Potential of Enoxaparin to Maintain A-V Shunt Patency According to the SEP Protocol
A newly published study by authors from Singapore focused on the ability of the SEP protocol – short-term low-dose enoxaparin administration based on body weight – to maintain the patency of an arteriovenous (A-V) shunt after recurrent thrombosis.
Risk of A-V Shunt Thrombosis
An arteriovenous shunt (bypass) is essential for long-term hemodialysis in individuals with end-stage renal disease (ESRD). However, the problem with A-V shunts is their susceptibility to stenosis and thrombosis. Loss of patency then contributes to significant morbidity in these patients and increased costs of their care. The risk of loss of A-V shunt patency is particularly high in patients with recurrent thrombosis within 90 days after successful thrombectomy.
The optimal pharmacotherapy to maintain A-V shunt patency is not known. The cited study therefore evaluated the efficacy and safety of short-term low-dose subcutaneous enoxaparin based on body weight, the so-called SEP protocol, which was jointly developed by hematologists, neurologists, and vascular surgeons, to maintain A-V shunt patency after recurrent thrombosis.
Study Methods − SEP Protocol with Enoxaparin
The enoxaparin dose in the SEP protocol was derived from the patient's weight and the administration length was 4 weeks. This protocol was prescribed to patients with recurrent A-V shunt thrombosis within 90 days after successful thrombectomy. Twenty-five patients were included in prospective follow-up. Contraindications to using the SEP protocol included the presence of active bleeding, concurrent anticoagulant therapy, or untreated congenital bleeding disorders. The prescribed enoxaparin doses were 20 mg for patients weighing < 50 kg, 40 mg for those weighing 50−100 kg, and 60 mg for patients with higher weights.
Results
The average age of patients was 66.4 ± 10.2 years, with men comprising 60% of the cohort. The A-V shunt had been in place for an average of 1.4 years (0.6−5.6 years), with 40% of the subjects having an autologous shunt. The average enoxaparin dose was 36.0 ± 8.2 mg or 0.64 ± 0.1 mg/kg/day, and the average administration duration was 30 days (interquartile range [IQR] 27.5−31.0). One patient experienced a minor bleeding complication (atraumatic gum bleeding that stopped spontaneously).
Kaplan-Meier analysis showed that while the average time to thrombosis before using the SEP protocol was 27.3 days (95% confidence interval [CI] 17.9−36.7 days), after using this protocol it averaged 183.5 days (95% CI 100.1−266.9 days; p < 0.001). Various previous thrombectomy procedures (administered thrombolytics, use of mechanical thrombectomy devices, drug-coated balloons, and stent grafts) did not significantly affect the benefits of the SEP protocol.
Conclusion
This study demonstrated that the SEP protocol with 4-week administration of low-dose subcutaneous enoxaparin based on patient weight is a feasible and safe method of thromboprophylaxis that prolongs A-V shunt patency after recurrent thrombosis.
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Source: Gan CH, Tan RY, Cheong MA, et al. Efficacy and safety of low dose, weight based subcutaneous enoxaparin protocol in recurrent arteriovenous access thrombosis. J Vasc Access 2023 Sep 19: 11297298231194102, doi: 10.1177/11297298231194102 [Epub ahead of print].
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