Hypertension in Pregnancy

Etiology & Definition Complicates 10-20% of pregnancies Complicates 10-20% of pregnancies Elevation of BP ≥140 mmHg systolic and/or ≥90 mmHg diastolic, on two occasions at least 6 hours apart. Elevation of BP ≥140 mmHg systolic and/or ≥90 mmHg diastolic, on two occasions at least 6 hours apart.

Categories Chronic Hypertension Chronic Hypertension Gestational Hypertension Gestational Hypertension Preeclampsia Preeclampsia Preeclampsia superimposed on Chronic Hypertension Preeclampsia superimposed on Chronic Hypertension

Chronic Hypertension “Preexisting Hypertension” “Preexisting Hypertension” Definition Definition Systolic pressure ≥ 140 mmHg, diastolic pressure ≥90 mmHg, or both. Systolic pressure ≥ 140 mmHg, diastolic pressure ≥90 mmHg, or both. Presents before 20 th week of pregnancy or persists longer then 12 weeks postpartum. Presents before 20 th week of pregnancy or persists longer then 12 weeks postpartum. Causes Causes Primary = “Essential Hypertension” Primary = “Essential Hypertension” Secondary = Result of other medical condition (ie: renal disease) Secondary = Result of other medical condition (ie: renal disease)

Prenatal Care for Chronic Hypertensives Electrocardiogram should be obtained in women with long-standing hypertension. Baseline laboratory tests Urinalysis, urine culture, and serum creatinine, glucose, and electrolytes Tests will rule out renal disease, and identify comorbidities such as diabetes mellitus. Women with proteinuria on a urine dipstick should have a quantitative test for urine protein.

Treatment for Chronic Hypertension Avoid treatment in women with uncomplicated mild essential HTN as blood pressure may decrease as pregnancy progresses. May taper or discontinue meds for women with blood pressures less than 120/80 in 1 st trimester. Reinstitute or initiate therapy for persistent diastolic pressures >95 mmHg, systolic pressures >150 mmHg, or signs of hypertensive end-organ damage. Medication choices = Oral methyldopa and labetalol.

Preeclampsia Definition = New onset of hypertension and proteinuria after 20 weeks gestation. Definition = New onset of hypertension and proteinuria after 20 weeks gestation. Systolic blood pressure ≥140 mmHg OR diastolic blood pressure ≥90 mmHg Systolic blood pressure ≥140 mmHg OR diastolic blood pressure ≥90 mmHg Proteinuria of 0.3 g or greater in a 24-hour urine specimen Proteinuria of 0.3 g or greater in a 24-hour urine specimen Preeclampsia before 20 weeks, think MOLAR PREGNANCY! Preeclampsia before 20 weeks, think MOLAR PREGNANCY! Categories Categories Mild Preeclampsia Mild Preeclampsia Severe Preeclampsia Severe Preeclampsia Eclampsia Eclampsia Occurrence of generalized convulsion and/or coma in the setting of preeclampsia, with no other neurological condition. Occurrence of generalized convulsion and/or coma in the setting of preeclampsia, with no other neurological condition.

Preeclampsia Severe Preeclampsia must have one of the following: Severe Preeclampsia must have one of the following: Symptoms of central nervous system dysfunction = Blurred vision, scotomata, altered mental status, severe headache Symptoms of central nervous system dysfunction = Blurred vision, scotomata, altered mental status, severe headache Symptoms of liver capsule distention = Right upper quadrant or epigastric pain Symptoms of liver capsule distention = Right upper quadrant or epigastric pain Nausea, vomiting Nausea, vomiting Hepatocellular injury = Serum transaminase concentration at least twice normal Hepatocellular injury = Serum transaminase concentration at least twice normal Systolic blood pressure ≥160 mm Hg or diastolic ≥110 mm Hg on two occasions at least six hours apart Systolic blood pressure ≥160 mm Hg or diastolic ≥110 mm Hg on two occasions at least six hours apart Thrombocytopenia = <100,000 platelets per cubic milimeter Thrombocytopenia = <100,000 platelets per cubic milimeter Proteinuria = 5 or more grams in 24 hours Proteinuria = 5 or more grams in 24 hours Oliguria = <500 mL in 24 hours Oliguria = <500 mL in 24 hours Severe fetal growth restriction Severe fetal growth restriction Pulmonary edema or cyanosis Pulmonary edema or cyanosis Cerebrovascular accident Cerebrovascular accident

