Optimal Control of HTN in Pregnancy. Dr. Shital Gandhi, MD, FRCPC, MPH University of Toronto September 13, 2013

Transcription

1 Optimal Control of HTN in Pregnancy Dr. Shital Gandhi, MD, FRCPC, MPH University of Toronto September 13, 2013

2 No conflicts of interest to declare

3 Objectives By the end of this session, participants should be able to: Part 1: Engage in the debate on the optimal target blood pressure for pregnant women Part 2: Choose an antihypertensive regimen in the treatment of: mild-moderate hypertension severe hypertension

4 Part 1: What is the ideal blood pressure in pregnancy?

5 Part 1: What is the ideal blood pressure in pregnancy? The ideal BP is that which leads to a healthy mother and baby Non-severe HTN Severe HTN Mother Baby Factors to keep in mind include etiology of HTN, and chronicity of HTN

6 Perinatal outcome in 444 pregnancies with HTN SGA 10 0 Control Preexisting NPGH PET N=98 N=199 N=147 Ferrazzani Am J Ob Gynecol 1990

7 BP > 160 mm Hg is associated with decreased birthweight, preterm delivery, abruption Ono, J Obstet Gynaecol Res June 2013

8 Prospective study of 822 women with chronic HTN Chappell, Hypertension 2008

9 Part 1: Optimal BP for fetal growth Rey et al. The prognosis of pregnancy in women with chronic hypertension. Am J Obstet Gynecol 1994; 171: 410 Prospective cohort study in 337 women with chronic HTN compared to population based outcomes antihypertensive medication started if DBP > 100 mm Hg Women with chronic HTN General Population Relative risk Perinatal Mortality 45/ / ( ) Premature delivery 34.4% 15.0% 1.6 ( ) SGA 15.5% 6.3% 2.4 ( ) Weight Pre-eclampsia 21.2% 2.3% 6.5 ( )

10 Severe HTN is associated with Outcomes worse fetal outcomes Buchbinder, Am J Obstet Gynaecol 2002 Gestational Hypertension Mild (N=467) Severe (N=24) Preeclampsia Mild (N=62) Severe (N=45) Delivery <35 wks 8.4 % BW (g) SGA(%) Abruption %

11 Part 1: Optimal BP for mothers Martin, Obstet Gynecol 2005 Identifying upper limit for BP In preeclampsia, systolic BP > 160 mm Hg is associated with maternal stroke

12 Part 1: What is the ideal blood pressure in pregnancy? The ideal BP is that which leads to a healthy mother and baby Non-severe HTN Severe HTN Mother Baby >160 mm Hg systolic (acute) > mm Hg diastolic (acute, chronic) Factors to keep in mind include etiology of HTN and chronicity of HTN

13 Part 1: What is the ideal blood pressure in pregnancy? Avoiding low BP may be important

14 Fall in MAP and Birthweight von Dadelszen, Lancet 2000

15 Prospective study of maternal BP, birth weight and perinatal mortality Steer, BMJ 2004

16 Prospective study of maternal BP, birth weight and perinatal mortality Steer, BMJ 2004

17 There must be more data on this, surely! Cochrane review 2007: 46 trials with 4282 women enrolled in total Treatment of mild-moderate HTN: Doesn t prevent preeclampsia No difference in preterm birth, SGA Trend towards beta-blockers being associated with growth restriction Drug vs placebo: 50% reduction of severe HTN 2 studies (N=256) of tight vs less tight control showed no difference in rates of preeclampsia, fetal birthweight Magee BJOG 2007 El Guindy Journal Perinatal Medicine 2008

18 Part 1: What is the ideal blood pressure in pregnancy? The ideal BP is that which leads to a healthy mother and baby Non-severe HTN Severe HTN Mother Baby Treating won t prevent PET, but may prevent severe HTN Avoid BP that s too low >160 mm Hg systolic (acute) > mm Hg diastolic (acute, chronic)

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20 Part 1: Optimal target BP in mild-mod HTN SOGC guidelines 2008 Hypertension with no co-morbid conditions Target / mm Hg Hypertension with co-morbid conditions Target /80-89 mm Hg Pre-existing renal disease Cardiac disorders Diabetes Prior CVA

21 Part 1: What is the ideal blood pressure in pregnancy? The ideal BP is that which leads to a healthy mother and baby Non-severe HTN TARGET Co-morbidity No co-morbidity Severe HTN TARGET Mother / / < 160 mm Hg systolic (acute) Baby? 150/ < mm Hg diastolic (acute, chronic)

22 Part 2: Choosing antihypertensives Drugs for treatment of very high blood pressure during pregnancy Cochrane review 2012 Review of 24 trials involving 2949 women Insufficient data to conclude any antihypertensive is clearly better Drugs to avoid: Not effective: magnesium sulphate Ketanserin Nimodipine chlorpromazine Too effective: Diazoxide

23 Part 2: Choosing antihypertensives First-line therapies Labetalol Severe HTN mg IV, can repeat q30min, max 300 mg/day 1-2 mg/minute Hydralazine 5-10 mg IV, can repeat every 30 min mg/hr Nifedipine 5 mg orally Nitroglycerin, sodium nitroprusside cen be used in an ICU setting

24 Part 2: Choosing antihypertensives Non-severe hypertension Drug Starting dose Max dose Caution Labetalol 200 mg BID mg/day Avoid in asthma?neonatal brady Methyldopa 250mg BID 2-3 g/day Hemolytic anemia?postpartum mood Nifedipine XL 30 mg OD 60 mg BID Headache, edema Nifedipine PA mg BID/TID 180 mg daily Hydralazine 25 mg TID/QID 50 mg QID Reflex tachycardia Hydroclorothiazide 25 mg OD - Monitor for oligo Not a typical first choice

25 Summary The optimal BP is whatever is required for the best outcome for mothers and their babies (and families) Severe HTN is associated with increased risks of SGA, abruption, and maternal CVA (if PET). Keep BP < 160/110 mm Hg There is no compelling evidence that mild-moderate HTN requires therapy Keep co-morbidity in mind