Value of the cough maneuver for detecting right‐to‐left shunt during contrast transthoracic echocardiography

Aim To explore the value of cough maneuver ( CM ) in detecting right‐to‐left ( RLS ) during contrast transthoracic echocardiography ( cTTE ) and its mechanism. Method We enrolled 196 patients with a high level of clinical suspicion of RLS underwent cTTE for RLS detection. Valsalva maneuver ( VM ) (blowing into a face mask connected to a sphygmomanometer at 40 mm Hg for 10 seconds) and CM were performed to provoke RLS , respectively. A comparison of the two provocative maneuvers in terms of the RLS ‐detection rate, the degree of RLS , the mobility of septum primum was done. Results The detection rates of RLS for CM were significantly higher than that for VM (38.3% vs 32.1%), ( P  < 0.001). There was no significant difference between VM and CM in terms of detecting moderate‐ or severe‐extent RLS ( P  > 0.05), however, CM was significantly better than VM in detecting mild‐extent RLS ( P  = 0.004). CM caused a greater mobility of septum primum than VM (20.1 ± 0.2 mm vs 6.3 ± 0.1 mm), ( P  < 0.001). Conclusion Cough maneuver had a higher detection rate for RLS than VM during cTTE , maybe due to its greater mobility of septum primum than VM caused.