Reversible tonsillar prolapse in vein of Galen aneurysmal malformations: report of eight cases and pathophysiological hypothesis

We report eight cases of vein of Galen aneurysmal malformation (VGAM) assoicated with a Chiari type I malformation. In four cases magnetic resonance imaging (MRI) or computed tomography performed in the neonatal period did not demonstrate the posterior fossa anomaly, which appeared on later scans. In the other cases the MRI was performed in infancy and the anomaly was already present. We compared the venous phases of the posterior fossa angiograms and the MRI in these patients. In all eight cases, the angiograms showed a reflux in the cerebellar veins, via the petrous vein, associated with a uni-or bilateral stenosis or thrombosis of the distal posterior dural sinuses. Furthermore, in two cases the posterior fossa returned to normal on MRI following endovascular treatment, while in three cases the herniation of the cerebellar tonsils decreased after the embolization. Tonsillar prolapse becomes irreversible when the venous outlet is incapable of taking the flow even when the VGAM has been treated adequately. In eight additional cases of VGAM for which MRI and angiogram studies were available and in which stenosis or thrombosis of posterior dural sinuses was present without tonsillar prolapse, no reflux into the cerebellar veins was shown. We suggest that the posterior fossa hydrovenous congestion is a result of inadequate venous drainage and that the tonsillar descent is reversible if adequate venous drainage is reconstituted following therapeutic embolization of the fistula. Tonsillar prolapse is not a consequence of mass or raised intraventricular pressure. Our observation suggests that in some other conditions, the Chiari I malformations may be secondary to early hydrovenous dysfunction of the posterior fossa.     

Clinical features of hepatic artery thrombosis after pediatric liver transplantation

Thrombosis of the hepatic artery (HAT) is a severe complication of liver transplantation, and most cases need regrafting. The aim of this study was to review our experience with this complication. From January 1986 through January 1992, 76 liver transplants were performed in 59 pediatric patients at the Children's Hospital La Paz, Madrid. The diagnosis of HAT was made in 12 cases (15.7%). The common patterns of clinical presentation were: fulminant liver necrosis (5), bile leak due to necrosis of the bile duct (4), and relapsing bacteremia (3). Clinical symptoms of fulminant liver necrosis started within the first 2 weeks after transplantation, with rapid deterioration and steep rises in SGOT and SGPT levels. All these patients were retransplanted on an urgent basis, but only 1 is alive 4 years later. Four patients developed bile leaks 13 to 60 days after transplantation; SGOT, SGPT, and total bilirubin were only slightly increased. Three children were retransplanted electively and are alive with a mean follow-up of 3 years. One exceptional patient had a Roux-en-Y jejunostomy and is doing well 30 months later with his original graft. The 3 remaining children had episodes of septicemia with hepatic abscess, liver infarction, and pleural effusion. Liver function tests were normal, with bilirubin levels below 2 mg/dl. All patients were retransplanted, but only 1 is alive and well 13 months later. In the present series, we found that early HAT produces fulminant clinical deterioration requiring an urgent regraft. Late HAT presenting with either infection or bile leak allows time for treatment by elective retransplantation. The best survival was obtained in the latter group. Correspondence to: J. Vázquez     

Survey on the use of pulmonary scintigraphy, spiral CT and conventional pulmonary angiography for suspected pulmonary embolism in the British Isles

AIM: To determine current clinical practice in the radiological diagnosis of acute pulmonary embolism and assess the use of spiral volumetric computed tomography. METHOD: A survey of 327 acute hospitals including cardiothoracic and orthopaedic tertiary referral centres was undertaken to assess current utilization of lung scintigraphy, spiral computed tomography and pulmonary angiography in the investigation of suspected pulmonary embolism. Responses were received from 215/327 (66%) centres. RESULTS: Lung scintigraphy was provided by 208 hospitals (144 on-site and 64 off-site). Spiral CT services were provided by 111 (52%) hospitals (on- or off-site), 142 (66%) units had access to angiographic facilities. Sixty-three centres out of 215 (29%) offered both on-site lung scintigraphy and spiral CT while only 41/215 (19%) hospitals were able to undertake all three tests on-site. On average, 501 perfusion (Q) or ventilation-perfusion (V/Q) scintigrams were performed per hospital per year with 26 spiral CT studies and just 4.6 pulmonary angiograms. CONCLUSION: These data suggest that lung scintigraphy is frequently the only imaging test in patients other than chest radiography, despite the large number of indeterminate results reported in most series.     

