Valsalva maneuver procedures in the diagnosis of right-to-left shunt by contrast-enhanced transcranial doppler using agitated saline solution with blood as a contrast agent

Abstract

To compare two different timings for the performance of the Valsalva maneuver (VM) using an infusion of agitated saline solution with blood as contrast agent (CA) to right-to-left shunt (RLS) screening. 42 patients were submitted to a standardized contrast-enhanced transcranial doppler (cTCD) to screen for right-to-left shunt (RLS). cTCD technique was done with two different moments of the VM: [1] the CA injection during the VM (CAduringVM test); [2] the CA injection before the VM (CApreVM test). Positive MCA tests were observed in 47 (56%) CAduringVM tests and in 50 (59.5%) CApreVM tests, p=0.64. There was an almost perfect agreement for the positive tests between the CAduringVM and CApreVM test, r s=0.829 (95% CI 0.61-1.00, p<0.001). The present study demonstrates that there is no significant difference in the results of RLS screening by cTCD when two different moments of VM were done.