intra-operative endoleak was observed in 16.7% overall, and 3.3% were noted to have proximal endoleak. Aneurysm size larger than 60 mm (p =0.004), ex-smokers ( p =0.005) and age over 75 years ( p =0.01) were independently associated with endoleak of all types. Univariate and multivariate analysis revealed correlation between proximal endoleak and (i) diameter of the aneurysm neck-proximal (D2a), middle (D2b), distal (D2c), at all levels (p <0.005); (ii) proximal aortic neck length ( p =0.0001); (iii) aortic device diameter ( p =0.0024). No correlation was identified for angulation and form of the aortic neck. A model of the frequency of proximal endoleak, in relation to the ratio of the aortic device diameter to the distal aortic neck diameter, revealed that endoleak decreased when the aortic device diameter became oversized by more than 10% and confidence intervals remained tight for up to and over 20% oversize.

The mathematical model validated hypertension, aneurysm morphology, and endograft size as clinical factors significantly associated with stent-graft migration. These findings may have important implications for the choice and design of future stent-grafts.

Transferring patients from outlying units did not appear to prejudice operative outcome in this RVU. However, less than half of all RAAA patients were transferred, and only a small minority of those not transferred underwent surgery. Although the overall community mortality from RAAA was similar to that reported in earlier studies from other regions and countries where centralization has not occurred, centralization of vascular surgical services may be associated with an inappropriately low operation and survival rate for those patients who are not transferred to the regional center. The effect of centralization on the community outcome of emergent vascular surgical conditions requires further investigation.

Dissection of the internal carotid or vertebral artery has been recognized as a cause of stroke in young patients. It is disproportionate in its representation as a cause of stroke in this age group. Intimal tears, intramural hematomas, and dissection aneurysms may be the result of trauma or may occur spontaneously. Spontaneous dissection may be the result of inherent arterial weakness or in association with other predisposing factors. Clinical diagnosis is often difficult, but increased awareness and a range of modern investigations such as computerized tomography or magnetic resonance imaging may aid in diagnosis. Management options include antiplatelet therapy, anticoagulation, thrombolysis, and surgical or endovascular procedures. Prognosis is variable, and dissection may be asymptomatic but may lead to profound neurological deficit and death.