Abstract

Low-molecular-weight heparins (LMWH) are widely used for the treatment of venous thromboembolism as an alternative to standard he - parin (SH). The aim of this study was to compare the efficacy of these two types of heparins in pulmonary thromboembolism (PTE). We randomly assigned 54 patients (aged 57.16±15.9) hospitalised for PTE to either intravenous infusion with SH (n= 34) or subcutane - ous LMWH given twice daily (n= 20).

The patients were evaluated with lung perfusion scans, Doppler echocardiography and arterial blo - od gases at baseline, 10 days and 3 months after the therapy with either form of heparin. The baseline characteristics of the treatment groups were similar. The mean pulmonary vascular obstruction percent (PVO) in perfusion scans of the SH group was 43.3% at enrolment, 25.5% at day 10 and 13.3% at 3 rd month (p<0.001, p<0.001). Among the patients assig - ned to LMWH, the mean PVO was 47.6% at enrolment, 26.2% at day 10 and 21.4% at 3 rd month (p<0.001, p<0.005). No significant dif - ference was found between the groups in terms of improvement of PVO.

Maximum systolic pulmonary arterial pressure (PAP) mildly decreased with treatment in both groups with similar recovery rates (PAP in patients assigned to SH and LMWH; at enrolment, day 10 and 3 rd month were; 33.9, 30, 28.3 mmHg; 38.4, 34.7, 33.3 mmHg respecti - vely). PO 2 increased from 65.87 mm Hg to 76.48 mm Hg (p<0.001) in SH group whereas it increased from 67.16 mm Hg to 75.26 mm Hg (p<0.005) in LMWH group. Alveolar-arterial gradient decreased from 42.2 mm Hg to 25.3 mm Hg (p<0.001) and from 43.2 mm Hg to 29 mm Hg (p<0.005) in SH and LMWH groups respectively. No significant difference was found when the effects of two treatment mo - dalities on arterial blood gas changes were compared.

In conclusion, LMWH was no less effective than SH for the treatment of PTE.