"Patient and Hospital Characteristics Associated With Inappropriate Percutaneous Coronary Interventions"
http://content.onlinejacc.org/article.aspx?articleid=1738849   
JACC
"Conclusions  For nonacute indications, PCIs categorized as inappropriate were more commonly performed in men, whites, and those who had private insurance. Higher rates of PCI in these patient populations may, in part, be due to procedural overuse."