Arteriovenose

Arteriovenose, or an arteriovenous shunt, is an abnormal connection between an artery and a vein that bypasses the capillary network. It can be congenital, as in arteriovenous malformations, or acquired, as in arteriovenous fistulas formed after surgery, trauma, or certain medical procedures. These conditions can occur in various parts of the body, including the brain, spine, limbs, or other organs, and, in the context of hemodialysis, refer to surgically created access points.

The underlying feature of arteriovenose is a high-flow direct passage from arterial to venous circulation. This shunt can lead to hemodynamic changes such as increased cardiac workload, tissue hypoperfusion in surrounding structures (steal phenomenon), and structural vessel changes that predispose to aneurysm formation or rupture. Brain arteriovenous malformations carry a risk of intracranial hemorrhage; large fistulas can cause heart failure due to excessive venous return.

Clinical presentation depends on location and size. Brain AVMs may cause headaches, seizures, or hemorrhagic stroke; peripheral AVMs or AVFs can present as a palpable thrill, audible bruit, pain, swelling, or a warm, enlarging mass. Dialysis arteriovenous fistulas present with a vascular thrill and bruit and are used clinically to provide access for hemodialysis.

Diagnosis typically involves imaging studies. Doppler ultrasound is common for peripheral lesions; CT or MR angiography helps map anatomy; conventional catheter angiography is often the gold standard for detailed assessment. Treatment depends on symptoms and risk, ranging from careful observation to interventions such as endovascular embolization, microsurgical resection, or radiosurgery. Dialysis fistulas may require maturation optimization or revision. Prognosis is variable and disease-specific, with management tailored to minimize complications and preserve function.