title: A subnormal plasma volume in formerly preeclamptic women is associated with a low venous capacitance.
abstract: OBJECTIVE
  Pregnancy induces a smaller rise in plasma volume in formerly preeclamptic women with a pre-existent subnormal plasma volume than in their counterparts with a normal plasma volume. These women also have a three times higher recurrence rate of pregnancy-induced hypertensive disorders. In this study we tested the hypothesis that a subnormal plasma volume in these women is related to a lower capacitance of their venous compartment.
  
  
  METHODS
  In 31 nonpregnant formerly preeclamptic women with a subnormal plasma volume and eight parous controls, we infused intravenously 500 mL of a modified gelatin solution over 30 minutes. Before and after infusion we measured the circulating levels of alpha-atrial natriuretic peptide (alpha-ANP) and active plasma renin concentration (APRC). During volume loading, we recorded the change in heart rate, stroke volume, and cardiac output using pulse contour analysis. We measured the ratio of percent change in blood volume and percent change in cardiac output during volume loading as a marker for venous capacitance.
  
  
  RESULTS
  During volume loading, patients differed from controls by a larger rise in alpha-ANP, pulse rate, and cardiac output, and by a lower estimated venous capacitance. The concomitant response of stroke volume and APRC did not differ appreciably between groups.
  
  
  CONCLUSIONS
  Formerly preeclamptic women with a subnormal plasma volume differ from controls with a normal plasma volume by a reduced venous capacitance. These results support our hypothesis that, in these women, a subnormal plasma volume indicates the presence of a subnormal venous capacitance.
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital Maastricht, Maastricht, The Netherlands. R.Aardenburg@og.unimaas.nl
authors.forename: Robert
authors.initials: R
authors.lastname: Aardenburg
authors.forename: Marc E
authors.initials: ME
authors.lastname: Spaanderman
authors.forename: Dorette A
authors.initials: DA
authors.lastname: Courtar
authors.forename: Hugo W
authors.initials: HW
authors.lastname: van Eijndhoven
authors.forename: Peter W
authors.initials: PW
authors.lastname: de Leeuw
authors.forename: Louis L
authors.initials: LL
authors.lastname: Peeters
mesh_terms: D000328:Adult; D009320:Atrial Natriuretic Factor / Q000097:blood; D002302:Cardiac Output; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006400:Hematocrit; D006801:Humans; D010953:Plasma Volume / Q000502:physiology*; D011225:Pre-Eclampsia / Q000503:physiopathology*; D011247:Pregnancy; D012083:Renin / Q000097:blood; D018709:Statistics, Nonparametric; D013318:Stroke Volume / Q000502:physiology; D018924:Vascular Capacitance / Q000502:physiology
chemical_list: D009320:Atrial Natriuretic Factor; D012083:Renin