Branch Of Superior Mesenteric Artery Research Articles

Early Anastomotic Repair in the Rat Intestine is Affected by Transient Preoperative Mesenteric Ischemia

IntroductionDuring bowel surgery, perioperative blood loss and hypotension can lead to transient intestinal ischemia. Recent preclinical studies reveal that the strength of intestinal anastomoses can be compromised after reperfusion. So far, this phenomenon has not been investigated in the very first days of healing when wound strength is lowest. Material and MethodIschemia was induced in rats by clamping both the superior mesenteric artery and ileal branches for 30 min. Immediately after declamping, anastomoses were constructed in both terminal ileum and descending colon. The same was done in control groups after sham-ischemia. Anastomotic bursting pressure and breaking strength were measured immediately after operation (day 0) and after 1, 2, or 3 days. Anastomotic hydroxyproline content, gelatinase activity, and histology were analyzed. Results and DiscussionIn ileal anastomoses, at day 1, both the breaking strength and bursting pressure were significantly (p < 0.05) lower in the ischemic group, while at day 2, this was the case for the bursting pressure only. In the colon, the bursting pressure in the ischemic group was lower at day 1. Anastomotic hydroxyproline content remained unchanged. Increased presence of the various gelatinase activities was found in ileum only at day 0 and in colon at days 1 and 2. Histological mucosal damage was found in ischemia–reperfusion groups. ConclusionTransient mesenteric ischemia can negatively affect anastomotic strength during the very first days of healing, even if the tissue used for anastomotic construction looks vital.

Transient ischemic small-bowel ulcers secondary to acute superior mesenteric artery branch thromboembolism diagnosed by double balloon enteroscopy

Acute insufficiency of mesenteric arterial blood flow has many etiologies but the mechanism of injury is the same regardless of the cause. Acute mesenteric ischemia is generally diagnosed with computed tomography (CT) imaging [1]. It results in mortality rates exceeding 60 %. Many cases require urgent surgery for the removal of necrotic bowel [2]. Endoscopic images of the ischemic small bowel have rarely been reported [3]. We present a case of multiple jejunal ulcers secondary to acute superior mesentric artery (SMA) branch thromboembolism diagnosed by double balloon enteroscopy.

Experimental Study on Acute Ischemic Small Bowel Changes Induced by Superselective Embolization of Superior Mesenteric Artery Branches with N-Butyl Cyanoacrylate

To evaluate the degree of ischemic changes of the small bowel after superselective embolization of superior mesenteric artery (SMA) branches at the vasa recta level with N-butyl cyanoacrylate (NBCA) in dogs. In six dogs, superselective embolization was performed with NBCA in five isolated branches of the SMA at the vasa recta level. All dogs were sacrificed 24 hours after embolization. According to the extent of the NBCA mixtures on radiographs of the specimen, embolized segments were divided into group A (embolization of three or fewer vasa recta) or group B (embolization of four or more vasa recta). Histologic evaluation of the mucosal, submucosal, and muscle layers of the embolized segments was performed by a pathologist. In group A (n=15), histologic findings were normal in seven segments (47%). Mild ischemic changes were noted in the mucosal layer in eight segments, the submucosal layer in four segments, and the muscle layer in one segment. In group B (n=15), ischemic changes were noted in the mucosal layer in all 15 segments, the submucosal layer in 14 segments, and the muscle layer in 10 segments. The difference in ischemic damage between groups A and B was statistically significant. Superselective embolization involving three or fewer vasa recta of the SMA was relatively tolerable, and embolization involving four or more vasa recta carried an increased risk of substantial ischemic bowel damage. Further studies are necessary to determine the clinical implications of our findings in human subjects.

