Non-ischemic cardiac disease during pregnancy Ruben J. Azocar, MD Assistant Professor of Anesthesiology Boston University Medical Center
Introduction • Although the prevalence of clinically significant maternal heart disease during pregnancy is probably less than 1% its presence increases the risk of adverse maternal, fetal, and neonatal outcomes
CV Physiology of Pregnancy • Blood volume increases 30 to 50% • Plasma volume increase more than RBC mass leading to physiologic anemia • An estrogen mediated stimulation of the renin-angiotensin system results in retention of NA and water • HR increases 10 to 20 bpm
CV Physiology of Pregnancy • CO increase up to 45% by 24 wks • These increases begin during the 1st trimester • Peak by 20-24 wks and are sustained until term • In early pregnancy an increase in SV (20-30%) is responsible to the increase in CO • Later in pregnancy, the increase in HR is responsible since SV decreased due to IVC compression • Concurrently there is a substantial reduction in SVR by 21% with decreases in BP and decreases in PVR by 34%
CV Physiology of Pregnancy • Symptoms and PE of normal pregnancy mimic cardiac disease • Exertional dyspnea and orthopnea • Fatigue and Presyncope • Lower extremity edema • a and v waves may be pronounced in CVP tracing • Maximal apical impulse is displaced • 1st Heart sound the pulmonary component of 2nd might are accentuated • 3rd HS is heard in 80% of pregnant women
CV Physiology of Pregnancy • Murmurs frequently develop during pregnancy • Soft, mid-systolic, and heard along the left sternal border is heard in 90% women • Anemia might accentuate it • Intensity may increase as CO increases • Cervical venous hums and a continuous murmur due to increased mammary blood flow may also be heard • Echocardiography is warranted if: • Diastolic, continuous, or loud systolic murmurs (>2/6) • A fixed split 2nd sound • Associated with symptoms or an abnormal EKG
CV Physiology of Pregnancy • In normal pregnant women, echocardiography demonstrates: • Minor increases in the left and right ventricular diastolic dimensions (within the normal range) • A slight decrease in the LVES dimension and a minimal increase in the size of the left atrium • Increased transvalvular flow velocities due to the increased BV • Minor degrees of atrioventricular valve regurgitation
CV Physiology of Pregnancy • During labor: • CO increases 45% above pre-labor values • Uterine contraction “boluses” the patient • It might increase CO up to 65% of pre-labor values • The BP increases with uterine contractions/pain
CV Physiology of Pregnancy • Immediately after delivery • The cardiac filling pressure increase dramatically due to the decompression of the vena cava and the return of uterine blood into the systemic circulation • CO might increase to 80% of pre-labor values • The cardiovascular adaptations associated with pregnancy regress by approximately 6 weeks after delivery
Physiology of Pregnancy • Pregnancy is also a hypercoagulable state • Decreased in Protein S activity • Stasis • Venous hypertension
The problem • A Canadian analyses of the outcomes of pregnancy identified predictors of adverse maternal and fetal outcomes in a group of women with congenital or acquired heart disease (546 women and 599 pregnancies) • Approximately 40% of the women had a primary valve disorder • Adverse maternal outcomes included: pulmonary edema, sustained brady or tachyarrhythmias, stroke, cardiac arrest, or death • Adverse fetal outcomes included: premature birth, intrauterine growth retardation, respiratory distress syndrome, intraventricular hemorrhage, and death
Maternal outcomes • Incidence of adverse maternal cardiac events • 13% of completed pregnancies • More likely if: • EF below 40% • Left heart obstruction (AS with a valve area of less than 1.5 cm2 or MS with a valve area of less than 2.0 cm2) • Previous cardiovascular events (heart failure, tia, or stroke) • NYHA class II or higher • These events occurred in: • 4% of the women with none of these risk factors • 27 % of those with one risk factor • 62 % of those with two or more risk factors • The 3 women that died had two or more risk factors
Fetal outcomes • Abnormal functional capacity (NYHA class II or higher) and left heart obstruction were also predictors of neonatal complications • Other predictors of adverse fetal outcomes included: • The use of anticoagulant drugs throughout pregnancy • Smoking during pregnancy • Multiple gestation • Mother’s age (> 35 yrs or < 20 yrs) • Fetal mortality was: • 4 % among pregnancies in women with one or more of these risk factors, • 2% among those with none of these risk factors
