Reduction in thrombus formation by placement of endovascular stents at endarterectomy sites in baboon carotid arteries

W. C. Krupski, A. Bass, A. B. Kelly, S. R. Hanson, L. A. Harker

Research output: Contribution to journalArticlepeer-review

Abstract

Background. Although antithrombotic therapies with aspirin, dipyridamole, and heparin have decresed thrombo-occlusive events, they have not abolished these complications. Endovascular mechanical support, first reported by Dotter in 1969, has been proposed as a means to reduce both acute and chronic vessel closure by providing a supporting framework for the disrupted and sometimes dissected arterial wall. Methods and Results. To determine the effects of placing self-expanding stainless steel wire endoprostheses on the accumulation of thrombus at sites of carotid artery endarterectomy we measured platelet deposition continuously for 90 minutes and at 24 and 48 hours by gamma camera imaging of autologous 111In-labeled platelets in six stented and nonstented endarterectomized baboons that received heparin but no antiplatelet agents. At nonstented endarterectomy sites 5.36±1.25x108, 4.78±0.98x108, and 4.55±0.81x108 platelets per cm were deposited at 30, 60, and 90 minutes, respectively. In contrast, stented endarterectomy sites accumulated 0.99±0.31x108, 0.66±0.33x108, and 0.80±0.36x108 platelets per cm at 30 minutes (p=0.02), 60 minutes (p=0.004), and 90 minutes (p=0.002), respectively. Platelet deposition remained reduced at 24 and 48 hours in stented endarterectomized carotid arteries (ECAs) when assessed as a ratio between net radioactivity in the endarterectomized region versus whole blood radioactivity (p=0.006 and p=0.009, respectively). Both stented and nonstented ECAs remained patent acutely, although two of six nonstented ECAs occluded by 30 days. By comparison 11 of 14 nonstented ECAs remained patent in another group of control animals. Scanning electron microscopy of control and stented arteries at 30 days demonstrated equivalently confluent endothelium. Conclusions. We postulate that endovascular stents reduce the thrombogenic effects of flap formation, tearing, dissection, and vasospasm in ECAs.

Original languageEnglish
Pages (from-to)1749-1757
Number of pages9
JournalCirculation
Volume84
Issue number4
DOIs
StatePublished - 1991
Externally publishedYes

Keywords

  • Endarterectomy
  • Endoprosthesis
  • In-labeled platelets
  • Platelet deposition
  • Stents
  • Thrombosis
  • Vascular injury

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