Download PHYSIOLOGICAL CHANGES IN PREGNANCY DR SREEJITH

PHYSIOLOGICAL
CHANGES IN
PREGNANCY
Dr. Sreejith V
CO In labor
• Beginning of labor : > 7 L/min
• Uterine contraction : > 9 L/Min
• Anesthesia
: < 8 L/min
• Post partum CO continues to increase upto 72 hours due
to auto transfusion from uterus and reabsorption of
edema fluid
• CO falls to non pregnant values in a few wks after
delivery
Effect of these changes in CVD
• CCF In ventricular dysfunction
• The tachycardia reduces the time for diastolic filling in
MS, with resultant increase in left atrial pressure.
• Mitral regurgitation, the afterload reduction helps offset
the volume load on the left ventricle that gestation
imposes.
Pulmonary
capillaries
LV dilation / hypertrophy
Tricuspid
Aortic stenosis
Pulmonic
Mitral
Aortic stenosis at rest
Cardiac output not sufficient to cause critically high
LV intracavitary pressure / LV failure.
Resistance arterioles
Pulmonary
capillaries
(edema)
LV failure /
ischemia
Tricuspid
Aortic
Stenosis
Pulmonic
Mitral
Aortic stenosis with increased cardiac
output / arteriolar vasodilation:
Decreased SVR Fall in systemic BP and / or
increase in LV intracavitary pressure ischemia or
LV failure.
Resistance arterioles– decreased SVR
CO Variation with position
Clinical Findings in Normal Pregnancy
Elevated JVP [↑plasma vol]
↓B.S. at lung bases
S1 Loud
S2 wide split , accentuated [P2 delayed]
S3
Flow murm @ aortic, pulm; ESM
cervical venous hum, mammary souffle
Apex slightly left & up , prominent impulse
Pedal oedema :
↑ plasma vol & venous
pressures
Tachycardia
low DBP
PP ↑ [bounding pulses]
Investiga
Comments
tion
ECG
•Tachycardia
•LAD [ elev. Diaphragm]
•Increased ventricular voltage
•Increased Atrial & Ventricular ectopics
•Q wave and inverted T in lead III, an attenuated Q wave in
lead AVF, and inverted T in leads V1, V2, and, occasionally,V3
CXR
•CE
•Horizontal shift of heart
•Fullness of Left cardiac border & pulmonary vasc
Echo
•LV mass increased, LVED increased, RV & both Atrial enlarges
•Increased LVOT & RVOT velocities
•[gradients less reliable marker of stenotic severity, 2D valve area
best]
•Pros. Valve- valve gradients, PHT serial changes to be measured
•Systolic function increases first but may decrease in the last
Hypercoagulable state …
• Series of haemostatic changes,
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•
•
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Increase in concentration of coagulation factors
Platelet adhesivenes
Diminished fibrinolysis
Hypercoagulability and an increased risk of thrombo-embolic
events.
• Obstruction to venous return by the enlarging uterus
Drug clearance
• Increased intravascular blood volume
• Higher dosages of drugs required to achieve therapeutic
plasma concentrations,
• Increase drug clearance
• Raised renal perfusion
• Higher hepatic metabolism
CONGENITAL HEART DISEASES
COMPLICATING PREGNANCY
WHO CLASS IV RISK
• PAH
• Sev. Ventricular dysfunction (LVEF <30%, NYHA III - IV)
• Sev. MS
• sev. symptomatic AS
• Marfan syndrome : Aorta >45 mm
• BAV : Aorta > 50 mm
• Severe coarctation
Statistics
• Hypertensive disorders : 6–8%
• Congenital heart disease –western world
• Rheumatic valvular disease in non-western
• Leading causes of maternal death are acquired disease,
• Myocardial infarction,
• Aortic dissection,
• Cardiomyopathy
Cardiac evaluation
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Measure the bp, in left lateral recumbency
Proteinuria
Oximetry
BNP < 100 pg/mL - negative predictive value
ECG
ECHO
• Murmur and Dyspnoe
• Flow velocities increased
• TEE-safe
• TMT•
•
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•
•
Pre pregnancy
Safe in pregnancy also
To assess the functional class, and saturation
<70% of predicted functional aerobic capacity
Cycle
Radiological investigation
• There is no evidence of an increased fetal risk at doses of
radiation of 50 mGy
• There may be a small increase in risk of childhood cancer.
