Diagnostic Accuracy of Echocardiography and Intraoperative Surgical Inspection of the Unicuspid Aortic Valve

Unicuspid aortic valve (UAV) is a rare malformation that is often difficult to distinguish from a bicuspid aortic valve (BAV) with commissural fusion by echocardiography or intraoperative surgical inspection. This study assessed the accuracy of intraoperative surgical inspection and two-dimensional echocardiography in diagnosing UAV compared to a gold standard of pathological diagnosis. The Mayo Clinic echocardiographic database, tissue registry database and electronic medical record were searched for all patients assigned a diagnosis of UAV by any technique. Transthoracic (TTE), transesophageal (TEE) echocardiographic, and surgical diagnoses were compared to pathological diagnosis as the standard. A clinical diagnosis of UAV was applied to 380 patients by 1 or more method and in 196 (52%) a pathologic evaluation was available to compare to the clinical description given by TTE, TEE, or surgical inspection. Of these 196 patients, only 58 (30%) had a pathological diagnosis of UAV; the majority were found to be BAVs by pathologic evaluation (n = 132, 67%). For diagnosing UAV, the sensitivity and specificity were 15% and 87% for TTE, 28%, and 82% for TEE, and 52% and 51% for surgical inspection, respectively. Valves with bicuspid morphology and extensive commissural fusion were frequently misclassified as UAV by all methods. In conclusion, intraoperative surgical inspection and echocardiography have limitations for diagnosing UAV due to difficulties in accurately assigning a correct morphological diagnosis, which suggests that the current understanding of the natural history of UAV may be inaccurate.