Altered fibrin clot properties in patients with premature peripheral artery disease

INTRODUCTION It has been shown that formation of denser and poorly lysable fibrin clots is observed in elderly patients with peripheral artery disease (PAD). OBJECTIVES The aim of the study was to test the hypothesis that premature PAD is associated with more prothrombotic fibrin clot phenotype. PATIENTS AND METHODS Ex-vivo plasma fibrin clot permeability, turbidity, and susceptibility to lysis were evaluated in 31 premature PAD patients (median ankle brachial index [ABI], 0.75; interquartile range, 0.5-0.8) aged 55 or less and 32 PAD patients (ABI, 0.66; 0.56-0.76) aged over 55 years. Subjects without PAD matched for age and sex (n = 40) served as controls. RESULTS Premature PAD patients were characterized by 32% lower clot permeability (K-s) (P < 0.001), 7% longer clot lysis time (t(50%)) (P = 0.004), and 31% higher maximum D-dimer levels released from fibrin clots (D-D-max) (P < 0.001) compared with controls. These differences remained significant after adjustment for risk factors and medications. None of the fibrin clot parameters differed between premature and older PAD patients. There were correlations between fibrin clot parameters and CRP in premature PAD patients and with ABI in older PAD patients. In a multiple regression model, premature PAD and ABI were independent predictors of K-s, and premature PAD and plasma fibrinogen of the maximum absorbance of a fibrin gel. CONCLUSIONS Plasma fibrin clots show similarly abnormal prothrombotic phenotype in premature and older PAD patients. However, different factors influence fibrin clot parameters in these patient groups. Premature PAD was an independent predictor of clot permeability and maximum absorbance of a fibrin gel.