PHYSIOLOGIC CONSIDERATIONS DURING PREGNANCY
A. CARDIOVASCULAR PHYSIOLOGY
► Higher rates of obesity, hypertension, and diabetes
o Half of adults aged 20 and older have at least one risk factor for cardiovascular disease
► Another related reason is delayed childbearing |
► Cardiac output increases by 30-50, average of 40%
o 20% of this total takes place by 8 weeks gestation and is maximal by mid-pregnancy (25-32 weeks)
o Increase heart rate (approx. 10bpm)
-12-16 weeks AOG
- 32-36 weeks AOG |
► Resting pulse and stroke volume are even higher later in pregnancy
► Increase venous pressure within lower extremities comparing upper extremities
► Multifetal pregnancies |
► After 28 weeks' gestation
► Heart failure develops peripartum {nl}} nbsp; - Preeclampsia, hemorrhage and anemia, and sepsis |
B. VENTRICULAR FUNCTION IN PREGNANCY
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►Hemodilution --> increased renin production
-increased end-systolic and end-diastolic dimensions
► For given filling pressures, there is appropriate cardiac output so that cardiac function during pregnancy is eudynamic
- Spherical remodelling ―> depressed longitudinal deformation |
Diagnostic Studies
▸ Electrocardiogram (ECG) |
▸ Radiography |
▸ Echocardiography |
▸ Cardiovascular MR Imaging |
▸ Cardiac catheterization |
Classification of Functional Heart Disease
▸ Class I. Uncompromised |
▸ Class II. Slight limitation of physical activity |
▸ Class III. Marked limitation of physical activity |
▸ Class IV. Severely compromised |
Risk Classification of CVD and Pregnancy
Risk Classification of CVD and Pregnancy (cont.)
PERIPARTUM MANAGEMENT CONSIDERATIONS
▸Women in NYHA class I and most in class II- No morbidity |
- Avoid contact with persons who have respiratory infections |
-Cigarette smoking and illicit drug use are prohibited |
▸ Women in NYHA class III and IV |
Prolonged hospitalization and bedrest |
LABOR AND DELIVERY
▸ Vaginal delivery under epidural anesthesia |
▸ Indication for Cesarean delivery |
- dilated aortic root >4 cm or aortic aneurysm; |
- acute severe congestive heart failure; |
- recent myocardial infarction; |
- severe symptomatic aortic stenosis; |
- warfarin administration within 2 weeks of delivery; |
- need for emergency valve replacement immediately after delivery |
ANALGESIA AND ANESTHESIA
▸ IV analgesia - Continuous epidural analgesia |
▸ Women with pulmonary arterial hypertension or aortic stenosis - narcotic regional or general anesthesia |
▸ Significant heart disease - Subarachnoid block not generally recommended |
▸ Cesarean delivery - epidural analgesia |
INTRAPARTUM HEART FAILURE
▸ Cardiovascular decompensation during labor may manifest as pulmonary edema with hypoxia or as hypotension, or both. |
-K-sparing diuretics B-blocking agents |
PUERPERIUM
▸ Decompression —> Intravascular compartment —> peripheral vascular resistance —> increased myocardial performance |
▸ For puerperal tubal sterilization after vaginal delivery, the procedure can be delayed up to several days to ensure that the mother has normalized hemodynamically |
SURGICALLY CORRECTED HEART DISEASE
Valve replacement before pregnancy |
Porcine tissue valves |
LIFETIME ANTICOAGULATION (MECHANICAL VALVE)
▸ Warfarin - dose given at <5mg/d |
▸ Heparin |
- high maternal mortality |
- Overdose: Protamine Sulfate |
DIAGNOSIS OF HEART DISEASE
RECOMMENDATIONS FOR ANTICOAGULATION
1. Adjusted-dose LMWH (SC below umbilicus) is given twice daily, given until 13 weeks, and then warfarin is substituted until near delivery and is replaced by Heparin again. |
2. In women judged to carry a high risk of thrombosis, warfarin is suggested throughout pregnancy, then Heparin is substituted close to delivery. In addition, aspirin, 75 to 100 mg, is given daily. Heparin is discontinued 24 hrs before delivery. If delivery happens while the anticoagulant is still effective, and extensive bleeding is encountered, then protamine sulfate is given intravenously. |
