Low-dose aspirin qualitatively affects the vascular response to Angiotensin II in hypertensive pregnant women

Forty-four women underwent an angiotensin sensitivity test (AST) at 32.4\ub135 (mean\ub1SD) weeks of gestation. They were divided into two groups according to the effective pressor dose (EPD) and were defined as AST positive (n=17) or AST negative (n=27) if the EPD was <10 or \ub110 nanograms/Kg/min, respectively. A regression line of the diastolic blood pressor response to angiotensin II (A II) was obtained for each woman and the mean dose:response curve for each of the two groups was computed. The mean dose:response curves from the AST positive and AST negative groups show no difference between the intercepts ( 1291\ub18.2 vs 127.3\ub16.6, respectively; p NS), but significant difference between the slopes (34.3\ub18.9 vs 195\ub172; p<0.00001) and the calculated thresholds (2.6\ub11.0 vs 4.8\ub12.4; p