Arteriovenosa

Arteriovenosa refers to the relationship or connection between an artery and a vein, either physiological or pathological. The term is commonly used in medical contexts to describe arteriovenous fistulas, arteriovenous malformations, and arteriovenous shunts. A physiological arteriovenous connection occurs in the retinal circulation and in the azygos venous system, allowing blood to bypass capillary beds for efficient oxygen delivery.

An arteriovenous fistula is an abnormal connection between an artery and a vein of the same blood pressure system. Fistulas can be surgically created, for example in hemodialysis access, or they can arise spontaneously following trauma or as a complication of surgical procedures. Arteriovenous malformations are congenital or acquired clusters of tangled blood vessels that directly link arteries to veins, bypassing capillaries. These malformations are found most often in the brain and spinal cord but can occur elsewhere in the body. They can cause ischemic injury, hemorrhage, or high-output cardiac failure depending on size and location.

The clinical presentation of arteriovenous lesions varies. Small fistulas may be asymptomatic and discovered incidentally during imaging for other reasons. Larger fistulas or malformations can produce pulsatile mass, bruit, and, if left untreated, progressive dyspnea, edema, or neurological deficits. Diagnostic workup typically includes duplex ultrasound, contrast-enhanced magnetic resonance imaging, or digital subtraction angiography, which provide detailed vascular mapping and hemodynamic assessment.

Therapeutic options are tailored to lesion type, size, and symptoms. Endovascular embolization is the preferred non-surgical approach for many arteriovenous malformations, using coils, liquid embolic agents, or stent-grafts. Surgical resection or ligation is considered for fistulas that are refractory to endovascular therapy or for selected malformations. In dialysis patients, proximal fistulas are preferred for adequate flow rates, while distal options may be considered when vessel quality is limited. Prognosis depends largely on early diagnosis and effective intervention; untreated large arteriovenous malformations in the central nervous system carry a significant risk of hemorrhage and neurological decline.