Type 2 endoleak embolization comparison: translumbar embolization versus modified transarterial embolization

PURPOSE

To evaluate the success of endoleak repair using translumbar (TL) endoleak embolization compared with a transarterial (TA) technique that involves embolization of the endoleak cavity itself in addition to the feeding artery.

MATERIALS AND METHODS

Eighty-four patients (mean age, 78.2 years; age range, 58-94 years) with type 2 endoleaks were included in this retrospective study. Patients underwent either TL endoleak embolization or TA embolization between January 2002 and December 2007. TA embolization involved entering the endoleak cavity through the inferior mesenteric or lumbar artery. Both the endoleak cavity and the feeding artery were then embolized by using coils through a microcatheter. TL embolizations were performed by using standard technique with coils and n-butyl cyanoacrylate as the embolization agents. Clinical success was defined as the absence of an endoleak and/or aneurysm enlargement at follow-up CT angiography. Statistical comparison was performed with the Fisher exact test.

RESULTS

Endoleak repair was successful in 72% (45/62) of the TL embolizations and 78% (18/23) of the TA embolizations, with a mean follow-up of 18.7 months (range, 1-84 months). There was no significant difference in clinical success between the two groups (P = .41). There were two (3.2%) complications in the TL group and no complications in the TA group.

CONCLUSIONS

The effectiveness of the TA endoleak embolization technique, which involves embolizion of the endoleak cavity and the feeding artery, is similar to that of TL embolization for treatment of type 2 endoleaks.

A novel model of ischemic enteritis induced in rats by stenosis of the superior mesenteric artery

AIMS

We established a new model of ischemic enteritis in rats and evaluated its usefulness for screening prophylactic drugs.

MAIN METHODS

Male SD rats were used after 18 h of fasting. Under ether anesthesia, the superior mesenteric artery (SMA) was exposed, and a calibrated stenosis was produced by placing a needle on a blood vessel, ligating both the vessel and needle, and then removing the needle from the ligature.

KEY FINDINGS

The stenosis caused severe damage on the anti-mesenteric side of the small intestine within 3 days; the severity of the damage increased with the gauge of a needle. No damage occurred in the small intestine following the stenosis with a needle of less than 21 gauge. Multiple hemorrhagic lesions occurred at an incidence of 100% when a 23-gauge needle was used. The development of enteritis was accompanied by enterobacterial invasion in the mucosa, with an up- regulation of inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production. The ischemia-induced enteritis was significantly prevented by repeated treatment with aminoguanidine (a selective iNOS inhibitor), L-NAME (a nonselective NOS inhibitor), ampicillin, and aztreonam (a gram- negative bacterium antibiotic), but not vancomycin (a gram-positive bacterium antibiotic).

SIGNIFICANCE

These results showed that a novel model of ischemic enteritis is induced in rats by stenosis of the SMA, this model may be useful for screening drugs against ischemic enteritis, and gram-negative bacteria as well as iNOS/NO are involved in the pathogenesis of enteritis in this model.

A case of Behçet's disease presenting with massive lower gastrointestinal bleeding

Behçet's disease, as initially described, is a triad of recurrent oral and genital ulcers and relapsing uveitis. Classified as a systemic vasculitis, it can involve both the arteries and veins of almost any organ. Intestinal Behçet's disease is characterized by deep ulcers, most commonly located in the ileoceal region, with tendency to bleeding and perforation at multiple sites. Here, we report a case of Behçet's disease presenting with lower gastrointestinal bleeding, mesenteric arterial thrombosis and duodenal perforation.

Refractory vasospasm with a malignant course

We present a patient with two rare disorders, recurrent vasospastic angina leading to cardiac transplant and acute aortic occlusion. The patient had recurrent episodes of coronary vasospasm presenting with unstable angina, acute myocardial infarction, and sudden cardiac death in spite of adequate therapy with nitrates and calcium-channel blockers. He went on to have a cardiac transplant. The patient later presented with acute aortic occlusion with concomitant renal and mesenteric artery spasm. The circumstances of the presentation raise the possibility of a generalized vasospastic predisposition that is responsible for both events. Smoking, the only known major risk factor other than atherosclerosis, was noted to be temporally related to both events in our patient.

