Occlusion of the Modified Blalock–Taussig Shunt: Unique Methods of Treatment and Review of Catheter‐based Intervention

Objective. To report unique methods of treatment and review catheter‐based intervention for occluded modified Blalock–Taussig shunts (BTS). Methods. Case reports and articles involving children undergoing catheter‐based treatment for occluded modified BTS were reviewed. Results. Literature review detailed 38 patients in whom occluded modified BTS were treated with 39 catheter‐based interventions. Thrombolytics alone were delivered by catheter in 13 cases. Balloon angioplasty was performed in 23 cases, 5 with stent implantation. Both thrombolytic delivery and angioplasty were performed in 3 cases, 2 with stent implantation. Intervention was initially successful at re‐establishing modified BTS patency in 35/39 (90%) of cases. Patency could not be established in 2 patients who then proceeded to the operating for surgical shunt revision. Two deaths occurred during the procedures. Three cases at Emory University demonstrate uncommon or unique instances of catheter‐based intervention: (1) declotting of a shunt in a patient supported by extracorporeal membrane oxygenation (ECMO); (2) declotting of a shunt via a right axillary arterial approach; and (3) declotting of a shunt using a carotid arterial (ECMO) cannula for percutaneous access. Conclusions. The use of catheter‐based techniques for the treatment of BTS occlusion is highly successful, and potentially avoids high‐risk re‐operative intervention. ECMO can provide for a stable patient during the procedure. Hopefully, with improved technology and innovative procedures, more children in the future with BTS occlusion can be served by successful percutaneous intervention.     

The incidence of deep vein thrombosis and pulmonary embolism with the elective use of external fixators

Little evidence exists about the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) with the use of external fixators. We investigated this in a cohort of 207 consecutive patients undergoing 258 elective frame applications by case note review. Case notes were obtained for 84 % of the sample population. The type of surgery, demographic data, thromboembolic risk factors and the incidence of DVT/PE were recorded. One patient experienced DVT (0.39 %) and one a PE (0.39 %). Both were of high risk and had received mechanical and chemical thromboprophylaxis during their inpatient stay. These complications were identified at least 3 months post-operatively. These findings help to more accurately counsel patients undergoing elective frame surgery on the risks of DVT/PE and also contribute to the discussion between surgeons about whether or not extended course chemical thromboprophylaxis would be of overall benefit.     

Acute celiac trunk thrombosis revealed by biliary peritonitis

Acute thrombosis of the celiac trunk is a very uncommon condition, which is a life-threatening emergency. The clinical presentation is highly variable depending on the extent of the ischemic territory. We report a case of biliary peritonitis related to an acute thrombosis of the celiac trunk. This case highlights the role of abdominal computed tomography in the diagnosis of acute upper abdominal pain.     

中性粒细胞外陷阱在血栓形成中的作用及研究进展

血栓性疾病严重危害人群健康。中性粒细胞外陷阱作为中性粒细胞的固有免疫机制之一,在帮助机体抵御病原体之外还可通过其结构的支架作用和组分的凝血激活作用促进血栓形成,并在动静脉血栓、抗凝脂综合征以及肿瘤相关血栓的动物疾病模型、人类血栓样本和体外实验中得到了证实。主要介绍中性粒细胞外陷阱的形成机制,重点介绍中性粒细胞外陷阱与血栓形成的关联,以及在血栓性疾病和新型冠状病毒肺炎中作用,旨在为血栓防治相关研究提供参考。     

Cerebrovascular changes in the rat brain in two models of ischemia

BackgroundVascular occlusion and cyanide neurotoxicity induces oxidative stress and degeneration in the brain. This oxidant induced stress changes the vascular dynamics of cerebral blood vessels, and participates in homeostatic response mechanisms which balance oxygen supply to hypoxic stress-sensitive neurons. The associated changes in vascular morphology include remodeling of the microvasculature and endothelial changes, alterations in regional circulation and variations in the blood brain barrier (BBB). This study compares alterations in physiology of the cerebral artery after a short-term oxidative stress induced by cyanide toxicity and vascular occlusion.MethodAdult Wistar rats (N = 30) were divided into three groups; vascular occlusion (VO) (n = 12), potassium cyanide administration (CN) (n = 12) and Control-CO (n = 6). The CN rates were treated with 30 mg/kg of orally administered KCN while the VO was subjected to global vascular occlusion, both for a duration of 10 days, described as the treatment phase. Control animals were fed on normal rat chow and water for 10 days. At the end of the treatment phase, n = 6 animals in each of the VO, CN and VO groups were anesthetized with sodium pentobarbital (50IP) and the CCA exposed, after which pin electrodes were implanted to record the spikes form the tunica media of the CCA. After day 10, treatment was discontinued for these animals, each remaining in the VO and CN groups (VO-I and CN-I) until day 20 (withdrawal phase) following which the spikes were recorded using the procedure described above.Results/DiscussionVascular occlusion and cyanide toxicity increased vascular resistance in the MCA (reduced lumen thickness ratio) and increased the diameter of the CCA after the treatment phase of 10 days. After 10 days of withdrawal, the VO group showed a reduction in resistance and an increase in the lumen width/wall thickness ratio (LWR) while the CN group showed increased resistance and a reduction in LWR.ConclusionCyanide toxicity increased vascular resistance by inducing degenerative changes in the wall of the artery while vascular occlusion increased resistance through mechanical stress and increased thickness of arterial wall. After the withdrawal phase, vascular resistance diminished in the VO to a significantly greater extent than the CN.     

Frequency of and factors associated with vascular complications after pediatric liver transplantation

Objectiveto evaluate the frequency and factors associated with vascular complications after pediatric liver transplantation.Methodrisk factors were evaluated in 99 patients under 18 years of age with chronic liver disease who underwent deceased donor liver transplantation (DDLT) between March of 1995 and November of 2009 at the Hospital de Clínicas de Porto Alegre, Brazil. The variables analyzed included donor and recipient age, gender, and weight; indication for transplant; PELD/MELD scores; technical aspects; postoperative vascular complications; and survival.Resultsvascular complications occurred in 19 patients (19%). Arterial events were most common, occurred earlier in the postoperative period, and were associated with high graft loss and mortality rates. In the multivariate analysis, the following factors were identified: portal vein diameter ≤ 3 mm, donor‐to‐recipient body weight ratio (DRWR), prolonged ischemic time, and use of arterial grafts.Conclusionthe choice of treatment depends on the timing of diagnosis; however, in this study, surgical revision or correction produced worse outcomes than percutaneous angioplasty. The reduction of risk factors and early detection of vascular complications are key elements to a successful transplantation.     

Thrombotic complications associated with stem cell transplantation

Thrombotic complications are common in stem cell transplantation (SCT) recipients and endothelial cell injury is a dominant contributing factor to the hemostatic impairments. Endothelial cells line the vascular bed and each vascular bed has a unique structural and functional properties. Therefore, understanding of these properties may hold important clues to site-specific diagnostics and therapeutics. The two most common thrombotic manifestations related to SCT, veno-occlusive disease (VOD) and thrombotic microangiopathy (TMA), are characterized by small vessel thrombosis in the microcirculation. In diffuse alveolar hemorrhage (DAH), although the clinical presentation is hemorrhagic, autopsy findings and mice experiments imply a thrombotic etiology. In the present review, the pathogenesis and treatment options of these three microcirculation thromboses are discussed.