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Verapamil eluting stents as a possible treatment for vasospasm after subarachnoid hemorrhage
  1. Pallavi Bhambri1,2,
  2. Ali Sarvi3,
  3. John H Wong4,
  4. Uttandaraman Sundararaj3,
  5. Alim P Mitha1,4
  1. 1Biomedical Engineering Program, University of Calgary, Calgary, Alberta, Canada
  2. 2Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
  3. 3Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta, Canada
  4. 4Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
  1. Correspondence to Dr A P Mitha, 12th Floor Neurosciences, 1403-29th Street NW, Calgary, Alberta, Canada T2N 4N1; amitha{at}ucalgary.ca

Abstract

Objective The only pharmacologic prophylaxis for cerebral vasospasm after subarachnoid hemorrhage is oral nimodipine. A novel way to mitigate this risk may be to design a drug eluting stent that elutes verapamil over the time period typically associated with vasospasm. In this study, we explore different methods of coating nitinol stents with a bioabsorbable polymer and determine the release profile of various verapamil coated stents for the potential treatment of vasospasm.

Methods Nitinol stents were coated with different concentrations of poly(lactic acid-co-glycolic acid) (PLGA) in chloroform solution and using three coating techniques: dip coating, spin coating, and electrospinning. Morphology of the coatings were studied with scanning electron microscopy. 12 verapamil eluting stents were then prepared using different verapamil concentrations and coatings with different numbers of layers. Drug release behaviors were studied using UV spectroscopy for 21 days.

Results Electrospinning at 20% w/v resulted in a smooth uniform coating without significant surface irregularities, and may be the most effective technique to coat stents. Stents with a single layer of PLGA/verapamil coating showed a two phase release profile (initial burst release followed by a slow rate of release) whereas stents with a bilayer coating showed a lower level of initial release followed by a slower sustained release phase.

Conclusions Development of verapamil eluting stents that elute drug over the time course typical of cerebral vasospasm, and for either immediate or prophylactic treatment, is technically feasible. Further in vitro and in vivo studies are required to determine whether this can improve the outcome of patients after subarachnoid hemorrhage.

  • Aneurysm
  • Hemorrhage
  • Stent
  • Subarachnoid
  • Technology

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