ENOXAPARIN IN UNSTABLE ANGINA : A MULTIVARIATE ANALYSIS OF
RISK FACTORS FOR MINOR AND MAJOR HAEMORRHAGE. CM. Reyes, MKC. Ng*, K. Byth, P. Fa, J.
Langford, K. Williams and DL. Ross. Departments of Pharmacy and Cardiology,
Westmead Hospital, Sydney, NSW. Enoxaparin (EN) is effective in the
management of unstable angina (UA). The
ESSENCE study showed a higher incidence of haemorrhagic complications in
patients treated with EN than in those treated with unfractionated heparin
(UFH), but the risk factors for this have not been fully evaluated. We aimed to assess the risk factors (RF) for
minor and major haemorrhage (H) in non .trial patients receiving EN for
UA. Methods:
Patients who received a principal diagnosis of UA (according to
International Classification of Diseases coding) over a 15 month period
(January 1998 to March 1999) were included in this retrospective study. During the study period, EN protocols for UA
were changed from 1mg/kg b.d. to 1mg/kg daily due to a perception of an
unacceptably high rate of bleeding complications. Patient files were examined for recorded incidents of H and for a
number of potential risk factors. The
data was entered into a statistical database (SPPS version 7). A multivariate logistic regression analysis
(MLRA) was undertaken to identify risk factors for H. Results: A total of 300 patients was recruited. The
best fitting MLRA of RF for minor H showed that the independent
predictors included an estimated creatinine clearance (Cockcroft-Gault)
<50mL/min (OR-3.4; 95%CI 1.3-9.6), ticlopidine therapy (1.7;
1.1-2.6), bolus UFH during coronary angioplasty (PTCA) (2.6; 0.9-7.2)
and coronary artery bypass grafting (CABG) (5.3; 1.1-25).
A MLRA of RF for major H showed that the sole independent predictor
was CABG (51; 16-160). The frequency of EN dose was not a
significant predictor of H overall. Conclusions: In a community population of patients receiving EN for UA, those
undergoing PTCA are at increased risk of minor H due to ticlopidine therapy and
bolus UFH during PTCA. CABG was the
most potent predictor of bleeding complications. Renal dysfunction increases H during EN therapy. EN dose should be reduced in patients with
significant renal impairment.
