Transcatheter heart valve (THV) replacement is an advancing field, with various valve designs incorporating features like flexible frames to improve valve hemodynamics, durability, and patient outcomes. Leaflet pinwheeling, a common metric, is thought to negatively impact long-term durability. This study investigates the pinwheeling index and its correlation with stress distribution across different THV designs. Three THV designs were created using an optimization framework, each with a nominal size of 26-mm and varying leaflet coaptation heights of 10-mm, 13-mm, and 16-mm. Each valve design was evaluated under two conditions:​ one with a rigid frame and one with a flexible frame. The valves were implanted with a 90 % area expansion ratio, and their performance was assessed by examining key mechanical parameters, including the pinwheeling index and maximum in-plane principal stress under a diastolic loading condition. At a coaptation height of 10-mm, the pinwheeling index was 0 % for both frame types. At 13-mm, the rigid frame maintained a low index of 2 %, while the flexible frame increased slightly to 4 %. At 16-mm, the index rose for both frames, with the rigid frame at 7 % and the flexible frame at 10 %. The study found that leaflet stress was unrelated to the pinwheeling index. While flexible frames may reduce stress and improve long-term durability, they increase the pinwheeling index. Therefore, the traditional pinwheeling index may not reliably predict accelerated leaflet degeneration across different valve designs in comparative analyses. A comprehensive evaluation incorporating computational modeling, digital image correlation, and experimental validation is crucial for preclinical assessments.