Preeclampsia superimposed on Chronic Hypertension Affects 10-25% of patients with chronic HTN Affects 10-25% of patients with chronic HTN Preexisting Hypertension with the following additional signs/symptoms: Preexisting Hypertension with the following additional signs/symptoms: New onset proteinuria New onset proteinuria Hypertension and proteinuria beginning prior to 20 weeks of gestation. Hypertension and proteinuria beginning prior to 20 weeks of gestation. A sudden increase in blood pressure. A sudden increase in blood pressure. Thrombocytopenia. Thrombocytopenia. Elevated aminotransferases. Elevated aminotransferases.

Treatment of Preeclampsia Definitive Treatment = Delivery Definitive Treatment = Delivery Major indication for antihypertensive therapy is prevention of stroke. Diastolic pressure ≥ mmHg or systolic pressure ≥160 mmHg Choice of drug therapy: Choice of drug therapy: Acute – IV labetalol, IV hydralazine, SR Nifedipine Acute – IV labetalol, IV hydralazine, SR Nifedipine Long-term – Oral methyldopa or labetalol Long-term – Oral methyldopa or labetalol

Gestational Hypertension Mild hypertension without proteinuria or other signs of preeclampsia. Mild hypertension without proteinuria or other signs of preeclampsia. Develops in late pregnancy, after 20 weeks gestation. Develops in late pregnancy, after 20 weeks gestation. Resolves by 12 weeks postpartum. Resolves by 12 weeks postpartum. Can progress onto preeclampsia. Can progress onto preeclampsia. Often when hypertension develops <30 weeks gestation. Often when hypertension develops <30 weeks gestation.. Indications for and choice of antihypertensive therapy are the same as for women with preeclampsia.

Risk Factors for Hypertension in Pregnancy Nulliparity Nulliparity Preeclampsia in a previous pregnancy Preeclampsia in a previous pregnancy Age >40 years or 40 years or <18 years Family history of pregnancy-induced hypertension Family history of pregnancy-induced hypertension Chronic hypertension Chronic hypertension Chronic renal disease Chronic renal disease Antiphospholipid antibody syndrome or inherited thrombophilia Antiphospholipid antibody syndrome or inherited thrombophilia Vascular or connective tissue disease Vascular or connective tissue disease Diabetes mellitus (pregestational and gestational) Diabetes mellitus (pregestational and gestational) Multifetal gestation Multifetal gestation High body mass index High body mass index Male partner whose previous partner had preeclampsia Male partner whose previous partner had preeclampsia Hydrops fetalis Hydrops fetalis Unexplained fetal growth restriction Unexplained fetal growth restriction

Evaluation of Hypertension in Pregnancy History History ID and Complaint ID and Complaint HPI (S/S of Preeclampsia) HPI (S/S of Preeclampsia) Past Medical Hx, Past Family Hx Past Medical Hx, Past Family Hx Past Obstetrical Hx, Past Gyne Hx Past Obstetrical Hx, Past Gyne Hx Social Hx Social Hx Medications, Allergies Medications, Allergies Prenatal serology, blood work Prenatal serology, blood work Assess for Hypertension in Pregnancy risk factors Assess for Hypertension in Pregnancy risk factors Physical Vitals HEENT = Vision Cardiovascular Respiratory Abdominal = Epigastric pain, RUQ pain Neuromuscular and Extremities = Reflex, Clonus, Edema Fetus = Leopold’s, FM, NST

