Severe Hypercoagulability With Nonbacterial Thrombotic Endocarditis After KRAS Inhibitor Exposure: A Perfect Storm
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Cecilia Villa-Etchegoyen1, Raymond B Fohtung2, Kwan S Lee2
1Department of Cardiovascular Medicine, Mayo Clinic, Phoenix, Arizona, USA; Department of Cardiovascular and Thoracic Surgery, Mayo Clinic, Phoenix, Arizona, USA.
Background:
Nonbacterial thrombotic endocarditis (NBTE) is a rare malignancy-associated condition causing systemic embolization and valvular dysfunction. Its presentation as new severe mitral regurgitation (MR) may be difficult to recognize.
Case Summary:
A 76-year-old man with metastatic pancreatic adenocarcinoma developed progressive dyspnea after treatment with the KRAS inhibitor daraxonrasib. Echocardiography demonstrated new severe MR with leaflet thickening and broad-based echodensities. His course was complicated by pulmonary embolism, recurrent coronary thrombosis, and persistently negative blood cultures. Transesophageal echocardiography confirmed bilateral leaflet involvement with a central coaptation defect. Anticoagulation was changed to low-molecular-weight heparin.
Discussion:
NBTE should be considered in patients with malignancy presenting with new MR and thrombotic events without evidence of infection. The temporal association with KRAS inhibition is noteworthy but does not establish causality.
Take-Home Message:
NBTE may present as subacute MR. Echocardiography and clinical context are essential for timely diagnosis and management.
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