branches occluded pre-EVAR, and patients with endoleaks other than ELII were excluded. The aortic branch diameter, peak flow velocity (PFVe), and amplitude of the dynamics of flow volume (AFV) were measured in each aortic branch pre-EVAR. Total flow volume per minute (TFV/min), defined as the sum of AFV/min, was calculated in each case. According to computed tomography findings one year post-EVAR, the aortic branches and patients were divided into patent vessel and occluded vessel groups and sac expanding and non-expanding groups. PFVe, AFV/min, and TFV/min were analysed via receiver operating characteristic curve analysis.

RESULTS

The patent aortic branches pre-EVAR (69 inferior mesenteric arteries [IMAs]; 249 lumbar arteries [LAs]) of 100 patients were included. Patent IMAs (n = 14) and occluded IMAs (n = 55), patent LAs (n = 23) and occluded LAs (n = 226), and expanding (n = 9) and non-expanding (n = 91) groups were compared, respectively. No statistically significant difference was observed in branch diameters (IMA; patent, 2.5 ± 0.8 mm, occluded, 2.5 ± 0.8 mm, p < .78 and LA; patent, 1.5 ± 0.3 mm, occluded, 1.5 ± 0.4 mm, p < .35). PFVe (IMA; patent, 262.6 mm2/sec, occluded, 183.4 mm2/sec and LA; patent, 142.6 mm2/sec, occluded, 47.7 mm2/sec) and AFV/min (IMA; patent, 8.4 mL, occluded, 5.2 mL and LA; patent, 4.2 mL, occluded, 1.4 mL) were higher in the patent vessel group (p < .050). TFV/min was statistically significantly higher in the expanding group (24.1 mL/min) than in the non-expanding group (7.0 mL/min) (p < .010).

CONCLUSION

Pre-EVAR haemodynamic analyses using 4D flow MRI were useful to detect aortic branches responsible for ELII and to predict AAA cases with sac enlargement. This analysis suggests a new strategy for pre-EVAR aortic branch embolisation.

Median arcuate ligament resection for a patient with ruptured pancreaticoduodenal artery aneurysm: A case report

INTRODUCTION AND IMPORTANCE

Median arcuate ligament syndrome (MALS) is a rare disease characterized by compression of the celiac artery (CA) by the median arcuate ligament (MAL). A small proportion of pancreaticoduodenal artery (PDA) aneurysms are caused by compression of the CA by the MAL. Here, we report a case of rupture of a PDA aneurysm associated with MALS that was treated with coil embolization followed by MAL resection.

CASE PRESENTATION

A 49-year-old man lost consciousness due to hypovolemic shock in the hospital two days after appendectomy. Contrast-enhanced multi-detector row computed tomography (MD-CT) showed a retroperitoneal hematoma and extravasation from the pancreaticoduodenal arcade vessels, therefore emergency angiography was performed. An aneurysm was detected in the anterior inferior PDA and coil embolization was performed for the inferior PDA. Three months after embolization, MAL resection was performed to prevent rebleeding from the PDA. Six months have passed after the surgery, the patient had no CA restenosis or PDA aneurysms.

CLINICAL DISCUSSION

MALS is a rare disease that results from the compression of the CA by the MAL. PDA aneurysms are associated with CA stenosis, and compression of the CA by the MAL is the most frequently reported cause of CA stenosis. There is no established treatment for CA stenosis after a PDA aneurysm rupture due to MALS.

CONCLUSION

It is suggested that MAL resection may be effective in reducing shear stress in the pancreaticoduodenal arcade. Improving blood flow through the CA by MAL resection might reduce risk of PDA aneurysm recurrence.

Patient-specific modeling of hemodynamic characteristics associated with the formation of visceral artery aneurysms at uncommon locations

Objective

Hemodynamic characteristics play critical roles in aneurysm initiation and growth. This study aims to explore the effect of common hemodynamic parameters on the formation of visceral artery aneurysms (VAAs), especially those from the pancreaticoduodenal arteries or other uncommon locations, using real patients' models.

Methods

Three-dimension vessel models of 14 VAAs from 13 patients were selected and constructed from computed tomography angiography (CTA) images. Aneurysms were manually removed to perform computational fluid dynamics (CFD) simulations of the models before aneurysm formation. Flow field characteristics were obtained and compared at the aneurysm forming and para-aneurysm areas. Aneurysm forming models were categorized into high-wall-shear stress (WSS) and low-WSS groups according to WSS value at aneurysm forming versus para-aneurysm areas.

Results

Computational fluid dynamics analysis revealed that the high WSS group had significantly higher WSSmax (P = 0.038), higher time average WSS (TAWSS) (P = 0.011), higher WSS gradient (WSSG) (p = 0.036), as well as lower oscillatory shear index (OSI) (P = 0.022) compared to the low WSS group. Significant higher WSSmax (P = 0.003), TAWSS (P = 0.003), WSSG (P = 0.041) and lower OSI (P = 0.021) was observed at the aneurysm forming site compared to both upstream and downstream areas.

Conclusion

Both local increase and decrease of WSS and WSS gradient were observed for the visceral artery aneurysm forming area. Computational fluid dynamics analysis could shed light on the pathogenesis of visceral artery aneurysms at uncommon vessel locations.

Spontaneous cessation of postpancreatectomy hemorrhage in a patient with celiac artery stenosis

Postpancreatectomy hemorrhage (PPH) is a severe complication of pancreatic surgery. This condition often develops on the background of pancreatic fistula. In our report, we demonstrate an unusual case of spontaneous cessation of severe postpancreatectomy common hepatic artery (СHA) hemorrhage after distal pancreatectomy in a patient with celiac artery stenosis (CAS). A 64-year-old male diagnosed with pancreatic tail tumor underwent extended distal pancreatectomy. He developed pancreatic fistula and was discharged with an abdominal drain, and was readmitted with severe postpancreatectomy hemorrhage from a pseudoaneurysm of the CHA. The bleeding stopped spontaneously due to CHA thrombosis. The patient developed no ischemic symptoms. Spontaneous severe postpancreatectomy hemorrhage cessation is an extremely rare phenomenon. Vascular anomalies must be considered when attempting interventional radiology treatment. CHA probably may be sacrificed with no ischemic consequences in case of severe hemorrhage in patients with CAS.

