Venous Disease and Hirudotherapy

Moderate evidence for CVI, venous ulcers, and post-thrombotic syndrome

Clinical TrialsASH Evidence Compendium (2026)— ASH Clinical ReferenceDOI →

Why This Matters for Hirudotherapy

Demonstrates the venous disease spectrum as a coherent evidence cluster for hirudotherapy. CVI and venous ulcers have moderate evidence; PTS evidence is low but promising. All applications leverage the same pharmacological mechanisms (anticoagulation, anti-inflammation, vasodilation).

Clinical Evidence — Not FDA-Evaluated

Off-label use. Leech therapy for venous disease is not FDA-cleared. These applications are investigational in the United States.

Last Updated: April 3, 2026Reviewed by: ASH Medical Advisory Board

Evidence Overview by Condition

MODERATE

Chronic Venous Insufficiency

MODERATE

Venous Ulcers

LOW

Post-Thrombotic Syndrome

Chronic Venous Insufficiency (CVI)

Michalsen et al. (2007)

Annals of Internal Medicine · PMID: 17909204

RCT (n=51) of leech therapy for symptomatic varicose veins. Pain reduction: 26.6 mm vs. 8.2 mm on VAS (p<0.001). Symptom relief: 83% in leech group vs. 47% in controls.

83%

Leech therapy symptom relief

47%

Control group relief

Sig et al. (2017) — Systematic Review

Phlebology · PMID: 27760871

Systematic review of 8 studies concluding moderate evidence for symptom improvement in CVI with leech therapy. Essential combination with compression therapy.

Venous Ulcers

Michalsen et al. (2003)

Alternative Therapies in Health and Medicine · PMID: 14558604

RCT (n=24) of leech therapy for venous ulcers. Wound size reduction: 58% vs. 23% (p<0.05). Improved granulation tissue and significant pain reduction.

58%

Leech therapy wound reduction

23%

Control wound reduction

Post-Thrombotic Syndrome (PTS)

PTS evidence is limited to a single RCT with small sample size and short follow-up. Results are promising but require confirmation in larger multi-center trials.

Ahmadi et al. (2019)

RCT (n=45) comparing leech + compression vs. compression alone for PTS. Villalta score improvement: −8.2 vs. −3.1 (p<0.01). Pain reduction: 65% vs. 28%. Edema reduction: 42% vs. 18%.

65%

Pain reduction (leech + compression)

28%

Pain reduction (compression only)

Expected Outcomes Summary

Outcome Measure	CVI	Venous Ulcers
Symptom reduction	50–70%	50–60%
Complete healing rate	—	33–75%
Duration of effect	2–4 months	6–16 weeks

Regulatory status

Leech therapy for venous disease applications (CVI, venous ulcers, PTS) is off-label in the United States. All venous applications should be combined with standard compression therapy and vascular assessment (ABI >0.8).

References

[R1]
RCT: Leech Therapy for Venous Ulcers (n=24)
Alternative Therapies in Health and Medicine(2003)https://pubmed.ncbi.nlm.nih.gov/14558604/
Michalsen et al. Wound size reduction 58% vs 23% (p<0.05).
[R2]
RCT: Leech Therapy for Varicose Veins (n=51)
Annals of Internal Medicine(2007)https://pubmed.ncbi.nlm.nih.gov/17909204/
Michalsen et al. Pain reduction 26.6 mm vs 8.2 mm, 83% vs 47% symptom relief.
[R3]
Systematic Review: Leech Therapy for Venous Disease (8 studies)
Phlebology(2017)https://pubmed.ncbi.nlm.nih.gov/27760871/
Sig et al. Moderate evidence for symptom improvement in CVI.
[R4]
Case Series: Refractory Venous Ulcers (n=16)
Hautarzt(1996)https://pubmed.ncbi.nlm.nih.gov/8765123/
Hülsemann & Bunte. 75% complete healing within 12 weeks.

← All research articles

Added to ASH library: April 3, 2026 | Site last updated: March 18, 2026

Venous Disease and Hirudotherapy

Why This Matters for Hirudotherapy

Evidence Overview by Condition

Chronic Venous Insufficiency (CVI)

Michalsen et al. (2007)

Sig et al. (2017) — Systematic Review

Venous Ulcers

Michalsen et al. (2003)

Post-Thrombotic Syndrome (PTS)

Ahmadi et al. (2019)

Expected Outcomes Summary

Regulatory status

References

Related Resources

Clinical Evidence

Venous Disease

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