title: Drag reducing polymers improve coronary flow reserve through modulation of capillary resistance.
abstract: We have shown that drag-reducing polymers (DRP) reduce microvascular resistance and improve myocardial perfusion during coronary stenosis. We used myocardial contrast echocardiography (MCE) and mathematical modeling to define the DRP microvascular effects. A non-flow-limiting left anterior descending (LAD) stenosis was created in 8 dogs. Intramyocardial blood volume, RBC velocity and flow in the LAD and circumflex (CX) beds were obtained from MCE at baseline, and in hyperemia, stenosis, hyperemia + stenosis, and hyperemia + stenosis + DRP. Microvascular resistances were calculated from a lumped-parameter model. During stenosis + hyperemia, LAD bed microvascular resistance increased (p<0.015), and capillary volume (p<0.002) and red cell velocity (p<0.0004) decreased relative to baseline. With DRP, during stenosis and hyperemia, LAD bed microvascular resistance decreased (p<0.04); there was an increase in capillary volume (p<0.007), RBC velocity (p<0.006), and flow (p<0.05). Decreased model-computed capillary resistance accounted for the reduction in LAD bed resistance after DRP. We conclude that DRP improve flow reserve during coronary stenosis by modulating capillary resistance. Primary modification of the rheological properties of blood to affect capillary resistance is a novel approach for the treatment of acute coronary syndromes.
authors: Cardiovascular Institute, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA. pacellajj@msx.upmc.edu
authors: John J
authors: JJ
authors: Pacella
authors: Marina V
authors: MV
authors: Kameneva
authors: Flordeliza S
authors: FS
authors: Villanueva
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D002200:Capillary Resistance / Q000187:drug effects*; D003326:Coronary Circulation / Q000187:drug effects*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology; D004195:Disease Models, Animal; D004285:Dogs; D006940:Hyperemia / Q000139:chemically induced / Q000188:drug therapy / Q000503:physiopathology; D008833:Microcirculation / Q000502:physiology; D011092:Polyethylene Glycols / Q000627:therapeutic use*; D014463:Ultrasonography
chemical_list: C098305:Polyox WSR-301; D011092:Polyethylene Glycols