Enoxaparin for unstable angina and ancrod for cardiac surgery following heparin allergy

Predictive factors for effectiveness and safety of enoxaparin for total knee arthroplasty in aged Japanese patients: a retrospective review

BACKGROUND

The aims of this study were to investigate predictive factors involved in effectiveness and safety of enoxaparin for prevention of postoperative venous thromboembolism in aged Japanese total knee arthroplasty (TKA) patients.

METHODS

Japanese patients over 65 years old who were administered enoxaparin for TKA were enrolled in this study. Their medical records were retrospectively reviewed. Data were corrected at the Izumi Regional Medical Center, from September 2009 to March 2014. Patients were stratified into groups according to whether enoxaparin was effective (no deep vein thrombosis event up to postoperative day 7) or not, and whether they had an adverse drug event (ADE) or not.

RESULTS

A total of 128 patients were included in this study. One hundred five (82.0%) patients were in the effective group and 20 (15.6%) in the adverse drug event (ADE) group. Anemia (13 patients), abnormalities in liver function tests (4 patients), clinically relevant non-major bleeding (4 patients) and urticaria (1 patient) were observed as ADEs. Multivariate logistic regression analysis showed that the serum total protein level at postoperative day 1 (POD1, before enoxaparin administration), was associated with effectiveness of enoxaparin, while the serum total protein and hemoglobin level at POD1 were involved in ADE caused by enoxaparin.

CONCLUSIONS

Although further large scale studies will be warranted, our results suggest that serum total protein level just before enoxaparin treatment for TKA relates to the effectiveness and safety of enoxaparin in a Japanese aged population. In addition, the results indicate that the development of anemia should be carefully monitored during enoxaparin treatment for TKA, particularly in patients with lower levels of serum hemoglobin before treatment.

Argatroban for anticoagulation during cardiopulmonary bypass in an infant

Heparin induced thrombocytopenia (HIT) is a rare, but potentially life-threatening complication of heparin therapy. In patients with HIT, alternative means of anticoagulation are necessary. The authors present an infant with HIT who required anticoagulation during cardiopulmonary bypass for tricuspid valve excision in the treatment of bacterial endocarditis. The direct thrombin inhibitor, argatroban, was successfully used. Previous reports regarding the use of argatroban and other nonheparin anticoagulants for anticoagulation are reviewed and suggestions regarding argatroban dosing in infants are presented.

Heparin-induced thrombocytopenia in the pediatric intensive care unit population

OBJECTIVES

To report the occurrence of heparin-induced thrombocytopenia (HIT), discuss its pathophysiology, and outline an approach to management in the pediatric intensive care unit (ICU) patient.

DESIGN

Retrospective case reports.

SETTING

Pediatric ICU in a tertiary-care center.

PATIENTS AND RESULTS

Two pediatric ICU patients (2 and 6 mos of age) who developed HIT in the pediatric ICU. One was receiving heparin as a flush solution through a central line and the other had full heparinization during cardiopulmonary bypass. Both had received heparin during their neonatal course and developed thrombocytopenia; however, HIT was not considered as a possible diagnosis. HIT was diagnosed using a heparin-induced platelet aggregation study. The thrombocytopenia resolved with the cessation of heparin administration. One of the patients developed a deep vein thrombosis around a femoral venous catheter.

CONCLUSION

Although well described in the adult literature, there have been a limited number of reports of HIT in pediatric-aged patients. Given its potential for morbidity, HIT should be considered in the differential diagnosis of thrombocytopenia in the pediatric ICU patient.

Cardiopulmonary bypass in humans: bypassing unfractionated heparin

Seven anticoagulants besides unfractionated heparin have been used for human cardiopulmonary bypass (CPB), mainly in patients with heparin-induced thrombocytopenia. The collective experience with these alternative anticoagulants provides a perspective on current efforts aimed at improving CPB anticoagulation. Unfortunately, each alternative currently lacks a standard dosing schedule and a reliable method of monitoring the adequacy of its anticoagulant effect during CPB. Most also lack proven antidotes. Thus, unfractionated heparin remains the anticoagulant of choice for standard CPB.

Delayed-type hypersensitivity skin reactions caused by subcutaneous unfractionated and low-molecular-weight heparins: tolerance of a new recombinant hirudin

BACKGROUND

Eczema-like infiltrated plaques at subcutaneous heparin injection sites are well-documented side effects of these anticoagulants. However, surgical interventions may be problematic if heparin is urgently needed in these patients.

OBJECTIVE

The aims of this study were to perform extensive allergy skin testing in 24 patients, including a pregnant woman in whom subcutaneous infiltrated plaques developed after subcutaneous heparin injections, and to find safe therapeutic alternatives for this group of patients.

METHODS

Patch, intradermal, and subcutaneous tests were performed with a panel of unfractionated heparins (UFHs), low-molecular-weight heparins (LMWHs), and heparinoids. Since 1997, we have also been performing allergy studies in 8 patients with lepirudin, a new recombinant heparinoid; tolerance of lepirudin was investigated by means of subcutaneous and intravenous injections. The allergy investigations in the pregnant woman were limited to patch tests with heparins and intradermal and subcutaneous tests with pentosanpolysulfate, which are not contraindicated during pregnancy.

RESULTS

In our study population 19 of 23 patients were sensitized to all the UFHs and LMWHs tested when intracutaneous and subcutaneous test results were read at up to 96 hours. LMWH was found to be a possible substitute in 4 patients. Five patients were also sensitized to the heparinoid pentosanpolysulfate. Sensitization to the heparinoid danaparoid was observed in 12 of the 13 patients who were tested with this substance. The administration of an intravenous bolus containing a therapeutic dose of lepirudin after negative subcutaneous provocation was tolerated without any side effects in all 8 patients. The pregnant woman was sensitized to LMWH but tolerated subcutaneous pentosanpolysulfate without any side effects.

CONCLUSION

Extensive allergy skin testing should be performed to find safe alternatives. With few exceptions, all patients react to both UFHs and LMWHs, as well as to danaparoid. The subcutaneous provocation test is the most reliable diagnostic measure. Intravenous lepirudin, and in some cases subcutaneous pentosanpolysulfate, appears to be a safe alternative in patients with eczema-like infiltrated plaques at subcutaneous heparin-injection sites.

New therapies for unstable angina and non-Q-wave myocardial infarction: recent clinical trials

Thrombosis after the rupture of an atherosclerotic plaque often precipitates the acute coronary syndromes of unstable angina and myocardial infarction. The combination of aspirin and heparin has been shown to reduce the occurrence of both symptomatic and asymptomatic ("silent") ischemia, myocardial infarction, and death in patients with these syndromes. However, heparin and aspirin each have significant limitations as antithrombotic drugs. Additionally, coagulation abnormalities may persist for several months after an acute ischemic event, and long-term anticoagulation may be beneficial. Because of the need for frequent anticoagulation monitoring and dosage adjustment, the use of heparin is limited to short-term treatment during the acute in-hospital phase. Recently several novel antithrombotic treatments have been developed. The benefits of direct thrombin inhibitors, platelet fibrinogen receptor antagonists, and low-molecular-weight heparins in the treatment of acute coronary syndromes have been demonstrated in randomized clinical trials.