Thrombolytic therapy

Abstract

The accepted role for thrombolytic therapy has until recently been limited because of its complexity and side-effects. It has generally been reserved for use systemically in a limited number of patients with acute, major pulmonary embolism or iliofemoral venous thrombosis, and locally in some patients with acute, peripheral arterial occlusion. Its indications have now been greatly expanded by the confirmation from large, multicentre trials completed within the last year that it is also effective in acute myocardial infarction, with a reduction in acute mortality of 20-25%. Moreover, administration has become greatly simplified as dosage regimens have been standardised and the need for laboratory monitoring eliminated. The standard thrombolytic agent used for nearly 3 decades has been streptokinase but within the last year recombinant, human, tissue-type plasminogen activator (the first 'third generation' thrombolytic agent) has become clinically available. This protein is the body's own chief plasminogen activator and has been produced by recombinant DNA technology. Compared with streptokinase, it appears to be both somewhat more effective and also safer (less bleeding and probably no allergic reactions). Other new thrombolytic agents are also being developed but the cost-effectiveness of the newer agents in relation to streptokinase will be for many the main practical issue.