The Experiment And Clinical Research Of Superior Mesenteric Venous Thrombosis

Objective:To summarize the experience in the diagnosis and management of SMVT and to assess the factors affecting the short-term outcome.To establish the model of SMVT in rats by ligation method. To observe the pathological physiological variation of the intestinal. To investigate the variation of OFR of Peripheral SMVT. To study the effect of LMWH administration on the intestinal microcirculation of SMVT rats with different time point.Methods:45patients of MVT in Tianjin Medical University General Hospital were reviewed from2000-2010. The Population characteristics,risk factors, clinical feature, examinations, treatment methods, prognosis were included.32rats were divided into group A:acute SMVT of Central type and group B: subacute SMVT of Central type。 The amples of intestinal wall were examined by light electron. The intestinal histopathology score were calculated.120rats were divided into group C:strangulated SMVT of peripheral type; group D:simple SMVT of peripheral type; group E:Sham operation group.The models of SMVT were established in rats by ligation method. At2h、8h、24h、48h、72h after operation, amples of intestinal wall and venous blood were obtained.amples of intestinal wall were examined by light and transmission electron microscopy. The TXB2、6-Keto-PGF1α、SOD、MDA were detected from the venous blood.56rats were divided into group L: LMWH group; group N:NS group; Sham operation group. strangulated SMVT models were set up. According to different time (Oh,12h,24h),L and N group were each divided into three subgroup randomly. Amples of intestinal wall were examined by light and transmission electron microscopy. The intestinal histopathology score were calculated.The effect was observed by detection the TXB2、6-Keto-PGF1α、SOD、 MDA in the venous blood at72h.Results:1、45patients were diagnosed MVT.25patients were male,20patients were female,median age52.6years.The main symptoms at the presentation were abdominal pain, abdominal distension,vomiting, bloody stool and fever.Enhancement CT is the most sensitive means.33patients were treated with anticoagulation and12patients were treated with operration.6patients died in30days.2、All the rats in group A died from4h to6h and the median survival was5.6h. Histological examinations:the extravasated blood in the each layer was found and the thrombus didn’t arise in the mesenteric venous.3、The rats in group B tolerated the operation and survival by the7d.The collateral circulation developed around the proximal of the superior mesenteric venous and the pancresticoduodenal veins.The extravasated blood was observed by histological examinations, no necrosis in smooth musle happened.4、Histological examinations in group C:the extravasated blood was observed at2h、8h; The serious mucosa necrosis was found at24h;Partly necrosis in smooth musle was found at48h,and the thrombus has arisen in the mesenteric venous;Destruction and necrosis was found in the each layer of intesinal at72h;All the rats died from76h to82h and the median survival was78.3h.5、Histological examinations in group D:The extravasated blood was observed at2h、8h; The mild mucosa necrosis was found at24h;The injuries was resricted in the mucosa and submucosa at48h、72h and no necrosis in smooth musle;The thrombus arised in the mesenteric venous at48h.6、Ultrastructural observation:Group C:blood stasis was found at2h;The leukocyte sticking along venular wall was found and the blood leaked out from the veins at8h; Large amount of micro thrombus formed at24h; The wide range of micro thrombus formed and the smooth musle cells rupture at48h; Lamellar hemorrhage and necrosis of intesinal could be observed at72h. Group D:Blood stasis was found at2h; Mitochondrion became vacuolization at8h;A few micro thrombus formed at24h; The injuries did not arise at48h; The injuries degraded gradually and few micro thrombus was found at72h.7、The results showed:the content of TXB2in group C steped up with the prolongation of the time after operation.and the content was accordingly higher than that in groupB (P<0.05). The content of TXB2in group D steped up before24h,and then degraded gradually.The content of6-Keto-PGF1α、MDA in groupC and group D steped up with the prolongation of the time after operation,and the content of group C was accordingly higher than that in groupB (P<0.05). The content of SOD in groupC signfacanly steped up temporarily after operation,and then degraded gradually. The content of SOD in groupD signfacanly steped up temporarily after operation,and degrade gradually before24h,and then restored after24h.7、The intestinal injuries of Group L0h、Group L12h restored. The content of TXB2、6-Keto-PGF1α、MDA degraded and the content of SOD rised.Conclusion:1、The imaging diagnosis has a higher acuracy in the central SMVT than the peripheral SMVT. The Peripheral SMVT has a greater chance of peritonitis、intestinal necrosis and having surgery.The range of bowel necrosis in the central SMVT is more abroad.2、It is difficult of CT to find venule thrombosis and it is important to continuous observation.3The patients of symptoms in3days short have a poorer prognosis and is apt to have surgery.4、The models of SMVT by ligation method is suitable to the studies of intestinal pathophysiology.5、The SMVT of peripheral type is apt to circulatory failure; The SMVT of central type is apt to intestinal injuries.6、Hemorrhagic ascites does not mean bowel necrosis;Bloody stool means injureis of the mucosa and submucosa.7、The injury of blood stagnation and microcirculatory disturbance are the principal factors of intestinal injuries. Large amount of micro thrombus make the intestinal circulation more serious and lead to bowel necrosis.8、SMVT leads to the lack proportion of TXA2/PGI2and make the micro circulation more serious.9、 OFR play a vital role on the generation and evolution of SMVT,The level of MDA and SOD is significant judgment criteria to the intestinal injury.10、The earlier LMWH administration can reduce the level of TXA2、PGI2and reduce the pathological injury to SMVT rats.11、The earlier LMWH administration can raise the level of SOD and reduce the level of MDA.It illusstrates that LMWH can resist to the oxidation and inflammation12、Earlier anti-coagulation can improve the results.By the time of24h,it can’t reverse the bowel necrosis.