Prevalence of patent foramen ovale in a consecutive cohort of 261 patients undergoing routine "coronary" 64-multi-detector cardiac computed tomography.

Background: A patent foramen ovale (PFO) is strongly associated with cryptogenic stroke (CS), neurological and other phenomena. The reported prevalence of PFO varies according to the imaging technique used and population studied.

Purpose: To measure prospectively, the prevalence of PFO in a cohort of consecutive patients attending for routine "coronary" CT angiography using standard, everyday coronary protocols including low-dose prospective ECG gated studies.

Methods: Standard coronary imaging protocols were used. PFOs were graded according to the classification of Williamson et al.

Results: 261 patients were studied. A PFO was identified in 22.6% (11.5% grade 1 (closed flap), 6.5% grade 2 (open flap) and 4.6% grade 3 (open flap with jet)). A further 6.1% had an atrial septal aneurysm.

Conclusions: The prevalence of all grades of PFO (22.6%) and open flap PFO (11.1% = grade 2 and 3) with this technique compares with 24.3% by trans-oesophageal echocardiography (TOE) and 14.9% by saline contrast echocardiography (SCE). Further comparative studies are required but we believe an open flap PFO or ASA should be identified and recorded during cardiac CT. This approach may identify those at risk of cryptogenic stroke as well as avoid unnecessary tests in stroke patients.