The patient was an 82-year-old woman whose painful left foot was horribly disfigured by ulcers and gangrene brought on by lack of circulation. Her doctors at what is now Oregon Health & Science University wanted to amputate, but when she objected, she was referred to Charles Dotter, a radiologist at the hospital who was experimenting with new ways to open up narrowed or blocked arteries. At the time, 50 years ago, clearing clogged arteries involved surgery, a long time in the hospital and a high risk of complications. Dotter’s idea was to try unblocking them with catheters—slender, hollow tubes normally used in radiology to prepare for X-rays by injecting contrast dye into blood vessels.

X-rays showed that the woman’s leg had a narrowing in the femoral artery, which supplies blood to the lower extremities. That made her a perfect first candidate for Dotter’s scalpel-free artery repair. On January 16, 1964, he inserted a guide wire into the patient’s femoral artery and threaded it to the narrowed area. He then passed a catheter along the guide wire, followed by another, wider catheter. The procedure caused the artery to expand, and blood flow quickly returned to the woman’s foot. Several of her badly damaged toes eventually fell off, but the woman was able to walk out of the hospital on her own, living free of foot pain until she died two and a half years later.

Dotter’s innovation, along with other groundbreaking work (such as developing an early version of the stent, a tube that props open blocked arteries), led him to be regarded as the father of interventional radiology. But Dotter’s ideas, like his personality, were bold enough that many physicians in the United States dismissed him as “Crazy Charlie” and long ignored the procedure he eventually called percutaneous transluminal angioplasty (PTA). (A Life magazine article featuring photos of Dotter performing angioplasty, with blazing eyes and a rictus grin, probably didn’t help matters.) Dotter’s approach to clearing arteries had a better reception in Europe. In 1977, German-born physician Andreas Gruentzig introduced the balloon-tipped catheter, which uses tiny inflatable pouches to dilate narrowed coronary arteries. Today, angioplasty is performed on more than a million patients each year.