Surgical diseases of the arteries

Surgical diseases of the arteriesWhen any body part is deprived of its oxygen supply, the part dies, the condition known as gangrene. This may occur in any body struc­ture in total or in part. In certain body areas correction of impaired circulation may be ac­complished by surgical approach to diseased ar­teries with an inadequate blood passageway. Many important advances have been made dur­ing recent years in this field of vascular sur­gery. Increased knowledge of the physiology of circulation, improved anesthesia, a wider range of diagnostic methods, and the development of artificial vessel replacements, are largely re­sponsible for these advances.

One important diagnostic method is the ar­teriogram. This is a series of rapidly taken x-ray films, taken as an opaque substance is in­jected into an artery to pass through the vessel and outline its inner contour. This is applicable for study of many regions of the body and par­ticularly of the arteries of the lower extremity and head. Sympathetic block is a procedure wherein the automatic nerve supply to blood vessels is anesthetized by injection into the re­gion of the nerves. This temporarily disrupts the nerve supply and relieves any spasm of the ves­sels. Study of the circulation before and after such block denotes what improvement may be expected from permanent disruption of the nerve supply by surgery. Other diagnostic im­plements are skin temperature gauges, constant temperature rooms, extremity blood pressure measurements, response to heat and cold appli­cations, and physical examination.

Arteriorrhaphy, or arterioplasty, is the general name applied to any operation for re­pair of an artery. The name of the artery be­comes part of the name of the operation, such as femoral arterioplasty. Repair may be by closure of an opening, re-union of a completely severed artery, or replacement of a segment of an artery with another segment of a vessel or artificial tube. Arteriorrhaphy may be indicated in injured arteries, for blood clots in arteries, constricted segment in an artery, or diseased segments of major arteries.

Arterial transplant is the replacement of a segment of an artery. This may be indicated after injury to an artery, in which case the pro­cedure is an emergency. In diseases such as arteriosclerosis and aneurysms, the flow of blood through the artery may be slowly but pro­gressively decreased as the caliber of the artery becomes smaller. In such case arterial transplant may be employed to replace the narrowed sec­tion. The most common use of transplants of arteries is in the lower extremity, where the cir­culation to the feet is diminished. Substances used to replace a vessel are various plastic and nylon tubes, veins taken from other regions of the body, and arteries taken from a deceased person, especially infants; these are frozen and preserved and prepared for later use.

Arterial ligation means the tying of an ar­tery to shut off the arterial blood flow in the artery itself and the branches to which it leads. This may be necessary in the case of hemor­rhage, and usually is a temporary measure. After the hemorrhaging area has been mended, the ligation may be removed. Arterial ligation is often necessary for operative procedures on a part. Emergency compression of an artery leading into a hemorrhaging area may be a life- saving procedure in injury. The application of pressure over the various sites (“pressure points”) which may control bleeding, and the use of the tourniquet have been publicized in many excellent books on First Aid and there­fore will not be repeated here.

Injuries to arteries may involve any vessel to any extent. When the vessel is a major one, prompt operative repair must be accomplished before the area supplied by the vessel becomes gangrenous. Injuries to the main arterial trunks in the arms and legs are common and may be associated with fractures and other injuries. The hemorrhage must be immediately stopped and the patient prepared for operative repair of the vessel. The vessel may be merely ruptured, com­pletely severed, or torn over a long segment. The operation may involve repair of the vessel or arterial transplant.

Arteriosclerosis (artery-hardening) is a progressive disease of ageing wherein the ar­teries become less elastic, thickened, and hard­ened. The exact causes are unknown but the change in the blood vessel wall is due to deposits of specific chemicals in the muscular wall; in advanced cases calcium becomes deposited and the arteries become bone-like. With the loss of elasticity of the arteries, high blood pressure may develop. Prevention and treatment of ar­teriosclerosis is most often a medical problem, but vascular surgery may be beneficial in certain cases. For example, replacement of the main arterial trunk (femoral artery) to the leg which has been narrowed by arteriosclerosis may pre­vent gangrene of the foot and leg.

