Clarence Crafoord was a Swedish cardiovascular surgeon

Surgery

Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

, best known for performing the first successful repair of aortic coarctation

Aortic coarctation

Coarctation of the aorta, or aortic coarctation, is a congenital condition whereby the aorta narrows in the area where the ductus arteriosus inserts.-Types:There are three types:...

 on 19 October 1944, one year before Robert E. Gross

Robert E. Gross (surgeon)

Robert E. Gross was a surgeon famous for being the first to cure patent ductus arteriosus by ligating it.-Sources:...

.
Crafoord also introduced heparin

Heparin

Heparin , also known as unfractionated heparin, a highly sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule...

 as thrombosis prophylaxis in the 1930s and he pioneered mechanical positive-pressure ventilation during thoracic operations in the 1940s.

Crafoord was professor of thoracic surgery

Thoracic surgery

Thoracic surgery is the field of medicine involved in the surgical treatment of diseases affecting organs inside the thorax . Generally treatment of conditions of the lungs, chest wall, and diaphragm....

 at Karolinska Institutet

Karolinska Institutet

Karolinska institutet is a medical university in Solna within the Stockholm urban area, Sweden, and one of Europe's largest medical universities...

from 1948 to 1966.