Increased levels of tissue plasminogen activator antigen and factor VIII activity in nonvalvular atrial fibrillation: relation to predictors of thromboembolism.
BACKGROUND
Given that nonvalvular atrial fibrillation (AF)-associated stroke can be either cardioembolic or atherothrombotic, we investigated the relationships between nonvalvular AF and hemostatic factors reflecting intrinsic thrombogenic and atherogenic potentials (tissue plasminogen activator [t-PA] antigen, plasminogen activator inhibitor-1, and factor VIII activity). We also evaluated the clinical applicability of these hemostatic factors by examining whether AF subjects with established clinical or echocardiographic predictors of thromboembolism had higher levels of these factors.


RESULTS
Of the 3,212 participants of a Chinese population-based study, 53 subjects (1.7%) with AF were identified. Among the hemostatic factors measured, t-PA antigen (median 12.8 vs 8.1 ng/mL; P < 0.01) and factor VIII activity (median 155% vs 133%; P < 0.05) were significantly higher in AF subjects after adjustment for age and sex. In multivariate analysis, features independently associated with t-PA antigen levels were AF, sex, body mass index, systolic blood pressure, total cholesterol, triglycerides, and left ventricular systolic dysfunction. Features independently associated with factor VIII activity levels included AF, age, and total cholesterol. Levels of both t-PA antigen and factor VIII activity were primarily elevated in AF subjects with predictors of thromboembolism (age > 75 years, hypertension, diabetes, and left ventricular systolic dysfunction), whereas in AF subjects with no thromboembolic predictors, plasma levels of hemostatic factors examined were similar to those without AF.


CONCLUSIONS
We demonstrated that nonvalvular AF was independently associated with increased peripheral levels of t-PA antigen and factor VIII activity. Levels of both hemostatic factors were primarily elevated in AF subjects with predictors of thromboembolism. Whether these hemostatic factors are independently predictive of future thromboembolic events in AF patients requires further investigation.
Wang
T D
TD
Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan, Republic of China.
Chen
W J
WJ
Su
S S
SS
Su
T C
TC
Chen
M F
MF
Liau
C S
CS
Lee
Y T
YT
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000941:Antigens / Q000097:blood; D044466:Asian People; D001281:Atrial Fibrillation / Q000378:metabolism*; D015331:Cohort Studies; D004452:Echocardiography; D005169:Factor VIII / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006490:Hemostatics / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D012737:Sex Factors; D013624:Taiwan / Q000453:epidemiology; D013923:Thromboembolism / Q000453:epidemiology / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000276:immunology* / Q000378:metabolism
D000941:Antigens; D006490:Hemostatics; D005169:Factor VIII; D010959:Tissue Plasminogen Activator