Assessment of hepatic arterial hemodynamics with 4D flow MRI: in vitro analysis of motion and spatial resolution related error and in vivo feasibility study in 20 volunteers

OBJECTIVES

To assess the ability of four-dimensional (4D) flow MRI to measure hepatic arterial hemodynamics by determining the effects of spatial resolution and respiratory motion suppression in vitro and its applicability in vivo with comparison to two-dimensional (2D) phase-contrast MRI.

METHODS

A dynamic hepatic artery phantom and 20 consecutive volunteers were scanned. The accuracies of Cartesian 4D flow sequences with k-space reordering and navigator gating at four spatial resolutions (0.5- to 1-mm isotropic) and navigator acceptance windows (± 8 to ± 2 mm) and one 2D phase-contrast sequence (0.5-mm in -plane) were assessed in vitro at 3 T. Two sequences centered on gastroduodenal and hepatic artery branches were assessed in vivo for intra - and interobserver agreement and compared to 2D phase-contrast.

RESULTS

In vitro, higher spatial resolution led to a greater decrease in error than narrower navigator window (30.5 to -4.67% vs -6.64 to -4.67% for flow). In vivo, hepatic and gastroduodenal arteries were more often visualized with the higher resolution sequence (90 vs 71%). Despite similar interobserver agreement (κ = 0.660 and 0.704), the higher resolution sequence had lower variability for area (CV = 20.04 vs 30.67%), flow (CV = 34.92 vs 51.99%), and average velocity (CV = 26.47 vs 44.76%). 4D flow had lower differences between inflow and outflow at the hepatic artery bifurcation (11.03 ± 5.05% and 15.69 ± 6.14%) than 2D phase-contrast (28.77 ± 21.01%).

CONCLUSION

High-resolution 4D flow can assess hepatic artery anatomy and hemodynamics with improved accuracy, greater vessel visibility, better interobserver reliability, and internal consistency.

KEY POINTS

• Motion-suppressed Cartesian four-dimensional (4D) flow MRI with higher spatial resolution provides more accurate measurements even when accepted respiratory motion exceeds voxel size. • 4D flow MRI with higher spatial resolution provides substantial interobserver agreement for visualization of hepatic artery branches. • Lower peak and average velocities and a trend toward better internal consistency were observed with 4D flow MRI as compared to 2D phase-contrast.

A Large Series of True Pancreaticoduodenal Artery Aneurysms

INTRODUCTION

True pancreaticoduodenal artery aneurysms (PDAA) are rare and prior reports often fail to distinguish true aneurysms from pseudoaneuryms. We sought to characterize all patients who presented to our health-system from 2004-2019 with true PDAA, with a focus on risk factors, interventions, and patient outcomes.

METHODS

Patients were identified by querying a single health-system PACS database for radiographic reports noting a PDAA. Retrospective chart review was performed on all identified patients. Patients with pseudoaneurysm, identified as those with a history of pancreatitis, abdominal malignancy, hepatopancreaticobiliary surgery, or abdominal trauma, were excluded. Continuous variables were compared using t-tests, and categorical variables were compared using Fisher's exact tests.

RESULTS

A total of 59 true PDAA were identified. Forty aneurysms (68%) were intact (iPDAA) and 19 (32%) were ruptured (rPDAA) at presentation. Mean size of ruptured PDAA was 16.4 mm (median size 14.0 mm; range 10 - 42 mm) and mean size of intact PDAA was 19.4 mm (median size 17.5mm; range 8 - 88 mm), this difference was not statistically significant (P = 0.95). Significant celiac disease (occlusion or >70% stenosis) was noted in 39 aneurysms (66%). Those with rupture were less likely to have significant celiac disease (42% vs 78%, P=0.017), and less likely to have aneurysmal wall calcifications (6% vs 53%, P=0.002). Thirty-seven patients underwent intervention (63%); with eight (22%) undergoing concomitant hepatic revascularization (2 stents and 6 bypasses) due to the presence of celiac disease. Eighteen patients with occluded celiac arteries underwent aneurysm intervention; of those, 11 were performed without hepatic revascularization (61.1%). Those with rPDAA experienced an aneurysm related mortality of 10.5% while those with iPDAA experienced a rate of 5.6%. One patient with celiac occlusion and PDA rupture who did not undergo hepatic artery bypass expired postoperatively from hepatic ischemia. Ruptured PDAA showed a trend towards increased need for aneurysm-related endovascular or open reintervention, but this was not statistically significant (47% vs 28%, P=0.13).

CONCLUSIONS

These findings support previous reports that the rupture risk of PDAA is independent of size, their development is often associated with significant celiac stenosis or occlusion, and rupture risk appears decreased in patients with concomitant celiac disease or aneurysm wall calcifications. Endovascular intervention is the preferred initial treatment for both intact and ruptured PDAAs, but reintervention rates are high in both groups. The role for hepatic revascularization remains uncertain, but it does not appear to be mandatory in all patients with complete celiac occlusion who undergo PDAA interventions.

Laparoscopic treatment of median arcuate ligament syndrome without ganglionectomy of the celiac plexus in the hybrid operating room: Report of a case

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The treatment of median arcuate ligament syndrome is the surgical release of the ligament.

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Symptomatic patients need the ligament release with wide excision of the celiac plexus.

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However, the majority of the patients with celiac artery compression remains asymptomatic.

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It might be enough to just release the ligament without ganglionectomy for asymptomatic patients.

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Hybrid operating room could allow for adequate ligament release without ganglionectomy.

Introduction

Median arcuate ligament syndrome (MALS) is a rare condition in which the median arcuate ligament (MAL) causes compression of the celiac artery (CA) and plexus. Although 13–50 % of healthy population exhibit radiologic evidence of the CA compression, the majority remains asymptomatic. With or without symptoms, MALS have a risk of developing collateral circulation that leads to pancreaticoduodenal artery (PDA) aneurysms that have high risk of rupture. The treatment of MALS is the surgical release of the MAL. However, the necessity of ganglionectomy of the celiac plexus is still unclear.