[Acute embolization into the veins in the splanchnic bed--an overview of current methods of diagnosis and therapies]

Acute mesentery artery embolization is a rare diagnosis. In case of late recognition the mortality may reach up to 93%. Acute abdominal pain, vomitus, rapid and sudden bowel evacuation with or without blood are the typical symptoms of the disease. Unfortunately, the symptoms do not often correlate with clinical findings. Plain X-ray of abdomen or CT tomography may show no signs of intestinal ischaemia. The diagnostic method to choose is either spiral CT angiography or contrast angiography, respectively. The most common therapeutical approach is surgical revascularization but in selected cases it is feasible to perform local thrombolysis with a microcatheter placed directly into the occluded artery. Papaverin vasodilatation and intravenous anticoagulation are also justifiable, catheter aspiration and stent implantation have also been challenged. Our review is to provide a detailed up-to-date information about the issue and is an extensive follow-up of our recently published case report [Superior mesentery artery embolization as a complication of the primary angioplasty solved by local thrombolysis. Vnitr Lék 2008; 54(9): 871-875].

Adult nesidioblastosis. Clinicopathologic correlation between pre-operative selective arterial calcium stimulation studies and post-operative pathologic findings

CONTEXT

Adult nesidioblastosis, a rare form of abnormal islet cell proliferation arising from the pancreatic ductal epithelium, is usually associated with severe hyperinsulinemic hypoglycemia. Overall, seventy-three cases of nesidioblastosis have been described in the English literature since the entity was first described by Laidlaw in 1938, and only a minute fraction of these have occurred in children.

CASE REPORT

We present the case of a previously healthy 45-year-old woman with new-onset severe hypoglycemia 4 and seizures. The differential diagnosis at presentation included factitious hypoglycemia and insulinoma. Extensive imaging and laboratory examination, including repeated CT and MRI scans, toxicology assays, and insulin-based chemical studies, were either inconclusive or negative. Subsequent testing involved stimulation of the pancreas through cannulation of the pancreatic vascular supply by interventional radiology. This testing revealed marked insulin release to low-level calcium challenge across multiple pancreatic segments. Based on these functional radiological findings, the patient underwent subtotal pancreatectomy. Gross and histologic examination of the resected tissue revealed no evidence of a pancreatic mass. Diffuse islet cell hyperplasia was noted in a pattern consistent with nesidioblastosis. The patient remained normoglycemic in the months following partial pancreatectomy.

CONCLUSIONS

Nesidioblastosis, while exceedingly rare in adult populations, should be considered in the differential diagnosis of severe hypoglycemia. This diagnosis cannot be easily made through routine diagnostic laboratory or radiological procedures and likely requires a histological tissue diagnosis.

Time- and dose-related regional fluxes of tissue-type plasminogen activator in anesthetized endotoxemic pigs

BACKGROUND

Acute endotoxinemia elicits an early fibrinolytic response. This study analyzes the effects of the dose and duration of endotoxin infusion on arterial levels of tissue-type plasminogen activator (tPA) and pulmonary, mesenteric and hepatic plasma tPA fluxes.

METHODS

Pigs were randomized to receive an acute, high-dose (for 6 h, n=13, high ETX) or a prolonged, low-dose (for 18 h, n=18, low ETX) infusion of endotoxin or saline vehicle alone (for 18 h, n=14, control). All animals were fluid resuscitated to maintain a normodynamic circulation. Systemic and regional blood flows were measured and arterial, pulmonary arterial, portal and hepatic venous blood samples were analyzed to calculate regional net fluxes of tPA. Plasma tumor necrosis factor (TNF-alpha) levels were analyzed.

