Abdominal Aortic Aneurysm neck morphology Pack-size legislation reduces severity of paracetamol overdoses Drug treatment reporting system in Dublin The pattern of plasma sodium abnormalities Acute haemodynamic effects of cigarette smoking Chronic conditions among an elderly population Walking on water

Background While aneurysm neck length, angulation and width have all been previously assessed in endovascular abdominal aortic aneurysm repair (EVAR), aneurysm neck shape has not been considered. Aims To analyse the influence of aneurysm neck morphology on outcome following EVAR. Methods Aneurysm neck morphology in 70 patients undergoing EVAR from April 2001 to May 2004 was determined using pre-operative CT scans and graft plans. Necks were classified as flared, parallel, irregular, conical, barrel or hourglass. End-points were death, Type I endoleak and graft migration. Results Forty-six per cent of necks were flared, 34% parallel, 9% irregular, 6% conical, 3% barrel and 3% hourglass. Mean follow-up was 20.2 months (range 4-35). There was one Type I endoleak and one graft migration. There were no aneurysm related deaths. Conclusions Assessment of aneurysm neck morphology should be part of the routine preoperative workup for EVAR. A classification system of AAA necks is suggested to facilitate this. ABDOMINAL AORTIC ANEURYSM NECk MORPHOLOGY: PROPOSED CLASSIFICATION SYSTEM CO McDonnell, M Halak, A Bartlett*, SR Baker Dept of Vascular Surgery, Sir Charles Gairdner Hospital, Perth, Western Australia; Zenith Planning Service*, Perth, Western Australia O RI G IN A L PA PE R IRISH JOURNAL OF MEDICAL SCIENCE • VOLUME 175 • NUMBER 3 5 PaTienTs & MeTHODs The CT scans and manufacturers’ endoluminal graft plans were reviewed in a consecutive series of 81 patients who underwent endovascular repair of abdominal aortic aneurysm at Sir Charles Gairdner Hospital from April 2001 to May 2004. Insufficient aneurysm neck length in 11 patients required the use of a fenestrated stent-graft and these patients were therefore excluded. The remaining 70 patients form the basis of this study. Wall-to-wall aneurysm neck measurements including thrombus, atheroma and/or calcium were taken at 3mm intervals, commencing at the level of the renal arteries and continuing inferiorly until a neck length of 21mm had been assessed. In an angulated neck the minimum diameter seen in an axial image was taken as the real diameter. A difference in diameter of 3mm or greater between consecutive measurements was taken as representing a significant contour change.9 Aneurysm necks fell into one of six categories based on neck morphology: flared, parallel, conical, barrel, hourglass and irregular (Figure 1). Aneurysms were repaired using the Zenith stentgraft (W.A. Cook, Brisbane, Australia) in 67 cases and the Talent LPS device (Medtronic AVE, Santa Rosa, U.S.A.) in three cases. Mean aneurysm diameter was 57mm (Range 48-85). Graft oversizing during planning was performed in accordance with the manufacturers’ recommendations. With the Zenith device, graft oversizing of 15% to 25% based on the largest aortic neck diameter was performed. With the Talent device, an average neck diameter was calculated using all the available neck measurements, as described elsewhere10 and the graft was subsequently oversized by 10-20% (Figure 2). All patients undergoing EVAR at Sir Charles Gairdner Hospital have been entered onto a prospectively maintained database with follow-up clinical and CT data entered at six weeks, six months and twelve months postoperatively and annually thereafter. Mean postoperative follow-up was 20.2 months (range 4-35). Primary end-points were the presence of Type I endoleak, graft migration and death and secondary end-points were the existence of any other type of endoleak and need for secondary intervention. resUlTs Flared necks were the commonest (n=32, 46%), then parallel (n=24, 34%), six (9%) were classified as irregular, four (6%) were conical, two (3%) were barrel and two (3%) were hourglass (Figure 3). Mean maximum neck diameter was 27.1mm (Range 2034mm), while mean endograft diameter implanted was 29.5mm (Range 22-36mm). There were nine endoleaks in total (13%), one Type I, seven Type II and one Type III. The Type I endoleak occurred in an aneurysm with a flared neck treated with a Zenith® graft and required the deployment of a proximal extension piece which was successful in excluding the leak. The secondary intervention rate was 11.4% (eight patients). None of the other seven interventions were related to the proximal sealing zone or aneurysm neck. Thirty day mortality was zero and there were six late deaths, none of which were aneurysm related. Only one incidence of graft migration was recorded. This occurred in an aneurysm with a flared neck treated with a Talent LPS device. While the entire suprarenal portion of the graft now lies below the renal arteries, the patient has not yet developed an endoleak. No instances of graft migration has been identified in the patients treated with the Zenith device.