HEMODYNAMIC PERFORMANCES OF SMALL-DIAMETER CARBOMEDICS AND ST-JUDE VALVES

Background and aims of the study: Optimal hemodynamic performances are of paramount importance when implanting a mechanical valve in patient s with a small aortic annulus. A Doppler echocardiographic study was p erformed to compare the hemodynamic performances of small CarboMedics and St. Jude valves. Materials and methods: Twenty-nine patients recei ving either a 19 mm (n = 10) or a 21 mm (n = 10) CarboMedics valve or a 19 mm (n = 9) St. Jude Med HP valve were evaluated. A Doppler echoca rdiographic study was performed at rest and two minutes after treadmil l exercise with the Brace protocol. Peak and mean gradients across the valve were estimated; effective orifice area, performance index and d ischarge coefficient were calculated. Heart rate, blood pressure and c ardiac output were all significantly increased with exercise. Results: Peak and mean gradients at rest were significantly higher (p < 0.05) in the 19 mm CarboMedics valve (40.2 +/- 15 mmHg and 22.6 +/- 9 mmHg, respectively) when compared either with 21 mm CarboMedics valve (27.6 +/- 6.8 mmHg and 14.2 +/- 3.4 mmHg, respectively) or with the 19 mm St . Jude HP valve (23.6 +/- 10.4 mmHg and 13.6 +/- 5 mmHg, respectively) . Peak and mean gradients were not modified with exercise for the 19 m m CarboMedics valve and significantly increased for the 21 mm CarboMed ics and the 19 mm St. Jude HP valves. Although these values were still higher in the 19 mm CarboMedics valve, they did not reach the level o f statistical significance when compared with the other two valve grou ps. Conclusions: The 19 mm St. Jude HP valve shows hemodynamic perform ances at rest that are similar to those of the 21 mm CarboMedics valve and superior to those of the 19 mm CarboMedics valve, With exercise b oth sizes of the CarboMedics valve show an in vivo discharge coefficie nt close to one, testifying to a full utilization of the internal orif ice area.