Imaging appearances and management of isolated spontaneous dissection of the superior mesenteric artery

Objective The objective of our study was to report the clinical and imaging features of isolated dissection of the superior mesenteric artery (SMA) and describe our imaging classification of this disease entity. Subjects and methods We retrospectively analyzed clinical presentation, imaging appearances and outcome of the 12 patients who were diagnosed as having spontaneous dissection of the SMA from 1991 to 2005 in our institution or its affiliated two hospitals. There were 11 males and 1 female with a mean age of 50 years (range, 43–61 years). The diagnosis of isolated dissection was established with CT within 24 h of the onset. Results We categorized SMA dissection into the following four types based on imaging appearances: type I, patent false lumen with both entry and re-entry (four patients), type II, ‘cul-de-sac’ shaped false lumen without re-entry (one patient), type III, thrombosed false lumen with ulcer like projection (ULP), which is defined as a localized blood-filled pouch protruding from the true lumen into the thrombosed false lumen (five patients) and type IV, completely thrombosed false lumen without ULP (two patients). One patient with type II underwent urgent surgery because of small bowel ischemia. One patient with type III underwent urgent embolotherapy for the treatment of rupture of a branch of the SMA. The remaining 10 patients were initially managed conservatively. In one of the conservatively treated patient, ULP had progressively dilated, and it was treated with stent placement and coil packing 22 months after the onset. The remaining nine patients were conservatively managed without any event during the follow-up period of 7–72 months. Conclusion Most of the patients with isolated SMA dissection can initially be managed conservatively if there are no clinical and imaging signs indicating ruptured SMA branches or bowel ischemia.

Pyrrolidine Dithiocarbamate Prevents Deleterious Effects of Remote Ischemia/Reperfusion Injury on Healing of Colonic Anastomoses in Rats

Pyrrolidine dithiocarbamate (PDTC) is a low-molecular-weight thiol antioxidant and potent inhibitor of nuclear factor-kappaB (NF-kappaB) activation. It has been shown to attenuate local harmful effects of ischemia/reperfusion (I/R) injury in many organs. In recent animal studies, a delaying effect of remote organ I/R injury on the healing of colonic anastomoses has been demonstrated. In this study we investigated whether PDTC prevents harmful systemic effects of superior mesenteric I/R on left colonic anastomosis in rats. Anastomosis of the left colon was performed in 40 rats randomly allocated into the following four groups: (1) Sham-operated group (group I, n = 10)-simultaneously with colonic anastomosis, the superior mesenteric artery and collateral branches divided from the celiac axis and the inferior mesenteric artery were isolated but not occluded. (2) Sham+PDTC group (group II, n = 10)-identical to sham-operated rats except for the administration of PDTC (100 mg/kg IV bolus) 30 minutes prior to commencing the experimental period. (3) I/R group (group III, n = 10)-60 minutes of intestinal I/R by superior mesenteric artery occlusion. (4) PDTC-treated group (group IV, n = 10)-PDTC 100 mg/kg before and after the I/R. On postoperative day 6, all animals were sacrificed, and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for investigation of anastomotic hydroxyproline (HP) contents, perianastomotic malondialdehyde (MDA) levels, myeloperoxidase activity (MPO), and glutathione (GSH) level. There was a statistically significant decrease in anastomotic bursting pressure values, tissue HP content and GSH level, along with an increase in MDA level and MPO activity in group III, when compared to groups I, II, and IV (p < 0.05). However, PDTC treatment led to a statistically significant increase in anastomotic bursting pressure values, tissue HP content and GSH level, along with a decrease in MDA level and MPO activity in group IV (p < 0.05). This study showed that PDTC treatment significantly prevented the delaying effect of remote organ I/R injury on anastomotic healing in the colon. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent for increasing the safety of the anastomosis during particular operations where remote organ I/R injury occurs.

Multiple Giant Superior Mesenteric Artery Branch Aneurysms

Mesenteric arterial branch aneurysms are rare. Giant, multiple, mesenteric branch artery aneurysms are even more uncommon, and only a few reports exist in the literature. We describe a 73-year-old asymptomatic female found to have an abdominal bruit and subsequently diagnosed with multiple mesenteric branch artery aneurysms by computed tomography and angiography. In addition, the patient was found to have celiac artery occlusion at its origin. Risk factors include hypertension, hyperlipidemia, grandmultiparity, and tobacco dependence. She was treated successfully with open surgery including ligation of multiple branch aneurysms and vein bypass reconstruction to preserve hepatic and mesenteric artery flow. Our purpose is to review this uncommon entity in terms of diagnosis, etiology, treatment options, and literature review.

