Objectives: Our goals were (1) to determine whether hypertension, proteinuria, and glomerular endotheliosis can be produced by chronic reduction of lower aortic pressure in pregnant rhesus monkeys and (2) to study the time course of the development of hypertension by means of longitudinal arterial blood pressure measurements in conscious, unrestrained pregnant rhesus monkeys.
Study design: Indwelling arterial catheters were placed at 103 +/- 4 days of gestation (term 160 days) for measurement of arterial pressure before and after reduction of lower aortic pressure. At 116 +/- 7 days lower aortic pressure was reduced by 24 +/- 11 mm Hg in 11 monkeys (experimental group) by a stricture on the aorta just below the renal arteries; six monkeys (controls) underwent a sham operation. Resting on the aorta just below the renal arteries; six monkeys (controls) underwent a sham operation. Resting pressures were measured three to five times per week by a tether-and-swivel system.
Results: Baseline arterial pressure averaged 81 +/- 6 mm Hg. In the experimental group four monkeys had adverse outcomes (one maternal death with severe hypertension, one abruptio placentae with stillbirth, and two spontaneous preterm deliveries with hypertension). There was one preterm delivery in the control group. Of the seven monkeys with aortic stricture who continued to term, four developed sustained hypertension (mean pressure 18 +/- 6 mm Hg above baseline), proteinuria, and moderate-to-severe glomerular endotheliosis. None of the controls had hypertension or proteinuria, but two had endotheliosis.
Conclusion: These observations confirm that a syndrome resembling preeclampsia can be produced by a reduction of lower aortic pressure, and they demonstrate that the associated hypertension is not an artifact of anesthesia. This model may prove useful in studying the pathophysiologic mechanisms of preeclampsia.