Hemodynamic effects of glucagon after acute mesenteric ischemia in rats

We have previously shown that iv glucagon improved survival in rats from 33 to 83% when given after, but not during, superior mesenteric artery (SMA) occlusion. This study investigated potential hemodynamic mechanisms of this effect. In Part 1, cardiac output (CO) was measured in 12 male Sprague-Dawley rats with an electromagnetic flow-probe that had been placed around the ascending aorta 5 days previously. Under pentobarbital anesthesia, the SMA was occluded for 85 min. All rats received normal saline (NS, 15 ml/kg/hr) for 1 hr before and after SMA declamping. Control rats (n = 6) received only NS. Treated rats (n = 6) received NS plus glucagon (1.6 micrograms/kg/min iv) for 1 hr postocclusion. CO decreased 50% during the first hour after SMA declamping in control rats, but only 11% in glucagon-treated rats (P less than 0.02). Systemic vascular resistance (SVR) increased by 90% in control rats by 1 hr after declamp, but only 9% in glucagon rats (P less than 0.04). Systemic blood pressure and heart rate were not different in the two groups. In Part 2, relative distribution of visceral blood flow was measured with radiolabeled microspheres injected in the aortic root before clamping, before declamping, and 1 hr postdeclamping in 10 rats (5 glucagon, 5 control) using the above protocol. After SMA clamping, the proportion of visceral blood flow distributed to the intestine fell from 45 to 20% (P less than 0.05). During reperfusion, the proportion of intestinal flow exceeded baseline (P less than 0.05), but was not different in control (64%) and glucagon-treated rats (56%).(ABSTRACT TRUNCATED AT 250 WORDS)     

The correlation of the D-dimer test and biphasic computed tomography with mesenteric computed tomography angiography in the diagnosis of acute mesenteric ischemia

Background

Early diagnosis is the main factor to improve the outcome of acute mesenteric ischemia (AMI). The goal of this study was to assess the correlation of the D-dimer test and biphasic computed tomography (CT) with mesenteric CT angiography for the diagnosis of AMI.

Methods

Selected consecutive patients with a clinical suspicion of AMI were admitted to the study. Blood samples were taken before biphasic CT with mesenteric CT angiography examination.

Results

The sensitivity and specificity values of biphasic CT with mesenteric CT angiography were 92.9% and 89.5%, respectively. The sensitivity and specificity of D-dimer testing for the diagnosis of AMI were 94.7% and 78.6%, respectively. D-dimer levels higher than 3.17 μg fibrinogen equivalent units/mL were more specific (P < .0001) and acted similarly to the biphasic CT with mesenteric CT angiography in the diagnosis of AMI.

Conclusions

In the setting of early diagnosis of AMI, the D-dimer test may improve our ability to diagnose patients in whom we cannot use multidetector row CT with CT angiography.     

门静脉高压症患者分流术围手术期血浆中NO及内皮素-1水平变化的意义

目的：了解肝硬化门静脉高压症患者分流术围手术期血浆中NO及内皮素-1（endothelin-1，ET一1）水平变化的意义。方法：用Griess法测外周血血浆中NO代谢产物N03-浓度，用放射免疫方法测定ET-1浓度，并测术中及术后各时相的门静脉压力。结果：手术前后肝硬化门静脉高压组患者外周血NO及ET-1浓度与单纯肝硬化组及对照组比较差异均有统计学意义（P〈0．05）。肝硬化门静脉高压组手术前后NO及ET-1水平下降与门静脉压下降均呈正相关（P〈0．05）。结论：远端脾肾分流术可刚氐门静脉压力，NO及ET-1水平的增高可能对门静脉血管阻力的增加有影响，NO及ET-1在肝硬化门静脉高压症的形成中有重要意义。     

