An 81-year-old woman was admitted to our hospital because of heart failure caused by severe aortic stenosis. On computed tomographic (CT) analysis, the annulus area was 612 mm2 (Fig. 1a), and the heights of left and right coronary ostia were 12.9 and 12.1 mm, respectively. The diameters of the sinuses of Valsalva were greater than 30 mm, which indicated a low risk of coronary obstruction (Fig. 1b). Coronary angiography showed a mild coronary lesion in the mid left anterior descending (LAD) and no stenotic lesion was observed in the left main coronary artery (LMCA) (Fig. 1c). Transcatheter aortic valve implantation (TAVI) was performed using a 29-mm Sapien 3 prosthesis (Edwards Lifesciences, Irvine, CA) (Movie S1) after confirming the coronary flow during balloon aortic valvuloplasty using 25 mm balloon (Fig. 1d). After valve implantation, ventricular fibrillation developed. Coronary angiography revealed 99% stenosis of the LMCA, which was covered by the frame of the valve (Fig. 1e). A drug-eluting stent was successfully implanted (Fig. 1f–h), and intravascular ultrasound revealed a protruding structure that had a high-echoic surface with backward attenuation without stent coverage (Fig. 1i; Movie S2). CT images 3 months later suggested that the commissure of the Sapien 3 prosthesis (Fig. 1j, k), which consisted of 2 struts (Fig. 1l), might have blocked the LMCA ostium (Movie S3). Calcification of the native aortic valve of left coronary cusp was minimal and may not reach the LCMA (Fig. 1n).