Prevalence of Patent Foramen Ovale in the Japanese Population- Autopsy Study

Patent foramen ovale (PFO) can cause ischemic stroke because of paradoxical embolism. Autopsy studies have shown that the prevalence of PFO is 25% in whites or blacks. However, there is a paucity of data on the prevalence of PFO in Asians. The aim of this study was to clarify the prevalence of PFO in the Japanese population.

We reviewed 52,717 autopsy reports, which were collected and edited by the Japanese Society of Pathology from 2009 to 2012. Next, we inspected consecutive 103 formalin-fixed specimens that had already been examined by certified pathologists from 2009 to 2013 to find PFO and atrial septal aneurysm (ASA). ASA was defined as ≥10 mm protrusion of the septum into the left or the right atrium. In the database of the Japanese Society of Pathology, the incidence of PFO was 0.08% (43/52,717). Inspection of heart specimens disclosed that the prevalence of PFO was 13.6% (14/103). None of the PFO cases was reported at the original autopsy. PFO was more frequently found in the subjects with ASA (50%) than in those without ASA (9.7%) (P=0.004).

PFO is under-reported in autopsy reports. Re-evaluation of heart specimens disclosed that the prevalence of PFO was 13.6%. The prevalence was lower than reported in the past.