Presentation of case

A 60-year-old man with a ruptured PDA aneurysm caused by MALS was admitted to our hospital for an emergency. After treatment for the ruptured PDA aneurysm by transcatheter arterial coil embolization, he underwent elective laparoscopic MAL release in the hybrid operation room to check blood flow of the CA intraoperatively. The angiography of the CA immediately after MAL release without ganglionectomy of the celiac plexus showed the antegrade blood flow to the proper hepatic artery instead of the retrograde flow via the pancreaticoduodenal arcade. The postoperative course was uneventful and the follow-up computed tomography revealed no residual CA stenosis.

Discussion

Unlike symptomatic MALS, it might be enough to just release the MAL without ganglionectomy of the celiac plexus for asymptomatic MALS, especially that with the treated PDA aneurysm.

Conclusion

Laparoscopic treatment of MALS in hybrid operating room could allow for adequate MAL release without ganglionectomy of the celiac plexus using the intraoperative angiography of the CA.

Outcomes After Open and Endovascular Repair of Non-Ruptured True Pancreaticoduodenal and Gastroduodenal Artery Aneurysms Associated with Coeliac Artery Compression: A Multicentre Retrospective Study

OBJECTIVE

True aneurysms of the peri-pancreatic arcade (PDAA) have been attributed to increased collateral flow related to coeliac axis (CA) occlusion by a median arcuate ligament (MAL). Although PDAA exclusion is currently recommended, simultaneous CA release and the technique to be used are debated. The aim of this retrospective multicentre study was to compare the results of open surgical repair of true non-ruptured PDAA with release or CA bypass (group A) vs. coil embolisation of PDAA and CA stenting or laparoscopic release (group B).

METHODS

From January 1994 to February 2019, 57 consecutive patients (group A: 31 patients; group B: 26 patients), including 35 (61%) men (mean age 56 ± 11 years), were treated at three centres. Twenty-six patients (46%) presented with non-specific abdominal pain: 15 (48%) in group A and 11 (42%) in group B (p = .80).

RESULTS

No patient died during the post-operative period. At 30 days, all PDAAs following open repair and embolisation had been treated successfully. In group A, all CAs treated by MAL release or bypass were patent. In group B, 2/12 CA stentings failed at < 48 hours, and all MAL released by laparoscopy were successful. Median length of hospital stay was significantly greater in group A than in group B (5 vs. 3 days; p = .001). In group A, all PDAAs remained excluded. In group B, three PDAA recanalisations following embolisation were treated successfully (two redo embolisations and one open surgical resection). At six years, Kaplan-Meier estimates of freedom for PDAA recanalisation were 100% in group A, and 88% ± 6% in group B (p = .082). No PDAA ruptured during follow up. In group A, all 37 CAs treated by MAL release were patent, and one aortohepatic bypass occluded. In group B, five CAs occluded: four after stenting and the other after laparoscopic MAL release with two redo stenting and three aortohepatic bypasses. Estimates of freedom from CA restenosis/occlusion were 95% ± 3% for MAL release or visceral bypass, and 60% ± 9% for CA stenting (p = .001). Two late restenoses following CA stenting were associated with PDAA recanalisation.

CONCLUSION

Current data suggest that open and endovascular treatment of PDAA can be performed with excellent post-operative results in both groups. However, PDAA embolisation was associated with few midterm recanalisations and CA stenting with a significant number of early and midterm failures.

Aneurysms of pancreaticoduodenal arcade: Clinical profile and endovascular strategies

Background and Aim

Pancreaticoduodenal arcade aneurysms (PDAAs) are uncommon lesions associated with a significant risk of rupture and mortality. This study describes the etiology, clinical presentation, and endovascular management strategies of PDAAs across a spectrum of indications.

Methods

The clinical records of patients with PDAAs referred for endovascular management from January 2018 till November 2019 were retrospectively reviewed. Data on presenting symptoms, associated etiologies, and outcomes after endovascular treatment were collected and studied.

Results

We found 15 patients with false and 1 patient with true aneurysm of pancreatoduodenal arcade (PDA). The associated conditions were coeliac artery stenosis, severe necrotizing pancreatitis, and chronic pancreatitis or iatrogenic (postendoscopic papillotomy and percutaneous metallic biliary stenting). The main presenting feature was gastrointestinal bleed, while 2 patients had abdominal pain and 1 had gastric outlet obstruction. A multiphase computed tomography scan demonstrated the ruptured aneurysm in all patients. Site of origin of PDAA influenced the choice of transarterial endovascular strategy (coiling for aneurysms of main trunk of arteries and glue injection for those arising from small arterial branches). This was carried out in an emergency setting for 12 patients and as an elective procedure in 4 patients. Technical success was demonstrated in all patients and clinical success in 14. The two patients who had rebleed were salvaged by repeat endovascular procedure. Postembolization syndrome was seen in three patients.

Conclusions

With advancing technology, endovascular strategies continue to evolve. Careful attention to ensure hemodynamic resuscitation and stability, correction of pre‐existing coagulopathy and attention to technique can lead to the possibility of endovascular approaches as a dependable option in the management of ruptured PDAAs.

Abnormal Flow Dynamics Result in Low Wall Shear Stress and High Oscillatory Shear Index in Abdominal Aortic Dilatation: Initial in vivo Assessment with 4D-flow MRI

PURPOSE

To characterize the non-laminar flow dynamics and resultant decreased wall shear stress (WSS) and high oscillatory shear index (OSI) of the infrarenal abdominal aortic dilatation, cardiac phase-resolved 3D phase-contrast MRI (4D-flow MRI) was performed.

METHODS

The prospective single-arm study was approved by the Institutional Review Board and included 18 subjects (median 67.5 years) with the dilated infrarenal aorta (median diameter 35 mm). 4D-flow MRI was conducted on a 1.5T MRI system. On 3D streamline images, laminar and non-laminar (i.e., vortex or helical) flow patterns were visually assessed both for the dilated aorta and for the undilated upstream aorta. Cardiac phase-resolved flow velocities, WSS and OSI, were also measured for the dilated aorta and the upstream undilated aorta.

