A Comparison of Transcranial Doppler and Transesophageal Echocardiography (with Conscious Sedation) in the Detection of Right-to-Left Cardiac Shunts

Background and Purpose Transesophageal echocardiography (TEE) is used and accepted as a method for detecting right-to-left cardiac shunts, most commonly caused by patent foramen ovale (PFO). Transcranial Doppler (TCD) is an accepted alternative test involving the injection of agitated saline with a timed and gauged Valsalva maneuver. Controversy exists about the exact role of PFO in patients with cryptogenic stroke and the resultant therapeutic alternatives; however, there is no controversy about the need to accurately detect the PFO. Methods We reviewed the records of 264 consecutive patients referred for TCD with the diagnosis of cryptogenic stroke or transient ischemic attack. Results A total of 89 (33.7%) patients had a positive TCD test for PFO; 39 went on to have TEE studies. A total of 19 of the TEE results failed to confirm the PFO (48.7%). TEE in the East Texas Region is routinely performed by the use of conscious sedation, which requires the supervising cardiologist to compress the abdomen to simulate Valsalva. Conclusion In the East Texas region, transcranial Doppler is superior to transesophageal echocardiography for the detection of right-to-left shunt in stroke patients, presumably because of the Valsalva limiting effect of intravenous sedation routinely given during the latter procedure.