RESUMEN
Cerebrovascular abnormalities (primarily looping of cerebellar arteries) are almost without exception concurrent with the Arnold-Chiari syndrome and hydrocephalus. Persistent essential hypertension may be a manifestation of pathological vessel-brain contact. Customary microvascular decompression may lead to blood pressure stabilization in the postoperative period for a long time. The paper presents a clinical case of a 52-year female patient with the Arnold-Chiari syndrome who underwent microvascular decompression of the left posterior inferior cerebellar artery at the level of the medulla oblongata. Surgical treatment regressed preoperative cerebellar, bulbar, and truncal symptoms, lowered blood pressure from 190/100 to 120/80 mm Hg, and stabilized it at this level.