T. Fischer et al., Vascular reactivity in patients with preeclampsia and HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome, AM J OBST G, 183(6), 2000, pp. 1489-1494
OBJECTIVE: Early structural and functional changes in the systemic vasculat
ure have been proposed to play a major pathogenetic role in preeclampsia an
d HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrom
e. The aim of the study was to determine vascular reactivity in patients wi
th preeclampsia with and without HELLP syndrome with respect to those in he
althy pregnant control subjects.
STUDY DESIGN: Forearm blood flow was measured by strain gauge plethysmograp
hy with the venous occlusion technique in 12 hypertensive patients with HEL
LP syndrome, in 8 patients with preeclampsia without HELLP syndrome, and in
8 healthy normotensive pregnant control subjects. To determine vascular re
activity the forearm blood flow was measured at baseline and after forearm
occlusion for a period of 5 minutes (reactive hyperemia). The investigation
s were repeated 4 to 6 months post partum. Forearm vascular resistance was
calculated as the ratio of mean arterial pressure to forearm blood flow.
RESULTS: Mean arterial pressure at rest was elevated in patients with preec
lampsia (116 +/- 20 mm Hg) and in patients with HELLP syndrome (110 +/- 16
mm Hg) with respect to healthy pregnant control subjects (86 +/- 10 mm Hg;
P<.05). Forearm blood flow at rest was not statistically different in patie
nts with preeclampsia (5.1 +/- 2.6 mL/min per 100 mL) and with HELLP syndro
me (4.7 +/- 1.5 mL/min per 100 mL) with respect to pregnant control subject
s (5.9 +/- 3.1 mL/min per 100 mL), however, forearm vascular resistance at
rest was elevated in patients with preeclampsia (25.9 +/- 9.5 units; P <.05
) and in patients with HELLP syndrome 124.6 +/- 6.9 units; P<.05) with resp
ect to healthy control subjects (17.0 +/- 6.1 units). During reactive hyper
emia the peak forearm blood flow, which is an indicator of maximal vasodila
tory capacity, was impaired in patients with preeclampsia (21.9 +/- 8.2 mL/
min per 100 mL; P <.05) but not in patients with HELLP syndrome (37.4 +/- 1
7.5 mL/min per 100 mL) and healthy control subjects (44.9 +/- 15.0 mL/min p
er 100 mL). Consequently. minimum forearm Vascular resistance was higher in
women with preeclampsia (6.1 +/- 1.9 units) than in both women with HELLP
syndrome (3.5 +/- 1.6 units) and the control subjects (2.8 +/- 2.4 units).
CONCLUSION: Despite similarly elevated forearm vascular resistances at rest
in patients with HELLP syndrome and in patients with preeclampsia, forearm
vascular resistance during reactive hyperemia did not differ significantly
from that in healthy control subjects in the women with HELLP syndrome but
was increased in women with preeclampsia. Vasodilatory reactivity thus is
reduced in preeclampsia but not in HELLP syndrome. which suggests different
alterations of the vasculature.