Low-molecular-weight heparin during percutaneous coronary interventions: Rationale, results, and recommendations

Macroscopic thrombus formation on angioplasty equipment following antithrombin therapy with enoxaparin

Increasing evidence suggests that treatment with the low molecular weight heparin enoxaparin during percutaneous coronary intervention (PCI) is safe and effective. We evaluated the incidence and consequences of periprocedural macroscopic thrombus formation on PCI equipment following antithrombin therapy with enoxaparin. Between April 2003 and December 2004, all patients undergoing cardiac catheterization following antithrombin therapy with enoxaparin were evaluated. All patients had blood sampled at the onset of procedure for subsequent measurement of anti-factor-Xa levels. Of the 4,504 patients who underwent PCI during this period, in 122 (3%) the procedure was performed within 8 hr of treatment with subcutaneous enoxaparin and no additional unfractionated heparin (UFH) was used periprocedurally. Of these, macroscopic thrombus was observed on PCI equipment in 6 patients (5%) necessitating withdrawal of all catheters and wires. All patients had therapeutic anti-factor-Xa levels at the time of PCI, and had been treated with double antiplatelet therapy with aspirin and clopidogrel. No periprocedural thrombus was observed in 356 patients who were >12 hr of the last dose of enoxaparin and received UFH at the time of PCI. Following observation of thrombus, additional anticoagulation with UFH resulted in significant epistaxis in one patient. In another patient, the procedure was complicated by distal coronary embolization. Percutaneous coronary intervention following antithrombin therapy with enoxaparin is associated with a 5% incidence of macroscopic thrombus formation on PCI equipment. The necessity for subsequent exchange of all equipment and/or the need for additional anticoagulation may have disastrous consequences for the patient. Our findings suggest that the safety of antithrombin therapy with low molecular weight heparin during PCI requires further evaluation.

Newer Pharmacotherapy in Patients Undergoing Percutaneous Coronary Interventions: A Guide for Pharmacists and Other Health Care Professionals

Significant advances in pharmacotherapy for patients undergoing percutaneous coronary intervention (PCI) have occurred during the past decade, including the introduction and approval of new antithrombin and antiplatelet therapies, as well as modifications in dosing, administration, and/or duration of older pharmacotherapy regimens. Also, off-label (i.e., not approved by the United States Food and Drug Administration) use of certain agents has become common. Given the novel nature of these agents and the nuances of therapy, the pharmacist and other health care professionals should play an integral role in collaboration with interventional cardiologists in development of hospital protocols, determination of appropriate agent selection, assessment of patient renal function and hematologic status, dosing, and monitoring for adverse effects. In this guide, the newer antiplatelet and antithrombin drugs that may be used during PCI are reviewed, and recommendations regarding the proper administration of these agents are provided.

Failure of enoxaparin during coronary stenting: a case report

A 90-year-old male underwent coronary stenting following a bout of coronary insufficiency. Coronary stenting was performed 6 hr following the last dose of low-molecular-weight heparin but was complicated by extensive intrastent clot formation. Low-molecular-weight heparin in the absence of a glycoprotein IIb/IIIa receptor blocker may be insufficient during percutaneous coronary intervention.