INCREASED TISSUE-PLASMINOGEN ACTIVATOR LEVELS IN PATIENTS WITH NONVALVULAR ATRIAL-FIBRILLATION

Objective: To determine whether plasma tissue plasminogen activator (t PA) levels (a) are higher in patients with nonvalvular atrial fibrilla tion (NVAF) than in control subjects in sinus rhythm; (b) differ betwe en NVAF patients with and without a history of an embolic event (trans ient ischemic attack or embolic stroke); and (c) differ in control sub jects with and without a history of thrombotic stroke. Design: Cross-s ectional study. Setting: Internal medicine outpatient group practice a nd anticoagulation clinic in 2 teaching hospitals. Patients: Seventy-f our NVAF patients (24 with and 50 without a history of an embolic even t), separated into 3 groups: no prior embolic event and no warfarin us e (group 1), no prior embolic event and warfarin use (group 2), and pr ior embolic event and warfarin use (group 3). Forty control subjects i n sinus rhythm (29 without and 11 with prior thrombotic stroke). Outco me measures: Plasma tPA levels. Results: The age-adjusted mean tPA lev els exceeded the upper limit of normal in all 3 NVAF groups but not in the control groups. The NVAF patients had significantly higher mean t PA levels than the control subjects (p = 0.015). The levels did not di ffer significantly between the NVAF patients with a history of an embo lic event and those without such a history. The control subjects with a history of thrombotic stroke had significantly higher mean tPA level s than the other control subjects (p = 0.03). Conclusions: NVAF patien ts, regardless of their history of embolic events, and control patient s with a history of thrombotic stroke have higher tPA levels than subj ects in sinus rhythm without a history of stroke. A prospective, longi tudinal study involving NVAF patients is required to determine whether high baseline tPA levels are associated with, and perhaps causally re lated to, an increased risk of stroke.