葛根素对家兔肝缺血再灌注一氧化氮、内皮素-1的影响

目的观察一氧化氮(NO)、内皮素-1(ET-1)在家兔肝缺血再灌注损伤过程中的变化及葛根素(Pur)对其的影响。方法实验家兔随机分为3组:对照组(C组,n=10)、缺血再灌注组(IR组,n=10)和葛根素治疗组(Pur组,n=10)。分别测定缺血前,缺血第45分钟及再灌注第45分钟时肝组织NO,ET-1含量,用电镜观察家兔HIRI及经Pur保护后的肝组织形态学改变。结果家兔缺血再灌注第45分钟时,与C组、Pur组比较:IR组血浆及组织NO含量均明显较低(P<0.01,P<0.05);IR组血浆及组织ET-1含量明显较高(P<0.01,P<0.05);与IR组比较,Pur组肝组织超微结构明显改善。结论葛根素可通过调节机体NO和ET-1水平而对肝缺血再灌注损伤发挥积极的保护作用。     

Diagnosis and management of acute mesenteric ischemia

The prevalence of significant splanchnic arterial stenoses is increasing, but remains mostly asymptomatic due to abundant collateral circulation. Acute insufficiency of mesenteric arterial blood flow accounts for 60 to 70% of cases of mesenteric ischemia and results mostly from a superior mesenteric embolus. Despite major advances have been achieved in understanding the pathogenic mechanisms of bowel ischemia, its prognosis remains dismal with mortality rates about 60%. The diagnosis of acute mesenteric ischemia depends upon a high clinical suspicion, especially in patients with known risk factors. Rapid diagnosis is essential to prevent intestinal infarction. However, early signs and symptoms of mesenteric ischemia are non specific, and definitive diagnosis often requires radiologic examinations. Early and liberal implementation of angiography has been the major advance over the past 30 years which allowed increasing diagnostic accuracy of acute mesenteric ischemia. CT and MR-based angiographic techniques have emerged as alternatives less invasive and more accurate to analyse splanchnic vessels and evaluate bowel infarction. The goal of treatment of patients with acute mesenteric ischemia is to restore intestinal oxygenation as quickly as possible after initial management that includes rapid hemodynamic monitoring and support. Surgery should not be delayed in patients suspected of having intestinal necrosis.     

D-dimer in the early diagnosis of acute mesenteric ischemia secondary to arterial occlusion in rats

BACKGROUND: Early diagnosis of mesenteric ischemia can be life saving. The aim of this study is to investigate the time-dependent diagnostic value of plasma D-dimer and other ancillary laboratory evaluations such as creatine phosphokinase, lactic dehydrogenase, aspartate aminotransferase, alanine aminotransferase, amylase, and leukocyte count in an experimental superior mesenteric arterial occlusion (SMA-O) model in rats. METHODS: Forty male Wistar-Albino rats were separated into 4 groups: 2-, 4-, 6-, and 12-hour SMA-O groups. After laparotomy, the SMA was identified and ligated for 2, 4, 6 and 12 h in the 4 respective study groups. Blood samples were taken for laboratory tests 2 h after laparotomy in the control group and at the end of the ischemic period in the study groups. RESULTS: The longer the duration of mesenteric ischemia, the higher were the serum D-dimer levels in the study groups, and statistical significance was obtained at 2 h (p = 0.021). Sensitivity, positive predictive value, negative predictive value, and accuracy of the relation were 88.8, 88.8, 100 and 90%, respectively. Leukocyte count was significantly higher than controls after 12 h. No other laboratory parameter correlated positively with the duration of mesenteric ischemia. CONCLUSION: Serum D-dimer measurements may be a valuable diagnostic parameter in the early diagnosis of mesenteric ischemia.     

急诊疑似肠系膜动脉缺血病人血浆D-二聚体的检测及临床意义

急性肠系膜动脉缺血（acute mesenteric artery ischemia，AMAD是外科急腹症之一，约占急腹症总数的1％。该病起病急、发展快、预后差，病死率高达59％-93％121。早期诊断是提高其生存率的最重要因素。目前选择性动脉造影和螺旋CT造影对AMAI确诊率高，但对疑似AMAI的急腹症病人常规采用上述检查。既不方便又不经济，因此需寻求一种更简便、低廉、敏感的检查方法。我们对2003年3月-2005年10月收治的疑诊AMAI的急腹症病人进行前瞻性研究，以评价血浆D-二聚体检测对AMAI病人的诊断价值。     

