3. I. Doppler Ultrasound A Doppler Ultrasound test uses bounced sound vibrations to check blood as it goes through a major artery or vein. It assists physicians in checking blood flow through the major blood vessels in the neck, arms and legs. It can show reduced or blocked flow narrowing in the major neck arteries that could lead to a stroke. It also can reveal blood clots in leg veins (dvt, or deep vein thrombosis) that could break loose and block blood flow to the lungs (aka pulmonary embolism). During gestation, Doppler ultrasound may be used to look at blood flow in a fetus to check it’s health).
4. Doppler Ultrasound (Cont’d) Doppler Ultrasound uses the principles of the Doppler shift (aka the Doppler effect), which was named after Austrian physicist Christian Doppler, who theorized it in 1842. It is the change in frequency of a wave for an observer moving relative to the source of the wave. As an example, it’s experienced when one’s on a moving train that passes the ringing bell at a railroad crossing. The received sound waves are higher (compared to the actual frequency) during the approach, identical at the instant of passing the bell and is lower as the train passes.
6. II. Extracorporeal Circulation Extracorporeal circulation (aka minimized extracorporeal circulation, or MECC) is a type of cardiopulmonary bypass (heart-lung machine) a part of cardiac surgery. The first successful use of extracorporeal circulation was in experiments on cats in 1937. These experiments were performed by Dr. John H. Gibbon, Jr. The first commercial extracorporeal circulation was the CorX System from Cardiovention, a start-up US company, around 1999. Another machine, the MECC Macquet, was introduced at about the same time. These machines are used often because a lower consumption of blood and blood products has been observed in the perioperative & postoperative phases. Also, a lower inflammatory respone has been measured in perioperative blood samples as compared to conventional cardiopulmonary bypass surgery.
8. III. PercutaneousTransluminal Coronary Angioplasty (PTCA) PercutaneousTransluminal Coronary Angioplasty (PTCA), also known as percutaneous coronary intervention (PCI) or angioplasty. This is the therapeutic procedure used to treat the stenotic or narrowed coronary arteries of the heart found in coronary heart disease. These narrowed arteries arise from the buildup of cholesterol-laden plaques that form due to athersclerosis, the most common form of arterioscerosis (a condition with thickening, hardening & loss of elasticity of the walls of the arteries). The term balloon angioplasty is commonly used to describe PTCA, which describes the inflation of a balloon within the coronary artery to crush the plaque into the walls of the artery. While balloon angioplasty is still done as part of nearly all PTCAs, it’s rarely the only procedure performed.
9. III. PTCA (Cont’d) Other procedures that are done during a PTCA include: 1. Atherectomy, or the incision of fatty substances. 2. The implantation of stents (stainless-steel tubes placed within blood vessels or ducts to widen the lumen, or the space cavity or channel within a tube or tubular organ or structure in the body. 3. Brachytherapy, which is the use of a radioactive source to inhibit restenosis(the reoccurrence of stenosis).