The Arterial System

Purpose: The arterial system is composed of a sophisticated network of “high pressure,” thick walled and flexible channels that serve as the conduits supplying blood to all of our tissues. Known as arteries, arterioles and capillaries, these vessels are not only susceptible to normal aging processes such as enhanced stiffness, but are particularly vulnerable to the atherosclerotic process which is brought on by lifestyle indiscretion.

Carotid: The left and right Carotid arteries arise from the thoracic aorta close to its origin near the heart. Dividing in half near the jaw, each supplies one half of the face and hemisphere of the brain. It is at the division point that blood flow eddies often commence deposition of plaque, which when significant are audible to the physicians stethoscope and visible with ultrasound or other imaging modalities. Identification of plaque before clinical events such as stroke is imperative.

Aorta: Arising from the heart at the aortic valve, the aorta is the largest vessel in our bodies. The coronary arteries, arteries to our arms, brain, spinal cord, gut, kidneys and legs all branch from the aorta. Dissimilar from other arteries, the aorta is more prone to distention and dilatation or so called aneurysm formation. Early detection of aneurysms prevents the disastrous consequences of rupture.

Renal: Each kidney is supplied by a rather large artery, ranging in caliber from 4 to 10 millimeters. These vessels in concert with the very fine capillaries in the kidney bed are responsible for regulation of our blood pressure. The capillaries are also involved in the excretory function of the kidney and can be adversely affected by such problems as diabetes mellitus.

Lower Extremities: The arteries to the lower extremities each branch from the aorta in the mid abdomen. After giving off several other arterioles in the pelvis, they supply the thigh and lower leg again with many subdivisions. The pulse in the groin or around the ankles is evidence of their function. Smoking is particularly hazardous and can yield extensive occlusions in some cases.

Problems

Stroke: Stroke is perhaps the most feared medical condition facing humans, and has gained significantly in public awareness. Strokes fall in to two types; 1) Hemorrhagic = direct bleeding in the brain tissue induced by such conditions as excessive hypertension, and 2) Ischemic = occlusion of a vessel providing cerebral blood flow with attendant cell death. Ischemic strokes are precipitated either through the embolic deposition of debris or through a lack of blood flow due to the progressive impedance of a prominent plaque.

Aortic Aneurysm/Dissection: Weakening of the layered wall of the aorta is often due to a combination of infiltration of atherosclerotic debris coupled with the force of poorly controlled blood pressure. In its chronic form this yields gradual dilatation of the structure, especially in the abdominal region. Aneurysms of over 5 centimeters raise concerns of rupture, which if acute often result in acute mortality. Similarly the hazard of death is high in aortic dissection which is more commonly evidenced in the portion of the aorta coursing through the chest cavity or thorax. This too represents a medical emergency.

Renal Failure/Hypertension: Whether related to common lipid issues or the more devastating consequences of diabetes mellitus, obstruction of the kidney arteries or capillaries not only can affect the blood filtering function of the kidneys, but also their role in the regulation of vascular tone and blood pressure. Occasionally, an isolated renal artery plaque or stenosis is detected, which if relieved by such maneuvers as stent placement can improve kidney blood flow and hypertension. More commonly, medications may provide the only solution, unless the disease process has progressed to the point of requiring dialysis or the use of the artificial kidney.

Claudication: Discomfort or pain in the calves represents claudication and is the most common symptom of stenoses in the lower limb vessels. With smoking being a common precipitant, the disease process often may be diffuse and difficult to reverse or repair. Although angioplasty and stent application may prove effective in the short term, aggressive life style remediation is usually mandatory