CardioNerds co-founder Dr. Dan Ambinder joins CardioNerds join Dr. Pooja Prasad, Dr. Khoa Nguyen and expert Dr. Abigail Khan (Assistant Professor of Medicine, Division of Cardiovascular Medicine, School of Medicine) from Oregon Health & Science University and discuss a case of mechanical valve thrombosis. Audio editing by CardioNerds Academy Intern, student doctor Adriana Mares.

 A 23-year-old pregnant woman with a mechanical aortic valve presented to the maternal cardiac clinic for a follow-up visit. On physical exam, a loud grade three crescendo-decrescendo murmur was audible and transthoracic echocardiography revealed severely elevated gradients across the aortic valve.  Fluoroscopy confirmed an immobile leaflet disk. Thrombolysis was successfully performed using a low dose ultra-slow infusion of thrombolytic therapy, leading to normal valve function eight days later.

Treatment options for mechanical aortic valve thrombosis include slow-infusion, low-dose thrombolytic therapy or emergency surgery. In addition to discussing diagnosis and management of mechanical valve thrombosis, we highlight the importance of preventing valve thrombosis during the hypercoagulable state of pregnancy with careful pre-conception counseling and a detailed anticoagulation plan.

See this case published in European Heart Journal – Case Reports.

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1. The hypercoagulable state of pregnancy presents a risk for women with mechanical heart valves with contemporary data estimating the rate of valve thrombosis during pregnancy at around 5%.
   
2. Thrombolytic therapy is a (relatively) safe alternative to surgery and should be considered first line for treatment of prosthetic valve thrombosis in all patients, especially in pregnant women.
   
3. Pre-conception counselling and meticulous anticoagulation management for patients with mechanical heart valves are key aspects of their care.
   
4. The evaluation for prosthetic valve thrombosis in pregnant persons requires a review of anti-coagulation history and careful choice of diagnostic testing to confirm the diagnosis and minimize risks to the parent and the baby.
   
5. Multi-disciplinary care with close collaboration between cardiology and obstetrics is critical when caring for pregnant persons with cardiac disease.
   

How can we counsel and inform women with heart disease who are contemplating pregnancy?

• Use the Modified World Health Organization classification of maternal cardiovascular risk to counsel patients on their maternal cardiac event rate and recommended follow-up visits and location of delivery (local or expert care) if pregnancy is pursued.
  
• To learn about normal pregnancy cardiovascular physiology and pregnancy risk stratification in persons with cardiovascular disease, enjoy CardioNerds Episode #111. Cardio-Obstetrics: Normal Pregnancy Physiology with Dr. Garima Sharma.
  

Adapted from the 2018 ESC Guidelines for the management of cardiovascular diseases during pregnancy

What is the differential diagnosis for a new murmur in a pregnant person who has undergone heart valve replacement?

1. Normal physiology – elevated flow from hyperdynamic state and/or expansion of blood volume in pregnancy.
   
   1. Pathologic – increased left ventricular outflow tract flow from turbulence of flow due to pannus ingrowth, new paravalvular leak, or obstructive mechanical disk motion from vegetation or thrombus.
      
   
   

What are diagnostic modalities for the evaluation of suspected prosthetic valve thrombosis?

• The 2020 ACC/AHA guidelines gave a class I recommendation for evaluation of suspected mechanical prosthetic valve thrombosis using transthoracic echocardiogram, transesophageal echocardiogram (TEE), fluoroscopy, and/or multidetector computer tomography.
  
• The goals multi-modality imaging are to assess valve function, leaflet motion, and presence and extent of thrombus while weighing the risks, benefits, and limitations of each modality.
  
• The hemodynamic effects with sedation required for TEE and radiation involved with each modality should be carefully assessed when choosing what modalities to pursue, particularly with regards to both parent and baby health.
  

What are the treatment options for prosthetic valve thrombosis in pregnant patients?

• The 2020 ACC/AHA guidelines gave a class I recommendation for treatment options using slow-infusion, low-dose fibrinolytic therapy or undergoing emergency surgery.
  
• Cardiac surgeries during pregnancy are associated with high rates of maternal and fetal adverse outcomes; therefore, a slow-infusion, low-dose fibrinolytic therapy is an attractive alternative option in hemodynamically stable patients.
  

What are the anticoagulation and antiplatelet strategies for pregnant patients with mechanical heart valves?

• All patients should be on aspirin 81mg daily unless they have active bleeding contraindications.
  
• No anticoagulation strategy has been proven to be superior for both the parent and the fetus.
  
• If low molecular weight heparin is used, strict monitoring of anti-Xa levels is recommended to optimize anticoagulation and prevent complications.
  
• Warfarin can be used throughout pregnancy if the therapeutic doses is ≤5 mg/day to reduce the risk of fetal toxicity. Warfarin teratogenicity is highest during the first trimester. However, after the 36th week patients require admission for transition to heparin to minimize risk of fetal intracranial hemorrhage and maternal bleeding during delivery.
  
• To learn more about anticoagulation during pregnancy, enjoy CardioNerds Episode #163. Cardio-Obstetrics: Pregnancy and Anticoagulation with Dr. Katie Berlacher.
  

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6. Özkan M, Çakal B, Karakoyun S, Gürsoy OM, Çevik C, Kalçik M, et al. Thrombolytic therapy for the treatment of prosthetic heart valve thrombosis in pregnancy with lowdose, slow infusion of tissue-type plasminogen activator. Circulation 2013;128:532–540.
   
7. Regitz-Zagrosek V, Roos-Hesselink JW, Bauersachs J, Blomström-Lundqvist C, Cífková R, De BM, et al. 2018 ESC guidelines for the management of cardiovascular diseases during pregnancy. Eur Heart J 2018;39:3165–3241.
   
8. D’Souza R, Ostro J, Shah PS, Silversides CK, Malinowski A, Murphy KE, et al. Anticoagulation for pregnant women with mechanical heart valves: a systematic review and meta-analysis. Eur Heart J 2017;38:1509–1516.