Acute coronary syndromes in pregnancy: a literature review ; 15JUNE 2022 SUMMARY BY DR MARIA RAFI

Acute Coronary Syndromes (ACS) in Pregnancy

Introduction

• 🌟 Rare but critical: ACS in pregnancy is a rare cause of maternal mortality.
• 🩺 Key to survival: Early recognition and a multidisciplinary team (MDT) approach improve outcomes.

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Epidemiology and Risk Factors

• 📊 Incidence:

  • 0.6–10 per 100,000 pregnancies worldwide.
  • Mortality rate: 5.1–11%.
  • UK MBRRACE-UK (2017–2019): Cardiovascular disease = leading cause of maternal deaths (17%).

• 📈 Increased risk:

  • Pregnant women are 3–4 times more likely to suffer ACS than nonpregnant women.
  • Rising incidence due to increased maternal age and comorbidities.

• 🔍 Risk Factors by Pathophysiology:

  • Pregnancy-Associated Spontaneous Coronary Artery Dissection (PASCAD):
    • Marfan syndrome, hypertension, family history of SCAD.
  • Atheromatous Disease:
    • Advanced age, obesity, smoking, diabetes, hypertension, dyslipidemia.
  • Thrombotic Risk:
    • Thrombophilia, hypertensive disorders, infections, multiparity, sickle cell disease.
    • Ergometrine use (linked to spasm).

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Pathophysiology

• 🔄 Physiological changes in pregnancy:
  • 50% increase in blood volume and cardiac output.
  • Increased basal heart rate; fluctuations in blood pressure and vascular resistance.
  • Prothrombotic state increases risk throughout pregnancy and postpartum.
• 💔 Coronary Flow & Ischemia:
  • Even minor reductions in coronary flow can cause ischemia due to increased cardiac demand.

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Types of ACS

1️⃣ ST-Elevation Myocardial Infarction (STEMI):

• 🚨 Key Features:
  • ST elevation/new LBBB on ECG + symptoms (chest pain, SOB, arrhythmias).
  • Biomarkers raised, but ECG is diagnostic.
  • 🌟 Time-critical: Target: restore coronary flow within 1 hour.
• 🩺 Accounts for ~75% of maternal ACS presentations.

2️⃣ Non-ST Elevation MI (NSTEMI):

• ⚠️ Clinical Presentation:
  • May include ST depression/T-wave inversion or normal ECG.
  • Raised biomarkers.
• 🛠️ Requires individual risk assessment for emergency or conservative management.

3️⃣ Unstable Angina (UA):

• 💢 Symptoms: Chest pain or SOB at rest.
• ECG may resemble NSTEMI but no biomarker rise.

4️⃣ Stable Angina:

• ⏸️ Relieved by rest, no biomarker rise, and often normal ECG.

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Aetiology of ACS in Pregnancy

• 🩸 PASCAD (Pregnancy-Associated SCAD):

  • Found in ~27% of cases; up to 43% in older studies.
  • Common in late third trimester/early postpartum.
  • Intimal tear → false lumen → intramural hematoma → luminal collapse.

• 🩹 Atherosclerosis:

  • Primary cause now due to maternal age and comorbidities.
  • Plaque rupture → thrombosis → coronary flow obstruction.
  • Seen in ~39–40% of cases.

• 🔗 Thrombosis/Thromboembolism:

  • Found in 10–20% of cases.

• 💢 Coronary Artery Spasm:

  • Rare (~2% of cases)

  Clinical Presentation

  • 🌟 Typical Symptoms:

    • Chest or epigastric pain radiating to the neck or arm.
    • Shortness of breath (SOB).

  • 🔀 Atypical Symptoms (more common in women):

    • Nonspecific pain, nausea, vomiting, and back pain.
    • Dyspnoea, hyperhidrosis, and agitation.

  • ⚠️ Critical Notes:

    • Symptoms often downplayed or dismissed in pregnant women (cognitive diagnostic bias).
    • Examination may be unremarkable.
    • Vital signs may show haemodynamic instability.

  • 🩺 ACS Subgroups Presentation:

    • PASCAD, Thrombosis, Coronary Artery Spasm: Typically present as STEMI or NSTEMI.
    • Atheromatous Disease: Can present as stable or unstable angina.

  • 🚨 Rare Presentation:

    • Cardiac arrest – managed per maternal cardiac arrest guidelines.
    • Always consider cardiac causes in cardiac arrest cases.

