THE IMMEDIATE EFFECT OF STREPTOKINASE ON SERUM LIPOPROTEIN(A) CONCENTRATION AND THE EFFECT OF MYOCARDIAL-INFARCTION ON SERUM LIPOPROTEIN(A), APOLIPOPROTEIN-A1 AND APOLIPOPROTEIN-B, LIPIDS AND C-REACTIVE PROTEIN

Lipoprotein(a) (Lp(a)) has close structural homology with plasminogen and, at least in vitro, may interfere with fibrinolysis. Any changes i n the serum Lp(a) concentration during and following myocardial infarc tion (MI) and whether the serum Lp(a) level is affected by streptokina se (SK) are therefore of interest. Serum Lp(a) levels immediately befo re and 3 h after completion of an intravenous infusion of SK in 39 pat ients with acute MI were not significantly different (median 31.3 mg/d l before and 35.9 mg/dl after). Furthermore, SK added during the serum Lp(a) assay did not affect the result, except at very high concentrat ions of SK (1000 units/ml). Serum Lp(a) and fasting lipids were measur ed daily for 3 days following definite MI in 13 patients and then afte r 14 and 42 days. There was no significant change in serum Lp(a) follo wing MI. In marked contrast, C-reactive protein levels in these patien ts increased steeply immediately following MI. Thus, there was no earl y 'acute-phase response' in serum Lp(a) levels after MI. However, grea ter variation in its concentration was observed at day 14 than at othe r times. Serum cholesterol, apolipoprotein B and apolipoprotein A1 con centrations decreased significantly following MI, whereas a significan t transient increase in serum triglycerides occurred. Forty-two days a fter MI all lipid and lipoprotein values had regained their day 1 leve ls, except for apo Al, which remained depressed.