Preoperative planning for transaortic septal myectomy using cardiac computed tomography in patients with subaortic septal hypertrophy associated with aortic stenosis: case series.

Background: Electrocardiogram-gated cardiac computed tomography (CT) imaging enables a more accurate understanding of the patient's cardiac anatomy. Preoperative planning for transaortic septal myectomy (TASM), based on cardiac CT, may be useful in patients with subaortic septal hypertrophy associated with severe aortic stenosis (AS). Case summary: Two elderly patients (age >80 years) with subaortic septal hypertrophy associated with AS underwent surgical aortic valve replacement (SAVR) and concomitant TASM after preoperative planning based on cardiac CT. Both patients showed subaortic septal hypertrophy with blood flow acceleration, left ventricular (LV) hypercontractility, and a short distance from the coaptation point of the mitral valve to the septum, resulting in possible dynamic LV outflow tract (LVOT) obstruction after resolution of AS. Optimal mid-diastolic images, selected from the 70-80% phase, were used for preoperative TASM planning. Planned sizes for myectomy based on multi-planar reconstruction were 10 × 26 × 9 mm (width × length × depth) and 10 × 25 × 9 mm for patient 1 and 2, respectively, while resected tissue size was 10 × 24 × 8 mm and 9 × 24 × 8 mm in patient 1 and 2, respectively. After TASM procedure, SAVR was performed with bioprosthetic valve. Postoperative course of both patients was uneventful with no evidence of complete atrioventricular block, septal perforation, or blood flow acceleration at the LVOT. Discussion: Preoperative planning based on cardiac CT images is safe and useful for guiding adequate myectomy and preventing associated complications in patients with subaortic septal hypertrophy associated with AS.