What Is Vascular Disease?

Renal Disease and HypertensionnnA patient with hypertension has an increased risk of developing renal disease. In stage I renal disease, the patient has a diminished renal reserve but no symptoms of renal disease. If untreated, the condition may progress to stage II renal disease, in which the patient experiences renal insufficiency. He'll have lost over 75% of his glomerular function and will begin to experience the effects of renal disease, such as anemia and mild hyperkalemia. Further uncontrolled hypertension can lead to stage III, end-stage renal disease, in which the patient may develop chronic renal failure. How it occurnnIn hypertension, increased vascular resistance of the sclerosed vessels causes blood to enter the glomerulus under high pressure, damaging the glomerular membrane. The impaired membrane loses its ability to filter selectively, leading to necrosis of the tubules.nnHypertension also interferes with the renin­angiotensin-aldosterone system, resulting in ischemia and reduced blood volume to the kidneys. Water and sodium reabsorption are increased in an attempt to increase the glomerular filtration rate, resulting in volume overload and higher vascular pressure, which cause sclerosis of the glomeruli.nnNoninvasive tests for peripheral vascular disease include segmental pressure measurements, anklebrachial indexes, and pulse volume recordings.nnFor a segmental pressure measurement, blood pressure cuffs are placed at four sites: on the thigh, directly above the knee, directly below the knee, and at the ankle. Then, the pressure cuffs are inflated sequentially. If systolic pressure decreases by 15% or more from one site to another, the patient may have significant lesions.nnA physician may order an exercise stress test along with an anklebrachial index and pulse volume recording. During the test, the patient exercises until he develops significant claudication. Then an anklebrachial index is performed by taking systolic blood pressures in the ankle and arm simultaneously. Severe claudication causes a significant difference between the ankle and brachial blood pressures during low-level exercise.nnPulse volume recordings are obtained at the same time as the anklebrachial index. If the patient has significant occlusions, the volume's amplitude will be reduced, and the height of its contour will be decreased.nnTwo invasive diagnostic tests, color flow Doppler ultrasonography and angiography, also can detect peripheral vascular disease. These procedures are performed to pinpoint the area of the lesion when surgery or angioplasty is planned. Color flow Doppler ultrasonography allows direct visualization of the major vessels and blood flow. Angiography provides information on the location and extent of the atherosclerotic disease.