Transient Profound Mesenteric Ischemia Strongly Affects the Strength of Intestinal Anastomoses in the Rat

Experimental data suggest that transient preoperative ischemia and reperfusion may compromise anastomotic strength. However, data on this subject are equivocal, in particular as to the onset and duration of this effect. This study was designed to comprehensively characterize the effects of profound transient intestinal ischemia on anastomotic healing during the first postoperative week. Ischemia was induced in rats by clamping both the superior mesenteric artery and ileal branches for 30 minutes. Immediately after declamping, anastomoses were constructed in both terminal ileum and descending colon. After three, five, or seven days, both bursting pressure and breaking strength were measured. Anastomotic collagen content, gelatinase activity, and histology were analyzed. Anastomotic leakage rate was 13 percent in ischemia-reperfusion group and 0 percent (P=0.02) in controls. The breaking strength in ileum remained significantly (P<0.05) lower in the ischemic groups than in the control groups at all time points. Bursting pressure in the ileum was not significantly different between ischemic and control groups at either of the time points measured. However, at Day 7 the bursting site was significantly more frequent within the suture line in the ischemic groups. In the colon, at Day 3 the bursting pressure was 35 percent lower in the ischemic group than in the control group (P<0.05). Anastomotic collagen content and gelatinase activity were similar in ischemic and control groups. Transient profound splanchnic ischemia compromises anastomotic strength throughout the entire first postoperative week. This effect does not seem to be caused by impaired accumulation of wound collagen.

Superior Mesenteric Artery Branch Aneurysm with Absence of the Celiac Trunk

Superior mesenteric artery and pancreaticoduodenal artery aneurysms are rare. Agenesis of the celiac axis has only been reported four times. The reported etiologies of superior mesenteric artery and branch artery aneurysms include infection, atherosclerosis, inflammatory processes such as pancreatitis, dissection, collagen vascular disorders, polyarteritis nodosa, and trauma. We report an aneurysm of the superior mesenteric artery (SMA) branch, the inferior pancreaticoduodenal artery, arising in a patient with congenital absence of the celiac trunk. The patient presented with intermittent left upper quadrant pain without weight loss or change in bowel habits. The aneurysm was identified on abdominal computed tomography scan with angiographic confirmation of the aberrant anatomy. The patient was treated by aneurysmectomy and pancreaticoduodenal artery reconstruction with an interposition vein graft from the SMA. The patient recovered without complications and is asymptomatic with a patent vein graft 2 years after operation.

Regional heterogeneity in EDHF‐mediated relaxation in the rat mesenteric vascular bed: role of small‐ and intermediate conductance calcium‐activated K+ channels

Background Calcium-activated K+-channels (KCa) are important regulators of vasomotor tone. Activation of these endothelial KCa channels result in smooth muscle hyperpolarization and relaxation. The relative contribution of the EDHF-mediated relaxation differs depending on the vessel type and size. It is unknown whether these KCa channels are differentially distributed along the same vascular bed and hence have different roles in mediating the EDHF response. We therefore assessed the role of small- (SKCa) and intermediate- (IKCa) conductance KCa channels in mediating EDHF-induced relaxations in both 4th and 1st-order side branches of the rat superior mesenteric artery (MrA). Methods and Results 2-mm segments of each MrA were mounted in the wire-myograph, incubated with L-NAME (100 μM) and indomethacin (INDO, 10 μM) and pre-contracted with phenylephrine (10 μM). Cumulative concentration-response curves to ACh (10−9–10−5 M) were performed in the absence or presence of the selective SKCa channel antagonist apamin (0.5 μM) or the selective IKCa channel antagonist TRAM-34 (10 μM). Maximal ACh-induced relaxations in the presence of both L-NAME and INDO were similar in both artery types (Emax 76±4% in 4th-order versus 75±7% in 1st-order MrA). Apamin almost completely abolished these relaxations in 4th-order MrA (Emax 2±2 %), but only partially blocked relaxations in 1st-order MrA (Emax 36±8%). TRAM-34 caused a significantly greater inhibition of the ACh-induced EDHF-mediated relaxation in 4th-order MrA compared to 1st-order MrA (Emax 26±7% versus 57±8%, respectively). Conclusion Our data demonstrate regional heterogeneity in SKCa and IKCa function, and stress the importance of KCa channels in smaller resistance-sized arteries, where the role of EDHF is more pronounced.