RESULTS

Non-laminar flow represented by vortex or helical flow was more frequent and overt in the dilated aorta than in the undilated upstream aorta (P < 0.0156) with a very good interobserver agreement (weighted kappa: 0.82-1.0). The WSS was lower, and the OSI was higher on the dilated aortic wall compared with the proximal undilated segments. In mid-systole, mean spatially-averaged WSS was 0.20 ± 0.016 Pa for the dilated aorta vs. 0.68 ± 0.071 Pa for undilated upstream aorta (P < 0.0001), and OSI on the dilated aortic wall was 0.093 ± 0.010 vs. 0.041 ± 0.0089 (P = 0.013). The maximum values and the amplitudes of the WSS at the dilated aorta were inversely proportional to the ratio of dilated/undilated aortic diameter (r = -0.694, P = 0.0014).

CONCLUSION

4D-flow can characterize abnormal non-laminar flow dynamics within the dilated aorta in vivo. The wall of the infrarenal aortic dilatation is continuously and increasingly affected by atherogenic stimuli due to the flow disturbances represented by vortex or helical flow, which is reflected by lower WSS and higher OSI.

Causal Relationship between Celiac Stenosis and Pancreaticoduodenal Artery Aneurysm: Interpretation by Simulation Using an Electric Circuit

Pancreaticoduodenal artery (PDA) aneurysm and celiac artery (CA) stenosis are rare diseases in themselves. Interestingly, however, there are more cases documented in the literature in which these two disease entities occurred together than could be coincidental, and CA stenosis has been suggested as the provocative condition in developing PDA aneurysm. This study is aimed at examining the causal relationship between CA stenosis and PDA aneurysm by simulating the splanchnic circulation with an electric circuit. A patient with multiple PDA aneurysms and collaterals with CA stenosis was treated in our institution using hybrid techniques. The patient's pre- and postoperative status was simulated using an electric circuit, and the two possible scenarios were tested for compatibility: the stenosis-first scenario vs. the aneurysm-first scenario. The simulation was performed in two ways: using Simulink® software (MATLAB® Release 2018b) and actual circuit construction on a breadboard. The stenosis-first scenario showed that as the CA stenosis progresses, the blood flow through PDA increases, favoring the development of an aneurysm and/or collaterals if the artery was already compromised by a weakening condition. On the other hand, the aneurysm-first scenario also showed that if the aneurysm or collaterals developed first, the aneurysm will steal the blood flow through the CA, causing it to collapse if the artery was already compromised by increased wall tension. Contrary to the common belief, this study showed that in patients suffering from concurrent CA stenosis and PDA aneurysm, either condition could develop first and predispose the development of the other. The simulation of splanchnic blood flow with an electric circuit provides a useful tool for analyzing rare vascular diseases that are difficult to provoke in clinical and animal studies.

Naturally shrunk visceral artery aneurysms by stenting for the superior mesenteric artery occlusion

A 77-year-old woman who had experienced postprandial abdominal pain for four years was admitted to our institution presenting sudden and severe abdominal pain. Contrast-enhanced computed tomography (CECT) demonstrated complete short-segmented occlusion in the orifice of the superior mesenteric artery (SMA), and saccular aneurysms in the right hepatic artery and the anterior superior pancreaticoduodenal artery. She was diagnosed with abdominal angina due to occlusion of the SMA. The SMA was recanalized by stenting, and a CECT scan confirmed naturally shrunk aneurysms after eight months. The patency of the SMA was maintained at five years after endovascular treatment.

CT and MRI assessment of intestinal blood flow

The accuracy of multi-slice computed tomography (CT) in the diagnosis of acute mesenteric ischemia is very high, however, it cannot demonstrate the small embolus of blood vessels and abnormal intestinal blood flow. The intestinal blood flow in chronic mesenteric ischemia decreases whereas there are few morphology changes, which leads to a high misdiagnosis rate of CT and CT angiography. In addition, inflammatory bowel disease, intestinal tumors, and portal hypertension can be diagnosed definitely by conventional CT, but the hemodynamics and microcirculation in these conditions cannot be assessed, which affects the accuracy of clinical staging and the assessment of therapeutic effect. For intestinal diseases, especially mesenteric ischemia, therefore, it is needed not only to make CT morphologic diagnosis but also to further assess the abnormal intestinal blood flow. In recent years, more and more CT and magnetic resonance imaging (MRI)-related new techniques for assessing blood flow have emerged, including CT perfusion, spectral CT imaging, magnetic resonance perfusion imaging, and phase contrast MRI. This paper reviews the clinical application and progress of these techniques for assessing intestinal blood flow.

Transarterial Embolization With Complementary Surgical Ligation of Gastroduodenal Artery for Ruptured Pancreaticoduodenal Artery Aneurysm

The association between pancreaticoduodenal artery aneurysm (PDAA) and local hemodynamic changes in pancreaticoduodenal arcades is well established. However, there are few case reports of PDAA associated with acute aortic dissection. In this article, we outline and discuss the case of a 61-year-old man diagnosed with a type A acute aortic dissection who underwent emergency surgery and developed sudden-onset severe abdominal pain and shock 10 days later. Contrast-enhanced computed tomography showed a ruptured PDAA with feeding vessels from the gastroduodenal and superior mesenteric arteries, with evidence that the celiac artery was diverged from a false lumen. Transarterial embolization via the superior mesenteric artery alone was not expected to achieve hemostasis, so we performed a hybrid procedure involving transarterial embolization cannulated from superior mesenteric artery with complementary surgical ligation of the gastroduodenal artery. The postoperative course was uneventful, and follow-up contrast-enhanced computed tomography showed no persistence of the aneurysm 8 days after the second operation. This case proposed that visceral arterial malperfusion due to acute aortic dissection can cause PDAA in the early postoperative period. Although previous reports suggest that endovascular treatment is preferable, it may not always be feasible. Since ruptured PDAAs are often not detected during surgery, surgical treatment can be overly invasive. Whereas, transarterial embolization with complementary clamping or ligation of the gastroduodenal artery for ruptured PDAA is less invasive and can control hemorrhage, especially when cannulation to the celiac artery is impossible. Notably, the technique did not cause organ ischemia, presumably because the small collateral vessels of the pancreaticoduodenal arcades permitted sufficient blood flow. If endovascular treatment is unable to achieve rapid hemostasis, this technique may be a useful option for ruptured PDAA.

