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Influence of altered blood rheology on ventricular-vascular response to exercise
journal contribution
posted on 2023-05-17, 02:39 authored by James SharmanJames Sharman, Brown, J, Holland, DJ, Macdonald, G, Kostner, K, Thomas MarwickThomas MarwickBlood (or plasma) rheology is related to cardiovascular risk. Mechanisms of this association are unclear but may be partially related to impaired left ventricular (LV) function and increased central blood pressure (BP) during light activity. This study aimed to test these hypotheses. Twenty patients (14 men; aged 61+/-12 years) with polycythemia rubra vera (n=16) or hemochromatosis (n=4) were studied at rest and during exercise at 50% of maximal heart rate before and after venesection (500 mL; volume replaced with saline) to elicit an acute decrease in plasma viscosity at stable BP. Controls (n=20) underwent the same protocol with 25-mL venesection. Central BP and augmentation index were determined by tonometry. Resting LV systolic (peak longitudinal systolic strain rate and strain) and diastolic functions were determined by tissue-Doppler echocardiography. Venesection with blood volume replacement decreased viscosity (1.46+/-0.10 to 1.41+/-0.11 centipoise), protein, and hemoglobin (P<0.05 for all) and increased strain rate and strain (P<0.001 for both) in patients but not in controls (P>|0.10 for all). There was no change in LV diastolic function (P|>0.12 for all). Exercise augmentation index in patients was reduced after venesection (24+/-12% to 17+/-9%; P=0.001) despite no significant change in other BP variables. Hemodynamics (resting or exercise) were not significantly changed in controls. Exercise central systolic BP correlated with triglycerides (r=0.59; P<0.001). However, neither exercise hemodynamic changes nor LV functional changes correlated with any biochemical changes after venesection (P>|0.05). We conclude that an acute change in blood rheology improves ventricular-vascular interaction by enhanced LV systolic function and reduced light-exercise central BP.
History
Publication title
HypertensionVolume
54Issue
5Pagination
1092-1098ISSN
0194-911XDepartment/School
Menzies Institute for Medical ResearchPublisher
Lippincott Williams & WilkinsPlace of publication
530 Walnut St, Philadelphia, USA, Pa, 19106-3621Rights statement
Copyright 2009 American Heart AssociationRepository Status
- Restricted