A comparative study of the use of epoprostenol and dihydralazine in severe hypertension in pregnancy

Abstract

Objective: To compare the antihypertensive effects of epoprostenol sodium (prostacyclin) with that of dihydralazine in acute hypertensive crises of pregnancy.

Design: A prospective randomized study. A minimum of 20 patients per group was considered statistically acceptable (alpha = 0.05, power = 0.9).

Setting: A large urban tertiary hospital.

Subjects: Forty-seven pregnant patients with diastolic blood pressures of > 100 mmHg were studied.

Intervention: Lowering of high blood pressure with either dihydralazine (n = 25), the standard drug for this purpose, or epoprostenol (n = 22).

Main outcome measure: A significant drop in high blood pressure was regarded as a fall of 15 mmHg diastolic and 30 mmHg systolic blood pressure.

Results: There were no statistically significant differences in the antihypertensive effects between the two treatment groups. Epoprostenol infusion caused less tachycardia; the mean pulse rate changed from 81.77 beats/min, before treatment to 88.36 at stabilization, compared with a change from 80.96 beats/min to 102.68 in the group treated with dihydralazine (P = 0.0024).

Conclusion: The place of epoprostenol in pregnancy might be in patients with severe hypertension and tachycardia and in those requiring acute control of severe hypertension on the operating table before general anaesthesia.

PIP: Researchers analyzed data on 47 black, pregnant women of more than 33 weeks gestation who had preeclampsia with diastolic blood pressure of at least 110 mm Hg and 1+ of proteinuria and were in the delivery department of King Edward VIII Hospital in Durban, South Africa to compare antihypertensive effects of dihydralazine infusion with that of epoprostenol sodium infusion. Overall, both treatments reduced the patient's systolic and diastolic blood pressures. No significant differences in the hypertensive effects existed between the 2 groups. Yet the reduction in blood pressures occurred much more quickly in the epoprostenol group than in the dihydralazine group (51.1 minutes vs. 86.8 minutes;p=.0072). Epoprostenol reduced high blood pressure in all 22 patients while dihydralazine did not adequately control blood pressure in 2 of 25 patients. Physicians had to perform a cesarean section in these 2 cases due to considerable deceleration of the fetal heart rate. They had to 1st administer the rapidly acting ganglion blocking agent, trimetaphan, before placing the women under general anesthesia. Their blood pressures returned to normal after delivery. Even though both groups experienced tachycardia after treatment, the pulse rate of dihydralazine patients was significantly higher than that of epoprostenol patients (102.68/minute vs. 88.36/minute; p=.0024). Only 2 women suffered from side effects. The epoprostenol patient experienced nausea and vomiting. The other patient received dihydralazine and experienced a severe headache. The researchers concluded that physicians should use epoprostenol in patients with severe hypertension and tachycardia and those who need acute control of severe hypertension on the operating table before endotracheal intubation (which tends to cause considerable increases in blood pressure) and administration of general anesthesia.