Related Experiment Video
Updated: Jul 16, 2026
Full-root Aortic Valve Replacement by Stentless Aortic Xenografts in Patients with Small Aortic Roots
Published on: May 21, 2017
A randomized comparison of the Cryolife O'Brien and Toronto stentless replacement aortic valves
John B Chambers1, Helen M Rimington, Ronak Rajani
1The Valve Study Group, St Thomas Hospital, London, UK. jboydchambers@aol.com
Objective:
A composite stentless valve might be less obstructive than a preparation incorporating the porcine right coronary muscle bar. The aim of this study was to compare early hemodynamic function in a prospective series of 78 patients randomized to receive either a Toronto or Cryolife O'Brien stentless valve.
Methods:
Echocardiography was performed early after surgery, between 3 and 6 months, and at 1 year after surgery.
Results:
The groups were matched demographically. The Cryolife O'Brien valve was significantly less obstructive in terms of effective orifice area (1.81 vs 1.30 cm2; P < .0001), mean pressure difference (7.1 vs 11.7 mm Hg; P < .0001), and peak velocity (1.7 vs 2.2 m/s) assessed at 1 year (P = .001). Bypass time was 91 (SD 22) minutes for the Cryolife O'Brien compared with 125 (SD 22) minutes (P < .0001) for the Toronto. There was a higher incidence of paraprosthetic regurgitation in the Cryolife O'Brien valve (16.7% vs 3.2%). Mortality and clinical events were similar.
Conclusion:
The composite valve was less obstructive than the porcine valve, suggesting that stentless valves cannot be considered as a homogeneous class.