3. Anticoagulant therapy with warfarin or heparin may be restarted 6 hours following vaginal delivery. If CS delivery, full anticoagulation is withheld, resuming heparin 6 to 12 hours or after 24 hours |
CARDIAC SURGERY DURING PREGNANCY
▸ Valve replacement - lifesaving |
▸ Elective surgery |
- Pump flow rate should remain >2.5 L/min/m2 |
- Normothermic perfusion pressure should exceed 70 mm Hg |
- Hematocrit should be kept >28 volumes percent |
PREGNANCY AFTER HEART TRANSPLANTATION
▸ Major complications |
- Rejections during the early puerperium |
- Renal failure |
- Spontaneous abortions |
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CONGENITAL HEART DISEASE
Atrial Septal Defects |
▸ Atrial septal defects (ASDS) - asymptomatic until the third or fourth decade |
▸ Secundum-type (70%) |
▸ Pregnant woman with ADS - managed with compression stockings and prophylactic heparin |
Ventricular Septal Defects
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▸ Paramembranous |
▸ Pregnancy is well tolerated with small-to- moderate sized shunts |
▸ Eisenmenger syndrome - pregnancy not advisable |
▸ 10-16% - can be inherited |
Atrioventricular Septal Defects
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▸ 3% of all congenital cardiac malformations Complications include |
▸ Complications include |
- 23% persistent deterioration of NYHA class |
- 9% significant arrhythmias |
- 2% heart failure |
▸ Seen in 15% of the offspring |
Persistent (Patent) Ductus Arteriosus
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▸ The ductus connects the proximal left pulmonary artery to the descending aorta just distal to the left subclavian artery |
▸ Prophylaxis for bacterial endocarditis is indicated at deliver |
▸ For unrepaired defects the incidence of inheritance is 4% |
Cyanotic Heart Disease
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▸ Producing right-to-left shunting of blood past the pulmonary capillary bed and developing cyanosis |
▸ Most common is Tetralogy of Fallot - maternal mortality rate approaches 10% |
▸ Ebstein anomaly |
Pregnancy after Surgical Repair
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▸ Transposition of the Great Vessels |
- Prior Mustard and Senning procedure |
▸ Single Functional Ventricle |
- Fontan repair - high risk for complications. |
▸ Eisenmenger Syndrome |
- Considered to be an absolute contraindication to pregnancy |
VALVULAR HEART DISEASE
Mitral Stenosis secondary to Rheumatic Endocarditis |
▸ Normal mitral valve - 4.0 cm2; stenosis <2.5 cm2 |
▸ Consequences: |
- passive pulmonary HTN |
- 25% of women with mitral stenosis have heart failure for the first time during pregnancy |
- pulmonary edema |
▸ Management |
- Limited physical activity |
- B-blocker drug therapy |
- If new-onset atrial fibrillation develops |
■ Intravenous verapamil, 5 to 10 mg |
■ Electrocardioversion is performed. |
- If Chronic fibrillation |
■ Digoxin, a B-blocker, or a calcium-channel blocker can slow ventricular response |
▸ Surgical intervention is considered for women with symptomatic severe mitral stenosis: Balloon valvuloplasty |
Mitral Insufficiency
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▸ Acute mitral insufficiency |
▸ Chronic mitral regurgitation |
Mitral valve prolapse
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▸ Myxomatous degeneration |
▸ B-blockers |
Aortic Stenosis
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▸ Congenital lesion: bicuspid valve |
▸ During pregnancy, several common events acutely lower preload further |
▸ Complication rates were higher if the aortic valve area measured |
Management |
▸ Asymptomatic - observation |
▸ Symptomatic: |
- Strict limitation of activity and treatment of infections |
- Critical aortic stenosis - intensive monitoring during labor is essential |
▸ During labor and delivery, narcotic epidural analgesia seems ideal and avoids potentially hazardous hypotension |
