Acute ischemic stroke, active malignancy and non-bacterial thrombotic endocarditis: an exploratory prospective observational study.

About 3-10% of patients with acute ischemic stroke (AIS) have active cancer. Malignancy-associated hypercoagulability (MAH) is an established cause of cancer-associated stroke. Nonbacterial thrombotic endocarditis (NBTE) is a severe manifestation of MAH. However, no prospective study has examined its prevalence and anticoagulation management in AIS. We conducted a prospective observational study at a tertiary center including patients with AIS or transient ischemic attack (TIA) and active malignancy. All patients underwent transthoracic echocardiography, followed by transesophageal echocardiography when indicated. Among 3,491 screened patients, 16 with active cancer and AIS/TIA were included. Eleven (68.8%) showed embolic patterns suggestive of MAH, and 6 (37.5%) had NBTE. NBTE patients numerically more frequently had multiterritory embolic infarctions (100% vs. 60.0%, p = 0.102) and prior ischemic stroke (66.7% vs. 10.0%, p = 0.028). 4/6 were on direct oral anticoagulants (DOACs), while none were on low-molecularweight heparin (LMWH). Under LMWH, vegetations resolved or regressed in 3/4, whereas under DOACs, progression or recurrent embolism occurred in several patients. Twelve-month mortality was high in both MAH (90.9%) and NBTE (83.3%) groups. NBTE was frequently identified in this prospective cohort of patients with cancer-associated stroke and consistently associated with multi-territory embolic infarction. Recognition may enable earlier diagnosis. Larger studies are needed to define optimal anticoagulation strategies.