RESULTS

Mesenteric tPA release and hepatic uptake increased maximally at 1.5 h in ETX groups related to dose. Maximal mesenteric tPA release [high ETX 612 (138-1185) microg/min/kg, low ETX 72 (32-94) microg/min/kg, median+/-interquartile range] and hepatic tPA uptake [high ETX -1549 (-1134 to -2194) microg/min/kg, low ETX -153 (-105 to -307) microg/min/kg] correlated to TNF-alpha levels. Regional tPA fluxes returned to baseline levels at 6 h in both ETX groups and also remained low during sustained low ETX. No changes were observed in control animals.

CONCLUSIONS

Endotoxemia induces an early increase in mesenteric tPA release and hepatic tPA uptake related to the severity of endotoxemia. The time patterns of changes in mesenteric and hepatic tPA fluxes are similar in acute high-dose endotoxemia and sustained low-dose endotoxemia.

Hemodynamic responses elicited by systemic injections of flavin adenine dinucleotide in anesthetized rats

Flavin adenine dinucleotide (FAD) elicits an endothelium-dependent vasodilation in isolated rat mesenteric beds via activation of P2Y-purinoceptors. The aims of this study were to characterize the hemodynamic responses elicited by systemic injections of FAD and flavin mononucleotide (FMN) in anesthetized rats and to determine the role of nitric oxide synthase (NOS), cyclooxygenase, P2Y/P2X-purinoceptors, and muscarinic receptor in these responses. FAD (0.05-1.0 micromol/kg, iv) elicited dose-dependent decreases in heart rate (HR), mean arterial blood pressure (MAP), and hindquarter vascular resistance (HQR), whereas it elicited an initial increase and then a decrease in mesenteric (MR) vascular resistance. The FAD-induced responses were not affected by the P2Y/P2X-purinoceptor antagonist suramin, the muscarinic receptor antagonist methyl-atropine, or the cyclooxygenase inhibitor indomethacin. The vasodilator actions of FAD were unaffected by the NOS inhibitor N-nitro-L-arginine methyl ester (L-NAME), whereas the bradycardia elicited by higher doses of FAD were diminished by L-NAME. FMN did not elicit hemodynamic responses in the absence or presence of L-NAME. In summary, FAD-induced bradycardia depends, in part, on the activation of NOS, whereas the vasodilator actions of FAD are not obviously due to newly synthesized nitrosyl factors. These findings and those in our companion manuscript support the concepts that the adenine moiety confers biological activity to FAD, which releases preformed pools of nitrosyl factors.

Characterization of a novel and potent collagen antagonist, caffeic acid phenethyl ester, in human platelets: In vitro and in vivo studies

OBJECTIVE

Caffeic acid phenethyl ester (CAPE), which is derived from the propolis of honeybee hives, has been demonstrated to possess multiple pharmacological activities. In the present study, CAPE (6-25 microM) specifically inhibited collagen-induced platelet aggregation and the ATP release reaction in platelet suspensions.

METHODS

Platelet aggregation, flow cytometric analysis, immunoblotting, and electron spin resonance (ESR) were used to assess the anti-platelet activity of CAPE. Fluorescein sodium-induced platelet thrombi in mesenteric microvessels of mice were used for an in vivo study.

RESULTS

CAPE (15-100 microM) produced a concentration-related rightward displacement of the collagen concentration-response curve, and the Schild plot gave pA(2) and pA(10) values of 4.28+/-0.07 and 3.14+/-0.73, respectively, with a slope of -0.83+/-0.16, indicating specific antagonism. CAPE (25 microM) also inhibited platelet aggregation stimulated by the glycoprotein VI agonist, convulxin, and the alpha(2)beta(1) integrin agonist, aggretin. CAPE (25 microM) also markedly interfered with FITC-collagen binding to platelet membranes. CAPE (15 and 25 microM) concentration-dependently inhibited collagen-induced platelet activation accompanied by [Ca(+2)](i) mobilization, phosphoinositide breakdown, activation of protein kinase C and mitogen-activated protein kinases (i.e., ERK2, JNK, and p38 MAPK), Akt phosphorylation, and thromboxane A(2) formation. In the ESR study, CAPE (15 and 25 microM) markedly reduced hydroxyl radical (OH) formation in collagen-activated platelets. In an in vivo study, CAPE (5 mg/kg) significantly prolonged the latency in inducing platelet plug formation in mesenteric venules of mice.

