View source for Cardiac disease in pregnancy and acute myocardial infarction

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{{Cardiac disease in pregnancy}}
{{CMG}}; {{AOEIC}} {{AC}}; {{CZ}}

==Overview==
In general, women of childbearing age are at relatively low risk for [[coronary artery disease]].  While rare, the risk of [[acute myocardial infarction]] ([[MI|AMI]]) is 3-4 times higher during pregnancy, and negative fetal and maternal outcomes are associated with this condition.

==Historical Perspective==
The first case was reported in the literature in 1922.

==Pathophysiology==
[[MI|Acute myocardial infarction]] can occur at all stages of pregnancy, and is more common in multi-gravid patients. 

The etiology of [[coronary dissection]] in pregnant patients is thought to be related to an excess of [[progesterone]], which causes changes in the vessel wall, including loss of normal corrugation elastin fibers, fragmentation of reticular fibers, and decreases in the amount of acid mucopolysaccharides.<ref name="pmid4225694">{{cite journal| author=Manalo-Estrella P, Barker AE| title=Histopathologic findings in human aortic media associated with pregnancy. | journal=Arch Pathol | year= 1967 | volume= 83 | issue= 4 | pages= 336-41 | pmid=4225694 | doi= | pmc= | url= }} </ref><ref name="pmid3792352">{{cite journal| author=Bonnet J, Aumailley M, Thomas D, Grosgogeat Y, Broustet JP, Bricaud H| title=Spontaneous [[coronary artery dissection]]: case report and evidence for a defect in collagen metabolism. | journal=Eur Heart J | year= 1986 | volume= 7 | issue= 10 | pages= 904-9 | pmid=3792352 | doi= | pmc= | url= }} </ref>  The increase in blood volume and [[cardiac output]] that occurs with pregnancy magnifies shear forces of the blood column in large vessels, which in combination with the vessel wall changes leaves these patients predisposed to coronary dissection.

In a review performed in 2008, [[myocardial infarction]] ([[MI]]) location was mostly (78%) in the anterior wall and involved the [[left anterior descending artery]]; the most common cause was [[coronary artery dissection]].<ref name="pmid18617065">{{cite journal| author=Roth A, Elkayam U| title=Acute myocardial infarction associated with pregnancy. | journal=J Am Coll Cardiol | year= 2008 | volume= 52 | issue= 3 | pages= 171-80 | pmid=18617065 | doi=10.1016/j.jacc.2008.03.049 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18617065  }} </ref>  

The angiographic findings on cardiac catheterization in series of pregnant women are as follows: 
:*[[CAD]] with or without thrombus 43% (58% in prepartum period)
:*Thrombus without [[CAD]] 21%
:*Normal coronaries 29% (75% in peripartum period [[MI|MIs]])
:*[[Coronary dissection]] 16% (33% in postpartum period)

==Risk Factors== 
* Family history of [[coronary artery disease]]
* [[Hyperlipidemia]]
* Low [[HDL]]
* High [[LDL]]
* [[Smoking]]
* Previous [[oral contraceptive]] use
* MI patients tend to be older (>35 years old)
* [[Multiparity]]
* Non-hispanic white or african american
* Chronic [[hypertension]]
* [[Diabetes]]
* History of [[eclampsia]] / [[pre-eclampsia]]

==Epidemiology and Demographics<ref>Ladner et al:Ostet Gynecol, 2005</ref>==
* Incidence ~1/10,000 to 1/37,500 deliveries
* Ages range 16-45

==Natural History, Complications, Prognosis==
* Outcomes better if [[MI]] early in pregnancy
* Maternal mortality rate is 7%-11% (most at time of [[MI]] or within 2 weeks- usually with labor and delivery) and a fetal mortality rate is 9%.

==Diagnosis==
===Diagnostic Criteria===
The following should be considered in diagnosis and treatment of this condition:
*Criteria for diagnosis of [[MI|AMI]] in pregnant women are in general the same as in non pregnant patients (symptoms, exam, ECG, biomarkers, +/- imaging/angiography). 37% of patients undergoing elective [[C-section]] have [[EKG]] changes suggestive of [[MI]] or [[ischemia]]. [[Echocardiography]] to assess regional wall motion abnormalities can be useful. 