Evaluation of Hypertension in Pregnancy Laboratory Tests Laboratory Tests CBC (Hgb, Plts) CBC (Hgb, Plts) Renal Function (Cr, UA, Albumin) Renal Function (Cr, UA, Albumin) Liver Function (AST, ALT, ALP, LD) Liver Function (AST, ALT, ALP, LD) Coagulation (PT, PTT, INR, Fibrinogen) Coagulation (PT, PTT, INR, Fibrinogen) Urine Protein (Dipstick, 24 hour) Urine Protein (Dipstick, 24 hour)

Management of Hypertension in Pregnancy Depends on severity of hypertension and gestational age!!!! Depends on severity of hypertension and gestational age!!!! Observational Management Observational Management Restricted activity Restricted activity Close Maternal and Fetal Monitoring Close Maternal and Fetal Monitoring BP Monitoring BP Monitoring S/S of preeclampsia S/S of preeclampsia Fetal growth and well being (NST, and U/S) Fetal growth and well being (NST, and U/S) Routine weekly or biweekly blood work Routine weekly or biweekly blood work

Management of Hypertension in Pregnancy Medical Management Medical Management Acute Therapy = IV Labetalol, IV Hydralazine, SR Nifedipine Acute Therapy = IV Labetalol, IV Hydralazine, SR Nifedipine Expectant Therapy = Oral Labetalol, Methyldopa, Nifedipine Expectant Therapy = Oral Labetalol, Methyldopa, Nifedipine Eclampsia prevention = MgSO4 Eclampsia prevention = MgSO4 Contraindicated antihypertensive drugs Contraindicated antihypertensive drugs ACE inhibitors ACE inhibitors Angiotensin receptor antagonists Angiotensin receptor antagonists

Management of Hypertension in Pregnancy Proceed with Delivery Proceed with Delivery Vaginal Delivery VS Cesarean Section Vaginal Delivery VS Cesarean Section Depends on severity of hypertension! Depends on severity of hypertension! May need to administer antenatal corticosteroids depending on gestation! May need to administer antenatal corticosteroids depending on gestation! Only cure is DELIVERY!!! Only cure is DELIVERY!!!

Hypertension Third leading cause of maternal mortality, after thromboembolism and non-obstetric injuries Third leading cause of maternal mortality, after thromboembolism and non-obstetric injuries Maternal DBP > 110 is associated with ↑ risk of placental abruption and fetal growth restriction Maternal DBP > 110 is associated with ↑ risk of placental abruption and fetal growth restriction Superimposed preeclampsia cause most of the morbidity Superimposed preeclampsia cause most of the morbidity

Pregnancy Induced Hypertension HTN HTN Usually mild and later in pregnancy Usually mild and later in pregnancy No renal or other systemic involvement No renal or other systemic involvement Resolves 12 wks postpartum Resolves 12 wks postpartum May become preeclampsia May become preeclampsia

Hypertension Most common medical problem encountered during pregnancy Most common medical problem encountered during pregnancy 8% of pregnancies 8% of pregnancies 4 categories: 4 categories: Chronic Hypertension Chronic Hypertension Pregnancy Induced hypertension Pregnancy Induced hypertension Preeclampsia-eclampsia Preeclampsia-eclampsia Preeclampsia superimposed on chronic HTN Preeclampsia superimposed on chronic HTN *Hypertensive disorder in pregnancy may cause an increase in maternal and fetal morbidity and remains a leading source of maternal mortality* *Hypertensive disorder in pregnancy may cause an increase in maternal and fetal morbidity and remains a leading source of maternal mortality*

Pregnancy Induced Hypertension HTN HTN Usually mild and later in pregnancy Usually mild and later in pregnancy No renal or other systemic involvement No renal or other systemic involvement Resolves 12 wks postpartum Resolves 12 wks postpartum May become preeclampsia May become preeclampsia