CONCLUSIONS

The most important findings of this study suggest that CAPE specifically inhibits collagen-induced platelet activation. Thus, CAPE treatment may represent a novel approach to lowering the risk of or improving function in thromboembolism-related disorders.

Survival in nonocclusive mesenteric ischemia: early diagnosis by multidetector row computed tomography and early treatment with continuous intravenous high-dose prostaglandin E(1)

OBJECTIVES

The aim of the study was to establish a procedure for early diagnosis and treatment of nonocclusive mesenteric ischemia (NOMI).

BACKGROUND

NOMI has a high mortality rate, and early diagnosis and treatment are important for improving survival in patients with this condition.

METHODS

The subjects were 22 patients treated at our hospital over 13 years. Diagnostic criteria for NOMI were established based on the first 13 cases. In the 9 more recent cases, we performed abdominal contrast multidetector row computed tomography (MDCT) upon suspicion of NOMI based on these criteria. Imaging allowed definite diagnosis of NOMI, and continuous intravenous high-dose PGE1 administration was initiated immediately after diagnosis (dose, 0.01-0.03 microg/kg per min; mean administration period, 4.8 days).

RESULTS

Nine of the first 13 patients died of multiple organ failure associated with multiple intestinal necrosis. These cases suggested that NOMI may develop when 3 of the following 4 criteria are met after cardiovascular surgery or maintenance dialysis in elderly patients: symptoms of the ileus develop slowly from abdominal symptoms, such as an unpleasant abdominal feeling or pain; a requirement for catecholamine treatment; an episode of hypotension; and slow elevation of the serum transaminase level. In the 9 recent cases, definite diagnosis was made from spasm of the principal arteries in arterial volume rendering and curved planar reformation MDCT images. Early treatment with PGE1 prevented acute-stage NOMI in 8 of the 9 cases.

CONCLUSIONS

Early diagnosis of NOMI is possible using the above criteria and MDCT, and initiation of PGE1 treatment may increase survival in patients with NOMI.

Determinants of mortality and treatment outcome following surgical interventions for acute mesenteric ischemia

BACKGROUND

Acute mesenteric ischemia (AMI) is associated with high morbidity and mortality due in part to its diagnostic difficulty and operative challenges. The purpose of this study was to review our experience of surgical management in patients with this condition and to identify variables associated with adverse outcomes following surgical interventions.

METHODS

Hospital records and clinical data of all patients undergoing surgical interventions for AMI were reviewed during a recent 12-year period. Clinical outcomes as well as factors influencing mortality were analyzed.

RESULTS

A total of 72 patients (41 females, overall mean age 65 years, range 34 to 83 years) were included in the study. Thrombosis and embolism were the cause of AMI in 48 patients (67%) and 24 patients (33%), respectively. Abdominal pain was the most common presenting symptom (96%), followed by nausea (56%). Preoperative angiogram was performed in 61 patients (85%). All patients underwent operative interventions, which included thromboembolectomy (n = 22, 31%), mesenteric bypass grafting (n = 33, 46%), patch angioplasty (n = 9, 12%), reimplantation (n = 5, 7%), and endarterectomy (n = 3, 4%). Bowel resection was necessary in 22 patients (31%) during the initial operation, and second-look operation was performed in 38 patients (53%). Perioperative morbidity and 30-day mortality rates were 39% and 31%, respectively. Univariate analysis showed renal insufficiency (P < .02), age >70 (P < .001), metabolic acidosis (P < .02), and symptom duration (P < .005), and bowel resection in second-look operations (P < .01) were associated with mortality. Logistic regression analysis showed age >70 (P = .03) and prolonged symptom duration (P = .02) were independent predictors of mortality.

