Background: Intracoronary (i.c.) thrombus is a frequent finding in patients (pts) 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.
Methods: To test this hypothesis we studied 13 pts with UA refractory to maximal medical treatment and ST segment shift in the anterior leads. Coronary angiography was performed and great cardiac vein blood flow (GCVF; thermodilution) was measured in all pts within 48 hours (mean 29 +/- 13 hrs) from the last chest pain episode. Following angiography, pts received i.v. wrokinase (UK: 1 million IU/30 min); aortic pressure and GCVF were measured before and every 10 min during drug infusion, for a total time of 90 min.
Results: At baseline angiography 5/13 pts (Group 1) had evidence of i.c. thrombus (intraluminal filling defect or thrombotic subocclusion) in the ischemia-related left coronary artery, whereas 8 pts (Group 2) did not. Overall, coronary hemodynamics did not change significantly following drug administration: GCVF was 103 +/- 65 on baseline and 117 +/- 68 ml. min after UK; p > 0.05. Conversely, group analysis showed that UK increased GCVF and decreased anterior coronary resistances (mean aortic pressure/GCVF) in Group 1 (respectively from 86 +/- 33 to 114 +/- 41 ml. min: p < 0.005; and from 1.37 +/- 0.68 to 1.01 +/- 0.44 mmHg/ml. min: p < 0.05) but not in Group 2 (both: p > 0.05), despite similar effects on aortic pressure.
Conclusions: Fibrinolytic treatment can be of therapeutic value in UA; UK has shown to increase regional coronary blood flow in selected pts presenting with refractory angina 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.