Does the Hancock Modified Orifice prosthesis (HMO-250) improve hemodynamic characteristics compared to the standard model 243 in patients undergoing aortic valve replacement?
The 21 and 23 mm Hancock Modified Orifice prostheses are hemodynamically supported only for patients with BSA <1.8 m2, and the 19 mm size is not recommended.
Nineteen patients with Hancock Modified Orifice prosthesis (HMO-250), size 19 to 23 mm, were recatheterized 6 to 16 months following aortic valve replacement (AVR). Although hemodynamic characteristics varied widely, HMO-250 compared favorably to the standard model 243 (less than 0.05). Mean peak resting gradient across HMO-250 was 14.8 torr at rest and rose to 26.8 torr with exercise. Systolic gradients for HMO-250, both resting and exercise, were improved for 21 mm (p less than 0.01), but not for 23 mm. Increasing the patient's body surface area (BSA) correlated with increasing gradients for 23 mm (p less than 0.05), but was unrelated to 21 mm. Effective orifice areas were similarly found to be improved with 21 mm HMO-250 but unchanged for 23 mm. Use of the 21 or 23 mm size HMO for AVR is supported only when the patient's body surface area is less than 1.8 m2. If the body surface area is greater than 1.8 m2, annulus enlargement and a larger size bioprosthesis should be employed. Use of 19 mm porcine xenograft for AVR is not supported.
Craver et al. (Wed,) studied this question.