Evaluation • The evaluation of a woman with clinically significant valvular heart disease should occur before conception and entail a full cardiac assessment • The history should focus on the patient's exercise capacity, current or past evidence of heart failure, and associated arrhythmias • Cardiac hemodynamics, including PAP and the severity of valve dysfunction, should be assessed by echo • Exercise testing may be useful if the history is inadequate to allow an assessment of functional capacity • During pregnancy evaluation each trimester and whenever there is a change in symptoms, in order to assess any deterioration in maternal cardiac status is the rule
Mitral Stenosis • Rheumatic MS is the most common valvular abnormality in pregnant women (60%) • Associated with pulmonary congestion, edema, and atrial arrhythmias during pregnancy or soon after delivery • The increased BV load and CO associated with pregnancy lead to an increase in left atrial volume and pressure, elevated pulmonary venous filling pressures, dyspnea, and decreased exercise tolerance • Increases in the maternal HR decrease the diastolic filling period, further increasing left atrial pressure and decreasing CO • The increased atrial pressure may cause arrhythmias
Mitral Stenosis • Mortality among pregnant women with minimal symptoms is less than 1% • Predictors of adverse maternal outcomes • Mitral valve area less than 1.5 cm2 • Abnormal functional class before pregnancy • Fetal mortality increases with deteriorating maternal functional capacity • 30 % when the mother has NYHA class IV
Mitral Stenosis • For women with mild or moderate symptoms • Medical therapy is directed to the treatment of volume overload • Diuretic therapy but avoiding hypotension and tachycardia • NA+ restriction • Reduction of physical activity • Beta-blockers decrease HR and prolong the diastolic filling period which provides symptomatic benefit
Mitral Stenosis • Development of AF requires prompt treatment, including cardioversion. • Beta-blockers and digoxin for rate control • Procainamide and quinidine are frequently used if suppressive antiarrhythmic therapy is needed • Due to the increased risk of systemic embolism in patients with MS and AF anticoagulant therapy is indicated
Mitral Stenosis • NYHA class III / IV or a valve area of less than 1.0 cm2 • Percutaneous balloon mitral valvuloplasty (PBMV) or valve surgery BEFORE conceiving appear to allow pregnancy with fewer complications than women treated medically • PBMV, during the 2nd trimester, has been associated with normal deliveries and excellent fetal outcomes • Fetal risks associated with exposure to radiation may be reduced by avoiding exposure during the first half of pregnancy • The uterus must be shielded and the patient should be informed about the possible risks • Mitral valvuloplasty has also been performed under TEE guidance
Mitral Stenosis • Open cardiac surgery has been performed during pregnancy for severe MS • Maternal outcomes are similar to the non-pregnant • Fetal loss in 10 to 30 % of cases
MS: Anesthesia management • Careful clinical evaluation early on in conjunction with the OB team to have a clear plan • ICU consultation • Vaginal delivery is the usual approach • Hemodynamic goals: • Avoidance of tachycardia and fluid overload • Preservation sinus rhythm • Increase of BV, CO and HR during pregnancy and labor may result in pulmonary congestion, tachycardia and atrial fibrillation
MS: Anesthesia management • Monitoring: • A-LINE and probably PAC • Labor and delivery is associated with an increase of 8 to 10 mm Hg in the left atrial and pulmonary wedge pressures • PAC used before and during delivery facilitates the management of hemodynamics in women with advanced disease
MS: Anesthesia management • Epidural anesthesia to achieve effective pain control • A mixture of LA and opioids is ideal • Pain control and minimization of BV/CO increase after delivery • Assisted-delivery devices during the second stage of delivery eliminate hemodynamic effects of valsalva maneuver during “pushing” • Cesarean section should be performed when there are obstetrical indications for it
Mitral Regurgitation • Most commonly due to mitral-valve prolapse and is usually well tolerated during pregnancy because of the reduction in SVR • Women with symptomatic MR may benefit from mitral-valve surgery (preferably repair )before becoming pregnant. • However, LV dysfunction associated with MR is unlikely to improve after surgery and will increase maternal risk during pregnancy • Diuretics and vasodilators may be indicated • Outcome data that would help to guide clinical decision making in this area are lacking.