Buerger’s disease (thrombo-angiitis obliter­ans) is a condition of the blood vessels in which the linings are inflamed so that blood clots form and impede the blood flow. This most often occurs in the legs and symptoms of impaired circulation become pronounced. Often there are spasms of the blood vessels which further curtail the flow of blood. When this has been demon­strated, surgery may be useful along with the usual medical measures. The operative pro­cedure (sympathectomy) involves disrupting the automatic nerve supply to the vessels which holds them in spasm.

Raynaud’s disease is a circulatory impair­ment brought about by a disturbance of the automatic nerve control of arteries. In essence, the involved arteries remain in marked spasm during the course of an attack and the symp­toms of impaired circulation ensue. The disease affects the upper extremity most often and fe­males more often than males. Along with medi­cal measures, surgery may be indicated to dis­rupt the nerve supply to the vessels by sympa­thectomy. Sympathetic block de­notes what improvement may be anticipated.

Arterial thrombus is the formation of a blood clot within an artery. Such may occur from several abnormal factors of the vessel or the blood’s ability to clot. Any artery may be involved, and in certain regions the condition is most serious as it impedes the flow of blood to a vital part. The blood clot may break loose from the lining of the artery to pass along in the blood stream, thereby becoming an arterial embolism. It then travels in the blood stream to a point where the caliber of a branch in the arterial tree is small and traps the floating clot. This then blocks the circulation at this point. Surgical therapy for thrombus and embolism may contribute to medical measures. The clot in the vessel causes spasm of the arterial tree and blocking the nerve supply to the arteries may relieve the spasm; this is done by sympathetic block of the nerve supplying the region involved. In this instance sympathetic block is therapeutic rather than diagnostic. With thrombus or em­bolism in certain areas it is possible to surgically remove the clot from the segment of the vessel. The vessel is opened, the clot removed, and the vessel closed. This must be accomplished as early as possible. Medical adjuncts include the use of drugs which lessen the blood’s ability to clot so that the clot will not enlarge and so that other clots may be prevented.

Aneurysms are abnormal contours along the course of an artery. These involve the larger vessels and interfere with the circulatory flow. There are several types. Fusiform aneurysm is a bulging dilatation of spherical shape along the course of an artery. This may be caused by infection, such as the aneurysm which develops as a complication of syphilis, in which case the aortic arch is the common site. A saccular aneurysm may be the result of an injury (traumatic aneurysm) wherein a weak­ness in the artery wall is produced; these most commonly occur on the extremities where in­jury is most frequent. This type aneurysms grad­ually enlarge from the constant pressure within them, and there may result a rupture of the sac with massive hemorrhage. Blood clots may form within them. Surgery is the only therapy. Opera­tion may be by reconstruction of the artery wall or by removal of the involved section; in the latter instance the vessel ends are re-united or a vessel transplant employed. Another operative method of treatment of these aneurysms entails wrapping the bulge with a foreign material such as a special form of cellophane; the reaction to the material causes scar tissue around the aneu­rysm to make its wall stronger and prevent en­largement.

Another type of aneurysm is the A-V aneu­rysm (arteriovenous aneurysm), where there is a communication between an artery and a vein. This may be congenital in origin or the result of injury. This abnormal blood passage­way may deprive the tissues of their oxygenated blood supply and also impede the venous blood’s return to the heart. The only definitive correc­tion is by operation, which entails either sever­ing the abnormal communication with repair of both vessels, or removing the entire involved section of the artery and/or vein. When the ar­tery is necessarily removed, re-union or arterial transplant is usually necessary.

When the inner lining of an artery becomes weakened, as may occur in certain degenerat­ing and ageing diseases, there may be rupture of this lining layer. Blood then seeps through the lining and splits (dissects) the arterial walls apart. This is known as dissecting aneurysm. The aorta is most commonly involved and the progression rapid; the blood between the layers causes the inner lining to bulge and narrow the inside caliber of the vessel, thereby impeding the flow of blood, or there may be rupture through the outer layer. The course is usually rapid and fatal. Fortunately, this disease is not extremely common and advances in vascular surgery to treat this condition appear promising.

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