Capsule Commentary on Rivera-Caravaca et al., Soluble Fibrin
Monomer Complex and Prediction of Cardiovascular
Events in Atrial Fibrillation: The Observational Murcia Atrial
Bethany T. Samuelson Bannow, MD
University of Washington, Seattle, WA, USA.
J Gen Intern Med 33(6):945
© Society of General Internal Medicine 2018
ivera-Caravaca et al.
report clinical outcomes in associ-
ation with varying levels of soluble fibrin monomer
complex (SFMC) in 1226 patients with atrial fibrillation re-
ceiving vitamin K antagonists (VKAs) for stroke prevention.
The outcomes examined were highly clinically relevant and
included ischemic stroke, a composite of adverse cardiovas-
cular events including mortality, cardiovascular mortality and
all-cause mortality. While associations between high SFMC
levels (>12 μg/mL) and cardiovascular event and mortality
outcomes were noted on multivariate analysis, no association
with ischemic stroke was found.
-VASc score, which utilizes seven clinical
features to predict risk of ischemic stroke among patients with
atrial fibrillation, is a well-established risk prediction model
used to inform decision making regarding prophylactic
anticoagulation in such patients.
Acknowledging this, the
authors appropriately investigated whether a finding of elevat-
ed SFMC levels impacted the clinical usefulness of this pre-
diction tool. No significant improvement was found.
This article is an excellent example of a well-planned and
executed but early investigation of a biomarker. As such,
caution is required in interpreting the clinical relevance of
these findings. The most important limitation of this study is
that all patients were already on anticoagulation with VKAs.
As previously stated, the purpose of risk prediction models in
the clinical care of patients with atrial fibrillation is generally
to inform decisions regarding the initiation of anticoagulation.
Furthermore, such decisions are generally based upon risk of
ischemic stroke—the one outcome for which this marker
lacked any predictive value—and in many practices, the use
of VKAs is being phased out in favor of newer, safer direct
As the authors state, this assay does not add significantly to
the clinical utility of existing risk prediction models, and
certainly at this point, it would be premature to base any
clinical decisions upon these findings. However, the promis-
ing findings of associations between high SFMC levels and
important cardiovascular and mortality outcomes suggest that
further studies, ideally in patients who have not yet started
anticoagulation, may demonstrate clinical utility. The astute
clinician will eagerly anticipate the results of such studies as
they may yet be practice-changing.
Corresponding Author: Bethany T. Samuelson Bannow, MD;
University of Washington, Seattle, WA, USA (e-mail: Bts99@uw.edu).
Compliance with Ethical Standards:
Conflict of Interest: The author has no conflicts of interest with this
1. Rivera-Caravaca JM, Roldán V, Romera M, Esteve-Pastor MA, Valdés
M, Lip GYH, Vicente V, Marín F. Soluble fibrin monomer complex and
prediction of cardiovascular events in atrial fibrillation: the observational
Murcia atrial fibrillation project. J Gen Intern Med. https://doi.org/10.
2. Lip GY, Nieuwlaat R, Pisters R, Lane DA, Crijns HJ. Refining clinical risk
stratification for predicting stroke and thromboembolism in atrial fibrilla-
tion using a novel risk factor-based approach: the euro heart survey on
atrial fibrillation. Chest. 2010;137:263–72. https://doi.org/10.1378/
Published online January 29, 2018