Abstract
OBJECTIVE: Contrast transthoracic echocardiography (c-TTE) is widely used for the diagnosis of patent foramen ovale (PFO), where the Valsalva maneuver (VM) serves as the standard provocative maneuver to optimize detection. This study aimed to evaluate diaphragmatic downward excursion (DDE) as a novel c-TTE-based parameter for objectively quantifying VM efficacy, thereby establishing a standardized assessment metric. METHODS: We studied 145 patients with high clinical suspicion of PFO-related conditions. All participants underwent both c-TTE and contrast transesophageal echocardiography (c-TEE) examinations. Based on intraoral expiratory pressure exceeding 40 mmHg under c-TTE, patients were divided into adequate Valsalva maneuver (AVM) group (n = 90) and non-adequate Valsalva maneuver (non-AVM) group (n = 55). We compared the two groups in terms of DDE at the roof of the right atrium (DDE-RRA) and intracardiac hemodynamic parameters. RESULTS: DDE-RRA was significantly lower in the AVM group than in the non-AVM group (7.3 mm vs. 3.1 mm, P < 0.001). ROC analysis identified 5 mm as the optimal cutoff value for evaluating VM efficacy, with a sensitivity of 77.8%, specificity of 92.7%, and an AUC of 0.90. The kappa test showed good agreement between DDE-RRA and insufflation manometry (kappa = 0.63, P < 0.001). Furthermore, the DeLong test demonstrated that the AUC of DDE-RRA was significantly greater than that of all assessed intracardiac hemodynamic parameters, including mitral and tricuspid peak E and A-wave velocities, as well as mitral and tricuspid velocity time integrals (all P < 0.05). CONCLUSION: DDE provides a simple and objective method for assessing VM efficacy under c-TTE, showing superior diagnostic performance compared with conventional intracardiac parameters. As this represents an initial attempt, further studies incorporating invasive validation are needed to confirm its clinical value.