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  • Nathan Riley, MD

Obgyno Wino Podcast Episode 19 - Pregnancy and Heart Disease - Part 1

Updated: Jul 25, 2019

“It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid souls who neither know victory nor defeat.” - Theodore Roosevelt

Pacific Redwoods Organic Red from Frey Vineyards

PB#212 - Published April 2019

Five Pearls

1. Counseling regarding the maternal and fetal risks in pregnancy complicated by cardiovascular disease (CVD), should ideally begin pre-pregnancy

2. The majority of maternal deaths from CVD are secondary to undiagnosed CVD or new-onset CVD of pregnancy

3. The increased maternal mortality and morbidity associated with CVD in pregnancy is related to the underlying physiologic changes that occur in pregnancy

4. A multi-disciplinary approach is required to optimize a pregnant woman's care in the setting of CVD (OB, MFM, neonatology, cardiology, anesthesiology, etc.)

5. When in doubt, give cards a shout.


Fun with epidemiology

- CVD affects 1-4% of pregnancies in the U.S.

- leading cause of death in pregnant women and women in the postpartum period in the United States: 4-5 deaths per 100,000 live births (10% morbidity)

- nonwhite and lower-income women disproportionately affected in part due to structural, institutional, and systemic barriers

- risk factors contributing to maternal mortality: race/ethnicity, age, preexisting hypertension, and obesity (esp if patient has obstructive sleep apnea)

- rising trend is attributable to rising trend in acquired heart disease; congenital heart disease trend is stable

- 50-75% of maternal deaths could be prevented if we considered it in our differential diagnosis of pregnant women when cardiovascular symptoms arise

- common presentation of acquired heart disease in pregnancy: heart failure, myocardial infarction, arrhythmia, aortic dissection


Let's talk for a moment about race...

- racial and ethnic bias exists in healthcare

- it leads to missed diagnoses or inappropriate treatment

- many women of color also tend to have greater mistrust in the health care system than white women

- all of these things contribute to higher rates of gestational diabetes, preeclampsia, preterm delivery, and low-birth-weight infants in non-hispanic black women compared with non-Hispanic white women


Physiologic changes in pregnancy

Hemodynamic:

- many normal physiologic changes put stress on the heart in pregnancy/labor:

- estrogen and progesterone have several important effects on the cardiovascular system

- estrogen increases angiotensin to help to fill up the vascular tank that's left sub-optimally filled due to the increased glomerular filtration and global vasodilation also seen in pregnancy

- you see a progressive increase in cardiac output and plasma volume w/ a progressive decrease in peripheral vascular resistance throughout pregnancy

- increased hydrostatic pressure and decrease oncotic pressure make women with CVD more highly susceptible to pulmonary edema, particularly in willy-nilly IV fluids administration and in patients who develop preeclampsia


Recall: Angiotensinogen is a protein produced in the liver, converted to angiotensin I by renin, then further to angiotensin II by angiotensin converting enzyme produced in the lungs and kidneys. Angiotensin II stimulates the release of aldosterone from the adrenals


Structural: - increased maternal atrial natriuretic peptide levels in the first week postpartum permit diuresis

- ventricles increase in size by 40 and 50% (right, left); 20% of women have diastolic dysfunciton at term

- most of these structural changes return to baseline w/in 1 yr postpartum


Hematologic/metabolic: - erythropoiesis and plasma increases are disproportionate, resulting in dilution anemia

- increase coagulability due to venous stasis, decreased mobility, and increased clotting factors such a fibrinogen

- increased O2 consumption, decreased insulin sensitivity, increased serum fatty acids


So what are some things to look out for that might be concerning for worsening cardiac disease in pregnancy?


Pre-pregnancy counseling for patients with known heart disease

- recommendations vary depending on the specific type of cardiac disease and clinic status of the patient

- various risk assessment models have been developed: CARPREG II, ZAHAR, and the modified WHO risk assessment (most widely used)


- establish multi-disciplinary care ("Pregnant Heart Team") with cardiology, MFM, neonatology, and a variety of other ad hoc team members, ideally before pregnancy

- look at all prior cardiac testing, obtain comprehensive review of symptoms, function, and family history

- in the case of a family history of cardiac disease, inquire about genetic testing that may have been performed (MYH7 mutations are associated with cadiomyopathies)

- pre-pregnancy counseling should include discussions around mortality/morbidity to the patient as a result of the physiologic changes seen in pregnancy and the need for increased surveillance throughout pregnancy and the postpartum periods

- pregnancy is NOT recommended for WHO class IV disease

- risk to the fetus include: risk of passing congenital defects to offspring, growth restriction, preterm birth, IUFD, and perinatal mortality compared to women without cardiac disease

- 1/3 of cardiac patients will require cardiovascular medication in pregnancy; attempt to switch to safer alternatives prior to conception

- ACE-I, ARB, and aldosterone antagonists (e.g. Aldactone, Spironolactone) are generally contraindicated as they can be teratogenic, but some cardiac conditions may be controlled only by these medications, and, as such, these and other interventions (e.g. warfarin in a patient w/ a mechanical valve prosthesis) require a risk/benefit analysis if the patient is determined to becoming pregnant

- the majority of maternal deaths from CVD had either undiagnosed CVD or new-onset CVD of pregnancy --> when in doubt, ask for help from members of your Pregnancy Heart Team


Comments on a few common maternal cardiac disease varieties


Congenital heart disease

- high risk lesions require frequent follow-up (pulmonary HTN such as that seen in Eisenmenger syndrome, severe left-sided heart obstruction, severe ventricular dysfunction, cyanosis, failing Fontan circulation, and complex arrhythmias)

