Abstract
Objective: Investigate effects of aspirin/dipyridamole and aspirin on blood viscosity (BV) in subjects with hyperhomocystememia (>14 µmol/L) and stable cardiovascular disease (CVD) or ≥ 20% risk for CVD were the aims of this study.
Method: Forty-seven subjects were treated with 14 days of either aspirin/dipyridamole (25 mg/200 mg twice-daily) or aspirin (81 mg daily). BV was measured from fasting specimens at 37°C from whole blood at shear rates ranging from 1,000 to 1s−1 by using a scanning capillary viscometer (Rheolog™; Rheologics Inc., Exton, Pennsylvania, USA).
Results: Aspirin/dipyridamole was more effective than aspirin therapy in reducing BV at shear rates of 1 s−1 (−3.03 [−3.88, −2.17] mPas vs. −0.07 [−1.06, 0.92] mPas; P<0.0001) and 2 s−1 (−1.86 [−2.72, −1.01] mPas vs. −0.21 [−1.20, 0.79] mPas; P=0.0136); however, there were no significant differences in blood viscosity at shear rates of 5 s−1 to 1000 s−1. Changes in hematocrit, a major determinant of whole BV, were greater in the aspirin/dipyridamole group than the aspirin group (P=0.043). After hematocrit adjustment, differences in BV between aspirin/dipyridamole and aspirin remained significant at 1s−1 (−2.78 [−3.68, −1.88] mPas vs. −0.04 [−1.05, 0.98] mPas; P<0.0001) and 2 s−1 (−1.62 [−2.52, -0.72] mPas vs. −0.17 [−1.19, 0.85] mPas; P=0.0315).
Conclusion: These findings may have important clinical benefits in the CVD prevention and treatment due to the contribution of BV in tissue perfusion and thrombus formation.
Acknowledgements
The author thanks Anna Huskin, RN, MS, who collected clinical data and administered study medications, and Helmut Schumacher, PhD, for his statistical analysis work on this study.
This study was supported through a research grant to Northwestern University by Boehringer Ingelheim GmbH (Mannheim, Germany). The author interpreted the data and wrote the results independently of the sponsor.
This research was performed at the Lipoprotein and Hemorheology Research Facility, Northwestern University, Chicago Illinois, USA