Preeclampsia New onset HTNNew onset HTN After 20 weeks of gestation, orAfter 20 weeks of gestation, or Early post-partum, previously normotensiveEarly post-partum, previously normotensive Resolves within 48 hrs postpartumResolves within 48 hrs postpartum With the following (Renal or other systemic)With the following (Renal or other systemic) Proteinuria > 300 mg/24hrProteinuria > 300 mg/24hr Oliguria or Serum-plasma creatinine ratio > 0.09 mmol/LOliguria or Serum-plasma creatinine ratio > 0.09 mmol/L Headaches with hyperreflexia, eclampsia, clonus or visual disturbancesHeadaches with hyperreflexia, eclampsia, clonus or visual disturbances ↑ LFTs, glutathione-S-Transferase alpha 1-1, alanine aminotransferase or right abdominal pain↑ LFTs, glutathione-S-Transferase alpha 1-1, alanine aminotransferase or right abdominal pain Thrombocytopenia, ↑ LDH, hemolysis, DICThrombocytopenia, ↑ LDH, hemolysis, DIC 10% in primigravid10% in primigravid 20-25% with history of chronic HTN20-25% with history of chronic HTN

Maternal Risk Factors First pregnancy First pregnancy Age younger than 18 or older than 35 Age younger than 18 or older than 35 Prior h/o preeclampsia Prior h/o preeclampsia Black race Black race Medical risk factors for preeclampsia - chronic HTN, renal disease, diabetes, anti-phospholipid syndrome Medical risk factors for preeclampsia - chronic HTN, renal disease, diabetes, anti-phospholipid syndrome Twins Twins Family history Family history

Mild vs. Severe Preeclampsia MildSevere Systolic arterial pressure 140 mm Hg – 160 mm Hg ≥160 mm Hg Diastolic arterial pressure 90 mm Hg – 110 mm Hg ≥110 mm Hg Urinary protein <5 g/24 hr Dipstick +or 2 + ≥5 g/24 hr Dipstick 3+or 4+ Urine output >500 mL/24 hr ≤500 mL/24 hr HeadacheNoYes Visual disturbances NoYes Epigastric pain NoYes

Etiology Exact mechanism not known Immunologic Immunologic Genetic Genetic Placental ischemia Placental ischemia Endothelial cell dysfunction Endothelial cell dysfunction Vasospasm Vasospasm Hyper-responsive response to vasoactive hormones (e.g. angiotensin II & epinephrine) Hyper-responsive response to vasoactive hormones (e.g. angiotensin II & epinephrine)

Symptoms of preeclampsia Visual disturbances Visual disturbances Headache Headache Epigastric pain Epigastric pain Rapidly increasing or nondependent edema - may be a signal of developing preeclampsia Rapidly increasing or nondependent edema - may be a signal of developing preeclampsia Rapid weight gain - result of edema due to capillary leak as well as renal Na and fluid retention Rapid weight gain - result of edema due to capillary leak as well as renal Na and fluid retention

Pathophysiology

Pathophysiology Airway edema Airway edema Cardiac Cardiac Renal Renal Hepatic Hepatic Uterine Uterine

Upper airway edema Upper airway edema Upper airway edema Laryngeal edema Laryngeal edema Airway obstruction Airway obstruction Potential for airway compromise or difficulty in intubation Potential for airway compromise or difficulty in intubation

Cardiac/Pulmonary Increased CO & SVR Increased CO & SVR CVP normal or slightly increased CVP normal or slightly increased Plasma volume reduced Plasma volume reduced Pulmonary edema Pulmonary edema Decrease oncotic/collid pressure Decrease oncotic/collid pressure Capillary/endothelial damage  leak Capillary/endothelial damage  leak Vasoconstriction Vasoconstriction  increase PWP and CVP  increase PWP and CVP Occurs 3 % of preeclamptic patients Occurs 3 % of preeclamptic patients

Hepatic Usually mild Usually mild Severe PIH or preeclampsia complicated by HELLP Severe PIH or preeclampsia complicated by HELLP  periportal hemorrhages  ischemic lesion  generalized swelling  hepatic swelling  epigastric pain