• (1:2000 vs. 1:3000)
MRI
• Useful to image Ao
• Avoid gadolinium
• Should be used in all patient s suspected of ascending Ao
Enlargement
Fetal Genetic Risk
• The recurrence risk varies between 3% and 50%
• Autosomal dominant Disoders - risk of 50%,
• Marfan syndrome,
• Hypertrophic cardiomyopathy
• long QT syndrome
• General Population 1%
Screening
• Genetic screening –
• chorionic villous biopsy can be offered in the 12th week
• Fetal echocardiography
• 19th to 22nd week
• Nuchal fold thickness
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12th to 13th week
For women over 35 years of age.
The sensitivity for the presence of a significant heart defect is 40%,
The specificity of the method is 99%.
The incidence of congenital heart disease with normal nuchal fold
thickness is 1/1000
General Principles of
Obstetric care
Antenatal Follow up
• Ranging from routine follow up to continuous hospital
admission
• Preferably in Tertiary care centre with cardiac and
cardiac surgical facilities
• Clinical examination and follow up echo
• Saturation
Induction of Labor
• Oxytocin and artificial rupture of the membranes are
indicated when the Bishop score is favourable.
• A long induction time should be avoided if the cervix is
unfavourable.
• Misoprostol or dinoprostone- there is a theoretical risk of
coronary vasospasm and a low risk of arrhythmias.
• Dinoprostone also has more profound effects onBP than
prostaglandin E1 and is therefore contraindicated in
active CVD.
Vaginal or caesarean delivery
• The preferred mode of delivery is vaginal
• Caesarean delivery should be considered for obstetric
indications
• Cardiac Indications•
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Dilatation of the ascending aorta >45 mm,
Severe aortic stenosis,
Pre-term labor while on oral anticoagulants
Eisenmenger syndrome,
Severe OR worsening heart failure
Mechanical prosthesis
Labor
• Once in labor, the woman should be placed in a lateral
decubitus position to attenuate the haemodynamic
impact of uterine contractions.
• Avoid maternal pushing, to avoid the unwanted effects of
the Valsalva
• Delivery may be assisted by low forceps or vacuum
extraction.
• Continuous electronic fetal heart rate monitoring is
recommended.
Anaesthesia
• Lumbar epidural analgesia is recommendable to reduce
pain
• Regional anaesthesia can cause systemic hypotension
and must be used with caution in patients with
obstructive valve lesions.
IE prophylaxis
• Not recommended
Post-partum care
• Slow i.v. infusion of oxytocin
• Prostaglandin F analogues to treat post-partum
haemorrhage
• Methylergonovine is contraindicated because of the risk
of vasoconstriction and hypertension.
• Meticulous leg care, elastic support stockings, and early
ambulation are important to reduce the risk of thromboembolism
Contraception
• Barrier methods (condom)
• The levonorgestrel releasing intrauterine device
• The safest and most effective
• 5% of patients experience vasovagal reactions at the time of
implant
• Progesterone only pills or dermal implants
• Highly complex heart disease
• (e.g. Fontan, Eisenmenger)
• A copper intrauterine device is acceptable in noncyanotic or mildly cyanotic women.
Percutaneous therapy
• After 4th month in 2nd trimester
• By this time
• Organogenesis is complete
• The fetal thyroid is inactive
• Uterus size small
Cardiac surgery with
cardiopulmonary bypass
• b/w 20th & 28th wk
• 1st trimester : high risk of fetal malformations
• 3rd trimester : high incidence of preterm delivery &
maternal complications
• Maternal complications are comparable to non-pregnant
Cardiac problems
Predictors of cardiac events
• Prior cardiac event
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Heart failure
Transient ischemic attack
Stroke
Arrhythmia
• (NYHA) class higher than class II
• Cyanosis
• Left-sided heart obstruction
• MVA < 2 cm2
• AVA < 1.5 cm2,
• EF < 40%
• Mechanical valve
Predictors of Cardiovascular Events
during Pregnancy
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NYHA class III / IV or cyanosis
Previous cardiovascular event
Left heart obstruction
Ejection fraction ≤0.40
• No. of points
0
1
>1
% Adverse Events
4-12
27-30
62-100
Specific lesions
Cyanosis
• Fetal and maternal hypoxia
• Increased thromboembolism
• Increased right to left shunt
• Worsening desaturation
• Paradoxical embolism
Cyanosis managment
• Restriction of physical activity
• Monitoring oxygen saturation
• Supplemental oxygen
• Prevention of venous stasis
• Use of compression stockings
• Avoiding the supine position
• For prolonged bed rest, prophylactic heparin administration
Pulmonary hypertension
• When the pulmonary hypertension exceeds
approximately 60% of systemic levels, more likely to be
associated with complications.
