Updated from 12:10 p.m. ESTGuidant ( GDT) added another problem to its growing list of device woes, saying Wednesday that it won't ship one of its stents because part of the Xience V line wasn't manufactured in a way that complied with quality measures. The Indianapolis-based company, which makes a variety of medical devices for patients with heart problems, also stopped enrolling participants in a clinical trial. Shares of Guidant dipped 11 cents to $78.29 following the news. Guidant said in a press release that it failed to follow "strict adherence to its quality standards" in making about 1% of its Xience V stents, and therefore won't release any of its current inventory of the product line. As a result, the company will take a charge of $15 million and delay the European rollout of the devices until the third quarter. Stents are mesh tubes designed to prop open arteries that have been clogged. Guidant said it halted patient enrollment in a late-stage Xience safety and efficacy study called Spirit III, but once new inventory is available, it will supply researchers with more of the stents. Guidant said its decision on the Xience is "to maintain the highest level of quality assurance." Questions about the quality of the products Guidant makes have had the company on the defensive for months. Last year, the company recalled tens of thousands of its implanted cardiac defibrillators after some of the devices were found to be defective. Defibrillators are designed to deliver an electric shock to patients with irregular heart rhythms. In some cases, patients underwent surgery to have the recalled devices removed. Earlier this month, the company recalled still more defibrillators after 39 incidents of low battery voltage were reported. Those devices weren't implanted, the company said, and no devices that have already been put in patients have demonstrated weak voltage.