Functional magnetic stimulation: A new modality for enhancing systemic fibrinolysis

Objective: To investigate whether functional magnetic stimulation (FMS) of the leg muscles could enhance systemic fibrinolysis, Design: A within-subject analysis of systemic fibrinolysis before and after 60 minutes of FMS, Setting: The Functional Magnetic Stimulation and Special Coagulation Labora tories in the Spinal Cord Injury Service at a Veterans Administration healt h care facility, Participants: Twenty healthy volunteers were recruited. The exclusion crite ria were: (1) personal or family history of venous or arterial thrombosis, (2) personal or family history of cardiac arrythmias, (3) current use of me dication, and (4) the presence of a cardiac pacemaker or other metallic imp lants. Main Outcome Measures: Whole blood clot lysis time (WBCLT) and tissue plasm inogen activator (t-PA) antigen determined at baseline and 10 and 60 minute s after FMS, Results: A significant decrease was observed in the mean WBCLT after FMS, T he WBCLT decreased from 17 +/- 1.3h before FMS to 12 +/- 1.0h and 11 +/- 0. 8h at 10 and 60 minutes post-FMS, respectively. The mean t-PA antigen level s did not show a significant change (p =.6701) from pre-FMS (6.7 +/- 0.91ng /mL) to 10min post-FMS (6.8 +/- 0.91ng/mL) and 60min post-FMS (7.0 +/- 1.02 ng/mL). Several. patterns of fibrinolytic response to FMS were observed. Th ey differed in relation to the degree of enhancement, the period at which m aximum enhancement occurred, and the corresponding t-PA antigen levels obse rved. Conclusions: The FMS-induced contractions of the leg muscles enhanced syste mic fibrinolysis ex vivo. The improvement in fibrinolysis occurred immediat ely after FMS and was also observed at 60 minutes post-FMS. FMS appears to produce a sustained enhancement of systemic fibrinolysis that may prove use ful in deep-vein thrombosis prophylaxis, (C) 1999 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine an d Rehabilitation.