Peripheral arteriogenesis is distinctly enhanced by increased fluid shear stress. Thus, the aim of this study was to investigate in the rat brain whether increased fluid shear stress can also stimulate cerebral arteriogenesis. To increase fluid shear stress in the cerebral circulation, we developed different shear stress models as the ligature of both common carotid arteries (Double-Ligature model), bilateral carotid ligature followed by creation of a unilateral arterio-venous fistula (two-stage protocol, Ligature-Shunt model), and unilateral arterio-venous fistula-creation alone (Solo-Shunt model). Blood flow changes were monitored in vivo by quantitative magnetic resonance imaginganalysis. Cerebral arteriogenesis was analyzed by magnetic resonance imaging and contrast agentangiography. For proliferation and accumulation of mononuclear cells, immunohistochemistry was performed. During the 14 days-observation period, blood flow increased maximal by 5.5-fold in the A. basilaris and 10.3-fold in the fistula-sided A. cerebri posterior of the Ligature-Shunt model. Considerable vessel growth was found in all shear stress-stimulated arteries. Comparative analysis of vessel length and diameter versus blood flow indicated a correlation between the growth of cerebral collaterals and rising intravascular flow rates (R 2 = 0.90/0.96). Immunohistochemistry showed the typical phases of arteriogenesis and accumulation of mononuclear cells. In conclusion, we provide evidence that fluid shear stress is not only the pivotal trigger of peripheral but also of cerebral arteriogenesis.

Iatrogenic Vascular Injuries in Sweden. A Nationwide Study 1987-2005Rudström H., Bergqvist D., Ögren M., Björck M. Eur J Vasc Endovasc Surg 2007;35:131-38. Objectives To study the epidemiology of vascular injuries, with special focus on Iatrogenic Vascular Injuries (IVIs) and time-trends.Design and methods From the Swedish national vascular registry, Swedvasc, prospectively registered data on vascular injuries during 1987-2005 were analysed and cross-referenced for mortality against the population registry.Results Of 1853 injuries, 48% were caused by iatrogenic, 29% penetrating and 23% blunt trauma. In the three groups median age was 68, 35 and 40 years, respectively. The annual incidence of procedures for vascular injuries increased from 1.2-1.6 per 100 000 inhabitants and the proportion of IVIs increased from 41 to 51%, during the period. Mortality was higher after IVI (4.9%) compared to non-IVI (2.5%). Patients with IVI also had more co-morbidities; 58% cardiac disease, 44% hypertension, and 18% renal dysfunction.Among 888 IVIs, right femoral arterial injury was the most frequent (37%). The most common vascular reconstruction was direct suture (39%) followed by by-pass or interposition graft (19%, of which prosthetics were used in over half the cases). Endovascular repair increased from 4.6% to 15% between 1987 and 2005.Conclusions Vascular injuries, in particular iatrogenic ones, appear to be increasing. Iatrogenic injuries affect vulnerable patients with comorbidities and are associated with a high mortality.

Due to the high incidence of temporary ipsilateral vocal cord dysfunction in patients undergoing retrojugular exposure of the carotid artery, we recommend the conventional ventrojugular approach, which can be performed by incision along the anterior border of the sternomastoid muscle or by transversal skin incision.

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