Timing of Valsalva maneuver and contrast injection for detecting patent foramen ovale on transesophageal echocardiography

Abstract

Background and purpose : For investigating right-to-left shunt with transcranial Doppler, the Valsalva maneuver (VM) is recommended to be commenced five seconds after injection of contrast agent. When using transesophageal echocardiography (TEE) for detection of patent foramen ovale (PFO), VM is recommended to be commenced before injection. The aim of this study is to clarify the detection rates of PFO with TEE conducted with different VM timings. Methods : We enrolled patients who underwent TEE for detecting PFO. We performed VM four times with contrast agent (CA), twice with VM performed prior to CA injection (PreInj-VC) and twice with VM performed after CA injection (PostInj-VC). We diagnosed the presence of PFO and classified as follows: non-PFO, small-PFO (< 30 bubbles), large-PFO (≥ 30 bubbles). We calculated the concordance rate of diagnosis for PFO between PreInj-VC and PostInj-VC. Results : Of 79 patients (median age 66 years, male 68%), 30 patients (38%) had PFO (10 patients, large PFO; 20 patients, small PFO). PFO was identified in 27 patients on PreInj-VC and in 28 on PostInj-VC. Diagnostic agreement between PreInj-VC and PostInj-VC was found in 71 patients (90%). Regarding the PFO size, the concordance rate for large PFO was 96% ( κ = 0.82, p < 0.001) and that for small PFO was 92% ( κ = 0.80, p < 0.001). Conclusion : Diagnostic agreement of the deference timings of VM, such as PreInj-VC and PostInj-VC, was as high as 90%. Moreover, two timings of VM made diagnosis of PFO more accurate.