ICD 10 code for Patent foramen ovale. Get free rules, notes, crosswalks, synonyms, history for ICD-10 code Q21.12.Patent foramen ovale. Persistent foramen ovale. Q21.12 Patent foramen ovale - ICD-10-CM Diagnosis Codes. DISEASES inferred 14. A condition in which the foramen ovale in the atrial septum fails to close shortly after birth. This document addresses surgical and ablative treatments for chronic headaches, such as migraine and tension type headaches, and occipital neuralgia. Several secondary endpoints, decrease in the mean number of migraine days per month and complete cessation of migraine, favored the PFO closure group. Patent foramen ovale.