Nonacute thrombolytic therapy: An adjunct to coronary angioplasty in patients with large intravascular thrombi

The presence of intravascular thrombus can make coronary angioplasty difficult or impossible to perform. To determine if thrombolytic agents could lyse large, nonacute thrombi, we retrospectively analyzed the angiograms of all 14 patients with unstable angina and large intravascular thrombi (>2 cm in length) who were treated with thrombolytic agents at The Johns Hopkins Hospital between October 1987 and April 1989. Twelve patients were treated with intracoronary streptokinase, and two with intravenous tissue plasminogen activator. Coronary arteriography was repeated immediately after treatment and a mean of 1.6 ± 0.3 days later. The degree of thrombolysis and change in distal vessel perfusion was evaluated. Thrombolysis was graded as considerable if there was >75% resolution of apparent thrombus, and as complete if no stenosis or only a discrete residual stenosis was apparent. Fifty-seven percent of patients ultimately achieved considerable or complete thrombolysis and were able to undergo successful angioplasty. Patients achieving considerable or complete thrombolysis had a 28 ± 7% increase in luminal diameter and demonstrated normalization of initially absent distal porfusion, except for the one patient who had normal distal flow prior to treatment. A maximal thrombolytic effect was evident only at the time of "delayed" angiography in all patients who responded to treatment and underwent both follow-up arteriograms. We conclude that thrombolytic agents can effectively lyse large, nonacute intravascular thrombi, thereby facilitating coronary angioplasty. A full thrombolytic effect does not occur for hours to days after drug administration, and may not become evident unless delayed angiography is performed.