Vascular surgery is a surgical subspecialty in which diseases of the vascular system, or arteries, veins and lymphatic circulation, are managed by medical therapy, minimally-invasive catheter procedures, and surgical reconstruction. The specialty evolved from general and cardiac surgery as well as minimally invasive techniques pioneered by interventional radiology. The vascular surgeon is trained in the diagnosis and management of diseases affecting all parts of the vascular system except those of the heart and brain. Cardiothoracic surgeons and interventional cardiologists manage diseases of the heart vessels. Neurosurgeons and interventional neuroradiologists surgically manage diseases of the vessels in the brain (e.g., intracranial aneurysms).