• Pulmonary hypertensive crises
• Pulmonary thrombosis
• Refractory right heart failure.
• Occurs even in patients with little or no disability before
or during pregnancy.
• Maternal death –in the last trimester and in the first
months after delivery
Pulmonary hypertension
• Maintain circulating volume,
• Avoid systemic hypotension,
• Avoid hypoxia, and acidosis which may precipitate
refractory heart failure.
• Supplemental oxygen - if there is hypoxaemia.
• Prostacyclin or aerosolized iloprost , sildenafil, NO
• Continuation of existing therapy
• Teratogenic effects of bosentan.
Eisenmenger
• Pulmonary hypertension with cyanosis
• With a live birth unlikely if oxygen saturation is ,85%.
• Maternal death as high as 50%
Eisenmenger
• The risks and benefits of anticoagulation considered on
an individual patient basis.
• Diuretics
• The lowest effective dose
• Avoid haemoconcentration
• Intravascular volume depletion.
• Microcytosis and iron deficiency
• frequently seen
• Supplemental iron.
ASD
• Common L to R shunt complicating pregnancy
• Prognosis
• Pulm hypertension
• Functional status
• Size of shunt
• Even large shunts are well tolerated if Pul. resistance <
3.0 WU
• Prior closure make pregnancy safer
Ventricular septal defect
• Depends on the severity of PH
• Functional status
• LV dimentions
• Small VSD- CLASS I
• Pre-eclampsia may occur more often than in the normal
population
• Vaginal delivery
Atrioventricular septal defect
• Arrhythmias
• Worsening of NYHA class
• Worsening of AV valve regurgitation
• PAH
• Cyanosis
• Paradoxical embolization
• Offspring mortality due to the occurrence of complex
congenital heart disease
• Ostium primum ASD may be well tolerated
Pulmonary valve stenosis
• Relatively well tolerated if the right ventricular pressure
is less than 70% of systemic pressure
• Right ventricular failure
• Arrhythmias.
• Balloon valvuloplasty if PG>64
• CS- severe PS and in NYHA class III/IV despite OMT
Tetralogy of Fallot
• Pre repair
• Arrhythmias , heart failure , thrombo-embolism
• Progressive aortic root dilatation,
• Endocarditis
• Post repair
• Palliation – depends on the degree of cyanosis
• Dysfunction of the right ventricle
• Moderate to severe pulmonary regurgitation
• Screening for 22q11 deletion - %
Pulmonary regurgitation
• Severe pulmonary regurgitation
• An independent predictor of maternal complication
• Bad outcome in patients with impaired ventricular fn..
• Pulmonary valve replacement
• Pre -pregnancy
• Preferably bioprosthesis
• TPVI – for refractory heart failure
Ebstein’s anomaly
• Outcome depend on
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The severity of the TR
The functional capacity of the right ventricle
Cyanosis
Previous cardiac event
• Usually be managed medically during pregnancy.
• Echocardiographic surveillance of RV function
• Early caesarean delivery If RV function deteriorates
Transposition of the great arteries
• Post operative- WHO risk class III.
• Atrial repair
• Atrial arrhythmia
• Severe impairment of RV function
• Great arterial repair
• Obstruction
• Regurgitation
• Bradycardia or junctional rhythm - b-blockers cautious
• An irreversible decline in RV function in 10%
Congenitally corrected transposition
of the great arteries
• WHO risk class III .
• Pre -disposed to developing AV block
• B-blockers must be used with extreme caution.
