Citing worries over a potential slowdown in the company's topline growth, particularly with its electrophysiology division, Needham downgraded Boston Scientific (BSX, Financials) to Hold on Friday.

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Analyst Mike Matson highlighted that the growth story for Boston Scientific depends heavily on its cardiac implant, Watchman. Watchman is a medical device that's effectively designed to reduce the risk of stroke in patients suffering from atrial fibrillation (AFib) who have failed to take long-term blood thinners.

Currently, under a global study called OPTION, the gadget is being studied on 1,600 individuals who have either received or advised ablation treatment for atrial fibrillation. Matson, however, felt he is uncertain over the influence of the trial. "New Medicare reimbursement and the OPTION trial may increase Watchman's use with ablation procedures, but without labeling or guidance changes, the impact may be limited," he said.

Though investor interest remains minimal, Matson also pointed out potential hazards about Boston Scientific's ACURATE trial for its aortic valve platform, implying that the result might impact the price by 5-10%. Also, Matson pulled his price target after Boston Scientific shares sped ahead of Needham's previous price estimate and he concluded the stock is now fairly valued.

This article first appeared on GuruFocus.