In vitro comparison of different mechanical prostheses suitable for replacement of the systemic atrioventricular valve in children.

OBJECTIVE

The aim of the present study was to compare the hydrodynamics of 4 different mechanical prostheses fitting the atrioventricular annulus in children.

METHODS

We tested different inverted aortic prostheses with a prosthesis-annulus relationship in the mitral chamber of the Sheffield pulse duplicator (Department of Medical Physics and Clinical Engineering, Royal Hallamshire Hospital, Sheffield, UK), analyzed by comparing the prosthetic housing diameter and the predicted annulus diameter based on body surface area (0.8 and 1 m(2) corresponding to an annulus diameter of 18.8-20.2 mm). The On-X 19 (On-X Life Technologies, Inc, Austin, Tex), SJM Regent 19 (St Jude Medical Inc, St Paul, Minn), Sorin Overline 18 (Sorin Biomedica, Saluggia, Italy), and Medtronic Advantage Supra 19 (Medtronic Inc, Minneapolis, Minn) valves with a housing diameter of 19 to 20 mm were hydrodynamically compared. The tests were carried out at increasing pulse rate of 72, 80, 100, and 120 beats/min for a stroke volume of 20 and 30 mL. Therefore, cardiac output ranged from 1.44 to 3.6 L/min.

RESULTS

Regardless of the pulse rate and stroke volume, the Medtronic Advantage Supra valve showed the highest mean diastolic pressure difference at each cardiac output (P < .05). The mean gradients were significantly lower for the Sorin Overline valve regardless of the cardiac output, stroke volume, and pulse rate (P < .05). The effective orifice areas observed followed exactly the same behavior: the lowest for the Medtronic Advantage Supra valve and the highest for the Sorin Overline valve. The Sorin Overline valve showed the highest closure volumes (P < .05), and the On-X prosthesis showed the highest leakage volumes (P < .05). The Sorin Overline valve had the highest total regurgitant volume (P < .05), and the Medtronic Advantage Supra valve had the lowest total regurgitant volume (P < .05). The On-X valve showed the highest total energy loss regardless of the pulse rate at 20 mL of stroke volume, which was comparable to the SJM Regent and Sorin Overline valves at increased stroke volume. The Medtronic Advantage Supra valve showed the lowest total energy loss regardless of cardiac outputs (P < .05).

CONCLUSIONS

This hydrodynamic evaluation model allowed us to compare the efficiency of currently available valve prostheses suitable for atrioventricular replacement in children. Among these prostheses, the Sorin Overline valve showed the best diastolic performance. On the other hand, for total energy loss, the Medtronic Advantage Supra valve demonstrated excellent performance.