Flow analysis in vascular shunts that bypass the carotid artery

When blood flow through a carotid artery is impaired and vascular surgery is necessary to restore adequate circulation a vascular shunt can be applied to maintain cerebral blood flow. Several vascular shunts are commercially available, but there is only limited test data on their flow capacity. The purpose of this study is to determine the flow capacity of three vascular shunt systems. A theoretical model has been developed for this purpose. To validate the model, in vitro flow measurements were taken. Application of the model showed that all shunts cause a decrease in blood flow. The amount of flow decrease varied widely from 13% (Javid shunt) to 55% (Pruitt-Inahara). In vitro measurements confirmed the validity of the model. In conclusion, it is important for the vascular surgeon to realise that vascular shunts show large differences in flow capacity. Of the three investigated shunts, the Javid has the highest flow capacity

Fluorescence labeling to study platelet and leucocyte deposition onto vascular grafts in vitro

Platelets and leucocytes are important participants in the response of the body to small diameter vascular grafts implanted into the arterial circulation. A sensitive and quick method for measuring platelet and leucocyte deposition contributes to material evaluation. With a newly developed fluorescence labeling method we examined the deposition of platelets and leucocytes onto vascular grafts in vitro. Human platelets and leucocytes were isolated and labeled with the fluorescence label Europium trichloride (EuCl3). After reconstitution of the labeled cells in plasma their functionality appeared intact and competitive with unlabeled cells. Eu-labeled platelets or leucocytes were then incubated with expanded polytetrafluoroethylene (ePTFE), Dacron and polyurethane (PU) vascular grafts in autologous plasma. beta-thromboglobin and thromboxane release from platelets and beta-glucuronidase release from leucocytes during the incubation experiments were measured. Platelets and leucocytes deposited significantly less onto ePTFE compared to Dacron and polyurethane (P <0.01). Our results are in accordance with results of in vivo studies using radio-active labeling to study platelet and leucocyte deposition. However, a new finding was that this reduced cell deposition may in part be due to possible toxic effects of ePTFE, shown by increased haemolysis and beta-thromboglobin release. (C) 1999 Elsevier Science Ltd. All rights reserved

Outcome of surgical treatment for carotid body paraganglioma

Background: The present study reviewed a 30-year experience of managing carotid body paraganglioma (CBP) and analysed clinical findings associated with perioperative morbidity. Methods: Clinical records, radiological findings and pathological reports of all patients who presented with CBP between 1966 and 1997 were reviewed. There were 39 consecutive patients with 45 tumours and median follow-up was 10 years. The Shamblin classification was used to define complication rates and long-term surgical results. Results: Preoperative information derived from magnetic resonance angiography (MRA) and colour Doppler imaging (CDI) was comparable to that from standard four-vessel arteriography. Forty-one CBPs were resected in 35 patients. Six patients had bilateral tumours and seven had multicentric tumours. The median duration of operation and blood loss were substantially higher for Shamblin type III tumours. All major vascular complications (four of 39 patients) and permanent neurological complications (three of 39) were observed in type III tumours. Conclusion: Surgical planning and prediction of perioperative complications can be obtained by staging derived from MRA and CDI. Severe complications occur predominantly in type III CBPs

Thoracic stent grafts with a distal fenestration for the celiac axis

Descending thoracic aneurysms can be treated with a stent graft provided that there is sufficient proximal and distal aortic neck length above the celiac axis. One of the options for the treatment of thoracic aneurysms with a too short distal neck is described in this report. For this purpose, a stent graft was constructed with a scallop for the celiac axis. Three cases are presented, and the technical details are described