CONCLUSIONS

Elderly patients and those with a prolonged duration of symptoms had worse outcomes following surgical intervention for AMI. A high index of suspicion with prompt diagnostic evaluation may reduce time delay prior to surgical intervention, which may lead to improved patient survival. Aggressive surgical intervention should be performed as promptly as possible in patients once the diagnosis of AMI is made.

Possible involvement of insulin, endogenous opioids and calcitonin gene-related peptide in remote ischaemic preconditioning of the brain

The present study has been designed to investigate the role of insulin, endogenous opioids and calcitonin gene related peptide (CGRP) on remote mesenteric ischaemic preconditioning induced reversal of global cerebral ischaemia-reperfusion injury in mice. Bilateral carotid artery occlusion of 10 min followed by reperfusion for 24 hour was employed in present study to produce ischaemia and reperfusion induced cerebral injury in mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Short-term memory was evaluated using elevated plus maze. Inclined beam walking and resistance to lateral push response, tests were employed to assess motor incoordination. Bilateral carotid artery occlusion followed by reperfusion produced cerebral infarction and impaired short-term memory, motor co-ordination and lateral push response. A preceding episode of mesenteric artery occlusion for 15 min and reperfusion of 15 min (remote mesenteric ischaemic preconditioning) prevented markedly, ischaemia-reperfusion-induced cerebral injury measured in terms of infarct size, loss of short-term memory, motor coordination and lateral push response. Anti-insulin serum, naloxone (an opioid receptor antagonist) and alpha-CGRP (8-37) (a selective CGRP receptor blocker) attenuated the neuroprotective effect of remote mesenteric ischaemic preconditioning. It may be concluded that neuroprotective effect of remote mesenteric ischaemic preconditioning probably is mediated through insulin, endogenous opioids and CGRP released as a consequence of mesenteric ischaemia and reperfusion in mice.

Acute gastrointestinal distress syndrome in patients with systemic lupus erythematosus

Cases of mesenteric vasculitis in systemic lupus erythematosus (SLE) are well described, however, individual patient with recurrent mesenteric vasculopathy producing repeated episodes with each exacerbation similar in character and quality has not been reported previously in the literature. We describe two SLE patients whose condition was complicated by repeated stereotypic, CT confirmed, episodes of lupus enteritis characterized by dramatic intestinal wall edema. Moreover, each flare was accompanied by significant hypocomplementemia and was rapidly reversible suggesting an acute gastrointestinal distress syndrome (AGDS) as a result of leukoaggregation and a gut capillary leak syndrome.

Adiponectin is a novel humoral vasodilator

OBJECTIVES

Perivascular adipose tissue secretes an adipocyte-derived relaxing factor(s) (ADRF) that opens K(v) channels in rat arteries. Visceral fat accumulation causes adipocyte dysfunction, including hyposecretion of adiponectin. We tested the hypothesis that ADRF might be adiponectin and that adiponectin plays a role in the paracrine control of vascular tone by perivascular adipose tissue.

METHODS AND RESULTS

We studied Sprague-Dawley rats, wild-type and adiponectin gene-deficient (Apn 1-/-) mice, and New Zealand obese (NZO) mice. In rat aortas, recombinant adiponectin at serum levels (2-5 microg/ml) inhibited serotonin-induced contractions. The effects were abolished by K(v) channel inhibition with 4-aminopyridine (4-AP, 2 mM). Similar effects were observed in NZO mouse mesenteric arteries. To study vascular function in Apn 1-/- mice, the mesenteric vascular bed was isolated, cannulated, and perfused at a constant 4-5-ml/min flow in the absence and presence of serotonin. 4-AP (2 mM) induced a similar increase in perfusion pressure in the Apn 1-/- perfused isolated mesenteric vascular bed, compared to wild-type mice. Removal of perivascular fat increased the vasoconstrictor responses, but abolished the 4-AP effects. The anti-contractile effects of perivascular fat were similar in mesenteric artery and aortic rings from Apn 1-/- and wild-type mice. Despite high adiponectin levels, the anti-contractile effects of perivascular fat were diminished in mesenteric arteries of NZO mice with age.

