(MENAFN - AFP) An implant device designed by US firm Boston Scientific to prevent strokes in high risk people helps avert blood clotting, a new study said.The umbrella-shaped device called "Watchman" can also serve as an alternative to treatment with anticoagulants of patients suffering from arterial fibrillation, a study by the manufacturer said.The trials involved 407 patients at 41 sites and compared the "Watchman" to warfarin, an anticoagulant medication, said the study, which was presented on Saturday.Of the people surveyed, 269 used "Watchman" and 138 took the blood thinner warfarin.The results show that "the device performed similar to warfarin with a rate ratio of 1.07", said the report, presented at an annual conference of the American College of Cardiology."The results ... add to the wealth of previously published data confirming the utility of the 'Watchmen' device as an option for the reduction of stroke in high risk patients," said Kenneth Stein, chief medical officer with the cardiac rhythm management department of Boston Scientific."'Watchman' is the only device-based alternative to anticoagulation that has undergone rigorous scientific study," he added."Watchman" is introduced into the heart via a catheter that goes through a vein in the groin.Atrial fibrillation affects approximately 15 million patients worldwide. Patients have a five times greater risk of stroke."Watchman" was approved for sale in Europe in 2005 and some countries in Asia in 2009, according to Boston Scientific.The results of the study will be submitted to the US Food and Drug Administration as part of a process to obtain approval for its marketing in the United States.