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Coronary heart disease, unstable angina, PTCA: new indications for low molecular weight heparins?
1International Institute of Thrombosis and Vascular Diseases, Frankfurt am Main, Germany.
Insights
Low molecular weight heparins (LMWHs) show promise in managing unstable angina and preventing reocclusions after percutaneous coronary intervention (PCI). Further research into long-term LMWH treatment may reduce restenosis rates in coronary heart disease patients.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Unstable angina in coronary heart disease (CHD) patients carries a high risk of myocardial infarction (MI) and death.
- Partial thrombotic occlusions are a major cause of unstable angina, potentially leading to MI.
- Unfractionated heparin (UFH) reduces anginal attacks but not MI, PTCA, or death rates within one month.
Purpose of the Study:
- To evaluate the efficacy of low molecular weight heparins (LMWHs) in improving outcomes for unstable angina patients.
- To assess the role of LMWHs in preventing early reocclusions and late restenosis after percutaneous coronary intervention (PCI).
Main Methods:
- Review of clinical studies and trials investigating LMWH treatment in unstable angina and post-PCI patients.
- Comparison of LMWH efficacy against UFH for preventing reocclusions and restenosis.
Main Results:
- LMWHs may improve outcomes in unstable angina patients with prolonged treatment.
- LMWHs show potential for preventing early reocclusions after PCI, possibly more effectively than UFH.
- Short-term LMWH treatment did not prevent late restenosis; ongoing trials explore long-term effects.
Conclusions:
- Prolonged LMWH treatment may enhance outcomes in unstable angina.
- Long-term LMWH therapy, potentially combined with platelet inhibitors, could reduce late restenosis rates after PCI.
Abstract:
Unstable angina in patients with coronary heart disease carries a high risk of myocardial infarction (MI) and death. Partial thrombotic occlusions of coronary arteries are a major causal factor in the development of unstable angina and consecutive thrombotic occlusions may lead to MI. Treatment with unfractionated heparin (UFH) has been shown to significantly reduce the frequency of anginal attacks, but not to affect the frequency of MI, PTCA and death within one month. Prolonged treatment with low molecular weight heparins (LMWHs) may improve the outcome in patients with unstable angina. New clinical studies in this area seem promising. In the prevention of early reocclusions after PTCA LMWHs may be more effective than UFH. Late restenosis after PTCA within 6 months occurs in 25-35% of patients. To date, no effective prophylaxis exists. In a recent trial, short-term treatment with a LMWH had no preventive effect on late restenoses. Ongoing trials with long-term treatment may lead to better results. In the near future long-term treatment, up to six months, with a LMWH alone or in combination with a platelet function inhibitor, possibly with reduced doses of both drugs, may reduce the frequency of restenosis.