Importance of Abdominal Compression Valsalva Maneuver and Microbubble Grading in Contrast Transthoracic Echocardiography for Detecting Patent Foramen Ovale

Background: Although transthoracic echocardiography (TTE) may be useful for patent foramen ovale (PFO) screening, the optimal methodologies remain unclear. The aims of this study were to evaluate the efficacy of the abdominal compression Valsalva maneuver and identify the optimal cutoff value of microbubbles in contrast TTE for detecting PFO, compared with transesophageal echocardiography and catheterization as the reference. Methods: One hundred thirty-four patients with cryptogenic stroke or migraine who had suspected PFO and underwent TTE and transesophageal echocardiography plus catheterization were enrolled. The sensitivity, specificity, and accuracy of TTE for PFO detection were analyzed according to different provocations (spontaneous Valsalva maneuver, abdominal compression Valsalva maneuver) and different cutoff values of microbubbles for a positive result (at least one microbubble, at least five microbubbles). Results: Eighty patients had PFO confirmed by transesophageal echocardiography and catheterization. When the cutoff was at least one microbubble, the sensitivity of TTE in detecting PFO was 93% with the spontaneous Valsalva maneuver and 99% with the abdominal compression Valsalva maneuver. When the cutoff was at least five microbubbles, sensitivity was 85% with the spontaneous Valsalva maneuver and 99% with the abdominal compression Valsalva maneuver. With the abdominal compression Valsalva maneuver, specificity was increased using the cutoff of at least five microbubbles compared with at least one microbubble (89% vs 57%). The abdominal compression Valsalva maneuver with the cutoff of at least 5 microbubbles provided the greatest accuracy of 95%. Conclusions: TTE with the abdominal compression Valsalva maneuver had excellent sensitivity. The cutoff of at least five microbubbles increased specificity. Our findings suggest that TTE with these criteria is valuable for PFO diagnosis.