Renal vein thrombosis and selective arterial or venous thrombolytic therapy

Summary Background: Renal vein thrombosis (RVT) complicating the nephrotic syndrome is associated with a poor prognosis. Methods/Results: RVT was diagnosed in 12 of 60 patients with a diagnosis of nephrotic syndrome suggested by computed tomography (CT) and subsequently confirmed by selective renal angiography. Fifty patients carried a diagnosis of primary glomerulonephritis with various pathological findings, and 10 patients had lupus nephritis. Renal vein and peripheral vein blood samples were collected in the 12 patients with RVT and were assayed for fibrin(ogen) degradation products (FDP), antithrombin III (AT III), VIIIR:AG, and fibrinogen. The results suggested a state of hypercoagulation. Of these 12 patients, 7 were given 200,000 units of urokinase (UK) over 60 minutes in divided doses selectively via the renal vein. Five patients were given 200,000 units UK selectively into the renal artery. All patients also received 2.5 mg/day warfarin and 75 mg/day persantine. Except for three patients with focal glomerulosclerosis, all patients received 40 mg/day prednisone. After 1 month, the CT scan and blood samples for FDP, AT III, VIIIR:AG, and fibrinogen were repeated. Patients receiving intra-arterial UK had complete resolution of their thrombi. Complete resolution was also suggested in 2 of the 7 patients receiving UK by renal vein, and there was partial resolution in the other five. The hypercoagulation state decreased in all patients. Conclusions: We conclude that RVT is not an uncommon event in patients with nephrotic syndrome. The diagnosis can be supported reliably using abdominal CT scanning. Although a small number of patients were included in this nonrandomized study, it appeared that intra-arterial thrombolytic therapy yielded better results. The patients with minimal change disease have a good prognosis.     

Diagnosis of cardiac thrombosis in patients with atrial fibrillation in the absence of macroscopically visible thrombi

Summary Cardiac thrombosis due to atrial fibrillation (AF) has been recognized as the most common cause of cerebral embolism. However, sometimes no macroscopic thrombus is found at autopsy in the heart of a victim of this type of cerebral embolism. We investigated morphological changes in the left atrial endocardium of 31 patients (including 21 cases with AF) who had died of cerebral embolism. Rough endocardium (RE) seen macroscopically provided evidence for the existence of atrial thrombosis. The RE that appeared in AF cases was due to a granular and wrinkled appearance of the endocardium associated with oedematous and fibrous thickening. Fibrin-thread deposits were also always distinguishable. Mural thrombi and oedema with neutrophil infiltration in the subendocardium could be seen under the microscope. Small areas of endothelial denudation and thrombotic aggregations were commonly observed by scanning electron microscopy (SEM). These SEM lesions were significantly more frequent in cases with AF than in controls (P< 0.001). The diagnostic success rate for atrial thrombosis among cases with AF increased from 33.3% to 81% when thrombi proven by histological investigation of the areas with RE were added. Left atrial RE may be an anatomically relevant finding for the existence of atrial thrombosis with AF, when the thrombosis cannot be detected upon gross observation at autopsy.     

Graduated compression stockings in the prevention of deep vein thrombosis in patients with acute myocardial infarction

Venous volume (venous capacity) of the calf is low in patientswith acute myocardial infarction, who also have a high riskof deep vein thrombosis (DVT). The effect of graduated compressionstockings on the venous volume and on the incidence of DVT wastherefore studied in 80 patients aged 70 years and above withacute myocardial infarction. Graduated compression stockingswere randomly fitted to one leg, the other serving as a control,after which the venous volume was measured by strain gauge plethysmography.The incidence of DVT was measured by the ¹²⁵I fibrinogen uptaketest. Venous volume was significantly higher in legs treatedwith graduated compression stockings compared to control legs.DVT developed in eight control legs but not in any leg treatedwith graduated compression stockings (P = 0.003). DVT was alsosignificantly more frequent in women compared to men and themajority of DVT developed in legs with very low venous volumevalues.     