Renal Adversely affected  proteinuria Adversely affected  proteinuria GFR and CrCl  decrease GFR and CrCl  decrease BUN increase, may correlate w/ severity BUN increase, may correlate w/ severity RBF compromised RBF compromised ARF w/ oliguria – PIH, esp. w/ abruption, DIC, HELLP ARF w/ oliguria – PIH, esp. w/ abruption, DIC, HELLP *Oliguria + renal failure may occur in the absence of hypovolemia. Be careful w/ hydration  pulmonary edema* *Oliguria + renal failure may occur in the absence of hypovolemia. Be careful w/ hydration  pulmonary edema*

Uterine Activity increased Activity increased Hyperactive/hypersensitive to oxytocin Hyperactive/hypersensitive to oxytocin Preterm labor – frequent Preterm labor – frequent Uterine/placental blood flow – decreased by 50-70% Uterine/placental blood flow – decreased by 50-70% Abruption – incidence increased Abruption – incidence increased

Morbidity / Mortality Maternal complications: Leading cause of maternal death in PIH is intracranial hemorrhage Leading cause of maternal death in PIH is intracranial hemorrhage Seizures Seizures Pulmonary edema Pulmonary edema ARF ARF Proteinuria Proteinuria Hepatic swelling with or without liver dysfunction Hepatic swelling with or without liver dysfunction DIC (usually associated with placental abruption and is uncommon as a primary manifestation of preeclampsia) DIC (usually associated with placental abruption and is uncommon as a primary manifestation of preeclampsia)

Morbidity / Mortality Fetal complications: Abruptio placentae Abruptio placentae IUGR IUGR Premature delivery Premature delivery Intrauterine fetal death Intrauterine fetal death

HELLP Syndrome HemolysisHemolysis Elevated Liver enzymesElevated Liver enzymes Low PlateletsLow Platelets < 36 wks< 36 wks Malaise (90%), epigastric pain (90%), N/V (50%)Malaise (90%), epigastric pain (90%), N/V (50%) Self-limitingSelf-limiting Multi-system failureMulti-system failure

HELLP Syndrome Hemostasis is not problematic unless PLT < 40,000 Hemostasis is not problematic unless PLT < 40,000 Rate of fall in PLT count is important Rate of fall in PLT count is important Regional anesthesia - contraindicated  fall is sudden Regional anesthesia - contraindicated  fall is sudden PLT count  normal within 72 hrs of delivery PLT count  normal within 72 hrs of delivery Thrombocytopenia may persist for longer periods. Thrombocytopenia may persist for longer periods. Definitive cure is delivery Definitive cure is delivery

Treatment Management of maternal hemodynamics & prevention of eclampsia are key to a favorable outcomeManagement of maternal hemodynamics & prevention of eclampsia are key to a favorable outcome MgSO 4 - Rx of choice for preeclampsia.MgSO 4 - Rx of choice for preeclampsia. Does not significantly reduce systemic BP at the serum concentration that are efficacious in treating preeclampsiaDoes not significantly reduce systemic BP at the serum concentration that are efficacious in treating preeclampsia GoalsGoals Control BPControl BP Prevent seizuresPrevent seizures Deliver the fetusDeliver the fetus

Controlling the HTN Hydralazine Hydralazine Labetalol Labetalol Nitroglycerin Nitroglycerin Nifedipine Nifedipine Esmolol Esmolol Na Nitroprusside – risk of cyanide toxicity in the fetus Na Nitroprusside – risk of cyanide toxicity in the fetus

Preventing Seizures MgSO 4 - Drug of choice. Narrow therapeutic index MgSO 4 - Drug of choice. Narrow therapeutic index Reduce > 50% w/o any serious maternal morbidity Reduce > 50% w/o any serious maternal morbidity 4g IV Bolus over 10 minutes, then 1g/hr 4g IV Bolus over 10 minutes, then 1g/hr Renal failure - rate of infusion  by serum Mg levels Renal failure - rate of infusion  by serum Mg levels Plasma Level should be between 4-6 mmol/L Plasma Level should be between 4-6 mmol/L Monitor clinical signs for toxicity Monitor clinical signs for toxicity Toxic: 10 ml of 10% Ca Gluconate IV slowly Toxic: 10 ml of 10% Ca Gluconate IV slowly

