Carotid Web: An Update Focusing on Its Relationship With Fibromuscular Dysplasia and Therapeutic Strategy

Carotid web was described more than 50 years ago as an atypical fibromuscular dysplasia (FMD) subtype with highly supporting pathological evidence as intimal FMD. In the following decades, the transition from catheter angiography or digital subtraction angiography (DSA) to non-invasive imaging techniques and the dramatic decrease in pathological procedures contributed to the gradual loss of this information. Currently, attention on the carotid web has increased due to its association with cryptogenic ischemic stroke. In fact, the underlying hypothesis is that the morphological features of the carotid web may determine a thrombogenic potential with artery-to-artery embolism. The pathology of the carotid web allowed identification of small thrombi embedded in the web pouch, and the features of thrombi endovascularly retrieved from intracranial arteries are very similar. The diagnosis of carotid web is usually made by non-invasive techniques, such as computed tomography angiography, ultrasound, and magnetic resonance imaging, requiring the concordance of two different techniques for confirming the diagnosis. DSA is usually considered in cases of diagnostic uncertainty and when interventional treatment of ischemic stroke or carotid web is considered. Treatment options in symptomatic cases include medical therapy (single or dual antiplatelets) or interventional approach (surgery or stenting), but there are no randomized controlled trials about therapy. The main aim of this review is to present the current knowledge on carotid web, retrieving historical data and angiographic classifications of FMD, as well as to discuss the biological plausibility of the association with stroke in symptomatic cases and the need for an updated classification of FMD, together with prospective data.