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Coronary hemodynamic effects of systemic thrombolysis in patients with unstable angina
A Pozzati1, R Bugiardini, F Ottani
1Institute of Patologia Medica and C.C.U., University of Bologna, Italy.
Insights
Intracoronary thrombus in unstable angina patients can be treated with urokinase (UK). This thrombolytic therapy improved coronary blood flow in patients with visible thrombus, suggesting its benefit in specific unstable angina cases.
Area of Science:
- Cardiology
- Interventional Cardiology
- Thrombosis
Background:
- Intracoronary thrombus is common in unstable angina (UA).
- Thrombolytic treatment may improve blood flow to ischemic areas by resolving thrombus.
Purpose of the Study:
- To investigate the effect of urokinase (UK) on coronary blood flow in patients with active UA and evidence of intracoronary thrombus.
Main Methods:
- 13 patients with active UA underwent coronary angiography and great cardiac vein blood flow (GCVF) measurement.
- Patients received intravenous urokinase (1,000,000 IU).
- GCVF and aortic pressure were measured before and after UK infusion.
Main Results:
- 5 patients had intracoronary thrombus (Group 1); 8 did not (Group 2).
- UK significantly increased GCVF and decreased coronary resistance in Group 1 (p<0.05).
- No significant changes were observed in Group 2.
Conclusions:
- Urokinase increases regional coronary blood flow in unstable angina patients with confirmed intracoronary thrombus.
- Angiographic findings may explain varied results in thrombolysis trials for UA.
Abstract:
Intracoronary (i.c.) thrombus is a frequent finding in patients with unstable angina (UA). Accordingly, thrombolytic treatment could be beneficial, as resolution of thrombus might result in increased delivery of blood flow to the ischemic regions. To test this hypothesis, we studied 13 patients with active UA and ST-segment shift in the anterior leads. Coronary angiography was performed and great cardiac vein blood flow (GCVF; thermodilution) was measured in all patients 25 +/- 14 h after the last chest pain episode. Following angiography, patients received i.v. urokinase (UK: 1,000,000 IU/30 min); aortic pressure and GCVF were measured before and every 10 min following drug infusion, for a total time of 90 min. At baseline angiography, 5 of 13 patients (Group 1) had evidence of i.c. thrombus (intraluminal filling defect or thrombotic subocclusion) in the ischemia-related left coronary artery, whereas 8 patients (Group 2) did not. Group analysis showed that UK increased GCVF and decreased anterior coronary resistance in Group 1 (respectively, from 86 +/- 33 to 114 +/- 41 ml/min: p less than 0.005; and from 1.37 +/- 0.68 to 1.01 +/- 0.44 mmHg/ml/min: p less than 0.05) but not in Group 2 (both: p = NS). In conclusion, UK has been shown to increase regional coronary blood flow in selected patients presenting with active UA, as well as evidence of i.c. thrombus at early angiography. Heterogeneity of angiographic findings could explain controversies in trials dealing with thrombolysis in UA.