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12
Biodegradable Polyesters Polymer–Polymer Composites with
Improved Properties for Potential Stent Applications
Lloyd D. Kimble and Debes Bhattacharyya

12.1
Introduction

The human body is an extraordinarily complex system comprised of many parts
and systems all working in unison to maintain and sustain health. Being mostly
fluid, it is not surprising that there are various tubes within the body with func-
tions ranging from delivery of nutrients to transmission of chemical signals to
removal of metabolic waste. Sometimes, these tubes may become compromised,
thus losing their ability to perform their roles. In such cases, medical intervention
can help to restore function by providing the vessels or tubes with support via the
useofstents. In general, astent is “a splint placed temporarily inside a duct, canal,
or blood vessel to aid healing or relieve an obstruction,” according to the Oxford
English Dictionary [1]. The practice of implanting or deploying a stent into a vessel
or tube is referred to as stenting.
Coronary arteries are vessels commonly treated by stenting because of the
prevalence of coronary artery disease (CAD). CAD has become very widespread
within many regions of the world and is the leading cause of death in the
United States andEurope[2].Fromhereonward, stents and stenting refer to
coronary artery stents and the implantation of stents into coronary arteries,
respectively. CAD is basically the buildup of plaque within the coronary arteries,
as shown in Figure 12.1. Excessive plaque buildup leads to constriction of flow
through the vessel, in which case the vessel must be treated to restore normal
flow.
The use of stenting began in 1986. The procedure begins with percutaneous
transluminal coronary angioplasty (PTCA), during which a balloon catheter is
used to expand the vessel at the target site and reshape the plaque to reduce the
constriction of blood flow, Figure 12.2a,b. Then a second catheter, with a stent
mounted over the end, is inserted into the vessel. Once the end of the catheter is
in the target region, the stent is implanted by balloon-expansion, as shown in of
Figure 12.2c,d. The balloon is then deflated and the catheter removed, leaving the
stent in place to provide support to the vessel, Figure 12.2e.

Biodegradable Polyesters, First Edition. Edited by Stoyko Fakirov.
© 2015 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2015 by Wiley-VCH Verlag GmbH & Co. KGaA.