  • 🛠️ Differential Diagnosis:

    • Pulmonary embolism (PE).
    • Aortic dissection.
    • Pneumonia, gastro-oesophageal reflux disease, musculoskeletal pain, anxiety.

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  Investigations

  Investigations for Myocardial Infarction (MI) 🏥💓

  • Electrocardiography (ECG) 📉

    • 🩺 First-line test for diagnosing MI in patients with chest pain.
    • ⚡ ST elevation is the most specific marker.
    • 📈 Serial ECGs are important as initial ECGs can be normal.
    • 🔍 Sensitivity of 12-lead ECG is ~50%, so other tests are needed.

  • Blood Cardiac Markers 🩸

    • ✅ Troponin I & Troponin T – Best markers for MI.
    • ⏳ Can take up to 12 hours to peak, so repeated testing is needed.
    • 🚫 Not affected by pregnancy, labor, or C-section.
    • ⚠️ Raised in pre-eclampsia & hypertension but stays below MI levels.

  • Echocardiogram (Heart Ultrasound) 🦻🫀

    • 🔍 Helps rule out other conditions like aortic dissection.
    • 📊 Can assess heart function & wall motion abnormalities.
    • 🤰 Safe to use in pregnancy.

  • Coronary Angiography 🏥📡

    • 🛑 Gold standard for diagnosing & treating MI.
    • 🩻 Uses X-ray and contrast dye to check for blocked arteries.
    • 🤰 Safe in pregnancy if done with abdomen shielding & minimal radiation exposure.

  Management of ACS in Pregnancy

  General Principles

  • 🩺 Multidisciplinary Team (MDT):
    • Involves obstetricians, cardiologists, anaesthetists, paediatricians, and the patient herself.
    • Care should be provided in facilities equipped with cardiac and obstetric intensive care units.
  • 🌟 Goal:
    • Stabilize the patient and individualize care based on clinical presentation and gestational age.

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  Reperfusion Therapy for STEMI in Pregnancy

  • Primary Percutaneous Coronary Intervention (PPCI) 🚑💉

    • Gold standard treatment for STEMI.
    • Coronary angiography & stenting help restore blood flow.
    • Bare metal stents (BMS) are preferred over drug-eluting stents due to limited safety data.
    • Growing evidence supports successful PPCI outcomes in pregnancy.

  • Thrombolysis (Clot-Dissolving Therapy) 💊🩸

    • Used when PPCI is not immediately available.
    • Intravenous t-PA (tissue plasminogen activator) is the preferred thrombolytic agent.
    • Safe in pregnancy as it does not cross the placenta.
    • Review of 28 case reports found no risk of birth defects (teratogenesis).

  • Risks & Considerations ⚠️

    • Maternal bleeding risk (8%), which can lead to fetal distress.
    • Decisions should be made in consultation with a cardiologist.
    • Early intervention is crucial to improve outcomes for both mother and baby.

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  Management of Non-ST Elevation Myocardial Infarction (NSTEMI) in Pregnancy

  🩸 First-Line Treatment: Antiplatelet Therapy

  • Goal: Prevent further clot formation, dissolve existing clots, and improve blood flow to the heart.
  • Medications Used:
    • Aspirin (Low-Dose) – Safe in pregnancy; reduces clot formation.
    • Clopidogrel (If Needed) – Used in selected cases but for the shortest duration possible.

  🏥 Coronary Angiography & Stenting

  • Indicated If:
    • Symptoms persist despite medical treatment.
    • Hemodynamic instability (low blood pressure, shock, etc.).
    • High-risk patients even after symptoms improve.
  • Procedure:
    • Angiography assesses the blockage.
    • Stenting (Revascularization) is done if required.
    • Discussed in multidisciplinary team meetings to balance risks and benefits.

  Medications Used in Acute Myocardial Infarction (AMI) in Pregnancy

  for prevention and treatment                                                                                                           🩸 Antiplatelet & Anticoagulant Therapy

  • Aspirin (Low-Dose 60–150 mg) ✅

    • First-line medication for preventing further clot formation.
    • Safe in pregnancy (confirmed by the CLASP study).
    • Slight increase in blood transfusion post-delivery, but no significant risks to the mother or baby.
    • Avoid high-dose aspirin due to potential risks.

  • Clopidogrel (Thienopyridine Derivative) 🛑⚠️

    • Used after stenting if needed.
    • Limited safety data, so use for the shortest duration possible.
    • A case study reported no adverse effects with 75 mg for 2 weeks after stenting in pregnancy.

