In vitro study of a standardized approach to aortic cusp extension

Purpose: Cusp extension technique (CET) is a reparative surgical procedure for restoring aortic valve function by suturing patches to the compromised native leaflets. Its outcomes are strongly dependent on the ability of the surgeon. We proposed and tested a novel approach on an in vitro model, aimed at standardizing and simplifying the surgical procedure. Methods: A set of standard pre-cut bovine pericardium patches, available in different sizes, was developed. The surgeon can choose the leaflet-specific patches to be implanted according to the patient anatomy, using a geometrical model of the aortic valve whose inputs are the measured intercommissural distances. The hemodynamic performance of this approach was evaluated on porcine aortic roots in a pulsatile mock loop. Hydrodynamic and kinematic evaluation of the samples was provided. Results: After CET, mean and maximum pressure drops were 3.1 ± 1.3 mmHg and 25.4 ± 5.0 mmHg respectively, and EOA was 3.8 ± 0.8 cm2. Static regurgitant fraction and closing volumes were 6.9 ± 2.7% and 7.0 ± 1.5 mL, respectively. All the hemodynamics changes induced by the surgery were statistically significant yet clinically irrelevant as compared to baseline. The treatment also induced a statistically significant alteration in the closing time of the valve. Conclusions: Our approach to cusp extension proved to be reliable and effective in restoring valve functioning, without significantly altering the physiological kinematics. The use of pre-cut patches considerably simplified the surgery, increasing standardization and repeatability.