HEMODYNAMIC COMPROMISE DURING CAROTID ANGIOPLASTY AND STENTING

摘要

Modern surgical treatment of arterial disease is moving towards minimally invasive procedures, as the benefits are numerous. However, one area that is resisting this trend is the treatment of carotid artery disease. For the past number of decades carotid endarterectomy surgery has been referred to as the "gold standard" in the treatment of carotid artery disease. However, in recent year's carotid angioplasty and stenting (CAS) has emerged to challenge carotid endarterectomy surgery (CES) as a viable alternative for the prevention of strokes. However uptake of this procedure has been hindered due to the perioperative complications associated with the treatment. During this procedure blood flow in one of the internal carotid arteries supplying blood to the brain is interrupted for a period of time. However, it has been shown that not all patients can accommodate this interruption. Qureshi et al. suggests that ischemic neurological deficits occur in 3 to 13% of patients as a result of hemodynamic compromise. A key element in maintaining sufficient cerebral perfusion is a ring like arterial structure at the base of the brain called the circle of Willis (CoW), figure 1. The role of the CoW is to connect all afferent arteries supplying the brain and redistribute oxygenated blood around the cerebral mass. However, studies have shown that among the general population the CoW demonstrates significant morphological variation, with less than 50% having a complete CoW[l]. The remainder of the population have a combination of absent or hypoplastic (narrow, string-like) vessels, which limit the ability of the CoW to operate effectively as a collateral pathway. Therefore cerebral perfusion depends not only on the status of the diseased artery but also on the patency of the collateral routes provided by the Circle of Willis. The aim of this study is to examine the hemodynamics in the CoW and determine the effect morphological variations in the CoW have in relation to hemodynamic compromise during the CAS procedure.