Researchers used electronic billing records to identify clinical characteristics of the patients, including
diseases, such as diabetes, peripheral vascular disease (a narrowing of vessels other than those of the
heart [such as in the leg]), or a history of heart failure or smoking. After “matching” patients
to make groups that had similar proportions of patients with each of these and many other characteristics,
they then compared the survival of those who had CABG with those who had PCI.