Cervical artery dissection

The cervical arteries, specifically the internal carotid arteries (ICA) and vertebral arteries (VA), are critical conduits for cerebral blood flow. These vessels possess a complex, multi-layered wall structure comprising the intima, media, and adventitia. Cervical artery dissection (CAD) is defined as a tear within these layers, most commonly occurring between the intima and media, or within the media itself.

This tear initiates a cascade of events, including intramural hematoma formation-bleeding within the vessel wall-and potential propagation of the dissection. This can lead to luminal narrowing (stenosis), occlusion, or the formation of pseudoaneurysms, all of which compromise cerebral perfusion and increase the risk of ischemic stroke. The precise etiologies are diverse, ranging from inherent weaknesses in the arterial wall to external forces.

CAD is broadly categorized into spontaneous and traumatic dissections. Spontaneous dissections, which account for the majority of cases, often occur without a precipitating event and are frequently associated with underlying arteriopathies-abnormalities in the blood vessel wall. These can include fibromuscular dysplasia (FMD), connective tissue disorders like Ehlers-Danlos syndrome or Marfan syndrome, and even less defined genetic predispositions.

Traumatic dissections result from direct injury, such as blunt force trauma to the neck (e.g., motor vehicle accidents, sports injuries, chiropractic manipulation), or penetrating injuries. The distinction is crucial as it can influence management strategies and prognosis. The fact that CAD is a leading cause of stroke in individuals under 50 highlights the importance of considering non-atherosclerotic causes of cerebrovascular events.

The mechanism by which CAD leads to stroke is multifaceted. Intramural hematoma can cause outward bulging of the artery wall, leading to stenosis and reduced blood flow. Thrombosis, or clot formation, can occur at the site of dissection, potentially embolizing (traveling) downstream to smaller cerebral arteries, causing an ischemic stroke.

Alternatively, the dissection can extend proximally or distally, leading to complete occlusion of the artery. The hemodynamic changes and inflammatory responses associated with the dissection process also contribute to the risk. Understanding these pathways is vital for developing targeted therapies that go beyond simply preventing clot formation.

Diagnosis of CAD relies heavily on advanced neuroimaging. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are primary tools, often revealing characteristic findings such as the 'string sign' (luminal narrowing), pseudoaneurysm, or intramural hematoma. Digital subtraction angiography (DSA) remains the gold standard for visualization but is more invasive. Therapeutic strategies are primarily aimed at preventing stroke.

Antiplatelet agents (e.g., aspirin, clopidogrel) are commonly used to inhibit platelet aggregation and thrombus formation. Anticoagulants (e.g., heparin, warfarin) may be employed in cases of arterial occlusion or rapid expansion of dissection. The choice of therapy is individualized based on the specific arterial involvement, presence of stroke, and patient factors.

Endovascular interventions, such as stenting, are reserved for select cases where medical management fails or is insufficient.

While many patients with CAD experience favorable outcomes with appropriate medical management, the long-term implications can include recurrent dissection, stroke, or cranial nerve palsies. The non-specific nature of initial symptoms, such as headache and neck pain, can delay diagnosis, underscoring the need for heightened clinical suspicion, particularly in younger patients presenting with these complaints. Ongoing research focuses on identifying genetic markers for arteriopathies, refining imaging techniques for earlier and more accurate detection, and exploring novel therapeutic agents that target the inflammatory and thrombotic processes more specifically.

Understanding the biomechanics of arterial wall injury and healing also holds promise for future preventative strategies.