Plasmin-α2-antiplasmin complex

Plasmin-α2-antiplasmin complex (PAP) is a 1:1 irreversibly formed inactive complex of the enzyme plasmin and its inhibitor α₂-antiplasmin.^[1][2][3][4] It is a marker of the activity of the fibrinolytic system and a marker of net activation of fibrinolysis.^[5][6] Excess of the PAP complex can lead to abnormal bleeding due to enhanced clot lysis leading to a hyperfibrinolytic state.^[7] The PAP complex can be useful in the determining the prognosis of a clot, but it is limited because it is measured using ELISA. ^[7]

Various uses of PAP as a marker

Low PAP levels can be indicative that patients with a past myocardial infarction have a higher risk of another coronary event within the following 2 years.^[8] Specifically, when PAP levels are less than 100 ng/ml there was an associated 2.2-fold increase in the risk for another coronary event.^[8] When the cut off is less than 100 there is a 5-fold increase in risk.^[8] This marker is useful in the clinical setting as a potential way to identify patients that are at higher risk. However, there was not a significant difference between the PAP levels of patients that were on anticoagulative therapy versus patients that were not on anticoagulative therapy.^[8] PAP is an independent marker for the risk of another coronary event post-MI, as the risk analysis remained constant when confounding factors (e.g. age, sex, BMI, smoking history, etc.) were controlled for.^[8]

PAP levels are increased with pregnancy^[9] and by ethinylestradiol-containing combined birth control pills.^[5] Conversely, levels of PAP do not appear to be affected with menopausal hormone therapy.^[6] PAP levels have been reported to be elevated in men with prostate cancer.^[10] PAP can be useful in predicting if a patient is at high risk for a perioperative pulmonary embolism.^[7]