A 46-year-old female with a history of hypertension, intracranial arteriovenous malformation, and previous mechanical mitral valve replacement is admitted to cardiology ICU with new onset of atrial fibrillation, shortness of breath, tachypnea, and crackles at both lung bases on auscultation.
The patient has:
International normalized ratio (INR) is 1.8. Transesophageal echocardiography demonstrates the following image of the bioprosthetic mitral valve (red arrows) in the midesophageal two-chamber view. The mean transmitral gradient was measured 12 mm Hg with continuous wave Doppler.
What is the next step in management?a. Heparin infusion and nitroglycerin infusion for afterload reduction
Correct Answer: C
Prosthetic valve thrombosis should be suspected in the setting of new onset heart failure, thromboembolism, or valve dysfunction in a patient with a mechanical valve. The incidence is estimated to be 0.3% to 1.3% per year. Thrombosis is more common on right-sided valves versus left-sided valves, the mitral valve versus aortic valve, and mechanical valves versus bioprosthetic valves. Anticoagulation therapy for all patients with a valve replacement includes daily aspirin with or without a vitamin K antagonist. The presence of a mechanical mitral valve requires lifelong vitamin K antagonist therapy with INR targets 2.5 to 3.5. This patient has an INR of 1.8 and is therefore subtherapeutic and at increased risk for prosthetic valve thrombosis. INR targets after mechanical aortic valve replacement require an INR of 2.0 to 3.0 because the higher velocity of flow through the valve helps to prevent blood stasis. Treatment of prosthetic valve thrombosis includes systemic anticoagulation, thrombolytic therapy, and/or surgery. Patients with subtherapeutic anticoagulation should receive intravenous heparin therapy. The 2014/2017 American College of Cardiology/American Heart Association guidelines recommend emergent surgery or low-dose thrombolytic therapy for patients with left-sided prosthetic valve thrombosis and signs of valve obstruction or heart failure. Patients with right-sided thrombosis are candidates for thrombolytic therapy. This patient has a history of an intracranial arteriovenous malformation, which is an absolute contraindication to thrombolytic therapy; therefore, urgent surgery should be pursued. Other absolute contraindications to thrombolysis include active internal bleeding, recent history of stroke, intracranial or spinal surgery, serious head trauma, intracranial neoplasm or aneurysm, and severe uncontrolled hypertension.