A global perspective on the dissemination of mental health research.

1500 www.thelancet.com Vol 374 October 31, 2009 a prospective, randomised controlled trial would be most welcome to assist with the choice of bridging anticoagulation. Andrea Colli correctly points out that the Mitrofl ow pericardial valve is available in Canada and has recently become available in the USA. Although the Carpentier-Edwards Perimount valve and its variants still account for most pericardial valves implanted in North America, a broader array of bioprosthetic valves has now entered the marketplace. We adapted the antithrombotic management algorithm presented in fi gure 2 from the ACC/AHA and ACCP guidelines for patients with prosthetic heart valves. Colli highlights areas of disagreement between the ACC/AHA and ACCP guideline recommendations regarding aspirin dosing. The algorithm presented is based on our own critical review of the evidence.