A 2011 study by Dr. Diana Zuckerman and Paul Brown of the National Center for Health Research, and Dr. Steven Nissen of the Cleveland Clinic, published in the Archives of Internal Medicine, showed that most medical devices recalled in the last five years for "serious health problems or death" had been previously approved by the FDA using the less stringent, and cheaper, 510(k) process. In a few cases the devices had been deemed so low-risk that they did not need FDA regulation. Of the 113 devices recalled, 35 were for cardiovascular issues.[39] This may lead to a reevaluation of FDA procedures and better oversight.