Aortic Insufficiency
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▸ Aortic valve regurgitation or insufficiency allows diastolic flow of blood from the aorta back into the left ventricle. |
▸ If symptoms of heart failure develop, diuretics are given and bed rest is encouraged |
Pulmonic Stenosis
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▸ Usually congenital |
▸ May be associated with Fallot tetralogy or Noonan syndrome |
▸ Surgical correction done before pregnancy; if symptoms progress - balloon valvuloplasty |
PULMONARY HYPERTENSION (cont)
Diagnosis |
▸ Symptoms may be vague |
▸ Chest radiography often shows enlarged pulmonary hilar arteries and attenuated peripheral markings |
▸ Final common pathway of pulmonary hypertension - right heart failure and death |
▸ The maternal mortality rate increased - idiopathic pulmonary hypertension |
Management
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▸ Activity limitation |
▸ Diuretics, supplemental oxygen, and pulmonary vasodilator drugs are standard therapy |
▸ Prostacyclin analogues |
▸ Inhaled nitric oxide |
▸ Phosphodiesterase-5 inhibitors |
▸ Bosentan - contraindicated in pregnancy |
INFECTIVE ENDOCARDITIS
▸ Risk Factors: |
- Congenital heart lesions Intracardiac devices |
- Intravenous drug users |
- Degenerative valve disease |
- Intracardiac devices |
▸ Diagnosis and Management: |
- Fever - 80% |
- Murmur |
- Constitutional symptoms |
▸ Duke's criteria: |
- Positive blood cultures for typical organisms and evidence of endocardial involvement |
▸ Pregnancy |
▸ The American Heart Association recommends prophylaxis for dental procedures in those with: |
- A prosthetic valve used in a valve repair |
- Prior endocarditis |
- Unrepaired cyanotic hear defect or repaired lesion with residual defect at prosthetic sites |
- Valvulopathy after heart transplantation |
INFECTIVE ENDOCARDITIS (cont)
HEART FAILURE
▸ Risk factors include |
- Preeclampsia |
- Hemorrhage |
- Infection |
▸Symptoms |
- Dyspnea |
- Orthopnea, palpitations, |
- substernal chest pain |
▸ Clinical findings include: |
- Persistent basilar rales, hemoptysis |
- Cardiomegaly and pulmonary edema |
▸Diagnosis |
- Acute flash edema |
- Onset: at the end of the second/beginning of the third trimester and peripartum |
▸ Management: |
-Diuretic administration |
- Hypertension - hydralazine |
- Chronic heart failure - Heparin |
CARDIOMYOPATHY
▸ Primary Cardiomyopathy |
▸ Secondary Cardiomyopathy |
Hypertrophic Cardiomyopathy
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▸ Hypertrophied and nondilated left ventricle (echocardiography) |
▸ Most women are asymptomatic |
▸ Sudden death - most frequent cause of death |
▸ Management: |
- Strenuous exercise is prohibited during pregnancy. |
- Drugs that evoke diuresis or diminish vascular resistance are generally not used |
Dilated Cardiomyopathy
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▸ Characterized by left and/or right ventricular enlargement and reduced systolic function |
Peripartum Cardiomyopathy
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▸ Diagnostic criteria: |
1. Development of cardiac failure in the last month of pregnancy or within 5 months after delivery |
2. Absence of a cause for the cardiac failure |
3. Absence of recognizable heart disease prior to the last month of pregnancy |
4. Left ventricular systolic dysfunction demonstrated by classic echocardiographic criteria |
▸ Preeclampsia with cardiomyopathy |
- Began postpartum |
- 50% recover within 6 months of delivery |
▸ Preeclampsia with hypertensive heart failure |
- Symptoms start antepartum |
- Mortality rate approaches 85% |
Other Cardiomyopathy Types
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▸ Arrhythmogenic right ventricular dysplasia |
- Progressive replacement of right ventricular myocardium with adipose and fibrous tissue. |
▸ Restrictive cardiomyopathy is probably the least common type |
-Inherited cardiomyopathy |
