Ischaemic Heart Disease(IHD) in Pregnancy
Prevalence of
IHD in pregnancy is 1:10,000
Incidence of Myocardial infarction in pregnancy is 7.5:100,000
Over all mortality rate is 37%
Risk factors
Diabetes
Smoking
Family history of myocardial infarction before age 60
Hypercholesterolaemia
History of chronic hypertension
Kawasaki disease,
Hypertrophic cardiomyopathy
Cocaine use
Atherosclerosis accounts for less than 50% of cases but dissection of coronary arteries is relatively common.
ECG
ECG changes in normal pregnancy.There could be left-axis deviation and non-specific ST and T wave
changes.Serial ECG is important in diagnosis.
Chest X ray-enlargement of the heart, straightening of the left
heart border, and increased vascular markings are features observed in myocardial infarction.
CK-MB correlates with non pregnant state but the usage is limited in labour and postpartum period.
Troponin-I is the marker of choice as the level is not affected by pregnancy,labour or obstetric anaesthesia.
Echocardiography helps to check abnormal ventricular wall motion.
Differential diagnosis
1.Acute pulmonary embolism
2.Aortic dissection
Management of MI is similar to non pregnant patients
Setting : Coronary care unit
Drugs:
1.Oxygen
2.Morphine
3.Nitrates
4.Aspirin
5.Beta blockers
6.heparin
Multidisciplinary care -cardiologist,obstetrician,anaesthesiologist
Primary PCI(
percutaneous coronary intervention) is the treatment of choice but if it isn't feasible
thrombolysis should be considered.
Anti coagulation is considered if
embolus is demonstrated in
angiography,otherwise risk of
thrombolysis slightly outweighs the benefit.
Tissue plasminogen activator
Large molecular weight Tissue
plasminogen activator wouldn't cross the placenta but there is a risk of premature labour and
haemorrhage.
Streptokinase
There is no reports linking to congenital defects.
Minimal amount crosses
placenta,so no
fibrinolytic effects on fetus.
Urokinase
It isn't
teratogenic in animal studies.It isn't known whether it crosses placenta but there are
proteinase inhibitors in the placenta which inactivates
urokinase.
angioplasty and systemic and local
thrombolytic therapy has been
described.'
Fragile'nature of coronary vessels in pregnancy should be kept in mind when considering angioplasty or
angiography.
Radiation exposure to fetus during cardiac
catheterisation &
interventional procedure is less than 0.01
Gy
Use of
clopidogrel also seems to be safe.
Delivery
Caesarean section is only indicated for Obstetric reasons . It doesn't improve the survival.Second can be limited with forceps.
Delivery with in the first two weeks after
ischaemic heart disease should be avoided if possible.ECG monitoring should be done in labour.Epidural
analgesia is recommended.
Third stage -avoid
ergometrine as it can cause coronary spasm
Good outcomes have been reported from subsequent pregnancies in patients with left ventricular aneurysm and also in patients who suffered cardiac arrest during MI.
Future pregnancy
There is no evidence to suggest that pregnancy predisposes for
another episode of MI but if the aetiology had been a coronary
embolus the risk of recurrence should be carefully considered.
Poor prognostic features
1.Left ventricular dysfunction
2.Persistence of
ischaemia
Statins should be discontinued preconception as there is a risk of fetal anomalies(CNS &Limb defects)
Useful article
Source
1.Nelson-
Piercy C. Handbook of Obstetric Medicine, Second Edition. 2
nd ed. Taylor & Francis; 2001.
2.
Swiet MD. Medical Disorders in Obstetric Practice. 4
th ed. Wiley-Blackwell; 2002
| 3. | Fayomi O, Nazar R. Acute myocardial infarction in pregnancy: a case report and subject review. Emerg Med J. 2007 Nov 1;24(11):800-801. |
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