Biomarkers for detection of a thrombus in the left atrial appendage: the search for the grail?

Patients with atrial fibrillation (AF) undergoing either pulmonary vein isolation (PVI) or direct current cardioversion (DCCV) most commonly undergo transoesophageal echocardiography (TOE) for definite exclusion of a thrombus in the left atrial appendage (LAA).1 As TOE as a semi-invasive procedure is not without risk to the patient and during the current times with a still ongoing SARS-Cov-2 pandemic for the clinician, a definite exclusion of LAA thrombosis before a PVI or DCCV using a readily available biomarker would minimise the risk for the patient and clinician alike. However, as far as now the quest to identify such a biomarker is still ongoing. In their manuscript Almorad et al 2 did compare two cut-offs of D-dimer to exclude LAA thrombus before DCCV. In their study patients did receive a transthoracic echocardiography 6 months before the TOE and D-dimer levels were measured at the day of the DCCV. Two cut-offs were used in the study, the first being 500 ng/mL as suggested by the manufacturer of the test and the second being an age-adjusted value 10 times the patients age.2 The main finding was that both cut-offs were able to identify the 13 patients with LAA thrombus whereby the age-adjusted cut-off had a higher specificity with 66.4% to 50.4% for the standard …