A valve prosthesis comprising: a valve body; and a self-expanding frame (11, 13, 15, 17), wherein the valve body includes a first leaflet (31a, 35a, 37a), a second leaflet (31b, 35b, 37b), and a third leaflet (31c, 35c, 37c), adjoining leaflets (31a-c, 35a-c, 37a-c) sewn together to form a first commissure point (41d, 43d, 45d), a second commissure point (41a, 43a, 45a), a third commissure point (41b, 43b, 45b), and a fourth commissure point (41c, 43c, 45c), wherein the four commissure points (41a-d, 43a-d, 45a-d) are sewn to the frame (11, 13, 15, 17), wherein the first leaflet (31a, 35a, 37a) is attached to the second leaflet (31b, 35b, 37b) at the first commissure point (41d, 43d, 45d) and the second commissure point (41a, 43a, 45a), and the third leaflet (31c, 35c, 37c) is attached to the second leaflet (31b, 35b, 37b) at the third commissure point (41b, 43b, 45b) and the fourth commissure point (41c, 43c, 45c). wherein the first commissure point (41d, 43d, 45d) and the second commissure point (41a, 43a, 45a) form a first angle (61a, 65a, 67a), the second commissure (41a, 43a, 45a) and the third commissure (41b, 43b, 45b) form a second angle (61b, 65b, 67b), the third commissure (41b, 43b, 45b) and the fourth commissure (41c, 43c, 45c) form a third angle (61c, 65c, 67c), the fourth commissure (41c, 43c, 45c) and the first commissure (41d, 43d, 45d) form a fourth angle (61d, 65d, 67d), wherein the center (11, 13, 15, 17) of the frame is a vertex of the four angles (11, 13, 15, 17), and wherein the first angle (61a, 65a, 67a) and the third angle (61c, 65c, 67c) are greater than the second angle (61b, 65b, 67b) and the fourth angle (61d, 65d, 67d). a valve body; and a self-expanding frame (11, 13, 15, 17), wherein the valve body includes a first leaflet (31a, 35a, 37a), a second leaflet (31b, 35b, 37b), and a third leaflet (31c, 35c, 37c), adjoining leaflets (31a-c, 35a-c, 37a-c) sewn together to form a first commissure point (41d, 43d, 45d), a second commissure point (41a, 43a, 45a), a third commissure point (41b, 43b, 45b), and a fourth commissure point (41c, 43c, 45c), wherein the four commissure points (41a-d, 43a-d, 45a-d) are sewn to the frame (11, 13, 15, 17), wherein the first leaflet (31a, 35a, 37a) is attached to the second leaflet (31b, 35b, 37b) at the first commissure point (41d, 43d, 45d) and the second commissure point (41a, 43a, 45a), and the third leaflet (31c, 35c, 37c) is attached to the second leaflet (31b, 35b, 37b) at the third commissure point (41b, 43b, 45b) and the fourth commissure point (41c, 43c, 45c). wherein the first commissure point (41d, 43d, 45d) and the second commissure point (41a, 43a, 45a) form a first angle (61a, 65a, 67a), the second commissure (41a, 43a, 45a) and the third commissure (41b, 43b, 45b) form a second angle (61b, 65b, 67b), the third commissure (41b, 43b, 45b) and the fourth commissure (41c, 43c, 45c) form a third angle (61c, 65c, 67c), the fourth commissure (41c, 43c, 45c) and the first commissure (41d, 43d, 45d) form a fourth angle (61d, 65d, 67d), wherein the center (11, 13, 15, 17) of the frame is a vertex of the four angles (11, 13, 15, 17), and wherein the first angle (61a, 65a, 67a) and the third angle (61c, 65c, 67c) are greater than the second angle (61b, 65b, 67b) and the fourth angle (61d, 65d, 67d).