Cardiac CT confirmation of normal prosthetic mechanical aortic valve function in patient with presyncope and significantly increased Doppler velocities

A 37-year-old man presented to our emergency department with unprovoked presyncope, breathlessness and atypical chest pain. His history included a Carbomedics 27 mm bileaflet mechanical aortic valve replacement (AVR) 18 years prior for endocarditis, severe aortic regurgitation and left ventricular systolic dysfunction (LVSD). A biventricular pacemaker (cardiac resynchronisation therapy with defibrillator (CRT-D)) was implanted 7 years later. Observations, including postural blood pressure, biventricular-paced ECG and bloods including troponin and D-dimer assays, were unremarkable. CRT-D interrogation demonstrated no arrhythmias. Although the international normalised ratio (INR) was satisfactory on admission (2.8), compliance with taking daily warfarin was inconsistent with poor anticoagulation clinic attendance. The time spent in therapeutic INR range was hence only 60%. Given the above and increasing Doppler AVR velocities on transthoracic echocardiography (TTE) 2 years prior (VMax 2.6 m/s (mean gradient 26 mm Hg) vs VMax 1.6 m/s (mean gradient 7 mm Hg) 8 years ago), TTE was repeated (figure 1A,B). This demonstrated a severely dilated and impaired left ventricle and significantly elevated AVR Doppler velocities (VMax 3.6 m/s (mean gradient 28 mm Hg), dimensionless index 0.22, acceleration time (AT) 130 ms and AT/ejection time ratio 0.5) compared with previous studies and reference values, especially when considering severe LVSD, leading to suspicion of severe AVR obstruction as cause of symptoms. There was no significant aortic regurgitation. However, TTE image quality was suboptimal due to echocardiographic windows and AVR reverberation artefact, precluding accurate leaflet assessment. …