Search

Patients with refractory angina pectoris and end-stage coronary artery disease represent an increasing clinical problem. Numbers of these patients will increase in the future for improved survival due to effective secondary prevention of coronary artery disease. Next to the evaluation of clinical symptoms non-invasive objective parameters of myocardial ischemia are of major relevance before initiation of alternative treatment modalities and for verification of antiischemic effectiveness. Based on our own experience it can be shown that in these patients testing which is mainly based on the patients physical exercise capacity is only of limited value due to the early occurrence of clinical symptoms. Furthermore diffuse perfusion abnormalities reduce the sensitivity of electrocardiographic and scintigraphic detection of ischemic changes. In contrast indirect measures of ischemia relating to the systolic or diastolic function of the left ventricle like doppler-echocardiography and radionuclide ventriculography seem to be promising approaches. This is confirmed by the results from the application of long-term intermittent urokinase therapy. Long-term intermittent urokinase therapy leads to an absolute enhancement of myocardial perfusion, which makes this approach superior to other medical interventions which are mainly based on a reduction of cardiac work-load.

Despite progress in the invasive revascularization procedures and even though conventional antianginal treatment has improved the quality of life in patients with symptomatic coronary artery disease considerably, an increasing number of patients suffers from end-stage coronary artery disease and refractory angina pectoris. For these refractory patients long-term intermittent urokinase therapy was developed as an antithrombotic intervention, which is based on its capacity to enhance thrombolysis and blood rheology, and may possibly lead to plaque regression. The coronary syndrome of refractory angina pectoris is characterized by a mismatch of severe coronary insufficiency and a relatively large amount of viable myocardium as indicated by an only moderately impaired left ventricular function. Prior to initiation of long-term intermittent urokinase therapy all potential measures to improve myocardial perfusion have to be considered in each patient. These supportive measures include rigorous reduction of LDL-cholesterol, which has proven antiischemic properties due to an improved endothelial function of epicardial conductance vessels possibly resulting in an antianginal effect. Apart from the proven antiischemic properties of long-term intermittent urokinase therapy in patients with refractory angina pectoris, objective signs of ischemic myocardial heart failure improve. Follow-up studies demonstrated a significant increase of left ventricular ejection fraction as evaluated with multi-gated blood pool analysis. Furthermore, left ventricular diastolic function normalized after a treatment period of 12 weeks. As the clinical effects last well beyond the actual treatment period and as they are accompanied by a remarkable increase in the quality of life, a complex approach as this one is justified in this highly symptomatic patient group.

Long-term intermittent urokinase therapy has been developed for patients with severe coronary artery disease and refractory angina pectoris. This therapeutic approach is predominantly effective at the microcirculatory level based on a combination of rheologic and fibrinolytic effects; furthermore, plaque regression seems to be a possible mechanism. Patients with refractory angina pectoris are characterized by severe coronary artery disease without a therapeutic option for conventional revascularization procedures, only slight impairment of left ventricular systolic function and hyperfibrinogenemia, which results in further enhancement of myocardial ischemia due to microcirculatory impairment of blood flow. In this article data on the anti-ischemic effectiveness as well as first results on the impact of this therapeutic approach on hemodynamics are described. A dose-response study, which compared 3 x 50,000 IU with 3 x 500,000 IU urokinase three times a week over a treatment period of 12 weeks demonstrated subjective as well as objective antiischemic effectiveness. Only patients who were treated with 500,000 IU per injection achieved marked increases in exercise capacity, while some patients in the low-dose group presented even with a deterioration of exercise performance. First hemodynamic studies could not show marked changes of systolic parameters, either at rest or during exercise. But a decrease of pulmonary capillary wedge pressure at rest after treatment with 500,000 IU per injection indicates an improvement of diastolic function as a result of enhanced myocardial perfusion. Echocardiographic measurements of transmitral Doppler flow in 21 patients with end-stage coronary artery disease demonstrated normalization of early and late diastolic filling rates in most cases. These changes were accompanied by a reduction of clinical signs of heart failure. Long-term intermittent urokinase therapy is a valuable approach as it not only improves quality of life during the actual treatment period but by the persistence of therapeutic effects following the cessation of therapy.

Interventions that modify lipid metabolism and blood coagulation have been shown to favourably influence the natural course of coronary artery disease in terms of the primary prevention and treatment of acute cardiovascular events. Various findings suggest that such interventions may also preserve and enhance myocardial perfusion in the chronic stage of the disease. Long-term intermittent urokinase therapy was developed for patients with end-stage coronary artery disease and refractory angina pectoris. A dose of 500,000 IU of urokinase given intravenously as a bolus three times a week for of 12 weeks reduced symptoms by 70% and was accompanied by objective improvements in myocardial perfusion and an increase of ergometric exercise capacity. The possible therapeutic mechanisms of long-term intermittent urokinase therapy-improvement of rheological blood properties mediated by fibrinogen reduction, thrombolysis of non-occlusive subclinical thrombi, and regression of atherosclerotic plaques-are discussed in the context of other antithrombotic approaches.

Symptomatic end-stage arterial disease in coronary artery or peripheral arterial occlusive disease represents an increasing clinical problem as cardiovascular mortality in these patient groups has declined due to improved secondary prevention. While in peripheral arterial occlusive disease amputation with subsequent life-long physical disability is the major problem, patients with end-stage coronary artery disease and refractory angina pectoris repeatedly report to the emergency ward with the clinical symptoms of unstable coronary syndromes, but myocardial infarction is generally ruled out. For these patients long-term intermittent urokinase therapy has been developed as an alternative treatment modality. Potential mechanisms for clinical effectiveness include improvement of rheological blood properties, thrombolysis of non-occluding arterial thrombi and possibly plaque regression. In coronary artery disease urokinase is applied as an intravenous bolus injection of 500,000 IU urokinase three times a week over a period of 12 weeks. This leads to a marked reduction of fibrinogen by about 35% and of clinical symptoms by around 70% accompanied by a reduction of exercise-induced myocardial ischemia. In observational studies in patients with peripheral arterial occlusive disease injections of 500,000 IU of urokinase were usually given daily for a shorter time period of three to four weeks with a clinical success rate, defined as a cessation or marked reduction of rest pain and/or salvage of a limb, of around 50%. Given the state of critical ischemia in both entities of atherosclerotic disease, long-term intermittent urokinase therapy represents a promising antiischemic approach. In particular in patients with peripheral arterial occlusive disease randomized controlled trials with prolonged treatment periods, which are likely to improve clinical results, are warranted.