Background: Transesophageal contrast echocardiography (cTEE) is considered to be the method of choice for diagnosing patent foramen ovale (PFO), but its diagnostic accuracy compared with color Doppler guided TEE in the presence of an Eustachian valve (EV) has not been evaluated. The main aim of this study was to assess the diagnostic accuracy for PFO diagnosis of color Doppler TEE at low pulse repetition frequency.
Methods: We ascertained the presence of PFO and EV using cTEE and transthoracic contrast echocardiography (cTTE) in 292 consecutive patients (age 42+/-12 years) with cryptogenic stroke. A diagnosis of PFO was based on the observation of right-to-left shunting of contrast bubbles or by color Doppler with pulse repetition frequency of 20-30 cm/s. An EV with a diameter of >1.5 cm in the bicaval view was considered large.
Results: Overall 204 patients (70%) had evidence of a right-to-left shunt by either contrast echo method. Shunting was demonstrated more frequently by color Doppler than by cTEE, either spontaneously (133 vs. 92; p=0.01) or during provocative maneuvers (166 vs. 184; p=0.01). The sensitivity of color Doppler was significantly higher than that of cTEE (90% vs. 81%; p=0.01). A large EV was found in 37 patients, 31 (84%) of whom had a PFO. The presence of a large EV did not significantly influence the sensitivity of color Doppler for detecting shunting through a PFO, but the sensitivity of cTTE and cTEE was significantly reduced (from 88% to 42%, p<0.001).
Conclusions: Color Doppler TEE is more accurate than traditional cTEE for PFO diagnosis and is not negatively influenced by the presence of an EV, provided that a low pulse repetition frequency is used.