# Ultra-thin, high strength, drug-eluting sutures for prevention of thrombosis in microvascular surgery

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2022 · $369,097

## Abstract

PROJECT SUMMARY
More than 550,000 microsurgery cases are conducted each year in the US to repair tissue following trauma,
cancer, or congenital deficiencies via transplantation of tissue from one part of the body to another (free flaps)
or reattachment of amputated body parts (replantation). The maintenance of patent vascular anastomoses is
critical to the success of any free tissue transfer, and as such, intra- or post- operative thrombosis is the most
feared complication for the surgeon and patient, and is the primary cause of free flap failure. Free flap failure
can lead to re-operations, extended inpatient stay, potentially-devastating functional and cosmetic morbidity, and
increased healthcare costs.3 Despite the advent of improved microsurgical instruments and training programs,
literature reports have indicated that anywhere from 6 to up to 25% of microsurgical cases result in re-operation
due to thrombosis at the microvascular anastomosis site. In each case, microvascular thrombosis caused by
hypercoagulability, blood flow stasis, and vessel wall injury (caused in part by damage to the vessel wall during
the surgical procedure, often using non-absorbable sutures) is the primary cause of failure. The use of sutures
for microvascular anastomosis and their placement directly at the wound site make them an ideal platform for
local, sustained drug delivery (no change in surgical practice and mitigates the risks of systemic drug
administration). We hypothesize that local delivery of anti-thrombotic drugs from sutures directly at the site of
the anastomosis can reduce the rate of thrombosis while securely and reliably connecting all types of vessels.
We describe a novel, highly versatile manufacturing platform capable of producing sutures composed of
hundreds of drug-loaded, polymeric nanofibers. Our preliminary data demonstrates manufacture of microsurgical
sutures capable of surpassing clinical strength specifications when loaded with a wide range of small molecules.
In particular, tacrolimus-eluting sutures demonstrated sustained drug delivery, suitable vascular repair, and safe
and significant inhibition of neointimal hyperplasia in comparison to systemic tacrolimus. We believe tacrolimus-
eluting sutures may also have potential to prevent post-operative thrombosis, and have identified additional drug
classes with potential to inhibit thrombosis via multiple mechanisms. Here, we aim to determine which drug class:
anti-coagulant (fondaparinux sodium), anti-platelet (acetylsalicylic acid, clopidogrel), or anti-inflammatory
(sirolimus, tacrolimus) provides optimal prevention of thrombosis via local drug delivery, and further optimize
formulations and manufacturing parameters to provide optimal drug loading and release. Anti-thrombotic sutures
will be evaluated in rat models of microvascular anastomosis thrombosis, and the most promising candidates
will be tested for safety, pharmacokinetics, and efficacy in a swine free flap model. If successfu...

## Key facts

- **NIH application ID:** 10521864
- **Project number:** 1R01HL161141-01A1
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Kunal Sailesh Parikh
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $369,097
- **Award type:** 1
- **Project period:** 2022-08-01 → 2027-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10521864

## Citation

> US National Institutes of Health, RePORTER application 10521864, Ultra-thin, high strength, drug-eluting sutures for prevention of thrombosis in microvascular surgery (1R01HL161141-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10521864. Licensed CC0.

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