Case report: unravelling the puzzle of unicuspid aortic valve with multimodality imaging.

Background: Unicuspid aortic valve (UAV) represents a rare congenital anomaly characterized by two subtypes: acommissural unicuspid aortic valve and unicommissural unicuspid aortic valve. Acommissural UAV is often diagnosed and corrected during the neonatal period due to haemodynamic instability. Unicommissural UAV leads to aortic stenosis (AS) in early adulthood. The diagnostic challenge associated with UAV primarily stems from its eccentric orifice opening and valvular calcification, resulting in difficult visualization of the commissures and localization of the orifice plane. This case report aims to demonstrate the unique morphological features of UAV through a comprehensive analysis using multimodality imaging. Case summary: A 61-year-old woman presented to the emergency department for recurrent episodes of dyspnoea. Severe AS was diagnosed on transthoracic echocardiography (TTE) by Doppler haemodynamic measurement. However, follow-up transesophageal echocardiography (TEE) and CT transcatheter aortic valve replacement showed moderate AS by planimetry. Following this, patient was monitored closely, but her dyspnoea kept worsening. Cardiovascular magnetic resonance (CMR) was performed due to persistent dyspnoea, identifying UAV with eccentric loophole orifice with unicommissural attachment and opposite free leaflet edge. The patient was managed medically. Discussion: TTE is the test of choice for AS that defines valvular morphology by direct visualization and grades the severity by haemodynamic measurement. However, the accuracy of TTE can be limited by poor acoustic windows and heavy valvular calcification. TEE measures aortic valve area (AVA) by planimetry that requires accurate localization of the AV orifice plane. Similarly, it applies to multi-detector computed tomography (MDCT). While CMR is expensive and mainly available in tertiary centres, it can provide additional information when there is discordance.