Stentless bioprostheses have ideal haemodynamics, even in the small aorticroot

Objective: To determine normal Doppler and 2D gradients and flow characteri stics of the Freestyle(R) stentless aortic bioprosthesis related to valve s ize. Background: The Freestyle(R) stentless aortic bioprosthesis is one of the newer aortic xenografts. Only limited data are available of the echocar diographic flow characteristics during a mid-term follow-up period of this valve. Therefore valve performance related to valve size was measured durin g a follow-up period of two years. Methods: 175 consecutive patients with a Freestyle(R) aortic bioprosthesis underwent an echocardiographic and Doppl er examination according to a common protocol. Investigations were done wit hin 4 weeks after operation, after 3 to 6 months, and after 1 and 2 years. Results: With a valve size from 19 to 27 mm mean gradients decreased from 8 .0 +/- 5.1 mmHg at discharge to 5.8 +/- 3.8 mmHg after 3-6 months (p < 0.00 1). Thereafter gradients remained stable. The performance index, the ratio of the measured effective orifice area in the patient divided by the effect ive orifice area measured in vitro increased from 69 +/- 20% at discharge t o 79 +/- 29% after one, two and three years. Performance index was especial ly very high in the smaller sized valves with a performance index of 85 +/- 17% for the 21 mm valve. During follow-up mean gradients remained below 10 mmHg even in the 21 mm valve. Conclusion: Stentless xenografts have ideal haemodynamics, even in the small aortic root.