In a prospective but non randomised study to compare interrupted U clips with historical published results, the patency rate of coronary anastomoses was 100% at 6 months using the U clips compare to a patency rate of 90 -100% in the published series. (Wolf RK, Alderman EL, Caskey MP et al. Clinical and six month angiographic evaluation of coronary arterial graft interrupted anastomoses by use of a self closing clip device: a multicentre prospective clinical trial. J Thorac cardiovasc Surg 2003; 126(1): 168 - 178.)