Ferreira JP, Lam CSP, Anker SD, et al. - This study was undertaken to explore the relationship between D-dimer levels and the risk of stroke and other thrombotic, bleeding and fatal events, and whether D-dimer concentrations could predict rivaroxaban 2.5 mg twice daily (vs. placebo) effect in patients enrolled in the COMMANDER-HF trial who were in sinus rhythm, had heart failure with reduced ejection fraction and coronary artery disease. Among 5,022 patients, baseline measurement of D-dimer was available in 4107 (82%). Rivaroxaban decreased the risk of stroke but the benefit may be confined to patients with D-dimer concentrations above 515 ng/mL in COMMANDER-HF. There is a need for prospective trials to confirm these findings.