MgSO 4 Toxicity 5-10 mEq/L – Prolonged PR, widened QRS 5-10 mEq/L – Prolonged PR, widened QRS mEq/L – Depressed tendon reflexes mEq/L – Depressed tendon reflexes mEq/L – SA, AV node block, respiratory paralysis mEq/L – SA, AV node block, respiratory paralysis >25 mEq/L - Cardiac arrest >25 mEq/L - Cardiac arrest

Anesthetic Considerations Detailed preanesthetic assessment Detailed preanesthetic assessment Focuses on airway, fluid status, and BP control Focuses on airway, fluid status, and BP control Lab: CBC, BUN/Cr, LFTs Lab: CBC, BUN/Cr, LFTs Routine coagulation is NOT recommended unless there is clinical suspicion Routine coagulation is NOT recommended unless there is clinical suspicion PLT count - if neuraxial techniques are considered PLT count - if neuraxial techniques are considered

Regional Anesthesia Labor epidural - advantage of a gradual onset of sympathetic blockade  provides cardiovascular stability & avoids neonatal depression. Labor epidural - advantage of a gradual onset of sympathetic blockade  provides cardiovascular stability & avoids neonatal depression. Epidurals may reduce vasospasm and HTN – may improve uteroplacental blood flow Epidurals may reduce vasospasm and HTN – may improve uteroplacental blood flow Reduce risk of airway complications and avoid hemodynamic alterations associated with intubation Reduce risk of airway complications and avoid hemodynamic alterations associated with intubation

Regional (part 2) Neuraxial anesthesia in preeclamptic pt - still controversial Neuraxial anesthesia in preeclamptic pt - still controversial Many studies  this is the best option Many studies  this is the best option National High blood Pressure Education Program Working Group National High blood Pressure Education Program Working Group “Neuraxial, epidural, spinal and combined spinal-epidural (CSE), techniques offer many advantages for labor analgesia and can be safely administered to the parturient with preeclampsia. Dilute epidural infusions of local anesthetic plus opioid produce adequate sensory block without motor block or clinically significant sympathectomy. “ “Neuraxial, epidural, spinal and combined spinal-epidural (CSE), techniques offer many advantages for labor analgesia and can be safely administered to the parturient with preeclampsia. Dilute epidural infusions of local anesthetic plus opioid produce adequate sensory block without motor block or clinically significant sympathectomy. “

Regional (part 3) Possibility of extensive sympatholysis with profound hypotension Possibility of extensive sympatholysis with profound hypotension  decrease CO & uteroplacental perfusion  decrease CO & uteroplacental perfusion Single shot spinal technique  controversial Single shot spinal technique  controversial Recent analysis suggest that it can be used safety in pt with severe preeclampsia undergoing C-section. BP decline similar to epidural. Hypotension can be avoided by meticulous attention to anesthetic technique and careful volume expansion Recent analysis suggest that it can be used safety in pt with severe preeclampsia undergoing C-section. BP decline similar to epidural. Hypotension can be avoided by meticulous attention to anesthetic technique and careful volume expansion

General Anesthetic Techniques Laryngeal response  blunted by pre-treatment with hydralazine, nitroglycerin or labetalol Laryngeal response  blunted by pre-treatment with hydralazine, nitroglycerin or labetalol Airway edema  increased risk of difficult airway situation Airway edema  increased risk of difficult airway situation Neuraxial techniques  preferred method, contraindicated in the presence of coaguloapthy Neuraxial techniques  preferred method, contraindicated in the presence of coaguloapthy In pt receiving MgSO 4, SUX activity  potentiated In pt receiving MgSO 4, SUX activity  potentiated Enhanced sensitivity to non-depolarizing muscle relaxants Enhanced sensitivity to non-depolarizing muscle relaxants MgSO 4 blunts response to vasconstrictors and inhibits catecholamine release after sympathetic stimulation MgSO 4 blunts response to vasconstrictors and inhibits catecholamine release after sympathetic stimulation

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