Hemodynamic Simulation of Pancreaticoduodenal Artery Aneurysm Formation Using an Electronic Circuit Model and a Case Series Analysis

Objective: To assess mechanisms underlying aneurysm formation using a simple electronic circuit model.

Materials and Methods: We created a simple circuit model connecting the celiac artery (CA) to the superior mesenteric artery via the pancreaticoduodenal arcade. We retrospectively reviewed 12 patients with true pancreaticoduodenal artery aneurysms (PDAAs) who received open or endovascular treatment between 2004 and 2017. We set the resistance of each artery and organ voltage and calculated flow volume and rate in response to degrees of simulated CA stenosis from 0% to 99.9%.

Results: Flow volume rates of the anterior pancreaticoduodenal artery and posterior pancreaticoduodenal artery decreased to zero when CA stenosis increased from 0% to 50% and then increased drastically, at which point flow direction reverted and the flow was up to three times the initial rate. The gastroduodenal artery (GDA) also showed reversed flow with severe CA stenosis. In 12 patients with PDAA, eight presented with a CA lesion, and the other patients presented with comorbidities causing the arteries to be pathologically fragile, such as Marfan syndrome, Behçet’s disease, and segmental arterial mediolysis. All four GDA aneurysms were not accompanied by CA lesions.

Conclusion: The mechanism underlying CA-lesion-associated PDAA formation may be partially explained using our model.

The benefits of extrinsic ligament release for potentially hemodynamically unstable pancreaticoduodenal arcade aneurysm with median arcuate ligament syndrome: a case report

Background

A pancreaticoduodenal artery aneurysm (PDAA) occurring in close association with median arcuate ligament syndrome (MALS) is rare. A surgical procedure, such as median arcuate ligament (MAL) release, should be considered in such cases, but the operative criteria remain unknown. In this study, we reported an extremely rare case of PDAA with periarteritis nodosa (PAN) and MALS.

Case presentation

A 60-year-old man was transferred to our department with sudden onset of abdominal pain. We initially diagnosed his condition as a PDAA rupture with MALS based on enhanced computed tomography (CT). We promptly performed transcatheter arterial embolization (TAE) of PDAA, and the angiogram showed stagnant contrast agent in the celiac trunk, indicating total celiac artery occlusion. Follow-up enhanced CT three weeks after the first TAE clearly demonstrated newly formed, multiple aneurysms in the pancreaticoduodenal arcade and the hepatic artery. These findings indicated a systemic disorder, such as PAN or segmental arterial mediolysis, as the underlying cause. Therefore, we started corticosteroid therapy and performed diagnostic angiography to clarify the celiac artery’s patency. Contrary to the initial angiography, the second angiography showed sustained blood flow in the celiac artery. Nevertheless, we performed both extrinsic MAL release and consecutive TAE because of the risk of multiple aneurysms rupturing due to an uncontrolled systemic disorder and consequent hepatic ischemia. The patient had no episode of recurrence until one year of follow-up.

Conclusions

It is important to evaluate risk for hemodynamically unstable events to decide the best treatment strategy for MALS.

Hemodynamic Analysis to Assist Treatment Strategies in Complex Visceral Arterial Pathologies: Case Reports and discussion from Pancreaticoduodenal Artery Aneurysm with Superior Mesenteric Artery Occlusion

BACKGROUND

Pancreaticoduodenal artery aneurysms (PDAAs) with occlusion of the superior mesenteric artery (SMA) are extremely rare. In the present study, we used computational fluid dynamics (CFD) to analyze the hemodynamics of a patient-specific PDAA with occlusion of the SMA preoperatively and then decide the treatment strategy in terms of the potential postoperative hemodynamics.

METHODS

A 3D model of a 69-old-year female with PDAA was reconstructed based on CT images. The virtual postoperative models of the aneurysmectomy with or without revascularization were numerically simulated in terms of hemodynamics including the flow field and wall shear stress (WSS).

RESULTS

Aneurysmectomy with revascularization would result in the original aneurysm site experiencing abnormally high WSS and pressure, which may possibly lead to the recurrence of PDAA. However, aneurysmectomy without revascularization would lead to stagnant flow in the blocked posterior-inferior pancreaticoduodenal artery (PIPDA). As a result, the PIPDA may soon be completely occluded after surgery and the SMA perfusion would be guaranteed. Finally, aneurysmectomy without revascularization was performed in this patient. The postoperative six-month computed tomography angiography result finely matched to the preoperative CFD simulation result.

CONCLUSIONS

This study gained insights into hemodynamics of PDAA. In addition, it demonstrated that utilization of CFD analysis also possibly helps assist the operation strategies for vascular diseases.

Flow dynamics of type II endoleaks can determine sac expansion after endovascular aneurysm repair using four-dimensional flow-sensitive magnetic resonance imaging analysis

OBJECTIVE

The objective of this study was to investigate the hemodynamic parameters of type II endoleaks (T2ELs) to predict sac expansion using four-dimensional flow-sensitive magnetic resonance imaging (4D-flow MRI) analysis.

METHODS

Patients who underwent endovascular aneurysm repair (EVAR) and were diagnosed with a T2EL were included in the study. Using 4D-flow MRI at 7 days, the peak flow velocity and amplitude of dynamics of blood flow per minute were measured in each T2EL vessel. The peak flow velocity was defined as the maximum of the absolute value of the blood flow velocity. The amplitude of dynamics of blood flow in the tributary arteries was defined as the sum of the absolute values of the inflow and outflow volume in each vessel. The amplitude of dynamics of blood flow in the tributary arteries per sac was calculated in each sac. The aneurysm sac diameter was measured by computed tomography (CT) at 1 year. The patients were divided into two groups according to the presence or absence of sac expansion.

