Coronary occlusion (CO) is a lethal complication of transcatheter aortic valve replacement (TAVR) (incidence, 0.35%–4.0%; in-hospital mortality, approximately 50%). Although static computed tomography thresholds (ostial height >12 mm) remain the assessment standard, CO still occurs in 14.3% of patients meeting them. We developed a biphasic digital twin (BDT) integrating systolic and diastolic electrocardiogram-gated computed tomography angiography to assess dynamic CO risk in a 71-year-old woman with severe aortic stenosis. Biphasic aortic root dynamics and bilateral virtual valve-to-coronary distance (VTC) were evaluated at two implantation depths. Ostial height varied by approximately 5%, whereas leaflet volume increased by 22.0% in diastole. Right coronary ostial displacement (4.28 mm) was 1.74-fold that of the left (2.46 mm), and the sinotubular junction rotated 8.7°. A commissural calcified mass remained stable. Implantation 5 mm deeper reduced diastolic left VTC from 8.96 to 6.54 mm (–27%) but increased systolic right VTC from 4.57 to 5.93 mm (+29%). Delayed CO occurred 30 min after extubation despite patent intra-procedural angiography; surgery confirmed calcified anchoring, stent deflection, and coronary compression. Static coronary height did not capture dynamic CO risk in this patient. BDT may support individualised, biphasic, bilateral assessment by integrating dynamic leaflet expansion, asymmetric root motion, and calcified anchoring.