Therapeutic perspective of the revascularised carotid artery

Abstract

This thesis describes research on the results of different treatments of stenotic lesions in the carotid artery. Several aspects of the outcome following treatments done by catheterization through the arterial system (endovascular, CAS) or by conventional open surgical approach (endarterectomy, CEA) were compared. These procedures are carried out in patients with symptomatic stenotic lesions in the carotid artery. The patients were treated because they suffered from a recent cerebrovascular accident or TIA and are at risk for recurrent symptoms due to the stenotic lesion in the carotid artery. The aim of the treatment is to prevent the recurrence of these neurological symptoms. In this thesis, different aspects of both treatments are compared. In particular, the degree of restenosis after both procedures and the changes in hemodynamics and blood flow velocities in both carotid arteries (internal and external carotid artery) were analysed. We analysed the results and complication rates of both procedures in elderly patients (> 80 years). We observed a higher complication rate in elderly patients following endovascular procedures compared to the complication rates during surgical procedures. We attempted to explain this higher complication rate through analysing certain histological characteristics of the carotid plaque of the elderly patients. We observed that carotid plaques in the elderly have more unstable characteristics compared to younger patients. This might be an explanation the fact that the elderly are more at risk for neurological complications during CAS. The rate of apparent restenosis was higher following CAS, mainly due to the fact that the increase in flow velocities following these procedures seems an on going process while flow velocities following CEA remain relatively stable. Management of these restenotic lesions is challenging but both an endovascular as a surgical approach seem feasible options in the treatment of these lesions. We describe a cohort in which restenotic lesions in a previously placed stent are treated by explantation of the stent through CEA. We observed a low complication rate during these procedures and the artery remained patent during follow-up. The external carotid artery could act as a possible collateral pathway for retinal and cerebral perfusion in the case of severe stenosis or occlusion of the internal carotid artery. Treatment of stenotic lesions in the internal carotid artery by CAS could jeopardize this pathway due to “overstenting” the origin of the external carotid artery. In a randomized cohort we analysed the patency of the external carotid artery and concluded that flow velocities in the external carotid artery increase more following CAS but this increase does not lead to higher occlusion rate compared to CEA. This means that the possible collateral pathway through the ECA remains patent following CAS. In two other manuscripts, we describe the patency of the external carotid artery in a cohort of patients treated by CAS and CEA. Occlusion of the external carotid artery is rare following both procedures.