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Effects of thrombolytic therapy in unstable angina: clinical and angiographic results
C de Zwaan1, F W Bar, J H Janssen
1Department of Cardiology, University of Limburg, Academic Hospital, Maastricht, The Netherlands.
Insights
Unstable angina often involves coronary thrombosis. Thrombolytic therapy showed some success in reducing stenosis, but its clinical effectiveness requires further study in placebo-controlled trials.
Area of Science:
- Cardiology
- Interventional Cardiology
- Thrombosis Research
Background:
- Unstable angina is frequently associated with intracoronary thrombus formation.
- The efficacy of thrombolytic therapy in unstable angina remains incompletely understood.
Purpose of the Study:
- To investigate the incidence of intracoronary thrombus in unstable angina patients.
- To evaluate the effects of thrombolytic therapy on coronary stenosis and outcomes.
Main Methods:
- Retrospective analysis of 21 patients receiving intracoronary streptokinase.
- Prospective study of 20 patients receiving intravenous recombinant tissue-type plasminogen activator (rt-PA).
- Coronary angiography performed before and after thrombolytic treatment.
Main Results:
- A decrease in coronary stenosis severity was observed in approximately 50% of patients in both treatment groups.
- Thrombus burden decreased post-treatment in 16 out of 41 patients.
- No significant differences in ischemic symptoms or need for intervention were noted between responders and non-responders.
Conclusions:
- Unstable angina exhibits a high incidence of coronary thrombosis.
- Current data suggest thrombolytic therapy can reduce stenosis but does not permit assessment of clinical efficacy.
- Further placebo-controlled studies are needed to determine the risk/benefit ratio of thrombolytic therapy in unstable angina.
Abstract:
The incidence of intracoronary thrombus and the effects of thrombolytic therapy were studied in 41 patients with unstable angina. All patients underwent coronary angiography 2 to 69 h (mean 19) after their last attack of chest pain. Immediately after angiography, 21 patients received intracoronary streptokinase (250,000 IU in 45 min) and were retrospectively analyzed. Twenty patients received intravenous recombinant tissue-type plasminogen activator (rt-PA) (100 mg in 3 h) and were involved in a prospective study. Eleven of the 21 patients from the streptokinase group and 11 of the 20 patients from the rt-PA group showed a decrease in the severity of the coronary stenosis on repeat angiography 1 day later. A decrease in coronary obstruction was primarily observed in 10 of 13 patients with a complete stenosis and in 6 of 9 patients with a subtotal stenosis and markedly diminished coronary flow. Improvement in coronary anatomy was not determined by the clinical characteristics of the patients. Twenty-eight of the 41 patients had angiographic evidence of intracoronary thrombus formation before and 16 had such evidence after thrombolytic treatment. Nine patients developed a small increase in serum cardiac enzymes before or during treatment. Ischemic symptoms and the incidence of surgical or angioplastic intervention were not different in patients with or without a reduction in coronary artery stenosis after fibrinolytic therapy. These observations suggest a high incidence of coronary thrombosis in patients with unstable angina. The data do not permit assessment of the clinical therapeutic efficacy of thrombolytic therapy. Better risk stratification and placebo-controlled prospective studies are required to obtain information on the risk/benefit ratio of such therapy in unstable angina.