RESULTS

Of 155 patients who underwent EVAR, both CT angiography and 4D-flow MRI were performed in 107 patients at 7 days after EVAR. Among them, 39 (36.4%) were found to have a T2EL, of whom 28 were re-evaluated with CT angiography and 4D-flow at 1 year; 7 patients had expanding sacs (expanding group), whereas 21 had nonexpanding sacs (not-expanding group). At 7 days, 28 patients had 80 T2EL vessels detected by 4D-flow MRI, of which 39 vessels (48.8%) had stopped flowing at 1 year (transient vessels); 41 vessels (51.3%) had sustained flow (persistent vessels). The persistent vessels had significantly larger peak flow velocity and amplitude of dynamics of blood flow. The comprehensive analysis of T2EL vessels per sac identified that the amplitude of dynamics of blood flow in the tributary arteries per sac was significantly higher in the expanding group than in the not-expanding group. A receiver operating characteristic curve analysis revealed that the sensitivity and specificity of sac enlargement at a cutoff value of 3750 mm³/min were 85.7% and 76.2%, respectively.

CONCLUSIONS

The fate of aneurysm sacs with T2ELs after EVAR has remained difficult to predict. A comprehensive analysis of concurrent multiple T2EL vessels using 4D-flow MRI analysis may enable prediction of the sac expansion after EVAR.

Clinical impact of collateral circulation in patients with median arcuate ligament syndrome

PURPOSE

We aimed to analyze computed tomography (CT) findings and medical records of patients diagnosed with median arcuate ligament syndrome (MALS) and evaluate possible risk factors associated with vascular complications that develop in patients with MALS.

METHODS

This retrospective study was approved by the institutional review board, and the requirement to obtain informed consent was waived. A total of 37 consecutive patients were diagnosed with MALS using both axial and sagittal CT reconstruction imaging at a single institution over a 7-year period. Dynamic contrast-enhanced CT data, medical records, and angiography results were reviewed.

RESULTS

Thirty-two (86.5%) patients were asymptomatic and incidentally diagnosed with MALS using CT. Seventeen (45.9%) patients exhibited significant arterial collateral circulations and nine (24.3%) were found to have splanchnic artery aneurysms, including one (2.7%) with acute bleeding secondary to aneurysm rupture. Peripancreatic vascular network including pancreaticoduodenal arcades and dorsal pancreatic artery was the most common site for development of both collateral circulations (16/22, 72.7%) and aneurysms (9/16, 56.3%). Splanchnic artery aneurysms were significantly more common in patients with collateral circulations (8/17, 47.1%) compared with those without collateral circulations (1/20, 5%) (P < 0.01). At least one peripancreatic vascular aneurysm was found in five of nine patients with splanchnic artery aneurysms (55.6%).

CONCLUSION

Splanchnic artery aneurysms are not uncommon in asymptomatic patients with collateral circulations caused by significant celiac trunk stenosis or obstruction due to median arcuate ligament. Therefore, careful imaging evaluation is necessary in patients with peripancreatic collateral circulations associated with MALS and regular follow-up is recommended for possibility of aneurysm development and rupture. Prophylactic endovascular treatment should be specifically performed in patients with pancreaticoduodenal arcade aneurysms to prevent life-threatening aneurysm rupture regardless of size.

Median arcuate ligament syndrome and aneurysm in the pancreaticoduodenal artery detected by retroperitoneal hemorrhage: A case report

Here, we report a case with successful treatment of inferior pancreaticoduodenal artery aneurysm rupture due to celiac artery trunk compression caused by the median arcuate ligament. When clinicians see visceral aneurysms, the possibility of arcuate midline ligament compression syndrome (MALS) and ligamentectomy for MALS should be considered.

Hemodynamic benefits of celiac artery release for ruptured right gastric artery aneurysm associated with median arcuate ligament syndrome: a case report

Background

It has been reported that median arcuate ligament syndrome is closely associated with gastric or pancreaticoduodenal artery aneurysms. Hemodynamic state plays an important role in the formation of the aneurysms. These aneurysms are treated with open resection or endovascular exclusion. However, whether revascularization of the celiac artery can prevent the aneurysm formation is unknown. This report indicated a possibility that prophylactic revascularization for celiac artery stenosis resulted in decreased shear stress on the collaterals, which may otherwise be susceptible to new aneurysms.

Case presentation

This report describes a 51-year-old man who presented with epigastric pain at our hospital. According to contrast enhanced computed tomography (CT), he was diagnosed with a ruptured right gastric artery aneurysm and celiac artery stenosis caused by the median arcuate ligament (MAL). He had a vascular anomaly of the common hepatic artery arising from the superior mesenteric artery (SMA). His vital signs were stable. We informed him of the situation and he chose open surgery rather than endovascular treatment. Following, we resected the aneurysm and transected the MAL. Intraoperative angiography after transection of the MAL showed the antegrade blood flow to the splenic artery instead of the retrograde flow via the prominent collaterals. Follow-up CT confirmed narrowed collateral vessels between the SMA and the celiac artery without de-novo aneurysms.

Conclusion

While the necessity of celiac artery release could be questioned, the present case supports the hemodynamic benefits of MAL transection in terms of de-novo aneurysm prevention.

Pancreaticoduodenal Artery Aneurysm Associated with Celiac Trunk Stenosis: Case Illustration and Literature Review

Pancreaticoduodenal artery aneurysms (PDA) are rare visceral aneurysms. Celiac trunk stenosis represents a common attributable aetiology for those aneurysms. Therefore, an alternative treatment approach, which differs from those isolated aneurysms, is recommended. We hereby present a 77-year-old male patient who was admitted with sudden onset of severe abdominal pain and significant drop in haemoglobin, occurring within a 24-hour interval. Contrast-enhanced computed tomography revealed a ruptured visceral aneurysm arising from the anterior branch of the inferior pancreaticoduodenal artery. A severe stenosis was also noted at the take-off of the celiac trunk. Selective catheterization of the supplying branch of the superior mesenteric artery, followed by coil embolization of the aneurysm, was performed, resulting in cessation of flow within the aneurysm, with preservation of the posterior branch, supplying the celiac territory. PDAs are usually asymptomatic and discovered incidentally at rupture. The risk of rupture is independent of the aneurysmal size and is associated with a 50% mortality rate. The consensus on coping with aneurysms is to treat them whenever they are discovered. Selective angiography followed by coil embolization represents a less invasive, and frequently definitive, approach than surgery. The risk for ischemia mandates that the celiac territory must not be compromised after embolization.

