Medtronic Plc has recalled 6,912 units of loading system of a recently approved heart device after reports of the presence of particulates. 

The medical device maker said it received 8 reports related to the issue out of 7,347 potentially affected units through July 6, but no reports of "adverse patient effects". 

All affected systems have been withdrawn from the market, Medtronic spokeswoman Wendy Dougherty told Reuters on Thursday, adding that no affected loading systems had been released commercially in the United States.

The U.S. Food and Drug Administration classified the recall as "Class 1", implying there is a reasonable probability that the use of or exposure to the product could cause serious side-effects or death. 

The product, EnVeo R Loading System, is part of Medtronic's CoreValve Evolut R system, which was cleared for marketing in the United States in June.

The Evolut device is approved for transaortic valve replacement (TAVR) in patients with severe aortic stenosis — a condition where the aortic valve narrows — and for whom surgery is too risky.

The presence of particulates could potentially lead to the introduction of a blockage in the bloodstream, Medtronic said in a letter to customers.

The issue has been resolved with improvements in the manufacturing process, Dougherty said.

Shares of the medical device maker, which bought Ireland-based Covidien in January for about $50 billion, closed down about 2 percent at $77.41 on the New York Stock Exchange.