Effect of intravenous glucagon on the survival of rats after acute occlusive mesenteric ischemia

The purpose of this study was to determine the optimal timing of intravenous glucagon infusion for the treatment of acute occlusive mesenteric ischemia. The superior mesenteric artery (SMA) was occluded for 85 min in 106 Sprague-Dawley anesthetized rats. The animals were divided into 12 treatment groups according to the timing of glucagon and saline administration, and survival was measured to 48 hr. Without treatment, all rats died within 24 hr. Intravenous saline (10 ml/kg/hr) for 2 hr did not significantly improve 48-hr survival (17-33%). Glucagon (1.6 micrograms/kg/min iv) plus saline (10 mg/kg/hr iv) for 2 hr after SMA occlusion significantly improved survival from 33% (saline control) to 83% (P less than 0.02). The same treatment begun 1 hr before SMA release (during ischemia) did not significantly improve survival (33% at 48 hr). Glucagon infusion during occlusive mesenteric ischemia was detrimental when added to effective postischemia treatment, reducing survival from 83 to 33% (P less than 0.02). Adequate saline infusion was required for glucagon efficacy after ischemia, as shown by an intermediate 48-hr survival of 50% when only maintenance saline (1.5 ml/kg/hr) was given. These data suggest that glucagon therapy should be delayed until after operative release of an acute SMA occlusion and should be accompanied by vigorous volume expansion.     

Successful management in the case of mesenteric ischemia complicated with acute type a dissection.

We report a case of acute type A dissection with ischemic enterocolitis due to blood flow insufficiency in the superior mesenteric artery. A 67 year-old man, with medicated ischemic heart disease and hypertension, presented to another hospital with chest pain radiating to the back and epigastrium. Contrast-enhanced computed tomography revealed a type A dissecting aneurysm, that extended from the ascending aorta to the left common iliac artery, with a 50-mm diameter in the ascending aorta. Celiac trunk and left renal artery arose from the false lumen, and the superior mesenteric artery (SMA) was compressed by the thrombosed false lumen. Symptoms of acute mesenteric ischemia clearly developed. Then, a large amount of tarry stool (melena) was discharged. First, an emergency saphenous vein bypass was performed from the common iliac artery to the superior mesenteric artery at the orifice of the ileocolic artery where it was free from dissection. Then total arch replacement was performed using cardiopulmonary bypass. The patient's postoperative course was uneventful, and the abdominal symptoms completely disappeared. This case demonstrates that prompt surgical relief of ischemia in major organs is important to save lives in the cases of acute aortic dissection with ischemic complications.     

���Գ�ϵĤѪ�ܹ�Ѫ��ȫ����Ϻ�����

目的 探讨急性肠系膜血管供血不全的诊断和治疗。方法 对1972年11月至1999年10月经治的20例急性肠系膜血管供血不全的临床资料进行回顾性分析。结果 该病多为高龄，常伴有心血管疾病和发生绞窄性肠梗阻，病死率很高（本组为45%）。结论 充分认识该病，选用恰当的检查技术，早期诊断，及时手术，是提高急性肠系膜血管供血不全治疗效果的关键。     

Pharmacologic treatment of occlusive mesenteric ischemia in rats

This study assessed the contribution of angiotensin II, oxygen-free radicals, and vasopressin to the mortality of acute mesenteric ischemia in rats. Rats received saline replacement (16 ml/kg/hr) for 3 hr during and after 85 min of superior mesenteric artery (SMA) occlusion. Only 21% of rats that received saline alone (n = 14, control) survived 48 hr, significantly less than the 100% survival of sham-operated rats (no SMA occlusion, n = 5, P less than 0.01). Neither teprotide (an angiotensin converting-enzyme inhibitor), allopurinol (to reduce oxygen-free radical formation), nor a specific vasopressin antagonist [1-(beta-mercapto-beta,beta-cyclopentamethyleneproprionic acid), 2-(O-methyl) tyrosine arginine-vasopressin] improved 48-hr survival, which was 17% in each group (n = 6, each). Survival improved significantly to 86% (n = 7, P less than 0.001) when intravenous glucagon (1.6 micrograms/kg/min) was given for 2 hr after SMA reperfusion. Survival after dopamine infusion (12 micrograms/kg/min iv) was 67% at 48 hr, a nearly significant improvement (n = 9, P less than 0.06). These results suggest that angiotensin II, oxygen-free radicals, and vasopressin do not contribute significantly to the high mortality observed after acute intestinal ischemia in this rat model, but that glucagon, and to a lesser extent, dopamine, are potentially therapeutic.     

