Clinical experience and Doppler echocardiographic assessment of the first one hundred ATS AP (advanced performance) prosthetic valve in the aortic position.

BACKGROUND AND AIM OF THE STUDY: The ATS Medical mechanical bileaflet valve is composed of pyrolitic carbon and is available in two forms: Standard and Advanced Performance. The study aim was to evaluate the clinical results and define, in blinded manner, the Doppler echocardiographic characteristics of normally functioning ATS AP prostheses with respect to their size.

METHODS: One hundred patients (63 men, 37 women; mean age 63.6 +/- 10.6 years) were studied between January 1996 and February 1999. Doppler echocardiography was performed at least three months after valve replacement (mean 1.68 +/- 0.86 months; range: 3 months to 3 years).

RESULTS: The in-hospital mortality was 3%, and there were four late deaths. None of the deaths was valve-related. Thromboembolic and anticoagulant-related hemorrhagic rates were 0.55% per patient-year (pt-yr) and 1.1% per pt-yr, respectively. Maximum and mean gradients were calculated using the simplified Bernoulli equation. Functional valve surface area was assessed using the continuity equation and time-velocity integrals using echographic measurements to calculate the subaortic surface. The Doppler velocity index was obtained from the ratio of subaortic and transaortic velocities. For the most frequently used aortic valve (22 mm), the maximum pressure gradient was 18.67 +/- 8.31 mmHg, the mean gradient 9.97 +/- 3.84 mmHg, functional surface area 1.50 +/- 0.35 cm2, and Doppler velocity index 0.41 +/- 0.08.

CONCLUSION: Based on Doppler echocardiographic characteristics, the new ATS Medical AP prosthesis, when implanted in the aortic position, has an excellent hemodynamic profile which compares favorably with that of similarly designed prostheses. The clinical results show a very low rate of thromboembolic and anticoagulant-related hemorrhagic events, perhaps due to the new design of the pivoting area.