Impact of ultrasound contrast agent during transoesophageal echocardiography on the sizing of the left atrial appendage

Introduction Interventional closure of the left atrial appendage closure (LAAC) has been established as an alternative treatment in patients with atrial fibrillation (AF) and an increased risk of stroke. So far it is unknown whether the use of ultrasound contrast agent (UCA) would influence the correct sizing of the LAA and thereby have an impact on device selection during interventional LAAC. Methods Between January 2017 and April 2018, 223 transoesophageal echocardiography (TOE) examinations were prospectively performed in adult patients with non-valvular AF (Impact of the use of ultrasound contrast agent on the detection of thrombi in the left atrial appendage during transesophageal echocardiography (CONDOR) study). LAA was examined both with and without the use of UCA. The following measurements were taken at 0o, 45o, 90o and 135o: diameter of LAA ostium, maximal depth of the LAA, maximal available depth of the LAA orthogonal to the ostial plane and area of the LAA. Results The use of UCA had no relevant influence on the size determination of the LAA. Additionally, Bland-Altman blots demonstrate a high degree of correlation between the measurements with and without UCA with no evidence for a systematic effect arising from the use of UCA. When comparing the measurements of two independent investigators, the use of UCA rather leads to a higher variability than to an improved precision. Discussion Despite the fact that the use of UCA during TOE leads to an improved rule out of thrombi, our study shows that there is no advantageous effect of UCA on the size determination of the LAA and should therefore not be used for this purpose.