Low-Molecular-Weight Heparin Versus Unfractionated Heparin in Acute STEMI
Low-Molecular-Weight Heparin Versus Unfractionated Heparin in Acute STEMI
Background Whether low-molecular-weight heparin (LMWH) is superior to unfractionated heparin (UFH) in acute ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI) with drug-eluting stents (DESs) remains unclear.
Methods A total of 3,372 STEMI patients who underwent primary PCI with DESs received either LMWH (n = 1,531 patients, subcutaneous enoxaparin 1 mg/kg, bid for 3–5 days plus reduced dose of UFH [50 U/kg] during PCI) or UFH alone (n = 1,841 patients, intravenous bolus injection of 5,000 U, followed by 24,000 U/d infusion for at least 48 hours). The bleeding events and clinical outcomes during in-hospital and at 8 months were compared.
Results The incidences of major and minor bleeding events were similar between the 2 groups. Multivariable Cox regression analysis showed that LMWH group had lower incidences of cardiac death (adjusted odds ratio [OR] 0.55, 95% CI 0.39–0.77, P < .001), total death (adjusted OR 0.50, 95% CI 0.37–0.68, P < .001), and total major adverse cardiac events (adjusted OR 0.77, 95% CI 0.62–0.95, P = .017) at 8 months as compared with UFH group. Similar results were obtained across different subgroups including different DESs, age, and sex.
Conclusions The LMWH enoxaparin combined with reduced dose of UFH (50 U/kg) administration as an adjunctive antithrombotic therapy in STEMI patients undergoing primary PCI with DESs seems to be safe and efficacious. However, randomized clinical trials are needed to confirm this conclusion.
Drug-eluting stents (DESs) have drastically changed the landscape of percutaneous coronary intervention (PCI) with significant reductions in angiographic restenosis rate and the need for repeated revascularization. Although there is no recommendation from current guidelines, the off-label use of DESs in acute myocardial infarction (AMI) setting has been very common in the real world clinical practice. However, concerns have been raised regarding the safety of DESs in patients with AMI due to the risk of stent thrombosis. Several previous studies have shown that the DESs implantation in AMI was associated with an increased risk for acute and subacute stent thrombosis. Not only the delayed endothelial healing due to the DESs itself but also the altered environment with high thrombin activity and markedly increased platelet reactivity was proven in the early period of AMI in patients undergoing primary PCI.
Although low-molecular-weight heparins (LMWHs) have several well-established potential advantages over unfractionated heparin (UFH) as antithrombin agents, it is still controversial whether the LMWHs can be optimal antithrombin agents in the AMI setting. Moreover, little has been known to date that whether LMWHs are superior or similar to UFH in the off-label use of DESs in AMI. Therefore, the present study was aimed to evaluate the safety and efficacy of LMWH versus UFH specifically in patients with acute ST-segment elevation myocardial infarction (STEMI) who underwent primary PCI with DESs, in Korea Acute Myocardial Infarction Registry (KAMIR).
Abstract and Introduction
Abstract
Background Whether low-molecular-weight heparin (LMWH) is superior to unfractionated heparin (UFH) in acute ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI) with drug-eluting stents (DESs) remains unclear.
Methods A total of 3,372 STEMI patients who underwent primary PCI with DESs received either LMWH (n = 1,531 patients, subcutaneous enoxaparin 1 mg/kg, bid for 3–5 days plus reduced dose of UFH [50 U/kg] during PCI) or UFH alone (n = 1,841 patients, intravenous bolus injection of 5,000 U, followed by 24,000 U/d infusion for at least 48 hours). The bleeding events and clinical outcomes during in-hospital and at 8 months were compared.
Results The incidences of major and minor bleeding events were similar between the 2 groups. Multivariable Cox regression analysis showed that LMWH group had lower incidences of cardiac death (adjusted odds ratio [OR] 0.55, 95% CI 0.39–0.77, P < .001), total death (adjusted OR 0.50, 95% CI 0.37–0.68, P < .001), and total major adverse cardiac events (adjusted OR 0.77, 95% CI 0.62–0.95, P = .017) at 8 months as compared with UFH group. Similar results were obtained across different subgroups including different DESs, age, and sex.
Conclusions The LMWH enoxaparin combined with reduced dose of UFH (50 U/kg) administration as an adjunctive antithrombotic therapy in STEMI patients undergoing primary PCI with DESs seems to be safe and efficacious. However, randomized clinical trials are needed to confirm this conclusion.
Introduction
Drug-eluting stents (DESs) have drastically changed the landscape of percutaneous coronary intervention (PCI) with significant reductions in angiographic restenosis rate and the need for repeated revascularization. Although there is no recommendation from current guidelines, the off-label use of DESs in acute myocardial infarction (AMI) setting has been very common in the real world clinical practice. However, concerns have been raised regarding the safety of DESs in patients with AMI due to the risk of stent thrombosis. Several previous studies have shown that the DESs implantation in AMI was associated with an increased risk for acute and subacute stent thrombosis. Not only the delayed endothelial healing due to the DESs itself but also the altered environment with high thrombin activity and markedly increased platelet reactivity was proven in the early period of AMI in patients undergoing primary PCI.
Although low-molecular-weight heparins (LMWHs) have several well-established potential advantages over unfractionated heparin (UFH) as antithrombin agents, it is still controversial whether the LMWHs can be optimal antithrombin agents in the AMI setting. Moreover, little has been known to date that whether LMWHs are superior or similar to UFH in the off-label use of DESs in AMI. Therefore, the present study was aimed to evaluate the safety and efficacy of LMWH versus UFH specifically in patients with acute ST-segment elevation myocardial infarction (STEMI) who underwent primary PCI with DESs, in Korea Acute Myocardial Infarction Registry (KAMIR).
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