Detection of right to left shunting through a patent foramen ovale in Japanese patients with ischemic stroke by transesophageal echocardiography using a standardized Valsalva maneuver.

We attempted to clarify the usefulness of transesophageal echocardiography performed using a standardized Valsalva maneuver to detect the presence of a patent foramen ovale in Japanese patients with ischemic stroke. Four hundred ninety six patients with ischemic stroke who were admitted to the Yokohama City Brain and Stroke Center between September 1999 and February 2002 were enrolled for the study. All the enrolled patients underwent transesophageal echocardiography with contrast injection and color Doppler imaging. During the procedure, a standardized Valsalva maneuver was performed to induce right to left shunting through a patent foramen ovale. Other related structural abnormalities, such as atrial septal aneurysm and the Chiari network anomaly, were also detected by the test. Transesophageal echocardiography without the Valsalva maneuver revealed a functional right to left communication in only 8.2% of the ischemic stroke patients, whereas the procedure conducted using a standardized Valsalva maneuver to provoke shunting revealed a patent foramen ovale in 15.3% of the patients. The presence of an atrial septal aneurysm or the Chiari network anomaly was not sensitive or specific enough to predict the presence of a patent foramen ovale as diagnosed by transesophageal echocardiography using the standardized Valsalva maneuver. Our results suggest that the standardized Valsalva maneuver is a safe and useful technique to detect the presence of a patent foramen ovale, which is potentially known to be associated with paradoxical embolism.