I think there are two reasons.

First, all aspects of any trial (its design, conduct, analysis, and interpretation) have to get the approval of the scientific community before the company’s conclusions are accepted as valid. This is because the company’s interpretation of the results might be flawed for some reason or be biased. An objective assessment of the trial can only be obtained by independent peer review at a congress and/or in a journal. The quickest route is a congress, these days usually coupled with a simultaneously released publication in an electronic journal. For this reason, I think it’s likely that at least one paper on BETonMACE has already been written and is being refereed for publication in an e-journal such as NEJM or JACC, to be released when the AHA presentation is given (often a final slide is shown providing the url). 

The second reason is that this is part of the deal with the investigators. It’s a universal understanding between inustry and academia that clinical trials will be treated like any other scientific experiment. To them it’s science, not business.