AN UNEXPECTED INTRAOPERATIVE UNUSUAL CASE OF AORTIC STENOSIS

Introduction Aortic stenosis is the most frequent valvular pathology in the developed countries (1). It is most often due to the calcified or degenerated aortic valve as a manifestation of ageing. Sub-valvular aortic stenosis is rare in the adult population being more common in children accounting for 8-20% of left ventricular outflow tract (LVOT) obstructions (2). Stenosis degree may change depending on the malformation varying from a minor ridge to a complete fibrous ring or tunnel. Although proper timing for surgery is unclear, diagnosis might be more difficult in the adult patient with transthoracic echocardiography as subvalvular portions of the LVOT might be shaded by calcium and difficult to visualize. We report a case of a 65 years old lady diagnosed with severe aortic stenosis and scheduled for aortic valve surgery. Methods The patient presented to our department with recent history of shortness of breath and clinical and transthoracic echocardiographic diagnosis os severe aortic stenosis. The maximum blood velocity across the aortic valve was 4.8 m sec-1 at continuous Doppler sampling. She was scheduled for aortic valve replacement. After establishing hemodynamic monitoring, general anaesthesia induction was performed with remifentanil, propofol and cisatracurium and maintained as TIVA. According to our protocol, a transesophageal echocardiography (TEE) was positioned and a baseline TEE was performed. Results TEE demonstrated a massive concentric hypertrophy of the left ventricle, a membranous subaortic stenosis and a normal aortic valve (fig. 1A,1B,1C). Surgery was then halted as the patient's written consent had been obtained for a valve replacement. Then the patient was further investigated by ECG gated cardiac CT scan, which confirmed the subvalvular membrane. The patient was then operated to remove the subvalvular membrane and a partial septal myectomy was also executed (fig 1D). She completely recovered and was discharged home on p.o. day 5. Discussion Differential diagnosis between aortic valvular stenosis or stenosis due to a subvalvular obstruction might be tricky, but is crucial for the operation result. TEE 2D and 3D imaging recognised the anomaly prior to surgery and so allowed to properly address the cardiac disease leading to post-operative success. Perioperative TEE should be performed in a systematic manner according to the current guidelines (3), but beyond the level of re-confirming the expected findings prior to surgery. TEE allowed for rapid and thorough recognition of previously undiscovered pathology leading to proper patient's management and case resolution, so confirming the importance of perioperative TEE in the setting of surgical treatment of heart valve diseases.