Differential roles of rho‐kinase and protein kinase C (PKC) in contractile responses of rat aorta and mesenteric artery

Rho-kinase and protein kinase C (PKC) have each been shown to mediate vasoconstriction via calcium sensitization in response to G protein-coupled receptor (GPCR) stimulation. However, the relative contributions of rho-kinase and PKC to vascular contraction, and whether their roles vary between large and small blood vessels, are not well understood. We therefore assessed the relative roles of rho-kinase and PKC in mediating vascular contraction in isolated rings of aorta (Ao), superior mesenteric artery (MA) and second order branches of the superior mesenteric artery (BMA), from male Sprague-Dawley rats. We tested the effects of the rho-kinase inhibitor, Y-27632 (1μM), and the PKC inhibitor, Ro 31-8220 (5μM) either alone or in combination, on contractile responses to phenylephrine (PE). Maximum responses of Ao and MA to PE were reduced by Y-27632 (n=3-10; P<0.05), whereas responses of BMA were unaffected. Ro 31-8220 partly reduced contractile responses to PE in Ao and MA (n=3-10; P<0.05). Responses of BMA were completely abolished by Ro 31-8220 (n=6-7; P<0.05), and endothelial removal did not alter this effect. Co-treatment with Y-27632 and Ro 31-8220 abolished contractile responses in all arteries. Thus, contractile responses of Ao and MA to PE can involve both rho-kinase and PKC, to varying degrees. In BMA, PKC appears to exclusively mediate these contractile responses, with no apparent role for rho-kinase.

Regional heterogeneity in acetylcholine-induced relaxation in rat vascular bed: role of calcium-activated K+ channels

Ca+ -activated K+ -channels (KCa) regulate vasomotor tone via smooth muscle hyperpolarization and relaxation. The relative contribution of the endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxation differs depending on vessel type and size. It is unknown whether these KCa channels are differentially distributed along the same vascular bed and hence have different roles in mediating the EDHF response. We therefore assessed the role of small- (SKCa), intermediate- (IKCa), and large-conductance (BKCa) channels in mediating acetylcholine-induced relaxations in both first- and fourth-order side branches of the rat superior mesenteric artery (MA1 and MA4, respectively). Two-millimeter segments of each MA were mounted in the wire myograph, incubated with Nomega-nitro-L-arginine methyl ester (L-NAME, 100 micromol/l) and indomethacin (10 micromol/l), and precontracted with phenylephrine (10 micromol/l). Cumulative concentration-response curves to ACh (0.001-10 micromol/l) were performed in the absence or presence of selective KCa channel antagonists. Apamin almost completely abolished these relaxations in MA4 but only partially blocked relaxations in MA1. The selective IKCa channel blocker 1-[(2-chlorophenyl) diphenylmethyl]-1H-pyrazole (TRAM-34) caused a significantly greater inhibition of the ACh-induced relaxation in MA4 compared with MA1. Iberiotoxin had no inhibitory effect in MA4 but blunted relaxation in MA1. Relative mRNA expression levels of SKCa (rSK1, rSK3, and rSK4 = rIK1) were significantly higher in MA4 compared with MA1. BKCa (rBKalpha1 and rBKbeta1) genes were similar in both MA1 and MA4. Our data demonstrate regional heterogeneity in SKCa and IKCa function and gene expression and stress the importance of these channels in smaller resistance-sized arteries, where the role of EDHF is more pronounced.

