William Weintraub, chief of cardiology at Christiana Care Health System in Delaware and the study's lead investigator, said the results call for more collaboration between heart surgeons who perform bypass surgeries and interventional cardiologists who deploy stents to make sure patients are carefully evaluated and informed of their options before their procedures.

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They brought in a second set of study participants and asked them to perform the same four mental tasks.

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Researchers recruited 48 adults for the study who were asked to learn and perform a specific finger pattern (pushing keys on a keyboard in a particular sequence as fast as possible in 30 seconds).

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HeartWare said that the FDA was requiring the company to perform a post-approval study in the form of a registry consisting of 600 HeartWare patients and an additional 600 control patients.

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