• An irreversible decline in RV function has been described
in 10%
• Class 4
• NYHA III or IV,
• EF < 40%
• severe TR
Fontan circulation
• Successful pregnancy is possible in selected patients with
intensive monitoring - class III
• Class 4
• Patients with oxygen saturation ,85% at rest,
• Depressed ventricular function, and/or moderate to severe AV
regurgitation
• Protein-losing enteropathy
Aortic Stenosis
• Severe AS – CI
• Bicuspid aortic valve - imaging of the ascending aorta
before pregnancy,
• CS
Coarctation of the aorta
• Repaired
• Restenosis
• Site rupture
• Unrepaired
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Hypertension
Risk of aortic rupture
Rupture of a cerebral aneurysm
PIH
Associated bicuspid aortic valve- aortic dilation
Coarctation of the aorta
• Close surveillance of BP
• Avoid aggressive treatment to prevent placental
hypoperfusion.
• PCI is associated with a higher risk of aortic dissection
• Should only be performed if severe hypertension persists
despite maximal medical therapy and there is maternal
or fetal compromise.
• The use of covered stents may lower the risk of
dissection.
Aortic dilation
• Marfan syndrome
• Ehlers–Danlos syndrome
• Bicuspid aortic valve
• Turner syndrome
• Annuloaortic ectasia
• Tetralogy of Fallot
• Aortic coarctation
• Hyperrtension, Atherosclerosis
Aortic dilation
• Increased the susceptibility to dissection
• Haemodynamic changes
• Hormonal changes which lead to histological changes in the
aorta
• Dissection timing
• Last trimester of pregnancy (50%)
• The early postpartum period (33%)
• The diagnosis of aortic dissection should be considered
in all patients with chest pain during pregnancy as this
diagnosis is often missed.
Marfan syndrome, Bicuspid aortic
valve
• Factors for dissection
• Family history of dissection,
• Rapid growth
• Following elective aortic root replacement, patients
remain at risk for dissection in the residual aorta.
• 50% of the patients with a bicuspid aortic valve and AS
have dilatation of the ascending aorta
• Associated Mitral regurgitation
Ehlers–Danlos syndrome type 4
• Increased bruising
• Hernias
• Varicosities
• Rupture of large vessels
• Rupture of the uterus.
• Contraindication for pregnancy
Management of aortic complicaltions
• Monitoring by echocardiography at 4–12 week intervals
throughout the pregnancy and 6 months post-partum
• b-blockers in patients with Marfan syndrome
• Celiprolol - Ehlers–Danlos syndrome type IV
• Fetal growth should be monitored when the mother is
taking b-blockers.
Surgery
• Marfan syndrome - pre-pregnancy surgery is
recommended when the ascending aorta is ≥45 mm,
• Bicuspid AV - pre-pregnancy surgery should be
considered when the ascending aorta is ≥50 mm.
• If progressive dilatation occurs during pregnancy, before
the fetus is viable, aortic repair with the fetus in utero
should be considered.
• When the fetus is viable, caesarean delivery followed
directly by aortic surgery is recommended
Mode of delivery
• CS should be considered when the aortic diameter
exceeds 45 mm
• If 40– 45 mm, vaginal delivery with expedited second
stage and regional anaesthesia is advised to prevent BP
peaks, which may induce dissection.
• Caesarean delivery may also be considered in patients
with Ao 40-45, based on the individual situation.
Hypertrophic cardiomyopathy
• Frequently diagnosed for the first time in pregnancy by
echocardiography.
• Intermittent high catecholamine state of pregnancy ↑ LVOT
obstruction
• Epidural anaesthesia causes systemic vasodilation and hypotension
in severe LVOTO
• Fluids must be given judiciously and volume overload must be
avoided
• The implantation of an ICD should be considered in patients with
high risk factors for sudden cardiac death
• All other management is the same, except for amiodarone for
rhythm control
• Atenolol - class d
Take home message
• Hemodynamic of pregnancy
• Normal abnormal cardiac findings
• WHO class
• Risk prediction
• Basic principles of obstetric care
• Common congenital cardiac problems
QUESTIONS
• Aortic diameter in Marfan syndrome above which
pregnancy contraindicated
• Normal increase in cardiac output
• Risk of aotic rupture is maximum at which trimester
• Safe limit of radiation exposure to foetus
• Risk of fetus having congenital heart disease in general
population
• Only proven risk to fetus if exposed to low dose
radiation is
• Saturation below which pregnancy contraindicated
• Beta blocker which is not class c
Thank you