Aneurysms of Peripancreatic Arterial Arcades Coexisting with Celiac Trunk Stenosis or Occlusion: Single Institution Experience

Introduction. True aneurysms of peripancreatic arterial arcades (PAAAs) are rare. Most of them coexist with celiac axis stenosis/occlusion due to median arcuate ligament (MAL) compression or atherosclerosis. The aim of this study was to evaluate the cause of celiac axis lesion and characterize the anatomy of the aneurysms. These findings may have important management implications. Material and Methods. A retrospective analysis of 15 patients with true PAAAs was performed. The diagnosis was established by contrast-enhanced CT, using a 64-MDCT scanner. We evaluated the most probable cause of celiac axis lesion. Aneurysms were characterized by their number, location, size, and morphology. Location of the aneurysms was classified either as pancreaticoduodenal arteries (PDA) or as dorsal pancreatic arteries (DPA) as they may represent different collateral pathways between superior mesenteric artery and celiac trunk. Results. A total of 32 true PAAAs were identified. Celiac trunk was occluded in 12 patients and critically narrowed in 3 patients. Celiac axis lesion was categorized as secondary to MAL compression in 14 cases and due to atherosclerosis in 1 case. The most common location of the aneurysms was inferior pancreaticoduodenal arteries. Only in 1 case aneurysms involved both PDA and DPA. Conclusions. Coexistence of PAAAs with celiac axis compression as well as involvement of either PDAs or DPAs has important therapeutic implications. The uninvolved collateral pathway may be sufficient to preserve effective circulation in celiac trunk branches in case of resection or embolization of the aneurysms. However, further studies are crucial to confirm our findings.

Phase-contrast MRI evaluation of haemodynamic changes induces by a coeliac axis stenosis in the gastroduodenal artery

OBJECTIVE

To evaluate the correlation between the gastroduodenal artery (GDA) haemodynamic changes and the degree of coeliac axis (CA) stenosis using phase-contrast MRI.

METHODS

The study was institutional review board approved, and written informed consent was obtained from patients included prospectively. A two-dimensional phase-contrast MRI was performed in 23 patients scheduled for a potential complex supramesocolic surgery, in a plane perpendicular to the GDA, during inspiration and expiration. The peak and mean velocities (V_p and V_m), mean flow rate (Q_m) and flow direction at inspiration and at expiration have been correlated with the degree of CA stenosis evaluated by CT.

RESULTS

13 of 23 patients presented CA stenosis due to the median arcuate ligament (34-80% of stenosis), 4 of them had associated atheromatous calcifications. V_p, V_m and Q_m of GDA presented a significant and linear relationship with the degree of CA stenosis, at inspiration as well as at expiration (r > 0.74, p < 0.001). Velocities and flow rates presented a different pattern depending on the degree of CA stenosis: <34% (n = 10), flow direction remained physiological with low velocities and flow rates; >60% of stenosis (n = 5), a reverse flow direction with increased velocities and flow rates were observed; variable patterns between 34% and 60%.

CONCLUSION

Phase-contrast MRI permits the evaluation of haemodynamic changes in GDA induced by CA stenosis, including median arcuate ligament compression, and could be of great interest in therapeutic decision making in supramesocolic surgery, such as liver transplantation or duodenopancreatectomy, by detecting haemodynamically significant stenoses. Advances in knowledge: Physiological phase-contrast MRI detects haemodynamically significant stenoses of the CA by evaluating haemodynamic parameters in the GDA. Physiological phase-contrast MRI demonstrates that flow in the GDA can be a direct marker of the real haemodynamic impact of a CA stenosis on the hepatic vascularization and could thus participate in the pre-surgical work-up of duodenopancreatectomy or hepatic graft, whereas existing pre-operative imaging are only morphological.

Non-invasive evaluation of pulmonary arterial blood flow and wall shear stress in pulmonary arterial hypertension with 3D phase contrast magnetic resonance imaging

Background

Recently, time-resolved 3D phase contrast magnetic resonance imaging (4D-flow) allows flow dynamics in patients with pulmonary arterial hypertension to be measured. Abnormal flow dynamics, such as vortex blood flow pattern in the pulmonary artery (PA), may reflect progression of pulmonary arterial hypertension (PAH). Some reports suggested that abnormal blood flow parameters including wall shear stress (WSS) could be markers of PAH. However, it was not fully assessed clinical usefulness of these variables. We aimed to assess whether these flow dynamic parameters, such as vortex formation time (VFT) and WSS, were associated with right ventricular (RV) function.

Results

Fifteen subjects, nine with PAH and six healthy volunteers, underwent 4D-flow. Differences of Blood flow patterns, blood flow velocities and WSS between PAH patients and healthy volunteers were evaluated. We also assessed the association between VFT, WSS and RV function in PAH patients. Both vortex blood flow patterns and early systolic retrograde flow in the main PA were observed in all patients with PAH. The PA flow velocities and WSS in patients with PAH were lower than those in healthy volunteers, but that blood flow volumes in the MPA, RPA and LPA and SV in the MPA were broadly comparable between the groups. The mean VFT was 35.0 ± 16.6 % of the cardiac cycle. The VFT significantly correlated with RV ejection fraction, RV end systolic volume, and RV end systolic volume index (RVEF = 75.1 + (−85.7)·VFT, p = 0.003, RVESV = 12.4 + 181.8·VFT, p = 0.037 and RVESVI = 10.6 + 114.8·VFT, p = 0.038, respectively) in PAH patients, whereas WSS did not correlate with RV function.

Conclusions

We confirmed that abnormal blood flow dynamics, including the vortex formation and the early onset of retrograde flow, low WSS in the PA were characteristics of PAH. The VFT may be associated with right ventricular dysfunction, whereas WSS was not. Our results suggest that 4D-flow is an effective means of detecting right heart failure as well as diagnosing PAH.

Clinical trial registration URL: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi. Unique identifier: UMIN000011128

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-2755-7) contains supplementary material, which is available to authorized users.

