(Reuters) – An FDA advisory panel offered a mixed view of Boston Scientific‘s (NYSE:BSX) Watchman heart device today, concluding it is probably safe but not particularly effective in reducing the risk of stroke in patients with a certain type of irregular heart beat.

Despite the lack of likely effectiveness, the panel voted 6-5, with 1 abstention, that the benefits outweigh the risks, with some panelists saying it should be an option for patients.

The FDA is not obliged to follow the advice of its advisory panels but typically does so.

Boston Scientific is seeking approval of the device to reduce the risk of stroke and blood clots in patients with non-valvular atrial fibrillation who would typically be treated with warfarin, a standard oral treatment that has some limitations.

The advisory panel has met twice before to discuss the product. In December 2013, it voted in favor of its safety and efficacy.

However, follow-up clinical trial data showed an additional risk of ischemic stroke in patients who received the Watchman. The new information prompted new questions about the device’s benefits and risk and led to today’s meeting.

BSX shares closed up 3.1% at $12.14 apiece.