In this presentation, I talked about different ways to treat the blocked coronary artery and after that we discussed about the treatments of Infarcted site of heart. S.Mohammad Zargar Biomedical Engineering Student at University of Isfahan

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Presenter : S.Mohammad Zargar
Supervisor : Dr. Mahdikhani
Faculty of Engineering
Department of Biomedical Engineering

2. Treatments
Surgeries and procedures for atherosclerosis include:
 Angioplasty
 Stent placement
 Coronary Artery Bypass Grafting surgery (CABG)
 Atherectomy
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3. CABG
Coronary artery bypass
grafting (CABG) is a type
of surgery - where arteries
or veins from other areas in
the body are used to
bypass the narrowed
coronary arteries. CABG
can improve blood flow to
your heart, relieve chest
pain, and possibly prevent
a heart attack.
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Atherectomy
Unlike angioplasty and stents, which push plaque into the vessel wall,
atherectomy cuts plaque from the wall of the artery. While atherectomy is
usually employed to treat arteries it can be used in veins and vascular
bypass grafts as well.
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5. Angioplasty
In the late 1970s, doctors began using balloon
angioplasty to treat coronary arteries that got too
narrow.
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Coronary Stents
Because no new support is left, in a small percentage of cases, the artery
will regain its previous shape or even collapse after the balloon is
deflated. About 30% of coronary arteries treated with balloon angioplasty
get narrower again.
To solve these problems, small stents were created that could be
mounted on the balloon and put into a blood vessel. The stent expands
when the balloon is inflated, locks into place, and forms a permanent
scaffold to hold the artery open after the balloon is deflated and removed.
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7. BMS
First-generation stents were made of
bare metal. Although they almost
eliminated the risk of the artery
collapsing, they only modestly reduced
the risk of re-narrowing.
About a quarter of all coronary arteries
treated with bare-metal stents would
close up again, usually in about 6 months.
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8. DES
Stents coated with drugs that interrupted the re-narrowing are called
drug-eluting stents.
While bare-metal stents (BMS) are still utilized, drug-eluting stents
(DES) now offer clinicians the ability to prevent restenosis via a
different mechanism.
Advantages:
In clinical trials, these
reduced re-narrowing cases to
less than 10%. They also
lowered the need for repeat
procedures for people with
diabetes, who have a bigger
chance of their arteries getting
narrow again.
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9. First Generation DES
 First-generation DES include sirolimus-eluting stents
(SES; 2003) and paclitaxel-eluting stents (PES; 2004).
 SES and PES revolutionized rates of restenosis after
cardiac procedures. These stents were developed to
prevent the proliferation of smooth-muscle cells and other
cell types seen with restenosis.
 PES and SES were compared in several clinical trials, most
of which concluded that SES were associated with lower
rates of clinical restenosis and late lumen loss. The
superiority of SES may be due to differences in mechanism
of action, timing of drug delivery, and cellular inflammatory
response for SES and PES at sites of overlapping stents.
Sirolimus
Paclitaxel
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10. Second Generation DES
 Second-generation DES, including
zotarolimus- and everolimus-eluting
stents (ZES, EES), were approved for
use in the United States in 2008.
 The newer stents, EES and ZES, are
thinner and more flexible and have a
cobalt-chromium alloy platform, which
makes them more deliverable than the
first-generation stents. These stents may
also be more biocompatible, thereby
generating less inflammatory response
and faster vessel endothelialization.
Zotarolimus
Everolimus
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11. DES
Although the underlying
principle of DES remains
constant, each type may
offer variations with
respect to deliverability
(ease of placement),
efficacy (preventing
restenosis), and safety
(thrombosis rates). The
use of dual antiplatelet
therapy (DAPT) with
stents has significantly
improved outcomes in
patients undergoing PCI.
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12. Still, there were concerns that drug-eluting stents
were associated with a rare but serious complication
called in-stent thrombosis. This is where a blood
clot forms in a stent one or more years after it's
implanted.
Because this complication can be fatal, it’s important
that people with drug-eluting stents take aspirin and
an anticlotting drug as prescribed until a doctor tells
them to stop.
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13. Dual Antiplatelet Therapy
Coronary rethrombosis and coronary restenosis
are sequelae of stent placement. Coronary
rethrombosis is defined as reocclusion of coronary
vessels by thrombin formation, and coronary
restenosis is reocclusion of coronary vessels and
smooth-muscle endothelial overgrowth. These
sequelae can lead to devastating events such as
MI and death. DES are associated with a reduced
risk of restenosis but an increased risk of
rethrombosis, specifically with early discontinuation
of DAPT.
Dual antiplatelet therapy (DAPT) = Combination of
aspirin and a P2Y12. platelet receptor inhibitor to
prevent stent thrombosis after a. percutaneous
coronary intervention. 2. Percutaneous coronary
intervention (PCI) = reperfusion of a coronary.
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14. Third-Generation Stents
if the BVS absorbed into the vessel wall over the next year, we
would expect a number of great things that the vessel might
resume some or most of its normal function.
A bioresorbable, biodegradable,
or bioabsorbable stent is
manufactured from a material
that may dissolve or be absorbed
in the body.
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Hot Tip
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Damaged Cardiac Tissue
Cardiac tissue damage due to myocardial infarction (MI) is one of the
leading causes of mortality worldwide. the body’s natural response after
MI is a process of fibrous remodeling that ultimately leads to scar
formation instead of functional myocardium formation. This scar formation
prevents the heart from functioning properly and eventually leads to
complete heart failure.
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17. Myocardial Infarction
Pharmaceutical therapy
Medical devices
Transplantation
Limitations
•High Invasiveness
•scarcity of donor
organs
•prolonged
hospitalization time
Limitations
•thrombosis or
stenosis of devices
•immune rejection
Treatments of MI
Tissue engineered organ
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18. CV TERM
As a result, there is a huge need
for developing new solutions to
repair or replace damaged
cardiac tissues. Injectable
hydrogels have emerged as a
promising approach for cardiac
repair in regenerative medicine.
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19. CV RM
In regenerative medicine approach, the appropriate cell types are
injected to the injured myocardium. These cells can be progenitor cells
or stem cells that can be differentiated into the necessary cardiac cell
types or even fully differentiated cardiac cells. Some biomaterials-alone
can be injected near the infarcted heart tissue to provide the
mechanical support to the injured heart tissue.
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CV TE
In tissue engineering, the
desired cell types are
grown in some natural or
synthetic biomaterials or
sometimes even without
any biomaterials, for the in
vitro formation of cardiac
tissue that could be
implanted around the
damaged areas of heart.
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21. Hydrogels
 Hydrogels are “water-swollen polymer networks” that have a high
percentage of water content identical to human tissues.
 They can be injected as a liquid and be crosslinked to a gel phase
using certain physical or chemical stimuli.
In situ cross-linking Methods:
 Thermo-sensitive hydrogels
 photo cross-linking
 pH-dependent
 Crosslinking
 Ionic crosslinking
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22. Design Parameters in synthesis of Hydrogels
 Biocompatible
 Biodegradable
 Bioresorbable
 Not triggering an immune response
 Contractible
 Elastic
 Able to sustain periodic contraction and relaxation
 Well-vascularizes
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