الفهرس 
Patients and methodsOnly 14 pages are availabe for public view
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Abstract
Summary
Summary
Coronary stent implantation has become the new standard
angiop.lasty procedure, and has fundamentally changed the practice of
interventional cardiology by reducing early complications and improving
the late clinical outcomes in a broad array of patients.
The present study was conducted in a trial to determine the
frequency of stent thrombosis and to provide a better understanding of the
underlying factors responsible for stent thrombosis, and it aimed also at
examining the short-term clinical outcomes of the new Drug Eluting
Stents (DES), which were primarily invented to combat long-term 10-
stent restenosis compared to conventional bare metal stents.
The sample included 60 patients who were classified according to
the type of stent received into 2 groups each included 30 patients. The
first group (Group I) included 30 patients (their ages ranged from 41 to
75 years with mean age of 57.9±8.6) who were treated with drug-eluting
stents, and the second group (Group II) included 30 patients (their ages
ranged from 41 to 77 years with mean age of 57.2±10.55) who were
treated with conventional stents.
The patients were followed up for the occurrence of major cardiac
events (death, myocardial infarction, target lesion revascularization) or
angiographically documented stent occlusion within a mean time interval
ofl month.
There were no significant differences between group I and group II
regarding age, sex, DM, hypertension, hyperlipidemia, smoking, prior MI
and prior PCI. However, group I included more patients with past history
ofCABG than group II [5 patients in group 1(16.7%) vs.l patient (3.3%)
in group II (p<0.05)].
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-- Summary
The mean and standard deviation of LVEF in group I were
54.7±7.4%, while in group II were 59.4±9%. LVEF was significantly
lower in group I than in group II [p<0.05].
There was a significant difference between group I and group II
regarding the type of stented vessel; group I included more patients who
received stents for LAD lesions than group II [20paients (66.6%) in group
I vs. 11 patients (36.7%) in group II, (p<0.05»).
Group I included more patients with multi-vessel disease than
group II [12 patients (40%) in group I had multi-vessel disease vs. 5
patients (16.7%) in group II (p<0.05»).
There was a significant difference between group I and group II
regarding the number of stents deployed per patient; the number of
patients who received more than one stent was higher in group I than it
was in group II [9 patients in group I (30%) vs. 3 patients (10%) in group
II (p<0.05)].
There was a significant difference between group I and group II
regarding sub-optimal stent expansion; 5 patients (16.6%) in group I had
sub-optimal results compared to only one patient (3.3%) in group II
(p<0.05).
Regarding the presence of slow flow after stent deployment, there
was a significant difference between group I and group II; group I
included 4 patients (13.3%) with slow flow while no patients (0%) in
group II had slow flow after stent deployment (p<0.05).
There was no significant difference between group I and group II
regarding the presence of residual dissections. However, group I included
more patients with residual dissections after stent deployment than group
II [4 patients (13.3%) in group I vs. I patient (3.3%) in group II
(p>0.05)].
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------------ Summary
Regarding the presence of pre-intervention thrombus, there was a
significant difference between group I and group II; the incidence of preintervention
thrombus was higher in group II than in group I [no patients
(O%)-in group I vs. 4 patients (13.3%) in group II (p<O.05)].
Nevertheless, only one of those patients who had pre-intervention
thrombus suffered from subacute stent thrombosis.
The mean diameter of stents deployed in group I was larger than
the mean diameter of stents implanted in group II [ 3.2±0.34 rom in group
I vs. 3.I±O.3mm in group II (p<O.OI»).
The mean length of stents deployed in group II was longer than the
mean length of stents implanted in group I [17.3±3.25mm in group I vs.
20.9±4.6mm in group II (p<O.OI)].
-There was no significant difference between group I and group II
regarding the inflation pressure. Routine high-pressure inflation (~14
ATM) was applied in most of the cases.
There were also no significant differences between group I and
group II regarding clinical presentation or ACC/ AHA type of lesion.
The incidence of stent thrombosis was higher in group I than in
group 11[4 patients (13.3%) in group I suffered from stent thrombosis vs.
only one patient (3.3%) in group II]. However, this didn’t reach
statistical significance (p>O.05). Three patients from those who suffered
stent thrombosis in group I had post procedural MI vs. one patient in
group II (p>O.05).
Among those who experienced stent thrombosis, two patients in
group I needed emergency catheter based revascularization versus one
patient in group II (p<O.05). Only one patient from those receiving drugeluting
stents died after the occurrence of stent thrombosis while no
patients died in group II, with overall mortality rate 1.7%.
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__________________ ------ Summary
In the present study, some factors had relatively higher risk for
stent thrombosis than the others, and some of these factors were
suggested to be predictors of stent thrombosis. The presence of slow flow
after stent deployment, the presence of residual dissections., sub-optimal
stent expansion, the number of stents deployed per patient and low LVEF
were suggested to be strong predictors of stent thrombosis.
It is recommend that multiple stents and longer stents should be
used only when needed to cover significant extrastent stenosis or
dissection.
The overall clinical experience with the drug-eluting stent doesn’t
suggest an increased propensity for stent thrombosis. Nevertheless, some
precautions have to be followed regarding the safety of drug-eluting
stents, such as the need of higher inflation pressure, appropriate sizing,
extension of post procedural dual antiplatelet therapy, optimally, to one
year and the use of glycoprotein Ilb/IlIa inhibitors for complex stent
procedure, long stents and/or procedure that require multiple drug-eluting
stents.
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