Quantifying the mechanical and histological properties of thrombus analog made from human blood for the creation of synthetic thrombus for thrombectomy device testing

J Neurointerv Surg. 2018 Dec;10(12):1168-1173. doi: 10.1136/neurintsurg-2017-013675. Epub 2018 Apr 25.

Abstract

Background: Untreated ischemic stroke can lead to severe morbidity and death, and as such, there are numerous endovascular blood-clot removal (thrombectomy) devices approved for human use. Human thrombi types are highly variable and are typically classified in qualitative terms - 'soft/red,' 'hard/white,' or 'aged/calcified.' Quantifying human thrombus properties can accelerate the development of thrombus analogs for the study of thrombectomy outcomes, which are often inconsistent among treated patients.

Methods: 'Soft'human thrombi were created from blood samples ex vivo (ie, human blood clotted in sample vials) and tested for mechanical properties using a hybrid rheometer material testing system. Synthetic thrombus materials were also mechanically tested and compared with the 'soft' human blood clots.

Results: Mechanical testing quantified the shear modulus and dynamic (elastic) modulus of volunteer human thrombus samples. This data was used to formulate a synthetic blood clot made from a composite polymer hydrogel of polyacrylamide and alginate (PAAM-Alg). The PAAM-Alg interpenetrating network of covalently and ionically cross-linked polymers had tunable elastic and shear moduli properties and shape memory characteristics.

Conclusions: Due to its adjustable properties, PAAM-Alg can be modified to mimic various thrombi classifications. Future studies will include obtaining and quantitatively classifying patient thrombectomy samples and altering the PAAM-Alg to mimic the results for use with in vitro thrombectomy studies.

Keywords: device; stroke; thrombectomy.

MeSH terms

  • Adult
  • Blood Physiological Phenomena*
  • Elasticity / physiology*
  • Female
  • Humans
  • Male
  • Materials Testing / methods*
  • Rheology / instrumentation
  • Rheology / methods
  • Shear Strength / physiology
  • Thrombectomy / instrumentation
  • Thrombectomy / methods*
  • Thrombosis / diagnosis
  • Thrombosis / physiopathology*
  • Young Adult