Outcomes of Pregnancies at Risk for Hypertensive Complications Managed Using Impedance Cardiography

ABSTRACT

We assessed the effect of antihypertensive therapy guided by impedance cardiography on maternal and fetal outcomes in pregnancies at risk for hypertensive complications. We performed a retrospective review of the outcomes of 318 singleton pregnancies with chronic hypertension or prior preterm delivery due to preeclampsia whose antihypertensive therapy was guided by impedance cardiography. Hemodynamic subsets were compared using analysis of variance. Impedance cardiography was used to evaluate cardiac output and total peripheral resistance starting at less than 24 weeks. All patients received atenolol; 24% required additional therapy with a vasodilator. The mean gestational age at delivery was 37 ± 2 weeks. Preeclampsia developed in 14%. The incidence of birth weight less than the 10th percentile was 10%. There were no perinatal deaths, and 75% of the infants spent <3 days in the hospital. Hyperdynamic patients had less preeclampsia, less severe preeclampsia, fewer deliveries <34 weeks, and fewer neonatal intensive care unit days compared with those requiring a vasodilator. Antihypertensive therapy guided by hemodynamic information results in pregnancies delivering at or near term, little preeclampsia, and no increase in growth restriction. Hyperdynamic patients have better outcomes than patients with increased total peripheral resistance.

KEYWORDS

Hypertension - preeclampsia - hemodynamics - impedance cardiography - atenolol

REFERENCES

• 1 American College of Obstetricians and Gynecologists . ACOG Practice Bulletin number 29, July 2001. Chronic hypertension in pregnancy.  Obstet Gynecol. 2001;  98 177-185
• 2 American College of Obstetricians and Gynecologists . ACOG Practice Bulletin number 33, July 2001. Diagnosis and management of preeclampsia and eclampsia.  Obstet Gynecol. 2002;  99 159-167
• 3 Sibai B M, Lindeheimer M, Hauth J et al.. Risk factors for preeclampsia, abruptio placentae, and adverse neonatal outcomes among women with chronic hypertension.  N Engl J Med. 1998;  339 667-671
• 4 Easterling T R, Benedetti T J. Preeclampsia: a hyperdynamic disease model.  Am J Obstet Gynecol. 1989;  160 1447-1453
• 5 Easterling T R, Benedetti T J, Schmucker B C, Millard S P. Maternal hemodynamics in normal and preeclamptic pregnancies: a longitudinal study.  Obstet Gynecol. 1990;  76 1061-1068
• 6 Easterling T R, Benedetti T J, Schmucker B C, Carlson K L. Antihypertensive therapy in pregnancy directed by noninvasive hemodynamic monitoring.  Am J Perinatol. 1989;  6 86-89
• 7 Easterling T R, Brateng D, Schmucker B, Brown Z, Millard S P. Prevention of preeclampsia: a randomized trial of atenolol in hyperdynamic patients before onset of hypertension.  Obstet Gynecol. 1999;  93 725-733
• 8 Easterling T R, Carr D B, Branteng D, Diederichs C, Schmucker B. Treatment of hypertension in pregnancy: effect of atenolol on maternal disease, preterm delivery and fetal growth.  Obstet Gynecol. 2001;  98 427-433
• 9 Bosio P M, McKenna P J, Conroy R, O'Herlihy C. Maternal central hemodynamics in hypertensive disorders of pregnancy.  Obstet Gynecol. 1999;  94 978-984
• 10 Khaw A, Kametas N A, Turan O M, Bamfo J, Nicolaides K H. Maternal cardiac function and uterine artery Doppler at 11–14 weeks in the prediction of pre-eclampsia in nulliparous women.  BJOG. 2008;  115 369-376
• 11 Rand S, van Montfrans G A, Wolf H. Serial hemodynamic measurement in normal pregnancy, preeclampsia, and intrauterine growth restriction.  Am J Obstet Gynecol. 2008;  198 519e1-519e9
• 12 The Seventh Report of the Joint National Committee on Prevention .Detection, Evaluation, and Treatment of High Blood Pressure, US Dept. of Health and Human Services, Aug. 2004, pg. 50. Available at: http://www.nhlbi.nih.gov Accessed 1/11/2009
• 13 Ventura H O, Taler S J, Strobeck J E. Hypertension as a hemodynamic disease: the role of impedance cardiography in diagnostic, prognostic, and therapeutic decision making.  Am J Hypertens. 2005;  18 26S-43S
• 14 Doubilet P M, Benson C B, Nadel A S, Ringer S A. Improved birthweight table for neonates developed from gestations dated by early ultrasonography.  J Ultrasound Med. 1997;  16 241-249
• 15 Smith R D, Levy P, Ferrario C M. Value of noninvasive hemodynamics to achieve blood pressure control in hypertensive subjects.  Hypertension. 2006;  47 771-777
• 16 Haddad B, Sibai B M. Chronic hypertension in pregnancy. In: Sibai BM Hypertensive Disorders in Women. Philadelphia; W.B. Saunders 2001: 128
• 17 Butters L, Kennedy S, Rubin P C. Atenolol in essential hypertension during pregnancy.  BMJ. 1990;  301 587-589