- Pregnancy is not advised |
▸ Takotsubo cardiomyopathy |
- Rare form of acute reversible left ventricular apical wall ballooning |
ARRHYTHMIAS
Bradyarrhythmias |
▸ Compatible with a successful pregnancy |
▸ Some women with complete heart block have syncope during labor and delivery, and occasionally temporary cardiac pacing is necessary |
▸ Women with permanent artificial pacemakers usually tolerate pregnancy well |
Supraventricular Tachycardias
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▸ Paroxysmal supraventricular tachycardia |
- Twofold greater risk of septal defects |
- Embolic stroke |
▸ For acute treatment, raising vagal tone and blocking the atrioventricular node is done by: |
-Vagal maneuvers, which include Valsalva maneuver |
- Carotid sinus massage, bearing down |
- Immersion of the face in ice water |
- Intravenous adenosine is a short-acting endogenous nucleotide that also blocks atrioventricular nodal conduction. |
▸ Synchronize cardioversion - recommended |
▸ Long term anticoagulation |
- Intravenous metoprolol or propranolol |
- Intravenous verapamil |
- Intravenous procainamide |
- Intravenous amiodarone |
▸ Pregnancy may predispose otherwise asymptomatic women with Wolff-Parkinson-White (WPW) syndrome to exhibit arrhythmias |
Ventricular Tachycardia
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▸ Uncommon in healthy young women without underlying heart disease pregnancy |
▸ Emergency cardioversion |
Prolonged QT-Interval
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▸ Torsades de pointes |
▸ B-blocking agents-propranolol |
▸ Many medications may predispose to QT prolongation |
DISEASES OF THE AORTA
Aortic Dissection |
▸ Marfan syndrome and coarctation |
▸ Bicuspid aortic valve, Turner or Noonan syndrome and Ehlers- Danlos syndrome |
▸ Initial medical treatment - lower blood pressure |
▸ Proximal dissections - resected and the aortic valve replaced if necessary |
▸ Distal dissections - may be treated medically |
Marfan Syndrome
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▸ Autosomal dominant connective tissue disorder |
▸ 2 to 3 cases per 10,000 individuals |
▸ Characterized by generalized tissue weakness that can result in dangerous cardiovascular complications |
▸ Prophylactic aortic repair Prophylactic ẞ-blocking agents |
▸ Vaginal delivery with regional analgesia - <4cm |
▸ Elective CS - 4-5cm |
Aortic Coarctation
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▸ Relatively rare lesion |
▸ The aorta is abnormally narrowed and is often accompanied by abnormalities of other large arteries |
▸ Typical findings include hypertension in the upper extremities but normal or reduced pressures in the lower extremities. |
▸ Major complications with aortic coarctation include: |
- Congestive heart failure , and aortic rupture |
- Bacterial endocarditis of the bicuspid aortic valve |
▸ B-blocking drugs |
ISCHEMIC HEART DISEASE
Myocardial Infarction During Pregnancy |
▸ Mortality rate in pregnancy is higher compared with age- matched nonpregnant women |
▸ Coronary angiography - diagnostic gold standard |
▸ Myocardial ischemia is also associated with prostaglandin E1 vaginal suppositories given for labor induction |
▸ Treatment |
- Percutaneous transluminal coronary angioplasty and stent placement during pregnancy is successful |
- If the infarct has healed sufficiently, cesarean delivery is reserved for obstetrical indications, and epidural analgesia is ideal for labor |
Pregnancy with Prior Ischemic Heart Disease
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▸ Pregnancy in most of these women seems inadvisable |
- Ventricular performance should be assessed |
- For those who become pregnant before these studies are performed, echocardiography is done. |
- Exercise tolerance testing may be indicated, and radionuclide ventriculography exposes the fetus to minimal radiation |
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