CONCLUSION

Adiponectin is a novel humoral vasodilator that relaxes aortic and mesenteric rings by opening K(v) channels. Similar to the rat, perivascular adipose tissue of the mouse harbors an ADRF, which is malfunctional in NZO mice and is not adiponectin.

Differential effects of ET(A) and ET(B) receptor antagonism on oxidative stress in type 2 diabetes

Endothelin (ET-1) is chronically elevated in diabetes. However, role of ET-1 in increased oxidative stress in type 2 diabetes is less clear. This study tested the hypotheses that: 1) oxidative stress markers are increased and total antioxidant capacity is decreased in diabetes, and 2) activation of ET(A) receptors mediates oxidative stress whereas ET(B) receptors display opposing effects. Plasma total antioxidant status (TAS) and 8-isoprostane (8-iso PGF(2alpha)) as well as total nitrotyrosine levels in mesenteric resistance vessels were measured in control Wistar and diabetic Goto-Kakizaki (GK) rats (n=5-10) treated with vehicle, ET(A) antagonist (atrasentan, 5 mg/kg/day), or ET(B) receptor antagonist (A-192621, 15 or 30 mg/kg/day, low and high dose, respectively) for 4 weeks. 8-iso PGF(2alpha) (pg/ml) levels were significantly higher in low dose A-192621 treatment groups of control and diabetic rats than in atrasentan or high-dose A-192621 treated groups. Protein nitration was increased in diabetes and ET(A) receptor antagonism prevented this increase. TAS levels were similar in all experimental groups. Thus, ET-1 contributes to oxidative stress in type 2 diabetes and ET receptor antagonism with atrasentan or A-192612 displays differential effects depending on dose and receptor subtype.

Definitive role for natriuretic peptide receptor-C in mediating the vasorelaxant activity of C-type natriuretic peptide and endothelium-derived hyperpolarising factor

OBJECTIVE

C-type natriuretic peptide (CNP) has recently been suggested to represent an endothelium-derived hyperpolarising factor (EDHF) in the mammalian resistance vasculature and, as such, important in the regulation of local blood flow and systemic blood pressure. Additionally, this peptide has been shown to protect against ischaemia-reperfusion injury and inhibits leukocyte and platelet activation. Herein, we use a novel, selective natriuretic peptide receptor-C (NPR-C) antagonist (M372049) to highlight the pivotal contribution of CNP/NPR-C signalling in the EDHF-dependent regulation of vascular tone and investigate the mechanism(s) underlying the release and biological activity of CNP.

METHODS

In vitro pharmacological investigation was conducted in rat (Sprague-Dawley) aorta and mesenteric resistance arteries. Relaxant responses to CNP, atrial natriuretic peptide (ANP), the nitric oxide donor spermine-NONOate (SPER-NO) and the endothelium-dependent vasodilator, acetylcholine (ACh) were examined in the absence and presence of M372049 or inhibitor cocktails shown previously to block endothelium-dependent dilatation in the resistance vasculature. RT-PCR was employed to characterize the expression of NPR subtypes in the vessels studied.

RESULTS

M372049 produced concentration-dependent inhibition of the vasorelaxant activity of CNP in rat isolated mesenteric resistance arteries but not aorta; in contrast, M372049 did not affect relaxations to ANP or SPER-NO in either vessel. M372049 or ouabain alone produced small, significant inhibition of EDHF-dependent relaxations in mesenteric arteries and in combination acted synergistically to abolish such responses. A combination of M372049 with established inhibitors of EDHF-dependent relaxation revealed that multiple, distinct pathways coordinate the bioactivity of EDHF in the resistance vasculature, and that CNP/NPR-C signalling represents a major component.

CONCLUSIONS

These data substantiate CNP/NPR-C signalling as a fundamental pathway underlying EDHF-dependent regulation of vascular tone in the rat mesenteric resistance vasculature. An increased understanding of the physiological roles of CNP/NPR-C signalling in the vasculature (now facilitated by the identification of a selective NPR-C antagonist) should aid determination of the (patho)physiological importance of EDHF and might provide the rationale for the design of novel therapeutics.