Low incidence of heparin-induced skin lesions in orthopedic surgery patients with low-molecular-weight heparins.

BACKGROUND: Heparins are widely prescribed for prevention and therapy of arterial and venous thromboembolic diseases. Heparin-induced skin lesions are the most frequent adverse effect of subcutaneous heparin treatment in non-surgical patients (7.5%-39.8%); no data exist on surgical patients. Commonly, they are due to a delayed-type hypersensitivity reaction (DTH), but may also be a manifestation of life-threatening heparin-induced thrombocytopenia (HIT). Lesions of both entities resemble initially. The risk of HIT is highest among heparin-anticoagulated orthopedic surgery patients. OBJECTIVE: To determine incidence and causes of heparin-induced skin lesions in major orthopedic surgery patients. METHODS: In a prospective cohort study, consecutive patients with subcutaneous low-molecular-weight heparin (LMWH) treatment were examined for cutaneous adverse effects. Further diagnostics (skin biopsy, clinical/laboratory assessment for thrombosis, bleeding, HIT, cross-allergies) were performed. RESULTS: Six of 316 enrolled patients (1.9%; 95% CI: 0.4%-3.4%) developed heparin-induced skin lesions. All were caused by a DTH reaction, and none was due to HIT or other rare heparin-associated skin diseases. Therapeutic use (dosage) of LMWH was identified as only risk factor (odds ratio: 3.1, 95% CI: 1.4-4.9; P = .00141). In addition to DTH, 5 thromboembolic, 4 major bleeding complications but no cases of HIT or cross-allergies were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Orthopedic surgery patients have-unlike non-surgical patients-a low risk for heparin-induced skin lesions during LMWH treatment; all lesions were due to a DTH reaction. The risk for DTH differs considerably between individual patient cohorts. No association with HIT was observed. These data help to tailor anticoagulatory treatment individually and to increase patient safety.

Heparin-induced non-necrotizing skin lesions: rarely associated with heparin-induced thrombocytopenia.

SUMMARY BACKGROUND: Recently, there has been an increasing number of reports regarding adverse skin reactions to subcutaneous heparin administration. Case series have implied that heparin-induced skin lesions are predominantly associated with life-threatening heparin-induced thrombocytopenia (HIT) in at least 22% of patients. Skin lesions, therefore, have been included in clinical scores for HIT. OBJECTIVES: To determine the association of heparin-induced skin lesions with HIT. This would have a pivotal impact on further anticoagulatory management in patients with heparin-induced skin lesions. PATIENTS/METHODS: In our observational cohort study, 87 consecutive patients with heparin-induced skin lesions (85 occurring during low-molecular-weight heparin administration) were evaluated using a standardized internal protocol, including HIT diagnostics (heparin-platelet factor 4-ELISA, heparin-induced platelet activation assay), platelet count monitoring, clinical/sonographical screening for thrombosis, skin allergy testing and, if necessary, histology. RESULTS: None of the observed heparin-induced skin lesions was due to HIT; all lesions were caused by delayed-type IV-hypersensitivity reactions (DTH) instead. Even the cutaneous reaction in one patient with concomitant HIT could be classified histologically as DTH reaction, amounting to an association of heparin-induced skin lesions and HIT in 1.2% (1/87; 95% confidence interval, 0.00-0.06). CONCLUSION: Heparin-induced skin lesions associated with use of low-molecular-weight heparins do not seem to be strongly associated with a systemic immunologic reaction in terms of HIT and might rather be due to DTH reactions than due to microvascular thrombosis. Hence, we propose refining existing pretest probability scores for HIT, unless underlying causes have been clarified.

[Danaparoid in pregnancy in cases of heparin intolerance - use in 59 cases]. / Danaparoid in der Schwangerschaft bei Heparinunverträglichkeit - Einsatz in 59 Fällen.

UNLABELLED: During the use of fractionated or unfractionated heparin adverse events frequently occur that can endanger the continuation of therapy. Especially in pregnant patients with thromboembolic complications it may be difficult to find a suitable alternative anticoagulant when heparin-induced thrombocytopenia type II (HIT II) or allergic skin reactions occur. There are still limited data on the use of danaparoid in pregnancy. The main reason for heparin intolerance in the 59 reviewed pregnancies were either HIT II, described in 37/59 (62.7%) pregnancies, or cutaneous adverse effects in 19/22 (86.4%) of non-HIT-associated pregnancies (22/59, 37.3%). RESULTS: 40/59 pregnancies were carried to term under use of danaparoid and resulted in the delivery of a healthy infant. In 16/19 pregnancies, danaparoid was stopped due to a major adverse event. Five patients showed bleeding complications, seven fetal losses were documented, but there was no association with the use of danaparoid. In 31/59 (52.5%) pregnancies adverse events were documented, 14/31 (45.2%) could be attributed to danaparoid. Anti-Xa-activity was not detected in five fetal cord blood samples and in four maternal breast-milk samples. CONCLUSION: Danaparoid can be used as an alternative anticoagulant in pregnant women with high risk for thrombosis and heparin intolerance.

Influence of blood collection techniques on platelet function.

For investigations of platelet function it is recommended that venipuncture should be performed using ordinary needle systems instead of butterfly cannulae systems. Platelets might be activated in the long plastic tubes of butterfly systems. The aim of this study was to investigate the dependency of platelet function results on blood sampling using different collection systems. Therefore, blood of 25 healthy volunteers was collected from both arms using at the same time on one side a 21-gauge needle and on the other side a 21-gauge butterfly cannula system. Both samples of each volunteer were analyzed on the PFA-100. Platelet aggregation was performed on the Behring Coagulation Timer (BCT) and the optical aggregometer PAP-4 using ADP, collagen and arachidonic acid to induce platelet aggregation in platelet-rich plasma. No significant prolongation of the closure times on the PFA-100 with the COL/EPI cartridge and the COL/ADP cartridge was observed when using butterfly cannulae. The results of optical aggregometry were not significantly different. The maximum aggregation response did not differ significantly for both collection systems. Aggregometry and the PFA-100 system are not affected by different blood collection systems. Therefore butterfly cannulae can be used for sample collection to investigate platelet function.