- recommend against pregnancy or surgical correction prior to pregnancy

- potential for inheritance to the fetus should be discussed

- some genetic disorders are associated with congenital heart disease (e.g. Noonan, Down syndrome, and 22q11 microdeletion)

- fetal echo is recommended


Noncongenital valvular disease

- examples include rheumatic valve disease, MV prolapse, bioprosthetic valve prosthesis, or endocarditis affecting a valve

- echocardiogram and exercise stress testing are recommended in pts with moderate-severe disease (e.g. stenosis, regurgitation)

- symptomatic, severe valvular disease should be treated before pregnancy


Mechanical valve prosthesis

- some lesions require anticoagulation

- in addition, prescribe low-dose aspirin daily

- endocarditis prophylaxis may be required at time of delivery


Preexisting dilated cardiomyopathy

- helpful to get a baseline BNP, echo and exercise stress test

- 25-40% rate of major adverse cardiovascular events like heart failure during pregnancy

- advise against pregnancy or even termination in the presence of severe disease (EF <30%; class III/IV failure, severe valvular stenosis, aortic dilation, or pulm HTN)


Aortic aneurysmal disease and dissection

- before pregnancy, ideally the cause, location, and size would be elaborated

- usually ascending aorta is affected, but descending can be as well

- depending on severity and cause, pregnancy may be ill-advised

- treat with beta-blocker therapy and perform serial imaging throughout pregnancy

Arrhythmias

- palpitations warrant further workup (see below)

- most common atrial arrhythmias during pregnancy: premature atrial beats and paroxysmal SVT (both easily treated with medication)

- A-fib or A-flutter occur more often in the setting of underlying structural disease

- ventricular arrythmias are rarely encountered in pregnancy

- requires an investigation into underlying structural disease (see below)

- patients with prolonged QT syndrome are predisposed to v-tach

- treatment with beta-blocker may be appropriate


When is maternal cardiac testing warranted?

- if the patient becomes pregnant in the setting of known cardiac disease OR if a patient complains of new-onset dyspnea, chest pain, or palpitations during pregnancy, especially they have a strong family history

- if something comes back as abnormal, get cards involved


Natriuretic Peptides

- elevations of BNP/NT-proBNP may suggest heart failure (left ventricular systolic or diastolic dysfunction, preeclampsia)

- in non-pregnant patients, BNP >100, NT-proBNP >450 is diagnostic of heart failure

- in pregnancy, peptide levels increase twofold during pregnancy, further increase early after delivery, but they generally remain within normal range

- in high risk patients (dilated cardiomyopathy, congenital heart disease), it may be helpful to collect a BNP at baseline, then repeat every trimester (increases of BNP after 2nd trimester appear to predict adverse events)


Cardiac Troponin I, Troponin T, and "High-Sensitivity" Troponin

- specific and sensitive biomarkers for myocardial injury, though troponin I may be mildly elevated in the early postpartum period in women with severe preeclampsia and other non-cardiac conditions such as acute PE and chronic renal disease

- recommended if a patient presents with acute chest pain in order to evaluate for acute coronary syndrome


EKG

- recommended at baseline in pregnancy

- also if your patient presents with chest pain, dyspnea, or palpitations to assess for ischemia, infarction, or arrhythmias

- note: nonspecific ST-wave and T-wave abnormalities are found in up to 15% of pregnancies, usually in the left-sided precordial leads, but these will usually resolve soon after pregnancy


CXR

- recommended if a patient presents with dyspnea in order to assess for cardiac or pulmonary etiology


Echocardiogram

- great at baseline for patients with congenital heart disease, known valvular and aortic disease, cardiomyopathy, or those with history of exposure to cardiotoxic medications (e.g. doxorubicin) - cardiac cath might be recommended if etiology or etiology for pulmonary HTN can't be elaborated


Exercise stress test

- might help assess a patient's ability to tolerate pregnancy

- provides an objective assessment of maternal functional capacity and can elucidate exercise-induced arrhythmias

- recommended at baseline pre-pregnancy


CT

- recommended if a patient presents in pregnancy or postpartum with chest pain and you suspect PE or aortic dissection

- iodinated contrast agents cross the placenta; they are not teratogenic but can suppress fetal thyroid activity, thus only use them if absolutely critical to caring for mom

- if contrast is used, breastfeeding should not be interrupted


MRI

- preferred imaging modality in pregnancy to assess aortic dimension and in assessing ventricular function when echo non-diagnostic

- reserve gadolinium to those situations in which contrast will significantly improve diagnostic performance

- "In animal studies, gadolinium agents have been found to be teratogenic at high and repeated doses, presumably because this allows for gadolinium to dissociate from the chelation agent. In humans, the principal concern with gadolinium-based agents is that the duration of fetal exposure is not known because the contrast present in the amniotic fluid is swallowed by the fetus and reenters the fetal circulation. The longer gadolinium-based products remain in the amniotic fluid, the greater the potential for dissociation from the chelate and, thus, the risk of causing harm to the fetus " (see CO#723,

Guidelines for Diagnostic Imaging During Pregnancy and Lactation for more)

- if contrast is used, breastfeeding should not be interrupted


Prolonged cardiac monitoring (e.g. Holter)

- consider at baseline or if patient becomes symptomatic (e.g. palpitations, lightheadedness, or syncope) in pregnancy to assess for arrhythmia


D-dimer

- not recommended as routine evaluation in pregnancy or postpartum (elevations are normal in pregnancy)


In Part 2, I'll cover...

- identification, assessment, and management of patients at high risk of peripartum cardiomyopathy

- management of cardiac arrest in pregnancy, including perimortem cesarean delivery and resuscitative hysterotomy

- antepartum, intrapartum, and postpartum management of patients with CVD

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