Degenerations

Disturbances of the Heart
by Oliver T. Osborne, M.D.

(Page 12 of 21)

Coronary Sclerosis

While disease of the coronary arteries may occur without general arteriosclerosis, it is so frequently associated with it that it is necessary to give a brief description of the general disease. Arteriosclerosis or arteriocapillary fibrosis is really a physiologic process naturally accompanying old age, of which it is a part or the cause, and it should be considered a pathologic condition only when it occurs prematurely. It may, however, occur at almost any age after 30, and is beginning to be frequent between 40 and 50. In rare instances it may occur between 20 and 30, and even in childhood and youth. It is much more frequent in men than in women. Its most common cause is hypertension; in fact, hypertension generally precedes it. The most frequent cause of hypertension today is the strenuousness of life, the next most frequent cause being the toxins circulating in the blood from overeating, overdrinking, overuse of tobacco and the overuse of caffein in the form of coffee, tea or caffein drinks. Another common cause of arteriosclerosis occurring too early is the occurrence of some serious infection in a person, typhoid fever and sepsis being most frequent. Syphilis is a frequent cause, especially of that form of arteriosclerosis which shows the greatest amount of disease in the aorta. Mercury used in the treatment of syphilis is more liable, however, than syphilis to be the cause of arteriosclerosis. Although this drug, even with the arsenic injections now in vogue, is necessary for the cure of syphilis, it probably tends to raise the blood pressure by irritating the kidneys and by diminishing the thyroid secretion, both of these occurrences predisposing to arteriosclerosis. From the fact that lead poisoning causes an increased blood pressure, lead is a probable cause of arteriosclerosis. With the greater knowledge of the danger of poisoning possessed by those who work in lead, chronic lead poisoning is becoming rare, as evidenced by the lessening frequency of wrist drop and lead colic.

Chronic nephritis is often a coincident disease, but the causes of the arteriosclerosis and the nephritis are generally the same. Alcohol, except as a part of overeating and as a disturber of the digestion, is perhaps not a direct cause of arteriosclerosis, as alcohol is a vasodilator. Hard physical labor and severe athletic work may cause arteriosclerosis to develop, and it is liable to develop in the arteries of the parts most used.

Hypertension is generally a prelude to arteriosclerosis, and everything which tends to increase tension promotes the disease; everything which tends to diminish tension more or less inhibits the disease. Therefore a subsecretion of the thyroid predisposes to arteriosclerosis, and increased secretion of the suprarenals predisposes to arteriosclerosis, the thyroid furnishing vasodilator substance and the suprarenals vasopressor substance to the blood. Furthermore. if these secretions are abnormal, protein metabolism is more or less disturbed.

While arteriosclerosis often occurs coincidently with gout, and gout apparently may be a cause of arteriosclerosis, still the two diseases are widely dissociated, and the causes are not the same.

Although the arterial pressure has been high before arteriosclerosis developed, and may remain high for some time in the arteries, unless the heart fails, the distal peripheral pressure, as in the fingers and toes, may be poor in spite of the high blood pressure. When the left heart begins to fail, pendent edema readily occurs.

Pathology

The pathology of arteriosclerosis is a thickening and diminishing elasticity of the arteries, beginning with the inner coat and gradually spreading and involving all the coats, the larger arteries often developing calcareous deposits or thickened cartilaginous plates - an atheroma. If the thickening of the walls of the smaller vessels advances, their caliber is diminished, and there may even be complete obstruction (endarteritis obliterans). On the other hand, some arteries, especially if the calcareous deposits are considerable, may become weakened in spots and dilation may occur, causing either smaller or larger aneurysms.

Histologically the disease is a connective tissue formation beginning first as a round-cell infiltration in the subendothelial layer of the intima. This process does not advance homogeneously; one side of an artery may be more affected than the other, and the lumen may be narrowed at one side and not at the other, allowing the artery to expand irregularly from the force of the heart beat. As the disease continues, the internal elastic layer is lost, the muscular coat begins to atrophy, and then small calcareous granules may begin to be deposited, which may form into plates. In the large arteries, the advance of the process differs somewhat. There may be more actual inflammatory signs, fatty degeneration may occur, and even a necrosis may take place.

However generally distributed arteriosclerosis is, in some regions the disease is more advanced than in others, and in those regions the most serious symptoms will occur. The regions which can stand the disease least well are the brain and coronary arteries, and next perhaps the legs, at the distal parts at least, where the circulation is always at a disadvantage if the patient is up and about.