Abstracts Category : Other

Methodological aspects on carotid artery intervention

by Magnus Jonsson

In Sweden, approximately 25000 patients suffer a cerebral infarction (stroke) annually. Stroke ranks as the third-leading cause of death, and is the leading cause of functional impairment. Carotid artery stenosis accounts for approximately 15% of all strokes and almost all of these are theoretically preventable.There are two conceptually different invasive methods used to treat carotid stenosis: carotid artery stenting (CAS) and carotid endarterectomy (CEA). There are various aspects of these treatments that remain to be evaluated in order to minimize the risks of poor outcome, namely: any differences in short-term and long-term outcomes after CEA or CAS, the potential risks of CAS early after a previous transient ischaemic attack (TIA)/stroke, and the methods to indicate the need of shunting during CEA. Furthermore, since data from randomised controlled trials (RCTs) are often from specialized high volume centres with selected patients, it is important to evaluate population-based results after CAS and CEA.The overall aim of this thesis was to investigate aspects of invasive treatment of carotid artery stenosis, in particular the outcome following endovascular treatment (CAS), and the efficacy of near-infrared spectroscopy in predicting selective shunt use during CEA.The outcome after endovascular treatment was investigated in three cohort studies (study I, II, and III). In study I, we analysed Swedish national short-term results of CAS and CEA and compared a high-volume centre with national results for CAS. In study II we evaluated the procedural risk of CAS, in relation to time from previous TIA /stroke. Study III assessed the long-term population-based outcomes after CAS as compared to CEA. In study IV, a multi- centre diagnostic study, we evaluated the ability of near-infrared spectroscopy (NIRS) to pre- dict cerebral ischaemia during CEA.Study I was a retrospective single-centre review of all consecutive patients treated with CAS at Sodersjukhuset between 2004-2011. These results were compared to data from the Swedish national registry for vascular surgery (Swedvasc), where data from all patients treated with CAS or CEA during the same period was extracted. We found that the Swedish national results for CAS were inferior to CEA, but also that it was possible to achieve acceptable results with CAS in a high volume centre. During the study period 464 CAS procedures were performed in Sweden, with 208 of them performed at Sodersjukhuset. The stroke and death rate at 30 days among patients in Sweden (Sodersjukhuset excluded) was 7.4%. In Sodersjukhuset, the stroke and death rate was 2.9%. The results for CAS on a national basis improved over time, the stroke and death rate during the first half of the period was 6.4%, compared to 3.6% in the sec- ond part of the study period, which was probably due to the learning curve for the procedure.In study II, all CAS performed for symptomatic carotid stenosis between 2005-2014, were included in a retrospective analysis. Study II