Problems in the management of pulmonary embolism

Pulmonary angiography remains the definitive technique for the diagnosis of pulmonary embolism but in practice is not universally available. Many patients can be managed quite safely without it but it should be employed without hesitation in certain problem patients. Thrombolytic treatment probably improves survival in patients who suffer an acute massive pulmonary embolus but it should not be used unless the embolus causes considerable haemodynamic disturbance. The best thrombolytic agent and the best administration regime remain uncertain. At present the simplest and cheapest effective regime for most patients is provided by a twelve to 24 hour infusion of streptokinase although in the future the new "clot-specific" agents such as rTPA and APSAC may be shown to be safer and/or more effective. In nearly all situations other than acute massive pulmonary embolism thrombolytic treatment is more expensive, slightly more dangerous but no more effective than heparin. When heparin is given there seems little to choose between intermittent injection and continuous infusion. Although there is no scientific proof it is logical to continue heparin for seven days since this is the time taken for any residual clot in the venous system to become firmly adherent to the vessel wall. The value of coagulation tests as a guide to adjustment of heparin dosage is not proved and seems to need reassessment in the light of the recent discovery of large diurnal variations in heparin activity.(ABSTRACT TRUNCATED AT 250 WORDS)