An abnormally elevated degree of internal force against the walls of the blood vessels defines high blood pressure, or hypertension. The National Heart, Lung and Blood Institute reports that a blood pressure reading of 140/90 mm Hg or higher constitutes hypertension. Although high blood pressure typically causes no symptoms, it can lead to serious and potentially life-threatening complications in the body. The American Heart Association states that high blood pressure affects approximately 74.5 million men and women in the United States.
Hypertensive Heart Disease
In patients with hypertension, the heart must pump more forcefully to overcome the elevated pressure in the arteries. Over time, the heart muscle cells grow larger and the heart wall increases in thickness, a condition termed left ventricular hypertrophy or LVH. Along with heart muscle growth, scar tissue develops in the heart wall. Although LVH enables the heart to pump more forcefully, the associated scarring stiffens the heart wall. The heart chambers fill with blood less efficiently, and the heart pumps a decreased volume of blood with each contraction. The National Heart, Lung and Blood Institute notes that among people with long-standing high blood pressure, LVH can lead to heart failure.
Blood Vessel Aneurysms
Elevated pressure in the arteries can weaken the blood vessel wall, which thins and bulges. A bulging area of a blood vessel is called an aneurysm. Aneurysms can burst, causing potentially devastating or life-threatening bleeding, or hemorrhage. According to the National Heart, Lung and Blood Institute, arteries supplying blood to the brain are common sites for hypertension-induced aneurysms. Rupture of a brain aneurysm causes a hemorrhagic stroke. Other common locations of arterial aneurysms include the blood vessels of the abdomen and legs.
Chronic Kidney Disease
Information from the Mayo Clinic notes that kidney damage may result from high blood pressure. Increased pressure within the arteries often damages the blood vessel walls. Inflammatory cells flood the area, and other cells lay down scar tissue. Platelets and cholesterol accumulate in these spots, creating atherosclerotic plaques. The affected blood vessels stiffen and blood flow decreases. Atherosclerosis in the kidney blood vessels can lead to progressive kidney damage. The National Institute of Diabetes and Digestive and Kidney Diseases notes that high blood pressure is the second most frequent cause of kidney failure in the United States.
Heart Attack
Hypertension is a major risk factor for heart attack. The same atherosclerotic process that adversely affects the kidneys can also occur in the blood vessels that supply the heart. Atherosclerosis in these vessels is termed coronary artery disease. The narrowed arteries of the heart often cannot deliver sufficient blood and oxygen to meet the heart's demands. People with coronary artery disease carry a significantly increased risk for heart attack, a condition in which heart muscle cells die due to lack of oxygen. The American Heart Association reports that approximately 17.6 million women and men in the United States had coronary artery disease as of 2006.
References
- National Heart, Lung and Blood Institute: Signs and Symptoms of High Blood Pressure
- American Heart Association: Why HBP Matters
- Mayo Clinic: High Blood Pressure, Complications
- Merck Manual for Healthcare Professionals: Hypertension, Pathology and Complications
- University of Maryland Medical Center: High Blood Pressure, Complications
