A prospective evaluation of atherosclerotic risk factors and hypercoagulability in young adults with premature lower extremity atherosclerosis

Purpose: Fifty-one consecutive patients with premature lower extremity atherosclerosis were prospectively evaluated for atherogenic risk factors and primary or acquired hypercoagulability, which might contribute to early ischemia and revascularization failure. Methods: Laboratory tests included plasma assays of (1) natural anticoagulants (NAC), lipoprotein (a) (Lp[a]), and anticardiolipin antibodies, and (2) fibrinolytic activators and inhibitors at baseline and stimulated after 20 minutes of upper extremity venous occlusion. Results: Forty-six (90%) of these 51 patients had laboratory abnormalities. One or more NAC deficiencies were found in 15 (30%) patients and included antithrombin III (n=5), protein C (n=8), protein S (n=4), and heparin cofactor II (n=2). Hypofibrinolysis was identified as a deficiency of stimulated tissue plasminogen activator in 22 (45%) patients and elevated plasminogen activator inhibitor-1 (PAI-1) in 29 (59%). Elevated Lp(a) was found in 43 (86%) patients. Five (10%) patients had anticardiolipin antibodies. Ten patients had combined NAC deficiency and hypofibrinolysis. Five (10%) patients had no abnormality. NAC deficiencies, especially protein C deficiency, were associated with acute ischemia ( p p p p p p p Conclusions: These data strongly support the hypothesis that the convergence of atherogenic risk factors and hypercoagulability play an important role in early ischemia and poor results reported for lower extremity vascular procedures in young adults.