Spontaneous resolving of the aneurysm of ileocolic artery, branch of superior mesenteric artery ----Imaging findings

A rare case of ileo-colic aneurysm- branch of superior mesenteric artery is presented. Injuries to branches of superior mesenteric artery are unusual and often difficult to diagnose, yet require prompt recognition and treatment to prevent exsanguinating hemorrhage or bowel ischemia(1).The present patient was a known case of RHD with severe AS and moderate AR and was operated in 2001.Patient has a history of trauma in right iliac fossa and was diagnosed as aneurysm on color Doppler, confirmed on CT angio, MR angiography and conventional; angiography. Since Patient was asymptomatic when came to radiology deptt, intervention was deferred for a week. After a week when color Doppler was performed it showed on resolved hematoma and no aneurysm. This is a unique case of ileocolic aneurysm resolving on its own .only few cases of ileocolic artery aneurysm have been reported in literature; either they are treated with laprotomy or by interventional procedure.

Mycotic aneurysm of superior mesenteric artery branch presenting as pulsatile abdominal mass

Mycotic aneurysm of superior mesenteric artery branch presenting as pulsatile abdominal mass

Chronic Vascular Rejection: Histologic Comparison Between Two Murine Experimental Models

Background We previously developed an experimental model to study chronic vascular rejection (CVR) in mice, the orthotopic aortic allograft. More recently we performed human arterial grafts into SCID/Beige mice reconstituted with human spleen cells. We report herein the differences in CVR lesions. Material and methods In the first model, recipient mice were C57BL/6 (H-2b), and donor mice were DBA/2 (H-2d). In the second model, terminal branches of the human superior mesenteric artery were transplanted into SCID/Beige mice in the infrarenal aorta. Human immune reconstitution was achieved by a single intraperitoneal injection of 30 × 10 6 human spleen cells. The presence of human lymphocytes and IgG was verified weekly. In both models, the vascular grafts were inserted in the infrarenal aortic position using the sleeve technique. The transplanted mice were sacrificed at 35 days after the operation. The grafts were analyzed by histology and morphometry. The mean intimal thickening was calculated based on transverse sections at 0.1-mm intervals. Results Typical CVR lesions developed with neointimal thickening, T-cell infiltration, and smooth muscle cell (SMC) proliferation in both models. In the mouse aortic model, disappearance of SMC in the media was noted in contrast to human arterial transplants, where the media remained intact. Conclusion Other groups have noted that arteries conserve their media in clinical organ transplants. From this point of view, the lesions in the second experimental model (human arteries) better reflect the pathology of CVR in clinical transplantation than the murine aortic transplant model.

Treatment of Pseudoaneurysm of the Ileocolic Artery with Microcoil Embolization in a Post-ileostomy Patient

Pseudoaneurysms arising from branches of the superior mesenteric artery (SMA) are very rare. It is important to recognize and treat a pseudoaneurysm because of the risk of bleeding and even death. Angiography is the standard means for detecting intestinal and mesenteric hemorrhage. Endovascular treatment is a prompt and effective method for control of gastrointestinal hemorrhage. Status post-ileostomy with pseudoaneurysm formation and active bleeding has not been reported in the literature. We present the first case of ileocolic artery pseudoaneurysm post-ileostomy successfully treated by transcatheter arterial microcoil embolization.

Automatic detection of calcifications in the aorta from CT scans of the abdomen 1: 3D computer-aided diagnosis

Rationale and objectives Automated detection and quantification of arterial calcifications can facilitate epidemiologic research and, eventually, the use of full-body calcium scoring in clinical practice. An automatic computerized method to detect calcifications in CT scans is presented. Materials and methods Forty abdominal CT scans have been randomly selected from clinical practice. They all contained contrast material and belonged to one of four categories: containing “no,” “small,” “moderate,” or “large” amounts of arterial calcification. There were ten scans in each category. The experiments were restricted to the vertical range from the point where the superior mesenteric artery branches off of the descending aorta until the first bifurcation of the iliac arteries. The automatic method starts by extracting all connected objects above 220 Hounsfield units (HU) from the scan. These objects include all calcifications, as well as bony structures and contrast material. To distinguish calcifications from non-calcifications, a number of features are calculated for each object. These features are based on the object’s size, location, shape characteristics, and surrounding structures. Subsequently a classification of each object is performed in two stages. First the probability that an object represents a calcification is computed assuming a multivariate Gaussian distribution for the calcifications. Objects with low probability are discarded. The remaining objects are then classified into calcifications and non-calcifications using a 5-nearest-neighbor classifier and sequential forward feature selection. Based on the total volume of calcifications determined by the system, the scan is assigned to one of the four categories mentioned above. Results The 40 scans contained a total of 249 calcifications as determined by a human observer. The method detected 209 calcifications (sensitivity 83.9%) at the expense of on average 1.0 false-positive object per scan. The correct category label was assigned to 30 scans and only 2 scans were off by more than one category. Most incorrect classifications can be attributed to the presence of contrast material in the scans. Conclusion It is possible to identify the majority of arterial calcifications in abdominal CT scans in a completely automatic fashion with few false positive objects, even if the scans contain contrast material.