Intra-left ventricular flow dynamics in patients with preserved and impaired left ventricular function: Analysis with 3D cine phase contrast MRI (4D-Flow)

PURPOSE

To examine how left ventricular (LV) volume and function affect flow dynamics by analyzing 3D intra-LV vortex features using 4D-Flow.

MATERIALS AND METHODS

Twenty-one patients with preserved (LVEF > 60%) and 14 with impaired LV function (LVEF < 40%) underwent 4D-Flow (at 3T).

RESULTS

In patients with preserved LV function, the intra-LV vortices developed in both the early and late diastolic phases. The shift of inflow vectors at the basal LV toward the posterior-lateral side of the LV and the mid-ventricular turn of inflow vectors toward the LV outflow could explain clearer vortex formation in the late diastolic phase. In patients with impaired LV function, the intra-LV vortices during the diastolic phase located at the more apical LV were larger and more spherically shaped. Both the distance to the vortex core and the vortex area correlated significantly with LV end-diastolic volume (r = 0.66 and 0.73), LVEF (r = -0.74 and -0.68), LV sphericity index (r = -0.60 and -0.65), and peak filling rate (r = -0.61 and -0.64), respectively (P < 0.01). The intra-LV vortices developed during the systolic phase in 10 cases. In those, some of the particles at the apical LV rotated within the LV, whereas in patients with preserved LV function, all of the particles were directed straight to the ascending aorta with accelerated flow velocity (256.8 ± 120.2 cm/s vs. 414.3 ± 88.2 cm/s, P < 0.01).

CONCLUSION

Vortex formation during the diastolic phase may be critical for both LV filling and ejection. 4D-Flow showed the 3D alterations of intra-LV flow dynamics by LV dilatation and dysfunction in a noninvasive and comprehensive manner. J. Magn. Reson. Imaging 2016;44:1493-1503.

Multiple Pancreatoduodenal Artery Arcade Aneurysms Associated with Celiac Axis Root Segmental Stenosis Presenting as Aneurysm Rupture

A 57-year-old woman was admitted to our unit suffering from hemorrhagic shock and upper abdominal pain. An enhanced computerized tomography (CT) scan evidenced a large retroperitoneal hematoma due to visceral arteries aneurysm rupture and a significant celiac axis root segmental stenosis due to median arcuate ligament compression. A selective splanchnic arteries angiography showed 3 saccular pancreaticoduodenal artery arcade aneurysm (PDAAs), 2 in the inferior posterior pancreaticoduodenal artery, and 1 smaller in the superior anterior pancreaticoduodenal artery. The largest aneurysm showed evident rupture signs. Both inferior PDAAs were successfully treated via endovascular coil embolization. The celiac trunk stenosis and small inferior PDAA did not require treatment. A CT scan control at 1-year follow-up did not reveal any new PDAAs. In cases of celiac artery trunk (CAT) steno-occlusive lesions, multiple aneurysms can develop in the pancreaticoduodenal arcade. PDAAs should be treated because of high rupture risk, regardless of diameter. Although endovascular treatment via coil embolization represents the treatment of choice nowadays, a simultaneous treatment of the associated CAT lesions is still debated. However, in cases of aneurysm embolization alone, one cannot exclude that other PDAAs might develop in these patients in the future. Close monitoring and accurate long-term follow-up is highly recommended in these cases.

Characteristics of intra-left atrial flow dynamics and factors affecting formation of the vortex flow – analysis with phase-resolved 3-dimensional cine phase contrast magnetic resonance imaging

BACKGROUND

The intra-left atrial (LA) blood flow from pulmonary veins (PVs) to the left ventricle (LV) changes under various conditions and might affect global cardiac function. By using phase-resolved 3-dimensional cine phase contrast magnetic resonance imaging (4D-Flow), the intra-LA vortex formation was visualized and the factors affecting the intra-LA flow dynamics were examined.

METHODS AND RESULTS

Thirty-two patients with or without organic heart diseases underwent 4D-Flow and transthoracic echocardiography. The intra-LA velocity vectors from each PV were post-processed to delineate streamline and pathline images. The vector images revealed intra-LA vortex formation in 20 of 32 patients. All the vortices developed during the late systolic and early diastolic phases and were directed counter-clockwise when viewed from the subjects' cranial side. The flow vectors from the right PVs lengthened predominantly toward the mitral valves and partly toward the LA appendage, whereas those from the left PVs directed rightward along the posterior wall and joined the vortex. Patients with vortex had less organic heart diseases, smaller LV and LA volume, and greater peak flow velocity and volume mainly in the left PVs, although the flow directions from each PV or PV areas did not differ.

CONCLUSIONS

4D-Flow can clearly visualize the intra-LA vortex formation and analyze its characteristic features. The vortex formation might depend on LV and LA volume and on flow velocity and volume from PVs.

Pancreaticoduodenal artery aneurysm formation with superior mesenteric artery stenosis

Celiac stenosis or occlusion is attributed partly to increase blood flow at pancreatic arcade from the superior mesenteric artery (SMA) system and may play a causal role in true aneurysm of pancreaticoduodenal artery (PDAA) formation. However, despite possible increased blood flow in the pancreatic arcades like celiac stenosis, PDAAs with a stenotic SMA are extremely rare, with only three cases have been reported in the literature. We report a case of PDAA with SMA stenosis and review the literature.

Pancreatoduodenal artery aneurysm resulting from median arcuate ligament compression successfully treated with laparoscopic ligament section

True aneurysms of the pancreatoduodenal arteries are frequently associated with stenosis or occlusion of the celiac trunk caused by median arcuate ligament compression. Celiac stenosis cannot be cured, even by transarterial embolization, which has recently become a good alternative to open surgical repair. To prevent recurrence, management of median arcuate ligament compression to correct hemodynamics in vascular networks should also be performed. Herein we report a case of pancreatoduodenal arterial aneurysm with median arcuate ligament compression that was successfully treated with minimally invasive laparoscopic median arcuate ligament section. The patient was discharged 4 days after surgery with no complications. Enhanced CT 1 month after surgery revealed no residual celiac trunk stenosis or aneurysm. Normalization of blood flow by laparoscopic median arcuate ligament section is a good option for some patients with a pancreatoduodenal arterial aneurysm.