Aortic Stenosis • Congenital valvular abnormalities are usually the cause of AS in young women in the US • Severe AS is poorly tolerated during pregnancy • Maternal and perinatal mortality of 17% and 32% have been reported • The pressure gradient is responsible for the HD changes seen in AS • The increased LVSP needed to maintain systemic arterial blood pressure increases stress in the ventricular wall • Lt ventricular hypertrophy develops leading to diastolic dysfunction, fibrosis, diminish coronary blood flow reserve and late systolic failure
Aortic Stenosis • Patients who are symptomatic or who have a peak outflow gradient of more than 50 mm Hg are advised to delay conception until after surgical correction • Termination of pregnancy should be strongly considered if the patient is symptomatic before the end of the 1st trimester • Aortic-valve replacement and palliative aortic balloon valvuloplasty have been performed during pregnancy with associated maternal and fetal risk
Aortic Stenosis • Hemodynamic goals: • Maintain normovolemia • NSR • Tachycardia decrease dyastolic filling time • Atrial “kick” is responsible for up to 40% of ventricular filling in this patients • Baseline SVR
Aortic Stenosis • The normal physiological changes of pregnancy can precipitate heart failure in patient with severe AS • The further increase of CO and BV during labor in face of the fixed CO of AS patients may precipitate: • Tachycardia which decreased diastolic time (and coronary perfusion time) and increases O2 consumption • Increases LVEDP • Ischemia might result
Aortic Stenosis • Vaginal delivery is preferred • Instrumental delivery to avoid hemodynamic changes of the valsalva manuver • Oxytocin may decrease SVR an increase PAP • Monitoring: • A-line • ?CVP ?PAC
Aortic Stenosis • Epidural analgesia • Pain control and also minimizes BV/CO increase after delivery • Avoid epinephrine “test dose” • Careful titration to avoid sudden decrease of SVR • Dilute LA with opioids to minimize sympathectomy
Aortic Stenosis Cesarean section GA has traditionally being advocated to avoid sudden decreases of SVR Opiod based induction Fetal depression. Pediatric team must be aware Case reports of epidural anesthesia with positive outcomes Careful titration of LA and fluid replacement/vasopressors to counteract sympathectomy Phenylephrine possible a better choice over ephedrine
Aortic Regurgitation • AI may be due to a dilated Ao annulus (as in Marfan's syndrome), a bicuspid Ao valve, or previous endocarditis • The reduced SVR of pregnancy reduces the volume of regurgitated blood • Women with an abnormal functional capacity or left ventricular dysfunction are predicted to have a high risk of abnormal maternal outcomes, but few data concerning this population are available
Aortic Insufficiency • Isolated AI can usually be managed with vasodilators and diuretics • ACE inhibitors should be discontinued during pregnancy, and other agents, such as hydralazine or nifedipine, should be substituted • Clinical and echo assessment should be performed before conception in women with AI due to Marfan's syndrome • Even in the absence of overt cardiac abnormalities, this syndrome predisposes women to unpredictable, but increased, risk during pregnancy.
Pulmonary hypertension • PHTN is associated with high maternal mortality (33 to 40 %), as well as with an increased rate of adverse neonatal events • Secondary PHTN due to valvular disease is associated with an increased rate of adverse maternal events, but the absolute risk of such events is unclear. • A systolic pulmonary-artery pressure that is more than 75 % as high as the systemic pressure places the woman at high risk.
Pulmonary hypertension • Hemodynamic objectives • Maintain the PAP as low as possible and the systemic pressure within the 15% above and below the basal level (the systemic pressure should always be higher than pulmonary pressure) • Avoid dysrhythmias and tachycardia, and maintain sinus rhythm
Pulmonary hypertension • Pregnancy and labor CV changes against goals: • Uterine contraction after delivery returns a large bolus of blood to the circulation. This can be poorly tolerated in patients with severe PHTN • The sudden hypervolemia can be treated with vasodilators, such as nitroglycerine, and diuretics. • A BP cuff inflated between the arterial and venous pressures around the thighs, can suddenly and reversibly decrease RV filling by reducing venous return • Air or amniotic fluid embolism could acutely increase pulmonary pressure
Pulmonary hypertension • Monitoring: • a-line and CVP or PAC should be used for monitoring or for drug administration • Vaginal delivery • Pain control with a mixture of local anesthetics in a low concentration and opioids via epidural • Forceps delivery, which decreases patient effort and hemodynamic consequences, is the technique of choice.
