Creation of a clinico-biological score for the exclusion of intra-atrial thrombus before catheter ablation of atrial fibrillation

Doctors are keen to use the most effective and least invasive diagnostic techniques possible.

To validate these techniques and to be able to offer them to as many people as possible, medical researchers are setting up clinical studies.

Atrial fibrillation is a heart rhythm disorder that causes the heart to beat faster and irregularly. An operation is recommended in case of resistance to drug treatments. One of the risks of the operation is the migration of a clot (thrombus) from the heart to the brain, which would cause a stroke. To avoid this risk, a transesophageal echography is performed, i.e. a tube must pass through the mouth, then the pharynx and finally the oesophagus in order to visualise the patient's heart.

As this examination is rather uncomfortable, a study was carried out to determine a risk score for having a thrombus in the heart that would allow a proportion of patients to avoid transesophageal echography.

As the risk of clot is low, the dataset includes clinical information from 2494 patients. Of these, 48 had a thrombus in their heart. Four criteria were selected to constitute the ATE score. These criteria are clinical (hypertension, heart failure, history of stroke) and biological (D-dimer level greater than 270 ng/mL). In this dataset, an ATE score of zero was strongly associated with the absence of a thrombus in the heart and would have allowed almost a third of patients to avoid undergoing transesophageal echography.

As with any clinical study, it is necessary to confirm the results by a new study with an independent population/data set before this new score can be used routinely. This was achieved with the EXTRALUCID-d CS study.