*Note that [[creatine kinase]] and its MB fraction can increase nearly 2-fold within 30 minutes after delivery, as can [[troponin]] levels.<ref name="pmid9914590">{{cite journal| author=Shivvers SA, Wians FH, Keffer JH, Ramin SM| title=Maternal cardiac troponin I levels during normal labor and delivery. | journal=Am J Obstet Gynecol | year= 1999 | volume= 180 | issue= 1 Pt 1 | pages= 122 | pmid=9914590 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9914590  }} </ref>

*If [[exercise stress testing]] is indicated, a submaximal protocol (<70% of maximal predicted [[heart rate]]) with [[fetal monitoring]] is preferred.<ref name="pmid8489079">{{cite journal| author=Kleinman B| title=Electrocardiographic changes during cesarean section. | journal=Anesthesiology | year= 1993 | volume= 78 | issue= 5 | pages= 997-8 | pmid=8489079 | doi= | pmc= | url= }} </ref>

*Radionuclide imaging using 99m technetium-labeled sestamibi or 201 thallium, as well as cardiac catheterization or interventional procedure, are expected to yield<11 rad of radiation to the conceptus, which is generally considered safe; termination of pregnancy is generally recommended at a level of 10 rads.<ref name="pmid6716610">{{cite journal| author=Elkayam U, Gleicher N| title=Cardiac problems in pregnancy. I. Maternal aspects: the approach to the pregnant patient with heart disease. | journal=JAMA | year= 1984 | volume= 251 | issue= 21 | pages= 2838-9 | pmid=6716610 | doi= | pmc= | url= }} </ref>
==Treatment==

===Medical Therapy===
====Pharmacotherapy====
The treatment of pregnant women with [[MI|AMI]] and its complications should follow the usual standard of care; a cardiologist should work in tandem with an obstetrician in order to tailor therapy to both the mother and the fetus.  Initial therapy generally consists of unfractionated heparin, low dose aspirin after a loading dose of non-enteric coated aspirin, and nitrates.  Care should be exercised with nitrates as they are excreted in breast milk and may cause fetal [[methemoglobinemia]].

====Common Drugs used in Patients with CAD and their Pregnancy Categories====
*[[Morphine|Morphine Sulfate]] ''(Risk Category C)''
*[[Nitrates|Organic Nitrates]] ''(Risk Category B: [[Nitroglycerin]]; Risk Category C: [[Isosorbide dinitrate]])''
*[[Beta blockers|Beta-Adrenergic Blocking Agents]] ''(Risk Category B: [[Metoprolol]]; Risk Category C: [[Atenolol]])
*[[CCBs|Calcium Channel Blockers]] ([[CCBs]]) ''(Risk Category C: [[Nifedipine]], [[Diltiazem]], [[Verapamil]])''

*[[ACEIs|Angiotensin Converting Enzyme Inhibitors]] and [[ARBs|Angiotensin Receptor Antagonists]] '''''Teratogenic''''' and should not be used

*[[Eplerenone]] ''(Risk Category B)''

*[[Statins|HMG-CoA Reductase Inhibitors]] ([[Statins]]) ''(Risk Category X)''. These agents may be teratogenic and are not recommended.

*[[UFH|Unfractionated (UFH)]] and [[LMWH|Low Molecular Weight Heparin (LMWH)]] ''(Risk Category B: [[LMWH]]; Risk Category C: [[UFH]])''

*[[Aspirin]] ''(Risk Category C)''  Low dose aspirin should be administered.

*[[Thienopyridine|Thienopyridine derivatives]] ''(Risk Category B)''

*[[Glycoprotein IIb/IIIa inhibitors]] ''(Risk Category B: [[eptifibatide]], [[tirofiban]]; Risk Category C: [[abciximab]])''

====Drugs to be Avoided====
* Avoid [[ACE inhibitors]] and [[warfarin]] due to teratogenicity
* [[Thrombolytics]] mostly untested
:* Greatest experience in massive [[pulmonary embolism]]
:* [[Streptokinase]] does not cross placental membrane in animals, but Ab found in neonatal spinal cord fluid
:* [[Urokinase]] not teratogenic in mice/rats
:* Risk for maternal hemorrhage (1 case of [[placental abruption]] reported); increased risk when given at time of delivery
:* Delivery best delayed at least 2-3 weeks

===Surgery===
====Interventional Therapy====
[[Primary PCI]] with intracoronary bare metal stent placement is the preferred treatment particularly in cases of [[spontaneous coronary dissection]].  Thrombolytic therapy can be considered if PCI is not available.

==References==
{{Reflist|2}}

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