  • Heparin (Low-Molecular-Weight & Unfractionated) ✅

    • Safe in pregnancy as it does not cross the placenta.
    • Used to prevent further clot formation.
    • Must be stopped 24 hours before labor to avoid excessive bleeding.

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  🫀 Blood Pressure & Vasodilator Medications

  • Labetalol (Beta-Blocker) ✅

    • Preferred beta-blocker for pregnancy.
    • Safe for controlling blood pressure and reducing heart strain.

  • Nitrates (e.g., Nitroglycerin) ✅⚠️

    • Used to widen blood vessels and improve blood flow.
    • Can be used in severe hypertension, pulmonary edema, and AMI.
    • Caution: Reports of fetal distress (bradycardia, loss of variability) with IV nitroglycerin.

  • Nifedipine (Calcium Channel Blocker) ⚠️

    • Safe in pregnancy, but should be avoided after an acute coronary event due to increased mortality risk.

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  🚫 Medications Contraindicated in Pregnancy

  • ACE Inhibitors & ARBs (e.g., Enalapril, Losartan) ❌

    • Severe fetal risks, including kidney damage, lung underdevelopment, growth restriction, and fetal death in the second & third trimester.
    • First-trimester use can cause heart and brain defects.

  • Statins (e.g., Atorvastatin, Rosuvastatin) ❌

    • Not recommended due to lack of safety data.

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  ⏳ Timing of Delivery

  • Delay delivery by 2–3 weeks post-AMI if possible to reduce maternal mortality risk.
  • If preterm delivery is expected, administer maternal steroid injections early for fetal lung maturity.
  • Delivery must take place in high-risk obstetric units with intensive care facilities.

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  🤰 Mode of Delivery: Vaginal vs. Cesarean Section

  • No clear preference—both vaginal and elective C-section are acceptable, depending on maternal & obstetric factors.

  • Vaginal Delivery Advantages
    ✔️ Less blood loss, infection, and thromboembolism risk
    ✔️ Epidural analgesia recommended to reduce stress on the heart & prevent excessive pushing.
    ✔️ Labour in the left lateral position to avoid pressure on major vessels.
    ✔️ Instrumental delivery (forceps/vacuum) advised to shorten the second stage and reduce heart strain.

  • Elective C-Section Advantages
    ✔️ Avoids labor-related hemodynamic stress (pain-induced BP spikes, pushing effort).
    ✔️ Allows planned delivery with a full medical team available.

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  ⚠️ Key Considerations During Delivery

  • Continuous Monitoring: Maternal ECG, pulse oximetry, BP, and fetal heart rate.
  • Invasive Monitoring: Arterial catheter if left ventricular function is impaired.
  • Oxytocin (Slow IV Infusion <2U/min) to reduce postpartum hemorrhage risk without causing hypotension.
  • Avoid Ergometrine 🚫 due to its vasoconstrictive effect, which can trigger coronary artery spasm.

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  🛌 Post-Delivery Care & Follow-Up

  • High-dependency/ICU monitoring for 24–48 hours post-delivery due to fluid shifts & cardiovascular instability.
  • Thromboembolic risk assessment & appropriate anticoagulation measures.
  • AMI Management During Delivery:
    • Beta-blockers, nitrates, and calcium channel blockers can be used if needed.
    • Nitroglycerin & calcium channel blockers may prolong labor due to tocolytic effects.
  • Postnatal Follow-Up:
    • General practitioner & cardiologist must be updated.
    • Contraception counseling based on cardiac function & AMI cause.
    • Future pregnancy recommendations depend on maternal heart recovery.

  5. Future Pregnancies

  • 🩺 Preconception Counseling:
    • Essential for women with IHD or previous ACS.
    • Optimize cardiac function and switch teratogenic drugs to safer alternatives.
    • Delay pregnancy for at least 12 months post-acute coronary event.
  • 🛡️ Contraception:
    • Contraindicated methods: Estrogen-based contraceptives in IHD.
    • Preferred: Progestin-only or non-hormonal methods.

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  Monitoring & Follow-Up

  • 🔍 Regular Monitoring:
    • MDT involvement throughout pregnancy.
    • Rapid assessment for any symptom changes.
  • 📋 Risk Stratification:
    • Use modified WHO classification for women with cardiac impairment (Class III/IV advised against pregnancy).
  • 🔄 Lifestyle Modifications:
    • Address modifiable risk factors (obesity, smoking, hypertension).