This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Wysocki, M. Articles by Bagge, U. Search for Related Content PubMed PubMed Citation Articles by Wysocki, M. Articles by Bagge, U. Social Bookmarking                         What's this?

Vasoconstriction During Acute Hypervolemic Hemodilution in Hypertensive Patients is Not Prevented by Calcium Blockade

Ove K. Andersson

Bengt Persson

Ulf Bagge

The reduction of blood viscosity by moderate acute hypervolemic hemodilution in untreated hypertensives can be associated with a secondary vasoconstriction. The aim of this study was to examine whether a vasodilating therapy prevents this hemodynamic reaction.

Twelve hypertensive patients (WHO stage II) were treated with the vasoselective calcium channel blocker isradipine in a placebo-controlled, double-blind, crossover study. Acute hypervolemic hemodilution was performed twice: at the end of the placebo period and after two months of treatment. Hemodilution was achieved by the intravenous infusion of 1000 mL saline over a 10- to 15-minute period. Arterial blood pressure, heart rate, cardiac output (dye dilution), renal blood flow, glomerular filtration, natriuresis, hemat ocrit, whole blood, and plasma viscosity were assessed before and after infusion. Flow resis tance and vascular hindrance in the central and renal circulation were calculated.

Acute hemodilution associated with a significant reduction of blood (P<0.01) and plasma (P<0.01) viscosity did not influence the mean arterial pressure and cardiac output. Consequently, the total flow resistance remained unchanged. However, as a result of hemodilution, the calculated vascular hindrance index in the systemic circulation increased, indicating a vasoconstrictive reaction, both with placebo (from 5.22 to 6.07 U x mPa^-1 x s^-1, P < 0.05) and during chronic treatment with calcium blockade (from 3.75 to 4.22 U x mPa^-1 x s^-1, P<0.02). Vasoconstriction was not observed in the renal circula tion, either during the placebo or active treatments.

The results of this study indicate that the systemic vasoconstriction evoked by the acute moderate hypervolemic hemodilution in hypertensive patients was not prevented by a calcium channel blockade.

Angiology, Vol. 49, No. 1, 41-48 (1998)
DOI: 10.1177/000331979804900105


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?