In general terms, if a patient presents initially with peripheral vascular disease, there is about a 90% chance that the patient also has coronary artery disease. On the other hand, if the patient initially presents with coronary artery disease, 10% of those patients have some evidence of peripheral vascular disease. In general, coronary artery disease generally presents itself in a patient earlier in life than does peripheral vascular disease, and both are manifestations of the atherosclerotic process.
Over the last decade, there has been a steady decline in cardiac morbidity and mortality. This is due to many reasons, including better risk factor control (reduction in smoking), the availability of anti-arrhythmic drugs, beta blocking drugs, calcium channel blocking drugs, and coronary bypass surgery. During this same period of time, there has been no tremendous scientific breakthroughs in the generalized atherosclerotic process.
As a result of the foregoing factors, there is a reasonable segment of the population who would have died of coronary artery disease, but now those patients live to present with peripheral vascular disease. In addition, over the past decade, there has been a sizeable increase in the number of people over 55 years of age and those people are generally classified as being "at risk" for peripheral vascular disease.
A wide range of physicians may deal with some type of vascular analysis. For example, general and family medicine physicians may study extremity symptoms and cerebral symptoms; cardiologists may study extremity systems, cerebral systems, and determine the degree of atherosclerosis; vascular surgeons are involved in extremity reconstruction, extra-cranial arterial disease and others; neurologists are involved in the study of cerebrovascular disease; radiologists are involved in interventions such as angioplasty, planing, and handling complications; orthopedics are involved in amputation healing and post-operative deep venous thrombosis (DVT); dermatologists are concerned about lesion healing; podiatrists are concerned about lesion healing and clearance for foot surgery; urologists are involved in the study of male impotence; obstetricians are involved in the study of deep venous thrombosis (DVT) and ophthalmologists study retinal emboli.
The most common evaluations in a vascular lab fall into three categories. First, there is evaluation of the arteries that supply blood to the lower body extremities of the patient. When an occlusion occurs in this area, the symptoms may range from resting foot pain, to the development of ulcers due to lack of blood flow, to pain only when walking. Further, vascular laboratories are sometimes requested to determine the presence or absence of thrombosis of the deep venous system in the lower extremities. Thirdly, these vascular laboratory facilities evaluate the degree of carotid artery disease. The carotid artery supplies the brain with blood and, when diseased, is a major cause of cerebrovascular accidents (i.e., stroke). Miscellaneous studies at vascular laboratories involve the study of upper extremities, compression syndromes, and male impotency (MI) studies.
Currently, there are pulse volume recorders available to study the upper and lower extremities of a patient. Such a study correlates the amount of blood flowing beneath a pressure cuff with each heartbeat of the patient. Bi-directional continuous wave ultrasound doppler probes are utilized to detect the movement and direction of blood flow through arteries and veins. Audio-frequency analyzer (AA) units are utilized by technicians and physicians to listen to and characterize the blood flow via a sensitive microphone. This involves an analysis of the audio signals. Ocular pneumoplethysmographs (OPG) are utilized to measure the ophthalmic artery pressure in the eyes of a patient. Photoplethysmographs (PPG) are used to monitor blood flow for histolic pressure measurements, venous reflux testing, and arterial blood flow. One example of bi-directional continuous wave ultrasound doppler system is manufactured by Hokanson as Model MD6. An OPG is manufactured by Electro-Diagnostic Instruments (EDI) as Model OPG-5D. AN PPG is manufactured by Hokanson, Model MD6RP.
In the past, all these instruments have been used independently to study the vascular system of a patient.