Platelet Analysis in the Thrombus Plus Serum BNP for Detecting Clot-Related Atrial Fibrillation. Results From the ITACAT Multicentric Registry.

Occult atrial fibrillation (AF) is a common cause of cryptogenic stroke. This study aimed to investigate the utility of surrogate markers within the clot (clot markers), in combination with serum biomarkers, to identify AF-associated clots in patients who underwent mechanical thrombectomy. Each retrieved thrombus was analyzed to identify fibrin, red blood cells, platelets - CD61 staining (PLT) and T-CD4 lymphocyte/macrophage/monocyte (CD4) profile. Serum biomarkers such as D-dimer, lipoprotein (A), and brain natriuretic peptide (BNP) were also assessed in the acute phase of the stroke. Patients with stroke-related AF and large artery atherosclerosis (LAA) stroke were compared by matched case-control design to identify markers associated with AF clot profile. The predictive abilities of clot markers and serum biomarkers to detect AF clot were tested in patients with cryptogenic stroke. In patients with AF clot, the PLT percentage was higher (66.64% vs. 55.43%, OR = 1.03); CD4 percentage was lower (3.84% vs. 7.95%, OR = 0.95); and BNP marker was higher (2114 pg/ml vs. 276 pg/ml, OR = 1.04) compared to LAA clot. PLT was independently associated to AF-clot (OR, 1.04) but demonstrated moderate ability to identify AF-clot cases (C-test 0.668, p = 0.018). The combination of PLT with BNP significantly improved AF-clot prediction (C-test 0.847, p < 0.001). The clot composition of patients with cryptogenic stroke and AF detection showed four-fold higher PLT and BNP pattern of risk than patients with cryptogenic stroke without AF detection (38.5% vs. 8.7%) (OR = 1.40). Integrating intra-thrombus platelet with serum BNP offers a promising approach for detecting AF-associated clots in patients with cryptogenic stroke.