Comparison of transthoracic contrast echocardiography and transesophageal contrast echocardiography for detecting right to left shunt in patients with petent foramen ovale / 中华医学超声杂志（电子版）

ABSTRACT

Objective To compare the effect of transthoracic contrast echocardiography (cTTE) with transesophageal contrast echocardiography (cTEE) for detecting right to left shunt (RLS) in patients with patent foramen ovale (PFO). Methods The prospective study was conducted in 29 consecutive patients with PFO who suffered from cryptogenic stroke and/or migraine. Contrast echocardiography was performed in all 29 patients. The cTTE was performed using transducer with second harmonic imaging modality (transmitting frequency 1.7 MHz, receiving frequency 3.4 MHz). The cTEE was performed using transducer with frequency 7 MHz. Ten milliliter saline solution of contrast were rapidly administrated through an antecubital vein. According to whether microbubble (MB) appearing in left atrium after complete opaciifcation of right atrium within the ifrst 3 circles, the results were classiifed by a four-level semi-quantitative categorizationLevel 1 (no PFO-RSL), no MB in left atrium; Level 2 (small PFO-RSL) 1-10 MBs; Level 3 (medium PFO-RSL) 10-30 MBs;Level 4 (large PFO-RSL)>30 MBs. Results The total detection rate of PFO-RSL was signiifcant different between cTTE and cTEE (86.2%vs 55.2%,χ2=5.711, P=0.017). In cTTE there were 4 cases at level 1, 1 case at level 2, 5 cases at level 3 and 19 cases at level 4. In cTEE there were 13 cases at leverl 1, 2 cases at level 2, 6 cases at level 3 and 7 cases at level 4. The comparison of semi-quantitative grading derived from cTTE and cTEE was also signiifcant different (Wilcoxon signed ranks test showed Z=-3.789, P=0.000). Conclusions The efifciency in detection of PFO-RLS with cTTE was better than with cTEE. Compared with cTEE, cTTE was easier in practice and brought less discomfort and complications to patients.