Experience with pharmacologic leeching with bivalirudin for adjunct treatment of venous congestion of head and neck reconstructive flaps
Harun A, Kruer RM, Lee A, Boahene K, Byrne PJ, Richmon JD (2018) · Microsurgery · n=10
Study Profile
- Design
- single-institution retrospective comparative cohort study of patients receiving intradermal bivalirudin injections (pharmacologic leeching) as adjunct treatment for venous congestion of head and neck reconstructive flaps at Johns Hopkins University School of Medicine, September 2012 through September 2015
- Sample size (n)
- 10
- Intervention
- Variable number of intradermal injections of bivalirudin (a synthetic 20-amino-acid analog of leech hirudin) directly into the venous-congested flap, followed by a small skin incision to allow extended passive bleeding — described by the authors as 'pharmacologic leeching' designed to mimic the physiologic effect of medicinal leech therapy
- Comparator
- Within-cohort descriptive comparison to historical leech therapy outcomes; bivalirudin used as adjunct (n=6) or solo (n=4); 2 patients underwent alternate therapy after the first bivalirudin injection
- Primary endpoint
- Improvement of flap congestion and reduction of partial/complete flap necrosis following bivalirudin administration
- Primary result
- Among 10 patients with free flap reconstruction of various head and neck defects (4 ALT, 2 pectoralis major, 2 fibula osseocutaneous, 1 supraclavicular, 1 radial forearm), 8 patients had assessable outcomes; among these 8, 4 developed partial necrosis and 1 developed complete necrosis requiring reconstruction; 2 patients required blood transfusions during treatment; authors concluded bivalirudin is feasible/safe as adjunct therapy for flap congestion but efficacy versus standard medicinal leech therapy requires further work
- Follow-up duration
- duration of hospitalization plus institutional postoperative monitoring
- PMID
- 29344982
Key Findings
- First published US clinical experience with intradermal bivalirudin as a 'pharmacologic leech' alternative
- Johns Hopkins protocol used intradermal injection plus skin incision to mimic the prolonged passive bleeding effect of leeches
- Safety profile feasible but efficacy outcomes mixed (5 of 8 evaluable flaps developed partial or complete necrosis)
- Two patients required blood transfusions — bleeding risk is not eliminated by switching from whole leech to synthetic analog
- Authors framed bivalirudin as a leech-alternative addressing infection risk (no Aeromonas), psychological aversion, and leech migration risk
Limitations
- Very small sample (n=10) - exploratory pilot only
- Retrospective single-institution design — outcome adjudication and indication selection biased
- Heterogeneous flap types pooled — efficacy may vary by flap and anatomical site
- No randomized comparator to medicinal leech therapy
- Bivalirudin is not FDA-cleared for this off-label intradermal use — investigational protocol only
Clinical Implications
Harun 2018 is the most cited US clinical attempt to develop a 'pharmacologic leech' alternative using intradermal bivalirudin. For US clinicians, the trial documents that direct thrombin inhibitor injection is feasible and may avoid some leech-specific harms (Aeromonas infection, psychological aversion, leech migration) but does not demonstrate equivalent salvage efficacy to medicinal leech therapy. The pilot is hypothesis-generating; pending randomized comparison, the K040187-cleared medicinal leech remains the standard of care for venous congestion of microsurgical flaps. The trial supports continued translational research into leech-derived pharmacologic alternatives but does not change current clinical practice.
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