Comparison of Left and Right Atrial Thrombus Formation and Coagulation Activity in Patients with Atrial Fibrillation - The 65th Annual Conference of the Israel Heart Society & The Israel Society of Cardiothoracic Surgery, 24-25 April 2018

Ehud Chorin Department of Cardiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel Michal Cipok Department of Hematology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel Varda Doitch Department of Hematology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel David Varon Department of Hematology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel Erel Jaffe Department of Hematology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel Aviram Hochstadt Department of Cardiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel Ohad Bentur Department of Hematology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel Liron Hadad Department of Cardiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel Sami Viskin Department of Cardiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel Raphael Rosso Department of Cardiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel

Background: Atrial fibrillation (AF) confers up to 5-fold increase in the risk of stroke. Anatomical considerations cannot completely explain the higher frequency of left system emboli compared with the right system. Several studies found regional differences in platelet activation and hypercoagulability in the left atrium (LA) compared with systemic circulation in patients with AF, suggesting local contributing factors.

Objective: To compare factors associated with thrombus formation using blood samples from both atria, and systemic circulation in patients with AF.

Methods: In a prospective trial of patients who underwent circumferential ablation of the pulmonary veins (CPVI) or left atrial appendage closure (LAAC), blood samples were collected from the femoral vein (FV), right atrium (RA) and left atrium (LA), sent to thromboelastography (TEG) and tested for thrombotic biomarkers levels. Results were assessed using non-parametric pairwise tests and Spearman`s correlation.
Results: 45 patients were included in the study, 37(82.2%) underwent CPVI, 8 (17.8%) had LACC, 33 (73.3%) were males and 12 (26.7%) were females, mean age was 62.6±13.6 and mean CHADS-VASC score was 2.2±1.6. TEG parameters were similar between FV and RA, while significant differences were noted when comparing RA and LA for Reaction time (longer in LA) and angle parameters (Steeper in RA), (p=0.001 and p=0.042 accordingly). Biomarker measurements were similar between the FV and the RA, yet 4/6 biomarkers showed significant inter-atrial difference: D-dimer, FVIII and vWF were higher in the RA (p<0.02), and GPIIb was higher in the LA (p=0.041). TEG parameters and biomarker levels in both atria and inter-atrial difference were not correlated to CHADS-VASC score.

Summary and Conclusion: There are significant changes in coagulation mechanism activation markers between both atria, which could be suggestive of hypercoagulability in the right atrium possibly due to natural anticoagulant mechanisms in the left atrium. Further research is needed to clarify these findings.