Cough maneuver is superior to Valsalva maneuver for detecting mild-extent right-to-left shunt.

Objective

The purpose of this study was to explore the different provocative maneuvers in detecting right-to-left shunt during contrast transthoracic echocardiography (cTTE).

Methods

We evaluated 378 patients for right-to-left shunt detection by cTTE at the quiet respiration, during Valsalva maneuver (blowing into a face mask connected to a sphygmomanometer at 40 mmHg for 10 s), and during cough maneuver, performed in random order, and the degree of right-to-left shunt as the number of microbubbles in the left atrium per frame after each provocative maneuver was recorded.

Results

The detection rates of right-to-left shunt for quiet respiration, Valsalva maneuver, and cough maneuver were 16%, 33%, and 38%, respectively (p < .001). The detection rate for cough maneuver was significantly higher than that for Valsalva maneuver (p < .001). There was no significant difference between Valsalva maneuver and cough maneuver in terms of detecting moderate- or severe-extent right-to-left shunt (p > .05), but cough maneuver was significantly better than Valsalva maneuver at detecting mild-extent right-to-left shunt (p = .001).

Conclusions

Cough maneuver is an effective alternative to Valsalva maneuver, with a higher detection rate for mild-extent right-to-left shunt during cTTE, maybe due to its own mechanical characteristics.