Abnormal plasma clot formation and fibrinolysis reveal bleeding tendency in patients with partial factor XI deficiency by Gillian N. Gidley, Lori A. Holle, John Burthem, Paula H. B. Bolton-Maggs, Feng-Chang Lin, and Alisa S. Wolberg BloodAdv Volume 2(10):1076-1088 May 22, 2018 © 2018 by The American Society of Hematology

Gillian N. Gidley et al. Blood Adv 2018;2:1076-1088 © 2018 by The American Society of Hematology

Clot formation assays performed with CTI-treated plasmas differentiate FXI-deficient bleeders from nonbleeders. Clot formation assays performed with CTI-treated plasmas differentiate FXI-deficient bleeders from nonbleeders. Clotting was triggered in CTI-treated plasmas from healthy individuals and FXI-deficient patients by recalcification and addition of tissue factor and phospholipids. Clot formation was monitored by turbidity. (A) Onset time, (B) rate (Vmax), (C) time to plateau, and (D) peak turbidity change for controls, all FXI-deficient patients, and only FXI-deficient patients with partial deficiency (16-60 IU/dL). Symbols represent plasmas from individual subjects; lines show median and interquartile range. *P < .05, **P < .005. B, bleeders; C, controls; mOD, milli optical density; NB, nonbleeders. Gillian N. Gidley et al. Blood Adv 2018;2:1076-1088 © 2018 by The American Society of Hematology

Fibrinolysis assays performed with CTI-treated plasmas differentiate FXI-deficient bleeders from nonbleeders. Fibrinolysis assays performed with CTI-treated plasmas differentiate FXI-deficient bleeders from nonbleeders. Clotting was triggered in CTI-treated plasmas from healthy individuals and FXI-deficient patients by recalcification and addition of tissue factor, phospholipids, and tissue plasminogen activator. Clot formation and lysis were monitored as an increase and subsequent decrease in turbidity. (A) Onset time, (B) rate (Vmax), (C) time to peak turbidity, (D) peak turbidity change, (E) area under the curve, and (F) lysis time for controls, all FXI-deficient, and only FXI-deficient patients with partial deficiency (16-60 IU/dL). Symbols represent plasmas from individual subjects; lines show median and interquartile range. *P < .05, **P < .005. Gillian N. Gidley et al. Blood Adv 2018;2:1076-1088 © 2018 by The American Society of Hematology

Fibrin network structure correlates with bleeding risk in FXI-deficient patients. Fibrin network structure correlates with bleeding risk in FXI-deficient patients. Clots were formed from CTI-treated plasmas by recalcification and addition of tissue factor and phospholipids in the presence of AlexFluor488-conjugated fibrinogen. Clots were scanned with a Zeiss LSM700 confocal laser scanning microscope (Carl Zeiss, Inc, Thornwood, NY) with a 63× oil immersion pan-apochromatic lens.42 Thirty optical sections (1024 × 1024 pixels) were collected at 0.36-μm intervals in the z-axis. Images were processed using 3-dimensional deconvolution algorithms (AutoQuant software × 3.0.1, Media Cybernetics Inc, Bethesda, MD). Fibrin network density analysis was performed as described in “Materials and methods.” (A) Representative confocal micrographs (z-projections of 30 individual slices) of plasma clots formed from a control individual and FXI-deficient nonbleeder and bleeder, as indicated. Images are 101.5 × 101.5 µm. (B) Fibrin network density (arbitrary units [A.U.]). Symbols represent plasmas from individual subjects; lines show median and interquartile range. Gillian N. Gidley et al. Blood Adv 2018;2:1076-1088 © 2018 by The American Society of Hematology

Plasmas collected in the absence of CTI show few significant differences in clotting between FXI-deficient nonbleeders and bleeders. Plasmas collected in the absence of CTI show few significant differences in clotting between FXI-deficient nonbleeders and bleeders. Plasmas from healthy individuals and FXI-deficient patients that were not collected in the presence of CTI were clotted by recalcification and addition of tissue factor and phospholipids. Clot formation was monitored by turbidity. (A) Onset time, (B) rate (Vmax), (C) time to plateau, and (D) peak turbidity change for controls, all FXI-deficient patients, and only FXI-deficient patients with partial deficiency (16-60 IU/dL). Symbols represent plasmas from individual subjects; lines show median and interquartile range. *P < .05, **P < .005. Gillian N. Gidley et al. Blood Adv 2018;2:1076-1088 © 2018 by The American Society of Hematology

Receiver operating characteristic analysis. Receiver operating characteristic analysis. Receiver operating characteristic curve analysis of FXI:C alone, APTT alone, APTT+Vmax from fibrinolysis assays (model 1, APTT+VmaxtPA), and APTT plus Vmax and AUC from fibrinolysis assays (model 2, APTT+VmaxtPA+AUCtPA). FXI:C and APTT were measured without CTI. Models 1 and 2 show assay results from plasmas collected in the (A) presence or (B) absence of CTI. Gillian N. Gidley et al. Blood Adv 2018;2:1076-1088 © 2018 by The American Society of Hematology