GENERAL ASPECTS OF HEART DISEASE IN PREGNANCY


(From a review around 1992)

I. Prevalence of "heart disease" among preg pts: 0.5-2%

A. Used to consist mostly of rheumatic HD and most of remainder of cong. HD (3:1 ratio)

B. Now ratio reversed due to better surgical tx of cong HD so survive to have kids and better tx of rheumatic fever so prev. of RHD is less

C. Also toxic, metabolic (e.g. dm), inf (e.g. syphilis)

II. Risk to mother is significant

A. Maternal HD dis accounts for 5% (brown) - 30% (Clark) of matmort in preg

B. The problem is the inability of diseased hearts to adapt to the CV changes of preg:

1. Increased plasma volume (CHF, ischemia, aortic aneurysm/dissection)

2. CO fluctuations--particularly bad if pulm HTN or MS

3. Slight tachycardia

4. Decreased SVR (bad for pts with r-l shunts and som valvular diseases)

5. Hypercoagulability (pts at risk for thrombosis, e.g. AFib, need heparin anticoag--coumarin is teratogenic)

C. Most maternal deaths due to HD in preg are from CHF

1. Rapid rise in vol in wks 6-24, so risk to pts with heart dis starts early

2. Most common when vol is at peak, after 32 wk--can't increase CO to match

3. Also common during labor with its high demands on CO

4. Very common immediately postpartum (large autotransfusion)

5. Pts with pulm HTN are at most risk because pulm hypoperf. on top of pulm edema

III. Diagnosis of HD in preg--h&p, ekg, eco, cxr, cath

A. Dx in preg complicated by nl changes of CV in preg, esp. size and sounds

B. Since dx difficult, if you suspect, must tx

IV. Prognostication

A. NYHA Classification sometimes used for prognostication

B. Newer system may be more predictive: is descriptive & includes etiologic dx--3 groups: I (<1%matmort), II (5-15%), III (>25%)

C. Ethical issue of going along with plan to continue dangerous pregnancy

C. Prognosis is constantly changing with advances in therapy, fetal monitoring, neonatology

E. Must attempt to evaluate baseline heart fn and ability to undergo further stress

F. Must also take into account prospects for pts. ability/willingness to adhere to restrictions on activity and poss of added complications, e.g. infection

G. Prog is worse with mom>35yo, h/o pulm edema or AFib

H. Parity NOT a significant factor

I. Subsequent course of mom's HD is NOT affected by whether she does or doesn't undergo pregnancy (longitudinal study c RHD?)

J. Prognosis for fetus:

1. Fetal congenital abn's--increased with cong. and syphilitic HD but not RHD

2. Babies of moms with HD in general tend to weigh less at birth

3. But perinatal mortality not affected by presence or absence alone of mat HD

4. Maternal decompensation (pulm edema, arrhythmias, etc.), can cause hypoxic damage to fetus

V. Indications for TOP

A. Previous cardiac decompensation, inc. AFib, but esp. CHF, outside of preg

1. 2/3 of CHF outside of preg will decompensate in preg

B. Class III/IV

C. >35yo

D. Pulm HTN

E. Noncompliance/lack of access to care

VI. Management

A. Much of the clinical approach to the preg pt c HD applies to all such patients or is specific for the pts NYHA class but not for the particular cause of the HD

B. Avoid infections, esp. respiratory, and treat aggressively if they occur-- can precip. CHF

C. Treat anemia, obesity, hyperthyroidism, which may be associated; any other med probs

D. Preventive Tx is vital in preg c HD; shown to greatly decrease mortality

1. Avoid cardiac decompensation by avoiding increased CO states

2. Devise with patient a specific daily "rest regimen,? e.g.

a. 10h/night in bed, scheduled morn/aft rests

b. Avoid strenuous activities, esp. after 20 wks when CO is already high

c. Arrange relief from strenuous household/work duties

d. No sex after week 20 if severe (?)

3. Sodium restriction is not indicated and may interfere with nl vol. expansion

4. Fe supplements important to mitigate anemia--will reduce cardiac work

E. Dig if clinically indicated for I/II; throughout preg for III/IV

F. If CLASS IV, admit 10-14d prior to EDC for "controlled rest"

G. If mom has mech valv. prosth, give heparin and ABX for duration of preg

H. Surgical Tx for anatomic heart lesions

1. Mitral valvulotomy for severe MS has been successfully performed in preg pts, but risk of hypoxic damage to placenta and fetus is high (mat op mort <3%)

2. Surg correction of a valve lesions does not guarantee lack of heart probs in preg

3. Women with mech. valv prosth have much probs in preg--endocard, thromboemboli, so women of childbearing age, preg or not, should get bioprosth, not mech

VII. Labor management

A. Go for spont--not longer/more failure c HD; no decrease in risk with induction

B. If inducing, use oxytocin, not ergot derivatives, which can cause HTN

C. S-G and a-line if hemodynamically sig. HD or suspect PULM HTN

D. Check pulse (should be <110 between contr) and RR (should be <24) Q15min

1. If too high, CHF is likely, so: give O2, DIG

E. Minimize pain, anxiety, musc. activity (all raise CO)

1. Epidural helps and has least effect on BP of most anesthetic modalities

2. Demerol or morphine as alternatives

3. Scopolamine and phenothiazines cause BP fluctuations and are NO GOOD

VIII. Delivery management

A. Try for vaginal--indications for c/s per usual (if do c/s, epidural is best anesth)

B. If op. deliv or episiotomy, SBE prophylaxis (amp/gent)

C. For vag. deliv, minimize "perineal phase" of labor, where effort and CO is greatest

D. Low-forceps extraction has been recommended for all vag births c mat HD but (grey book) forceps only nec. in primips or if lasts long time

IX. Postpartum management

A. Most common time for CHF (increased CO from autoxfsn from contracting uterus)

B. Be prepared even if no sx during preg or labor/delivery

C. No ergot derivatives postpartum (vide supra)

D. Lower pts legs promptly after delivery

E. If any cardiac sx during labor/delivery, keep in bed until gone. Others can ambulate

F. Class I pts can be d/c'd per normal, others stay till clearly hemodynamically stable

G. Volume overload resolves after about 1 wk

H. Continue activity restriction for initial weeks postpartum

I. If pt had problems at any point, be sure to discuss contraception/sterilization

J. Pt may also go into hypovolemic shock immediately postpartum; if pt has pulm. HTN, can get pulmonary hypoperfusion