大鼠急性肠缺血后血浆D-乳酸的变化及其与肠粘膜损害的关系

目的观察肠缺血再灌注时门、体循环Ｄ－乳酸的动态变化及其与肠粘膜损害的相关性。方法采用大鼠肠系膜上动脉阻断７５分钟后松夹进行重灌注的模型，分别于术前，阻断末，松夹后０．５，２，６小时活杀动物，观察门静脉和体循环Ｄ－乳酸水平、血浆内毒素含量及小肠病理形态学改变。结果肠缺血７５分钟后大鼠门静脉Ｄ－乳酸水平较伤前值显著上升（Ｐ＜０．０５），再灌注后呈进一步持续升高趋势。外周血Ｄ－乳酸的改变与门脉血基本一致，各时相点与门脉血含量相比差异无显著意义（Ｐ＞０．０５）。相关分析结果显示，门静脉血浆Ｄ－乳酸含量与肠粘膜损伤评分值呈显著正相关（ｒ＝０．４１５，Ｐ＜０．０１）。与此同时，大鼠肠缺血７５分钟门静脉内毒素含量迅速上升，再灌注后２小时达峰值。结论急性肠缺血再灌注可致肠粘膜屏障破坏，使门、体循环Ｄ－乳酸水平显著升高，其含量与小肠粘膜损害密切相关。因此，Ｄ－乳酸可作为新的血浆标志物应用于急性肠粘膜损害的早期诊断     

Early diagnosis in acute mesenteric ischemia. Case series and clinical review

The AA report on 12 cases of intestinal infarction for acute mesenteric ischemia (IMA) in critical patients observed in the last 2 years. In this work some clinical data, blood tests and strumental considerations are described. IMA is a vascular emergency with severe prognosis and high rate morbidity and mortality, often correlated to a diagnostic delay. The discrepancy between symptoms and clinical objectivity must suggest the suspect, especially in patients with cardiac pathology, short lasting diarrhoea, bowel hemorrhage or only abdominal pain rebel to the analgesics; with the laboratory indexes and strumental data it can be carried out an early diagnosis and then begin the more opportune therapeutical treatment. The increase of blood sugar together to the triad leucocytosis--haemoconcentration and metabolic acidosis, in previously non diabetic patients, confirm the suspect of IMA in the very initial phases of this pathology.     

Outcomes of antegrade and retrograde open mesenteric bypass for acute mesenteric ischemia

Background

Acute mesenteric ischemia (AMI) is a challenging clinical problem associated with significant morbidity and mortality. Few contemporary reports focus specifically on patients undergoing open mesenteric bypass (OMB) or delineate outcome differences based on bypass configuration. This is notable, because there is a subset of patients who are poor candidates for endovascular intervention including those with flush mesenteric vessel occlusion, long segment occlusive disease, and a thrombosed mesenteric stent and/or bypass. This analysis reviewed our experience with OMB in the treatment of AMI and compared outcomes between patients undergoing either antegrade or retrograde bypass.

