Increased whole blood and plasma viscosity in patients with angina pectoris and "normal" coronary arteries.

Blood and plasma viscosity was measured in eight patients with typical effort-induced angina pectoris who did not have coronary artery stenosis at angiography. The same variables were studied in 14 patients with angina pectoris and verified coronary artery disease that in most cases was extensive. Both groups of patients had significantly higher viscosity values in whole blood, at natural hematocrit as well as standardized hematocrit (45%), than 25 healthy subjects serving as a reference group. Plasma viscosity was also significantly elevated in both patient groups. The patients without coronary artery stenosis had as high blood and plasma viscosity values as had the stenosis group. It is concluded that increased blood and plasma viscosity should be added to the list of pathological findings in patients with angina pectoris in the absence of organic coronary artery stenosis.