Changes in Fibrinolytic Activity and Coagulation Factors after Left
Atrial Appendage Closure in Patients With Atrial Fibrillation
(HEART-CLOT Study)
Abstract
Background The left atrial appendage (LAA) is known to be the primary
source of thrombus formation in atrial fibrillation (AF). Our aim was to
investigate if LAA elimination (LAAO) from the cardiovascular system has
an effect on the coagulation and prothrombotic status in AF. Methods
Twenty two patients with nonvalvular AF not currently on anticoagulation
therapy participated in a single-center prospective study. We measured
fibrinogen and plasminogen levels along with Ks, clot lysis time (CLT),
and endogenous thrombin potential (ETP) before LAAO procedure, at
discharge and 1 month follow-up. Results 1 month after the LAAO
procedure compared to baseline value, we found Ks improved by 39.3%
measured in clots prepared from peripheral blood (p=0.019) and also
after adjustment for fibrinogen (p=0.027). Higher Ks was associated with
improved clot susceptibility to lysis (r=-0.67, p=0.013). We found
shortened CLT by 10.3% (p=0.0020); a 52% lower PAI-1 antigen levels
(p=0.023) along with 8.9% increased plasminogen activity (p=0.0077). A
tendency to decreased thrombin generation, reflected by decreased ETP
and peak thrombin generated, was observed 1 month after the LAAO
procedure (p=0.072 and p=0.087). No differences were found in tPA and
TAFI plasma levels (both p>0.05). Conclusions We confirm,
that LAA plays a key role in thrombogenesis and is the main source of
thrombus in AF. LAA elimination from the circulatory improve fibrin clot
permeability and susceptibility to fibrinolysis in peripheral blood.