 That same day, Dr. Richard K. Myler of St. Mary's Hospital in San Francisco performed the second coronary angioplasty in the United States.The initial form of angioplasty was 'plain old balloon angioplasty' (POBA) without stenting, until the invention of bare metal stenting in the mid-1980s to prevent the early restenosis observed with POBA.Bare metal stents were found to cause in-stent restenosis as a result of neointimal hyperplasia and stent thrombosis, which led to the invention of drug-eluting stents with anti-proliferative drugs to combat in-stent restenosis.