Superior mesenteric arteriovenous fistula causing massive hematemesis

Surgery 2003;134:102-4.

Embolization of visceral pseudoaneurysms with platinum coils and N-butyl cyanoacrylate.

We evaluated the efficacy of transcatheter embolization in visceral artery pseudoaneurysms with platinum coils and N-butyl-cyano-acrylate (NBCA). Over the past 7 years, 20 patients were treated by transcatheter embolization in the same sitting with diagnostic angiography. Four right hepatic, one cystic, two gastroduodenal, one cavernosal artery, three superior mesenteric artery branch, and 11 renal artery branch pseudoaneurysms were included in the study. Surgery was completely avoided in 19 patients. In the remaining patient with a superior mesenteric artery branch pseudoaneurysm, endovascular embolization was unsuccessful. Eighteen pseudoaneurysms were thrombosed with coil embolization alone. The remaining three pseudoaneurysms needed NBCA embolization. Two patients died from sepsis within 5 weeks after embolization. Emergent diagnosis and treatment are essential in visceral artery pseudoaneurysms because of the high rate of death. Transcatheter embolization with platinum coils is an efficient, safe treatment of choice. NBCA may be used to avoid proximal embolization of the visceral arteries that could not be catheterized selectively because of tortuosity, vessel size, or anatomic location.

Rupture of Mesenteric Artery Branch Aneurysm

We describe a case of ruptured mesenteric artery branch aneurysm. Since it is characterized by nonspecific clinical manifestations, aneurysm in this uncommon location is usually diagnosed following complications. Definitive diagnosis requires Doppler ultrasound followed by arteriography. The purpose of this report is to describe the pitfalls of diagnosis and define an appropriate management strategy. Unlike abdominal aortic aneurysm, isolated aneurysms of the superior mesenteric artery (SMA) branches are rare. Most cases are diagnosed after the occurrence of complications. Early diagnosis would be useful, since the natural course can be tragic without timely treatment. In this report, we describe one case of ruptured mesenteric artery branch aneurysm and review the literature for relevant data on the circumstances of discovery, methods of investigation, and appropriate management of these lesions.

A CASE REPORT OF ISCHEMIC STRICTURE OF THE JEJUNUM WITH PROTEIN -LOSING ENTEROPATHY

An 81-year-old woman was admitted to the hospital because of right upper abdominal pain and melena. Bleeding from the small intestine was suspected as a cause of melena, because we could not detect any bleeding lesion by gastrointestinal fiberscopy and total colonofiberscopy. The patient appeared systemically well, and was treated conservatively. On the 47th day after the onset of symptoms, the patient exhibited symptom of ileus. Barium-meal studies revealed a long stricture about 30cm in length of the jejunum 25cm distal to the Treitz ligament, Angiography from the superior mesenteric artery (SMA) showed obstruction of major branches of SMA. Despite adequate hyperalimentation, the patient presented remarkable hypoalubuminemia. Extravasation was seen in the strictured jejunum by 99mTc-labeled albumin scintigraphy. So, we diagnosed the case as ischemic stricture of the jejunum with protein-losing enteropathy. A partial resection of small intestine was carried out on 99th day after the onset, the resected jejunnum showed firm tubular stricture 33cm in length, with ulceration (UL-II) and fibrosis. These features were strongly suggestive of an ischemic process. It is rare that ischemic stricture of the jejunum causes protein-losing enteropathy. This rare case in which extravasation of protein was successfully demonstrated on imaging procedure is reporoted here.