Percutaneous Transluminal Coronary Angioplasty (PTCA)

   This procedure, known in medical terms as Percutaneous Transluminal Coronary Angioplasty (PTCA), is used to expand blocked arteries by inserting a slim hollow tube (catheter) through a major artery in an arm or leg and into the obstructed vessel. A small balloon at the tip of the catheter is inflated alongside the obstructing tissues, flattening them against the vessel wall, thereby restoring normal blood flow. About 405,000 initial and repeat angioplasties are performed in the United States each year at an average cost of $ 21,113.00. 


Coronary Artery Bypass Grafting (CABG)

    Also called Coronary Artery Bypass Graft (CABG), it is the surgical transplant of one or more blood vessels to carry (pipe) blood around the blocked portion of a coronary artery. This is a major operation that involves opening the chest and stopped the heart. About 485,000 such operations take place every year in the United States at an average cost of $32,347.00. 


Collateral Circulation

    This phrase refers to an auxiliary or supplemental network of tiny channels that usually lie dormant in muscular tissues and can be recruited to carry blood around obstructed main vessels. Collateral vessels begin to open or enlarge when a blockage in an artery produces a pressure differential across the well-supplied and poorly-supplied parts of the muscle. Over time, these accessory vessels can be transformed into significant conduits substituting for the blocked arteries. Probably because pressure differentials are lower, collateral circulations form less readily in the heart but can be life-saving when they do. The clinical benefits of EECP are believed to stem from enhanced development of collateral circulation to oxygen-deprived regions of the heart.( A possible explanation for the long-term reduction in angina often associated with one course of EECP treatment is that the procedure may improve the body’ s ability to develop collateral channels, which, once established, tend to remain.) 


Diastolic Pressure

    The period in the pumping cycle of the heart when the heart muscle relaxes, the chambers fill with blood, and the heart receives about 80% of its own supply of oxygen and other nutrients. 


Systolic Pressure

    The period when the heart contracts to force blood onward. The pumping action of the heart raises the blood pressure throughout the body to increase perfusion of tissues, but the heart muscle itself receives only about 20% of its supply at this time because the heart’s contraction squeezes and closes off many of its own blood vessels.  


What is augmentation?

    When the heart contracts during its pumping phase (systole), the coronary vasculature is squeezed by the powerful contraction of heart muscle, limiting the flow of blood to and within the muscle (myocardium). The myocardium must therefore receive most of its oxygenated blood during its period of relaxation (diastole), when the coronary arteries are most receptive to flow. Muscles, especially the large weight-bearing ones of the lower body, contain large numbers of blood vessels that cumulatively hold a large volume of blood. During EECP treatment, at the onset of each diastole, compressive air cuffs that surround the muscles of the lower body are quickly inflated in rapid succession; first at the calves, then at the lower thighs, and finally at the upper thighs and buttocks. The rapid and precisely timed “squeezing” of the muscles sends a wave of blood (and pressure) that travels toward the heart through both veins and arteries. The sequential compression ensures that the waves generated in the more distant calf muscles can pass under the next cuffs (lower thighs) and be reinforced (not trapped) by the second and third compressions of the sequence. The result of the combined compressions is an increase in venous return (delivery of deoxygenated blood to the right atrium), and an “augmentation” or enhancement of diastolic pressure, which improves myocardial perfusion (flow of blood through the coronary arteries and to the heart muscle). 


What is the blood pressure?

    The amount of blood pumped out of the heart (cardiac output), the tone of the walls of the arteries (vascular resistance), and the volume and viscosity of the blood influence the pressure (expressed in millimeters of mercury) of the blood against the walls of the arteries. Each blood pressure measurement has two numbers: the first or top number is systolic blood pressure (pressure within the arteries during systole, when the heart is contracting). The second or bottom number is diastolic pressure (pressure within the arteries when the heart is relaxing). Normally, systolic pressure is the higher number. During EECP treatment sessions, diastolic pressure is increased and systolic pressure is decreased, usually to a degree that diastolic pressure exceeds systolic pressure.  


What is the 冠状动脉硬化?

    Every year one million Americans develop atherosclerosis, partial or total blockage of arteries caused by deposits of fatty substances (plaques) in and on the walls of the vessels. The coronary arteries that supply blood to the heart are especially vulnerable.


What is the heart structure?

    An electrocardiogram is a recording of the heart’s electrical activity. It is detected by electrodes attached to the skin, and recorded in waves that are displayed graphically. The ECG provides information on heart rate, rhythm, and function. ECG may also indicate the presence of heart damage or inadequate blood and oxygen supply to the heart muscle, and abnormalities of heart structure.


What is re-stenosis?

   Unfortunately, treatment to clear blockages often result in cell regrow that can obstruct vessels again. This condition, called restenosis, occurs after about 20 to 30 percent of PTCA procedures. Repeat procedures are not uncommon, and restenosis rates after repeat PTCA are as high as 50 percent. 


What is systolic unloading?

    During EECP treatment, the air cuffs are simultaneously and quickly deflated at the beginning of each systole (ventricular contraction), relieving the compressive force that was being maintained by the inflated cuffs. This decompression allows vessels that had been “squeezed” by the cuffs to quickly re-conform, reducing resistance to the pumping action of the heart. This “unloading” of resistance during the heart’s contraction phase (systole) increases the heart’s output (volume of blood ejected with each contraction ). The heart’s oxygen demand is actually lowered as a result of the improved pumping efficiency.

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