Pathological Alterations in Blood Flow

Abstract

Pathological alterations in blood flow develop in response to a wide variety of diseases which affect both the macro-and microcirculation. To attempt to cover all aspects of this problem is simply not possible in a brief review. For this reason I will confine my comments to those flow abnor malities that occur secondary to atherosclerosis which involves the large and medium sized arteries of the lower extremities. Material for a review of this type can be found in two different types of reports. The first deals almost exclusively with the results of clinical experience and are usually intended to document the results of treatment. The second type of communication deals with investigative studies that have been undertaken to clarify or answer some of the current unknown aspects of a particular problem.I will concentrate on the clinical research activities that I roughly define as those efforts which extend beyond using the patient's history, physical examination, and patient testimony as the sole criteria of the functional disability that occurs and the results of therapy. While it has often been stated that physiologic measurements in peripheral arterial disease are of in terest only, it is becoming increasingly apparent that more objective methods of study will have to be applied to the human if we are to gain a more meaning ful understanding of cardiovascular disease. Although animal studies are helpful in perfecting and evaluating study methods, investigators have all too often attempted to apply the data to the human. We have not yet found a suitable analogue for human physiology, much less for human athero sclerosis. I t is now well known that the cardiovascular system of an anesthe tized animal bears little resemblance even to the awake animal. Further developments in instrumentation will permit the clinical researcher of the future to obtain data safely from the human. Then and only then will we find answers to many of our unsolved problems in the area of atherosclerosis and its effect on different vascular beds.We now know that atherosclerosis tends to involve particular segments of the arterial system which are in close relation to branch points, bifur cations, and areas where vessels follow a tortuous course. The process itself tends to involve the intima in its earliest stages but later the entire wall may become distorted by the process (1). Because the disease involves all coats of the arterial wall, it influences not only the pressure-flow characteristics of the system but its visco-elastic properties as well. Ideally, we would like to measure not only pressure and flow but obtain data on the changes in 1 Annu. Rev. Med. 1969.20:1-14. Downloaded from www.annualreviews.org Access provided by University of California -Davis on 02/09/15. For personal use only. Quick links to online content Further ANNUAL REVIEWS

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