Abstract 18241: Enhancement of Capillary Perfusion through Increased Arteriolar Pressure with Drag Reducing Polymers
Background: Drag reducing polymers (DRPs) restore capillary perfusion during severe coronary stenosis in canines. It is posited that DRPs alter blood flow hydrodynamics such that there is a reduction in pressure loss in the arterial compartment, thus providing higher precapillary driving pressure and enhanced capillary perfusion. However, this has not been proven. We tested the hypothesis that DRPs enhance capillary perfusion by reducing upstream arteriolar pressure loss. We employed intravital microscopy and the servonull technique for direct intra-arteriolar pressure measurement before and after DRP infusion in rats.
Methods: Rats (n=15) were sedated and the cremaster muscle was mounted on a microscope stage. A catheter was placed in the internal jugular vein for DRP infusion. An arteriole (range 48 to 132 μm diameter) was identified and cannulated using a 3 degree of freedom micromanipulator and 3 μm tipped glass micropipette. Arteriolar pressure measurements were obtained at baseline and repeated 20 minutes after intravenous infusion of DRP (polyethylene oxide, 1PPM)
Results: The mean baseline arteriolar pressure was 43 ± 11 mmHg. After DRP, the mean arteriolar pressure increased by 23 ± 50% (to 50 ± 12 mmHg, p=0.05). The Figure shows a pressure waveform from a 75μm diameter arteriole before and after DRP administration. In this experiment, simultaneous central aortic pressure and flow were measured with a microtip catheter and transit time flow probe, respectively. After DRP, arteriolar pressure was higher, with no change in central aortic pressure, indicating less pressure loss across the arterial compartment.
Conclusions: DRPs cause an increase in precapillary arteriolar pressure, which may, at least in part, explain its mechanism of capillary perfusion enhancement. Augmenting capillary perfusion by altering blood flow hydrodynamics is a unique and potentially valuable strategy for the treatment of compromised microvascular perfusion.
- © 2010 by American Heart Association, Inc.