As Kelvin stated, our ability to understand is only as good as our ability to measure. There is a large variety of existing therapies which effectively reduce blood viscosity. Monitoring viscosity is an important step. We can predict the progression of cardiovascular diseases only if we can establish baseline values and monitor changes over time.
The effects of treatments that affect blood viscosity—in atherosclerosis and other conditions—are continuing to be evaluated by observed outcomes like increased walking distance for patients with peripheral arterial disease, and decreased angina in those with coronary artery disease. Connecting interventions to outcomes by a physiologic measurement that is as easy as taking a blood pressure can help clinicians make effective adjustments in the therapy.
Hyperviscosity syndromes can be treated using active pharmaceutical agents. This section provides an overview of well-recognizable drug classes that have been reported to have antiviscogenic effects.
While related to blood donation, hemodilution is a separate treatment that has been shown to reduce risk of cardiovascular disease. The three types of hemodilution are as follows: hypovolemic hemodilution, isovolumic hemodilution, and hypervolemic hemodilution. The patient’s volume balance determines which one is used.
Hypovolemic hemodilution, which results from therapeutic phlebotomy, is used to treat patients with overt hypervolemia. Such patients include those with congestive heart failure, secondary hyperparathyroidism, obstructive lung disease, polycythemia, early cirrhosis, and early dementia. A potentially practical and effective method of hypovolemic hemodilution is to withdraw relatively small amounts of blood periodically.
Isovolumic hemodilution maintains a nearly constant blood volume balance through a combination treatment of therapeutic phlebotomy and infusion therapy, which is usually a plasma substitute. Among these are normal saline, albumin and amino acids, dextran 40 and dextran 70 (monosaccharides; molecular weights 40,000 and 70,000, respectively), and hydroxyethylstarch (HES) 200 and 450 (monosaccharides; molecular weights 200,000 and 450,000, respectively). Therapeutic phlebotomy can be combined with infusion therapy in isovolumic hemodilution in patients that may also have low blood pressure.
Hypervolemic hemodilution is primarily used during bypass surgery. After bypass surgery most patients leave the hospital with a hematocrit of 29.