More than 23 patients at St. John Medical Center may have had stents they did not need inserted into arteries in their hearts. The physician who placed those stents is no longer practicing at the Westlake hospital where he completed the procedures over the past two years. In addition, St. John is reviewing other stent work the doctor performed. Patients who receive the devices are at a slightly increased risk for complications. But hospital officials know of no deaths or serious side affects in these cases.