急性肠系膜上动脉缺血37例诊治转归

目的 探讨急性肠系膜上动脉缺血的诊治方法,提高诊治水平.方法 回顾分析1996年1月至2007年8月收治的37例急性肠系膜上动脉缺血患者的临床资料,结合文献讨论其病因、诊断及治疗.结果 急性肠系膜上动脉栓塞19例(51.4%),急性肠系膜上动脉血栓形成15例(40.5%),孤立的肠系膜上动脉夹层2例(5.4%),肠系膜上动脉瘤1例(2.7%).急诊误诊19例(51.4%).院内死亡18例(48.6%),多死于重症感染和多器官功能衰竭.存活的19例中3例遗留严重后遗症(短肠综合征2例,脑出血1例).共9例患者获得随访,平均随访15个月,其间5例死亡.结论 急性肠系膜上动脉缺血病因多样,早期干预可显著改善患者预后.     

急性肠系膜血管缺血性疾病误诊分析

目的探讨急性肠系膜血管缺血性疾病的误诊原因、诊断和治疗.方法回顾性分析1965～1999年急性肠系膜血管缺血性疾病20例临床资料.结果20例均经病理证实.初诊时多因表现为急腹症、症状与体症不符和缺乏特异性检查而误诊.19例行手术治疗,其中11例治愈,8例死亡;另1例因误诊时间过长,未能及时手术,终导致死亡.结论该病少见,症状和体征无特异性,易造成误诊.选择性动脉造影和D-二聚体检测是较敏感的检查,对诊断有积极作用.早期适当范围切除坏死肠段和术后抗凝治疗是防止复发、降低病死率的重要措施.     

急性肠系膜血管缺血性疾病的早期诊断和治疗(附14例报告)

目的　探讨急性肠系膜缺血性疾病的早期诊断和治疗方法。方法　分析 1987年 1月- 2 0 0 1年 12月急性肠系膜缺血性疾病 14例临床资料。结果　急性肠系膜上动脉栓塞 6例 ,急性肠系膜上动脉血栓形成 3例 ,急性肠系膜上静脉血栓形成 4例 ,非血管阻塞性急性肠缺血 1例 ,均经病理证实。 10例有与腹部体征不相符的剧烈腹痛 ,6例存在慢性肠缺血表现。选择性肠系膜动脉造影确诊 1例 ,CT确诊 2例 ,11例为术中发现。 14例均行手术治疗 ,术后均行溶栓、抗凝治疗 ,9例治愈 ,5例死亡。结论　①器质性心脏病、动脉硬化、血栓等病史伴与腹部不相符的剧烈腹痛是急性肠系膜缺血性疾病的重要临床特征 ;②选择性动脉造影和CT是最有价值的诊断方法 ;③血管的再管化、必要的肠切除和术前、后抗凝及溶栓是提高疗效的重要保证 ;④出现慢性肠缺血表现时 ,预防性抗凝可能是降低死亡率的有效方法     

Analysis of the Correlation of Plasma NO and ET-1 Levels in Rats With Acute Mesenteric Ischemia

Mesenteric ischemia is a devastating disease process that frequently challenges clinicians. To enhance the early diagnosis of gut ischemia and judgment of its severity, it may be helpful to detect the unusual existence or increase in biomarkers in the body fluid. The aim of the present study was to evaluate the correlation of plasma nitric oxide (NO) and endothelin-1 (ET-1) levels to mesenteric ischemia using an animal model. Acute mesenteric ischemia (AMI) was produced experimentally by occlusion of the mesenteric vessels in the terminal ileum by the tenting of a thread. The determination of plasma NO and ET-1 levels were obtained before operation (T0, baseline value), and at 10 (T10), 20 (T20), 30 (T30), and 60 (T60) min after the creation of AMI. Sham-operated rats served as controls. After 30 min of experiments, the plasma NO and ET-1 levels were significantly higher in the AMI group than in the control group (both p <. 01). Both the plasma NO and ET-1 levels in AMI group increased significantly after 30 min of ischemia (both p <. 001 vs. respective baseline value), and they were 60% and 84% above the baseline value, respectively. In addition, ischemic intestinal injury was confirmed by the significantly elevated histological scores in the AMI group after 60 min of ischemia (p <. 001). Our preliminary results suggest the possibility of important insights regarding NO and ET-1 changes into the mechanism of pathogenesis in AMI in rats. The increases in plasma NO and ET-1 levels may potentially be noninvasive biomarkers for the early detection of this disease.