Pregnancy Induced Hypertension

IN SUMMARY PREGNANCY INDUCED HYPERTENSION Classification of Hypertensive Disorders of Pregnancy • Onset of HTN without proteinuria after 20wks of gestation with resolution to baseline by 12wks postpartum o Preeclampsia (5-8%) • • 0.3 gm/dl in 24hrs or 1+ on urine analysis • Chronic HTN plus new onset proteinuria or other signs or symptoms of preeclampsia ACOG Jan. 2002 Figure removed due to copyright restrictions. Please see: Berg, C. J., H. K. Atrash, L. M. Koonin, and M. Tucker. "Pregnancy-Related Mortality in the United States, 1987-1990." Obstet Gynecol. 88, no. 2 (August, 1996): 161-7. Classification of Preeclampsia o Mild preeclampsia o BP 140/90 o 300mg of proteinuria in 24hrs o Severe preeclampsia (any of these) o BP 160/110 o 5gm of proteinuria in 24hrs o Oliguria or <500 ml in 24hrs o Cerebral of visual disturbances o Pulmonary edema or cyanosis o RUQ tenderness o Fetal growth restriction o Thrombocytopenia o Impaired liver function o Eclampsia o Presence of new-onset grand mal seizures in a woman with preeclampsia ACOG Jan. 2002 RISK FACTORS Nulliparity Age >40 y.o. African-American race Family history Chronic Renal disease Chronic hypertension Antiphospholipid syndrome Diabetes mellitus Twin gestation High body mass index Angiotensiongen gene T235 Homozygous Heterozygous 3:1 3:1 1.5:1 5:1 20:1 10:1 10:1 2:1 4:1 3:1 20;1 4:1 Adopted from ACOG Technical Bulletin 219, Washington, DC 1996 Measurement of Blood Pressure o Comfortable sitting position o Korotkoff V th sound should be used o If the V th sound is not present, use the IV th but should note as such o Some automated BP cuffs use the IV th sound o In serial readings use the higher set of values o Relative BP change of 30mmHg/15mmHg is no longer used as hypertension Clinical Predictors of Eclampsia o 254 Women with Eclampsia o No edema: 80 (32%) o No HTN: 58(23%) o No proteinuia: 49 (19%) Sibai 1990 o 383 Eclampsia collected from 279 Hospitals in UK  No proteinuria: 71 (22%)  No proteinuria or HTN: 36 (11%)  No hypertension: 32 (10%)  Headaches: 188 (50%)  Visual disturbance: 72 (19%)  Epigastric pain: 71 (19%) Douglass, 1994 “A disease of theories that have not stood the test of time” 1000 BC: First description of eclampsia is found in Kahun papyrus from Egypt 1800: An association between onset of hypertension and proteinuria and seizure during pregnancy was recognized 1950: A distinction between primary renal disease, chronic hypertension, epilepsy and preeclampsia/eclampsia became widely accepted Figure removed due to copyright restrictions. EVIDENCE FOR TROPHOBLASTIC INVASION Clinical Predisposing factors include Vascular disease (SLE, diabetes, chronic HBP)) Multiple gestation Hydatidiform mole Animal Studies Most successful models have induced utero-placental ischemia in rabbits, dogs and primates Human Studies Histopathology of the placental bed Doppler of uterine artery Figure removed due to copyright restrictions. Figure removed due to copyright restrictions. Adhesion Molecules Expressed by Cytotrophoblasts Villous Cytos �6/�4 E-cadherin Invasive Cytos �1/�1 �v/�3, �6 VE-cadherins PECAM VCAM Invasive Cytotrophoblasts in Preeclampsia (Lim et al Am J Path 152 (6) 1997 Figures removed due to copyright restrictions. Please see: Lim, K. H., Y. Zhou, M. Janatpour, M. McMaster, K. Bass, S. H. Chun, and S. J. Fisher. "Human Cytotrophoblast Differentiation/Invasion is Abnormal in Pre-eclampsia." Am J Pathol. 151, no. 6 (Dec 1997): 1809-18. CIRCULATING TOXIC FACTORS o Cytokines o IL-1 o IL-6 o TNF-alpha o Free fatty acid o Antioxidants o Angiogenic factors VEGF o Promotes angiogenesis o Induces nitric oxide and prostacyclin o Glomerular healing Anti-VEGF o Increases apoptosis o Impairs glomerular capillary repair o Increases proteinuria in rat model of messangio-proliferative nephritis o Increases proteinuria in experimental thrombotic microangiopathy Figure removed due to copyright restrictions. [Structure of sVEGFR-1 (sFlt-1).] First described by Kendall et al.(1993) and has been localized to trophoblast by Clark et al.1998. Has been shown to be produced in greater amount in trophoblasts isolated from preeclampsia (Zhou et al. 2002) Its role in distal organs and in various pathologic state is unknown Hypoxia may increase its production in trophoblast Figure removed due to copyright restrictions. Please see: Figure 1 in Luttun, A., and P. Carmeliet. "Soluble VEGF receptor Flt1: The Elusive Preeclampsia Factor Discovered?" J Clin Invest. 111, no. 5 (March, 2003): 600-2. Serum Levels of sFlt-1 Prior to onset of Preeclampsia Figures removed due to copyright restrictions. Serum Levels of PIGF Prior to onset of Preeclampsia Figures removed due to copyright restrictions. Parenteral Antihypertensive Agents in Pregnancy Drug Hydralazine Dose 5-10 mg IV Onset 10-20 min Duration 3-6 hrs Labetalol 20-80 mg IV 5-10 min 3-6 hrs Sodium Nitroprusside Nicardpine .25-10 ug/kg/min 5015 mg/h IV Immediate 1-2 min 5-10 min 1-4 hrs Side Effects Tachycardia Headache, flushing, angina Scalp tingling, vomiting, heart block N/V, thiocyanate toxicity Tachycardia,headaches, phlebitis Magnesium Sulfate • For severe PE and eclampsia: 4g in 20% solution at 1g/hr (IV) Maintenance: 5g MgSO4 in 50% sol. Q4hr  Eclampsia o Reversible posterior leukoencephalopathy o Renal insufficiency and hypertension o Immunosuppressive therapy o Eclampsia o Subcortical edema in the posterior circulation • • • • • Local hemorrhagic infarcts • • Loss of autoregulation--over perfusion -- vasogenic cerebral edema Pulmonary Edema • • Diastolic dysfunction Combined  •  Increased capillary permeability Narrowed COP-wedge pressure gradient o Decreased COP o Delayed mobilization of extravascular fluid o Iatrogenic fluid overload FUNDAMENTAL QUESTIONS 1. What happens to blood pressure as pregnancy advances? 2. What happens to blood volume in pre-eclampsia? 3. When does one typically develop pre-eclampsia? 4. List 5 risk factors for pre-eclampsia? 5. What are the clinical manifestaton of pre-eclampsia? 6. What happens in eclampsia? What are the changes one may see in the CNS? 7. What is VGEF? 8. What is sFlt1? What role might it play in pre-eclampsia? 9. Describe the alterations in trophoblastic invasion in pre-eclampsia. 10. What is the most effective therapy for pre-eclampsia? 11. Name some drugs used to control blood pressure in pre-eclampsia.