Effects of Nd-YAG laser on platelet function in vitro: A comparative study using the spectraprobe, ‘hot tip’ and bare fibres

The effects of Nd-YAG laser irradiation on platelet function in vitro were studied using platelet rich plasma obtained from the blood of healthy volunteers. Laser delivery was effected via the bare optical fibre, thermal hot tip fibre and spectraprobe and the effects of these probes on platelet function were compared. Fall in platelet count and mean platelet volume (MPV) were proportional to increasing energy delivery with all three probes, the effect being maximal with the spectraprobe, moderate with the hot tip and least with the bare optical fibre. A significant decrease in percentage aggregation of platelets in response to added ADP, collagen and ristocetin with increasing energy delivery was also observed with all three probes. The formation of preformed aggregates, however, showed an increase proportional to energy delivery with all three probes.The differential effects of the various probes used in this study on platelet function may enhance our understanding of the complex role played by platelets in the pathogenesis of complications such as arterial thrombosis and re-occlusion after laser angioplasty.     

泽兰有效部分对血小板聚集和血栓形成的影响

目的 研究泽兰有效部分L．F04：对血小板聚集和血栓形成的影响，探讨其活血化瘀作用机制。方法用高分子右旋糖酐静脉推注造成大鼠血瘀证模型，观察泽兰L.F04对二磷酸腺苷(ADP)诱导的大鼠体内血小板聚集以及体内动静脉旁路血栓、体外旋转环内血栓形成的影响。结果 L．F04 0．408，0．204g／kg对模型组大鼠ADP诱导的体内血小板最大聚集率明显增加皆有显著的抑制。且呈剂量依赖关系；与对照组相比，血瘀模型大鼠体外血栓质量明显增加，长度仅有增加趋势，L．F04高、低剂量(0．408，0．204g／kg)皆有抗血栓形成作用，L．F04高剂量对血栓干质量、湿质量的减轻尤为明显；L．F04高、低剂量对实验性动静脉旁路血栓形成均有明显的抑制作用，抑制率分别为27．41％，27．14％。结论泽兰L．F04可显著抑制血小板聚集及体内、外血栓形成。     

丹参素胶囊活血化瘀作用的实验研究

目的：研究丹参素胶囊对大鼠血小板聚集性和血液流变学及血栓形成的影响。方法：以ADP为诱导剂，观察其对体外血小板聚集率的作用；采用电刺激法，测定闭塞性血栓形成的时间；用冰水刺激制备“血瘀”模型，检测主要流变学指标。结果：丹参素胶囊能明显抑制由ADP诱导的大鼠血小板体外聚集活性，延长电刺激大鼠颈总动脉后血栓形成时间，降低“血瘀”大鼠全血粘度、血浆粘度、红细胞压积、红细胞电泳时间、卡松屈服应力以及红细胞聚集指数，改善机体血液流变性。结论：丹参素胶囊能明显降低血液“浓、粘、聚、凝”状态，具有良好的活血化瘀作用。     

吗啉环和哌嗪环类衍生物的抗血栓作用及其分子机制

目的研究吗啉环和哌嗪环类衍生物对血栓形成的影响及分子机制。方法利用小鼠尾动脉血栓模型，观察新化合物对血栓形成的影响。结果化合物MOPMC,2FBMPC,MPTMBC,DMHPPP和PPVP在1.0 mg·kg^-1可显著降低成栓率；而结构类似的化合物MAPC,4C3FBMOC,mTBMPC，MONVP和MPNVP对血栓形成均无明显影响；化合物DMHPPP对凝血系统和血小板聚集功能无显著影响，但可升高血浆中t-PA和PGI₂含量，降低PAI-1的活性和TXA₂的含量。结论吗啉环和哌嗪环类化合物可激活血管内皮细胞乙酰胆碱作用靶标而对抗血栓形成。