From the Guidelines
Marantic endocarditis, also known as nonbacterial thrombotic endocarditis (NBTE), should be managed with anticoagulation therapy using unfractionated heparin or low molecular weight heparin, such as enoxaparin 1mg/kg twice daily, to prevent further thromboembolic complications. This condition is characterized by sterile vegetations on heart valves that occur in patients with advanced malignancy, autoimmune diseases, or other hypercoagulable states. The primary management approach involves treating the underlying condition causing the hypercoagulable state, most commonly cancer or autoimmune disease 1.
Key Considerations
- The diagnosis of NBTE is difficult and relies on strong clinical suspicion in the context of a disease process known to be associated with NBTE, the presence of a heart murmur, the presence of vegetations not responding to antibiotic treatment, and evidence of multiple systemic emboli 1.
- Valvular vegetations in NBTE are usually small, broad-based, and irregularly shaped, with little inflammatory reaction at the site of attachment, making them more friable and detachable 1.
- Comprehensive hematological and coagulation studies should be performed to search for a potential cause, and multiple blood cultures should be undertaken to rule out infective endocarditis (IE), although negative blood cultures 1.
Treatment Approach
- Anticoagulation therapy is the mainstay of treatment to prevent further thromboembolic complications, with unfractionated heparin or low molecular weight heparin being preferred over warfarin, which may be less effective in this condition 1.
- Direct oral anticoagulants have limited evidence in this setting and are not recommended as first-line treatment 1.
- Patients should be monitored for embolic events, particularly to the brain, kidneys, and extremities, as these are common complications.
- Valve surgery is rarely indicated unless there is significant valvular dysfunction.
Prognosis
- The prognosis depends largely on the underlying condition, with cancer-associated marantic endocarditis generally carrying a poor prognosis.
- Early diagnosis and treatment with anticoagulation therapy can improve outcomes by reducing the risk of thromboembolic complications 1.
From the Research
Definition and Characteristics of Marantic Endocarditis
- Marantic endocarditis is characterized by the presence of sterile vegetations in the heart valves, and is associated with hypercoagulability states (cancer, autoimmune diseases, HIV) 2, 3.
- It is a rare non-infectious endocarditis that mostly affects the aortic and mitral valves 3.
- Marantic endocarditis is defined as a sterile endocarditis that is rarely encountered in clinical practice 4.
Complications and Presentation
- The main complications of marantic endocarditis are stroke, pulmonary thromboembolism, acute intestinal ischemia and splenic, renal and hepatic infarcts 2.
- It typically presents with signs and symptoms of embolisation, such as sudden loss of strength, acute respiratory failure, and distal ischemia 2, 3.
- Marantic endocarditis can also present with atypical symptoms, such as lower back pain, and may be diagnosed incidentally during autopsy 3, 5.
Diagnosis and Treatment
- Diagnosis of marantic endocarditis can be made using transesophageal echocardiography, which can show vegetations on the heart valves 2, 4.
- Treatment with anticoagulation can reduce the mortality of this disease, and early diagnosis is crucial to prevent complications 2, 4.
- Anticoagulation therapy, such as low-molecular-weight heparin, can be effective in preventing thromboembolic events in patients with marantic endocarditis 6.