Characteristics of Posterior Cerebral Circulation in Patients With Intractable Hiccups: A Case Series

Introduction: Certain vascular variations, including complete fetal-type posterior cerebral artery variants, may underlie the mechanisms contributing to intractable hiccups. Methods: Brain magnetic resonance angiography was performed in 230 patients with intractable hiccups who visited our hiccup consultation clinic. Based on the proposed morphological classification system, vascular distribution patterns and frequencies of the Circle of Willis (CW) were compared with those in five previously reported healthy cohorts. Results: Of the 230 patients, 215 (93.5%) had an incomplete CW type, which was significantly higher than that observed in the healthy cohorts (45.0–74.6%; all p < 0.001). Hypoplasia or absence of both posterior communicating arteries, resulting in isolation of the anterior and posterior CW, was the most common phenotype (140/230, 60.9%). This frequency was also higher than that reported in each of the healthy cohorts (8.7–42.8%; all p < 0.001). Conclusions: Incomplete CW patterns were prevalent among individuals with intractable hiccups, particularly those isolating the anterior and posterior CW. These findings suggest a possible association between intractable hiccups, cerebrovascular variants, and changes in cerebral blood flow.