Thrombolytic therapy: enhancement by platelet and platelet-derived mediator antagonists.

Coronary thrombolysis is the treatment of choice for patients with acute Q wave myocardial infarcts who have no contraindication to such therapy. However, the time required for thrombolysis to occur and the possibility of reocclusion of the infarct-related artery following thrombolytic therapy are problems. The time required for thrombolysis to occur with currently available agents ranges from 40 to 60 minutes and the frequency of reocclusion of the infarct-related artery after tissue-type plasminogen activator is 10 to 20%. We review experimental studies and clinical evaluations in which attempts have been made to develop adjunctive therapies that when coupled with available thrombolytic interventions might shorten the time to thrombolysis and delay or prevent reocclusion. From the studies done to date, it appears that a combination of thromboxane synthesis inhibitor and receptor antagonist with a serotonin receptor antagonist and heparin shortens the time to thrombolysis and delays or prevents coronary artery reocclusion in experimental canine models with copper coil-induced coronary artery thrombi. A monoclonal antibody to the platelet glycoprotein IIb/IIIa receptor given with tissue plasminogen activator and heparin also shortens the time to thrombolysis and delays or prevents reocclusion in experimental canine models. A mutant tissue plasminogen activator with a glycosylation defect and prolonged systemic clearance delays coronary artery reocclusion following lysis of three-hours coronary thrombi, induced by a copper coil. Thrombin inhibitors, including heparin, and synthetic inhibitors, given with tissue plasminogen activator and aspirin, appear to shorten the time to thrombolysis and delay or prevent coronary artery reocclusion in experimental canine models.(ABSTRACT TRUNCATED AT 250 WORDS)