Objective: Several cases have been reported of patients with severe hemorrhages caused by low-molecular-weight heparins (LMWH). The objective of the present report was to analyse risk factors for hemorrhage among patients diagnosed of hemorrhage due to LMWH.
Methods: Retrospective study (1989-1999) of patients diagnosed of LMWH hemorrhages in a third-level teaching hospital. A review was made of: a) clinical records from hospital files; b) reports of adverse drug reactions from a program on intensive surveillance of hospital adverse reactions. Information was collected of clinical perameters of patients, treatment, site, and severity of hemorrhage.
Results: A total of 36 patients diagnosed of LMWH hemorrhages were identified. The median age of patients was 76 years (range: 39 to 94 years). In 11 (31%) patients, hemorrhage originated during an ambulatory treatment, which prompted hospital admission. All patients had one or more risk factors for hemorrhage: age > or = 65 years (34; 94%); co-morbidities with hemorrhagic risk (28; 78%); use of platelet anti-aggregants or NSAIDs (17; 47%); length of treatment > 7 days (17; 47%) and use of anticoagulant doses (16; 44%). Hemorrhages occurred most commonly in the gastrointestinal tract and muscles (24; 67%). Most patients had major hemorrhages (26; 72%); and in 5 cases hemorrhages were fatal. In no patient was the dose adjusted by anti-Xa activity monitoring.
Conclusions: Most patients with LMWH hemorrhages have different risk factors for hemorrhage. A careful assessment of hemorrhagic risk factors on patients is needed when LMWH are used, particularly in the ambulatory setting. LMWH doses should be adjusted in patients with hemorrhagic risk factors.