National Affairs: CORONARY THROMBOSIS

Its Nature, Symptoms and Treatment

LIKE all the other muscles of the human body, the heart muscle itself requires freshly oxygenated blood to live. It gets its supply from the coronary arteries, which sprout from the trunk of the arterial tree, the aorta, and divide into hundreds of smaller branches to feed back into the heart muscle some of the arterial blood that the heart has just previously pumped out.

As humans grow older, the innermost layer (intima) of the arteries, ordinarily a thin, smooth membrane, tends to roughen and thicken in a process that may be compared to what happens when deposits of lime accumulate inside a water pipe. This change in the arterial wall is known generally as atherosclerosis.

The result of the thickening and roughening of the intima is to impede, or even stop, the passage of blood through the artery in which the condition exists. As the volume and surge of the blood decrease, a clot may form, often quite suddenly, around one of the rough projections that has grown on the arterial wall. The clot is a thrombus, the process of its formation is thrombosis, and if it happens in one of the coronary arteries, it is coronary thrombosis (while there are medical distinctions in their precise use, the terms “coronary occlusion” and “cardiac infarction” are generally synonymous with “coronary thrombosis”).

When a clot has caused a stoppage in a coronary artery, the area of heart muscle fed by that artery dies, just as, for example, the tissue of a finger dies if cut off from its blood supply. The damage is permanent, and its severity depends greatly on the size of the affected artery and the speed and completeness of the occlusion. If the artery in which the clot forms is small enough, a person may live to old age unaware of the thrombosis. If the closing of the artery occurs slowly enough, nearby arteries may grow in size and in their capacity to carry blood, and send out new sub-arteries to the danger area.

A mild coronary thrombosis could be one in which a relatively small coronary artery has been closed and a small heart area has suffered damage. One such attack increases the chance that the patient will have another, although modern anticoagulants reduce the danger.

The symptoms of coronary thrombosis vary greatly from patient to patient, but nearly always include a cramping pain in the chest that is sometimes very similar to the “gas pains” of indigestion. Often, the patient is short of breath, even when resting quietly, and may have to be propped up in bed. During and immediately after an attack, the blood pressure is usually low, the pulse rapid.

Despite the great advances in medicines and surgery, the main treatment still is rest, so as to keep the work done by the heart at a minimum and allow time for scar tissue to form. In many cases of lesser severity, the period of complete bed rest is about three weeks, followed by convalescence of two or three months; in more serious cases, convalescence lasts six months or more. Doctors’ long-term advice to most recovered coronary patients includes regular—but not strenuous—exercise, abstinence from tobacco, dieting against excess weight, and, insofar as it is possible, freedom from emotional tension. Under modern medical care, 80% of all coronary thrombosis cases survive their first attack, and many of them live long afterward.