Pulmonary Hypertension • Cesarean Delivery • Both general and epidural anesthesia have been used for cesarean delivery in patients with pulmonary hypertension. • The surgical procedure can lead to excessive bleeding and hypovolemia
Pulmonary hypertension • Induction of general anesthesia • Based on opioids • Lidocaine (1 mg/kg) reduces pulmonary and hemodynamic reactions during intubation • Induction can be complemented with pentothal, propofol, or etomidate • Succinylcholine can be used for intubation • Anesthesia could be maintained with use of short acting narcotic infusion, volatile anesthetics and/or propofol infusion
Prosthetic Heart Valves • Bioprostheses are not as durable as mechanical prostheses, but eliminate the need for anticoagulant therapy • Women with mechanical valves have a higher rate of thromboembolism and higher 10-year mortality, despite a lower rate of valve loss • Pregnancy does not appear to increase the rate of failure of mechanical prostheses or homograft nor accelerates the deterioration of bioprosthetic valves • Pregnancy in a woman with a mechanical valve is associated with an estimated maternal mortality of 1 to 4% with death usually resulting from complications of prosthetic-valve thrombosis.
Anticoagulation • There are no results of clinical trials to guide the choice of anticoagulant therapy during pregnancy • Monitoring is required in order to assess whether the antithrombotic effect is adequate • The effective doses of these drugs change during pregnancy because of changes in intravascular volume and body weight • In a series of 976 women with a total of 1234 pregnancies the use of any anticoagulant therapy resulted in major bleeding in 2.5 % of the pregnancies, with bleeding usually occurring at the time of delivery
Warfarin • In women with mechanical valves the use of warfarin throughout pregnancy was associated with the greatest maternal protection • Risk of thromboembolism, 3.9%, risk of death, 1.8% • Warfarin crosses the placenta • Fetal deformities and CNS abnormalities • High rate of fetal loss (30%) including spontaneous abortions, stillbirths, and neonatal deaths • Exposure to warfarin between 6 -12 wks of gestation was associated with a rate of fetal loss that was twice that associated with the use of unfractionated heparin • Fetopathic effects of warfarin use (nasal hypoplasia and bone stippling) occurred in approximately 6 % of cases,
Heparin • If heparin rather than warfarin was used during the 1st trimester, the risks of maternal thromboembolism and maternal death more than doubled (9.2% and 4.2% respectively) • The use of adjusted-dose heparin (titrated to a therapeutic activated PTT) throughout pregnancy was associated with the highest risks of maternal thromboembolism and maternal death (25% and 7 % respectively) • A large proportion of the women had ball-and-cage valves or older single-tilting-disk valves that are known to carry a high risk of thromboembolism • Long-term use of heparin is associated with maternal risks of HIT and osteopenia.
LMWH • Low-molecular-weight heparins have been used successfully to treat DVT during pregnancy • Lower risks of thrombocytopenia and osteopenia than unfractionated heparin • Probably safe for the fetus • There are insufficient data from studies of women with prosthetic heart valves to support the efficacy of this therapy or the use of any type of heparin throughout pregnancy • Nor has the use of low-molecular-weight heparin been studied in women with AF associated with valvular disease during pregnancy.
Anticoagulation Guidelines • Although definitive data are lacking authors recommend • Encourage education of the prospective parents and their involvement in the decision-making process • Warfarin to achieve a target INR of 2.0 to 3.0 throughout most of the pregnancy. • The only exceptions are the periods between 6 and 12 weeks of pregnancy and after 36 weeks of pregnancy, when they would opt for the closely monitored use of unfractionated heparin • This option was suggested because of medicolegal concern relating to the "off-label" use of warfarin and the risk of embryopathy.
Peripartum cardiomyopathy • Unknown etiology • Incidence 25-75/100000 in some series • Diagnosis: • Biventricular dilated cardiomyopathy in 3rd trimester or in puerperium • Absence of prior cardiac disease • 50% good prognosis if early reversion of symptoms but 25-50% mortality • Treatment: Supportive
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