fibrinopeptide-a and Peripheral-Vascular-Diseases

Almost a third of patients who undergo peripheral bypass procedures do not have suitable veins, making the use of prosthetic materials necessary. Prosthetic materials can cause platelet adhesion and activation of the coagulation cascade on the graft. One potential strategy to reduce this thrombogenicity is to covalently bind heparin to the endoluminal surface of grafts. This human in vivo study examined systemic effects of the endoluminal heparin and addressed whether graft implantation results in (1) a measurable reduction of systemic markers of hemostasis activation compared with control grafts and (2) antibody formation against heparin, potentially responsible for heparin-induced thrombocytopenia (HIT).. The study included 20 patients undergoing femoropopliteal bypass grafting, of whom 10 received a standard Gore-Tex Thin Walled Stretch Vascular Graft (W. L. Gore & Associates, Flagstaff, Ariz) and 10 received a heparin-bonded expanded polytetrafluoroethylene (ePTFE) graft (Gore-Tex Propaten Vascular Graft). Blood samples were drawn before and directly after the operation and at days 1, 3, 5, and week 6 after surgery. Established markers of in vivo activation of platelets and blood coagulation (prothrombin fragment 1+2, fibrinopeptide A, soluble glycoprotein V, thrombin-antithrombin complexes, and D-dimers) were measured using standard commercially available techniques. Antiplatelet factor 4/heparin antibody titers were measured using a commercially available enzyme-linked immunosorbent assay, and platelet counts were determined.. No statistical differences were observed in any of the markers of in vivo activation of platelets and blood coagulation between patients receiving Propaten or control ePTFE. Moreover, no antibodies against heparin could be demonstrated up to 6 weeks after implantation.. No measurable effect of heparin immobilization on systemic markers of hemostasis was found using a heparin-bonded ePTFE graft in vivo. Also, no antibodies against heparin could be detected up to 6 weeks after implantation.

Topics: Aged; Antibodies; Anticoagulants; Antithrombin III; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Female; Fibrin Fibrinogen Degradation Products; Fibrinopeptide A; Hemostasis; Heparin; Humans; Male; Middle Aged; Peptide Fragments; Peptide Hydrolases; Peripheral Vascular Diseases; Platelet Count; Platelet Glycoprotein GPIb-IX Complex; Polytetrafluoroethylene; Prosthesis Design; Prothrombin; Thrombocytopenia; Thrombosis; Time Factors; Treatment Outcome; Vascular Patency

Patients with intermittent claudication have been reported to have disturbances in blood rheology and haemostasis. Whether these disturbances are a result of, or largely independent of, smoking history and arterial narrowing has not yet been established. The levels of whole blood and plasma viscosity, haematocrit, von Willebrand factor antigen, fibrin D-dimer antigen and urinary fibrinopeptide A antigen were compared in 617 claudicants and 722 controls from two epidemiological studies in Edinburgh. After adjustment for age and sex, all factors, except whole blood viscosity and haematocrit, were significantly higher in the claudicants compared to controls (P < or = 0.001). The risk of intermittent claudication was significantly raised for unit change in each factor, except for whole blood viscosity and haematocrit. Adjustment for lifetime smoking had little effect on the odds ratios. After further adjustment for the ankle brachial pressure index (as a measure of the extent of peripheral arterial disease), haematocrit, von Willebrand factor and urinary fibrinopeptide A showed a significant independent relationship with the risk of intermittent claudication. We conclude that the association between selected rheological and haemostatic factors and leg ischaemia is largely independent of both smoking history and the extent of arterial narrowing, and may be directly related to microvascular ischaemia.

Topics: Aged; Blood Coagulation Factors; Blood Viscosity; Female; Fibrin Fibrinogen Degradation Products; Fibrinopeptide A; Hematocrit; Hemorheology; Hemostasis; Humans; Intermittent Claudication; Male; Middle Aged; Peripheral Vascular Diseases; Risk Factors; Smoking; von Willebrand Factor

Immunohistochemical studies of human atherosclerotic lesions have demonstrated the occurrence of fibrin deposition and its degradation in the arterial wall. We studied fibrinogen, the generation of thrombin, and the degradation of fibrin in 40 patients with stable peripheral arterial occlusive disease of varying severity, as assessed by the ankle/brachial pressure index and duplex ultrasonography and/or angiography. Circulating fibrinogen (functional and immunological), fibrinopeptide A, thrombin-antithrombin III complex, and D-dimer were measured. The severity of atherosclerosis was associated with both fibrinogen (both functional and immunological) and D-dimer (r = .57, P < .0002, and r = .57, P < .0001, respectively). Fibrinogen and D-dimer showed a significant positive correlation (r = .50, P < .001). Generation of thrombin was detected in 24 patients (60%) by fibrinopeptide A and levels of thrombin-antithrombin III complex. As a sign of coagulation activation and fibrinolysis, we found that thrombin-antithrombin III complex and the degradation of cross-linked fibrin were progressively associated with the extent of vascular disease. The plasmin-mediated fibrin breakdown contributed to increased levels of circulating fibrinogen, an established risk factor for thrombotic complications. The significant correlations between fibrinogen/D-dimer and the severity of atherosclerosis support previous pathological studies and imply that local degradation of cross-linked fibrin is involved in the progression of atherosclerosis.

Topics: Adult; Aged; Aged, 80 and over; Antithrombin III; Arteriosclerosis; Female; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysis; Fibrinopeptide A; Humans; Male; Middle Aged; Peptide Hydrolases; Peripheral Vascular Diseases; Radiography; Ultrasonography