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Serial thrombolysis-related changes after thrombolytic therapy with TPA in patients with acute myocardial infarction
1Division of Hematology & Cardiology, Veterans General Hospital, Taipei, Taiwan, R.O.C.
Insights
Recombinant tissue plasminogen activator (tPA) therapy for myocardial infarction alters hemostasis, causing temporary changes in coagulation factors. Elevated FDP levels may predict bleeding risk, necessitating close patient monitoring.
Area of Science:
- Cardiology
- Hematology
- Thrombolytic Therapy
Background:
- Acute myocardial infarction (AMI) requires prompt reperfusion therapy.
- Recombinant tissue plasminogen activator (tPA) is a key thrombolytic agent for AMI.
- Understanding tPA's impact on hemostasis is crucial for patient management.
Purpose of the Study:
- To evaluate hemostatic changes following tPA administration in AMI patients.
- To identify potential predictors of bleeding complications after thrombolysis.
- To assess the duration of tPA-induced coagulation alterations.
Main Methods:
- Twenty-nine AMI patients received tPA within 6 hours of symptom onset.
- Serial blood samples were collected pre- and post-tPA (up to 48 hours).
- Coagulation parameters including FDP, fibrinogen, PT, APTT, and lysis times were measured.
Main Results:
- tPA caused significant transient decreases in plasminogen, fibrinogen, and alpha 2-antiplasmin.
- Increases in FDP, D-dimer, PT, APTT, and reptilase time were observed post-tPA.
- Elevated FDP levels were associated with an increased risk of bleeding complications.
- Hemostatic changes generally normalized within 24 hours, but bleeding risk persisted longer.
Conclusions:
- tPA therapy induces predictable, temporary hemostatic changes in AMI patients.
- Markedly elevated FDP is a potential marker for bleeding risk.
- Close monitoring of coagulation and clinical signs is essential for 48 hours post-tPA treatment.
Abstract:
Twenty-nine patients with acute myocardial infarction were given recombinant tissue plasminogen activator (tPA) within 6 hr after onset of chest pain (mean: 3.2 hr) with a total dose of 100mg iv drip given within 3hr for thrombolytic therapy. Serial determinations of total FDP, FDP D-Dimer (specific for FbDP), fibrinogen (Fg), PT, APTT, reptilase time (RT), plasminogen, alpha 2-antiplasmin (AAP), euglobulin lysis time (ELT) and antithrombin III (ATIII) were performed before and 1, 2, 4, 6, 12, 24, 48 hr after initiation of tPA injection in the 29 patients in order to evaluate the hemostatic changes after thrombolytic therapy. Decreases of plasminogen, Fg, AAP & ELT were found from 1 hr after therapy and persisted to 24, 12, 24 & 12 hr, respectively, with the maximum decrease usually between 1-4 hr. Increases of FDP, FDP D-dimer, PT, APTT & RT were found from 1, 1, 2, 1 & 1 hr after therapy, respectively, and sustained to 24, 12, 12, 24 & 12 hr, respectively, with maximum increases between 1-4 hr. No significant changes of ATIII were noted during the 48-hr study-period. 4 of these 29 patients (13.79%) had the complication of localized bleeding, 1 of them needed 1 unit of packed red blood cell transfusion. All thrombolysis-related changes recovered within 24 hr after tPA therapy. No parameter we have studied so far could be used for the prediction of the possibility of coronary patency after tPA therapy. But markedly elevated FDP was found to be associated with high risk of bleeding complication. As the coagulation changes persist for 24 hr or longer, careful monitoring of the coagulation tests and close observation of clinical bleeding signs up to 48 hr are necessary in patients treated with tPA.