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Blood Viscosity Used to Monitor Changes
Case reports published in Alternative Therapies in Health and Medicine, a peer-reviewed scientific journal, describe the application of therapeutic phlebotomy (or blood-letting) in two patient cases: the first involving a patient presenting with severe angina and the second reporting progressive fatigue for a decade culminating in dementia. Both case studies, performed at the Paracelsus Clinic near Seattle, Washington, utilized serial phlebotomy in moderate amounts (0.5-pint or 250-cc per session) to mitigate symptoms and improve the quality of life.
Case 1 describes a 58 year-old, active housewife, who complained of episodes of chest pain “like an elephant on my chest,” clearly indicative of angina pectoris. She was cleared at the local hospital of having had a heart attack (myocardial infarction), and coronary angiograms were normal. However, the patient’s blood viscosity was tested and found to be extremely elevated. After phlebotomy was performed 8 times, the last episode of chest pain occurred 10 months after the initial episode. Twenty-two months after the initial viscosity measurement, her levels had approached the normal range.
Case 2 details a 66 year-old publisher whose symptoms were severe enough to lead him to consider discontinuing his business endeavors. While the patient’s CT cerebral angiogram was normal, his blood viscosity measurements were elevated. Phlebotomy was performed 5 times on the patient to improve microcirculation and cerebral perfusion. The patient’s symptoms were alleviated within a month of the last phlebotomy, and he was able to continue his business endeavors. In both cases studies, a thrombogenic potential index was utilized to monitor changes in blood viscosity.
Serial phlebotomy works to reduce blood viscosity by hemodilution, as the plasma is restored by hydration more rapidly than are the red blood cells. The study co-authors wrote that the subsequent reduction in viscosity leads to an increase in the delivery of oxygen to the body’s tissues by two physiologic mechanisms: (1) increased cardiac output and (2) reduced oxygen shunting that occurs normally between arterioles and venules. In the first mechanism, decreased viscosity reduces the flow resistance at the peripheral vessels, thus leading to greater oxygen delivery. In the second mechanism, the difference in oxygen concentration between the arterioles and venules leads to shunting, where oxygen is extracted from arterial blood to the veins. By reducing the viscosity, flow increases and the transit time to the capillaries is reduced, thereby limiting the amount of oxygen that is extracted from the arterioles.
According to the authors, “an evaluation of blood viscosity by clinical means is a useful, inexpensive outpatient clinical tool,” and “the best-known mechanism for correcting [abnormal viscosity] is repeated (but not excessively frequent) phlebotomy in small amounts.”