Venous thrombosis is a relatively usual but serious complication of pe
rmanent transvenous pacing. However, the pathogenesis has not been def
ined. To clarify underlying abnormalities in the coagulation-fibrinoly
sis system in patients with permanent transvenous pacemakers, we measu
red serum levels of fibrinopeptide A (FPA), thrombin-antithrombin III
complexes (TATs), plasmin-alpha(2) plasmin inhibitor complexes (PICs),
D-dimer (D-D), beta-thromboglobulin (beta-TG), and platelet factor 4
(PF4) in 53 patients with permanent transvenous pacemakers and 10 cont
rol subjects. The patients were divided into two groups, as follows, a
ccording to the presence of mural thrombus documented along the pacing
lead(s) by digital subtraction angiography and transesophageal echoca
rdiography: Group Th (-), patients without venous route thrombus; and
Group Th (+), patients with venous route thrombus. FPA and TAT levels
increased significantly even in Group Th (-), and further increased in
Group Th (+) compared with control subjects (FPA: 7.5 +/-4.9, 15.3 +/
-8.8 vs 3.0 +/-1.4 ng/mL, respectively,P<0.05; TAT: 2.9 +/-1.3, 4.8 +/
-2.3 vs 1.7 +/-0.6 ng/mL, respectively, P<0.05). There were no differe
nces in levels of D-D, PIC, beta-TG, and PF4 among control subjects, G
roup Th (-), and Group Th (+). These findings suggest that the hyperco
agulable state appears in patients with permanent transvenous pacemake
rs, even without apparent venous thrombosis. The patients with permane
nt transvenous pacemakers are thought to be in the prethrombotic state
even if they have no venous route thrombosis.