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The american journal of surgery (2010)
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Trauma remains the leading cause of death
in persons between aged 1 to 44 years of
and it is among the 10 leading causes of death
for persons of all age groups .
most deaths that occur during the first 24
hours following a traumatic event are the
result of hemorrhage .
however later in the course the resultant
hypercoagulable state contributes to the
development of
thromboembolic
complications as well as to the development
of acute repiratory distress syndrome and
multiple organ failure.
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The spleen is the most commonly injured
abdominal organ after blunt trauma and is also
commonly injured after penetrating trauma.
In the past century , the management of splenic
injury has continued to evolve from a focus almost
entirely on splenectomy to one of selective
nonoperative management .
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Prior studies have documented a significant
increase in thromboembolic disease in
patients who have undergone splenectomy
for various reasons.
In 1989 , pimpl et al reviewed 37,012
autopsies over 2 decades . Two hundre
two of these patients had undergone
splenectomy . pulmonary embolism was
the cause of death more frequently in the
splenectomy group than in the control
group (35.6% vs 9.7%)
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Of the 202 patients with splenectomy , 61 had
undergone splenectomy for trauma . Compared
with 123 trauma patients who did not undergo
splenectomy , a significant increase in the
incidence of pulmonary embolus was found (31% vs
8% ) .
Trauma patients admitted to orgon health &
science university with splenic injury were
candidates for the study.
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patients were excluded from eligibility for the
following reason:inability to obtain consent from
the patient or an appropriate designee,currently
undergoing therpeutic anticoagulation,any known
preexisting coagulopathy,or pregnancy.
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Patients who were managed whit
splenic presentation , either nonoperative
or splenorraphy . constituted the control
group , and those who required
splenectomy constituted the study group.
Fifty patients were enrolled in the
control group and 30 patients in the
splenectomy group.
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Laboratory studies collected included
complete blood count with differental, partial
thromboplastin time , fibrinogen , thrombin time ,
prothrombin time , international normalized ratio
fibrinogen , thrombin _ antithrombin complex ,
tissue plasminogen activator (tPA) ,
plasminogen activator inhibitor _ 1 (PAI_1) ,
PFA_100 including both collagen / epinephrine
and collagen/adenosine diphosphate tests , and
thromboelastography (TEG) .
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In addition , patients filled out a simple
questionnaire regarding their medical histories.
Following discharge, patients returned
approximately
6
weeks later for
followe_up coagulation parameters and a repeat
questionnaire.
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Splenectomy patients were older had higher
injury severity scores,and had longer intensive
care unit and hospital stays than control
patients.
Splenectomy patients had significant
leukocytosis and thrombocytosis at baseline.
At follow_up , the splenectomy patients had
higher white blood cell counts compared with
the control patients , but they were within the
normal reference range .
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platelet count in the splenectomy group remained
elevated above the reference range and above control
levels.
fibrinogen levels were initially elevated in both
groups,they remained elevated in the splenectomy group
compared with the controls .
tissue plasminogen activator,PAI_1 and activated partial
thromboplastin time were higher in splenectomy patients
only at baseline.
there was a trend toward more elevated levels of tPA
at follow_up in the splenectomy group.
international normalized ratio , prothrombin time ,
thrombin _ antithrombin complex , and PFA_100 tests
were not different between groups at either time point.
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Baseline TEG showed faster fibrin cross_
linking and enhanced fibrinolysis following
splenectomy compared with controls.
clot strength was elevated above the normal
range at baseline in the splenectomy patients
but was not significantly elevated compared
with controls . However at follow up , clot
strength was sigificantly greater in the splenectomy
group compared with controls .
Significant differences were detected between
splenectomy and control patients with respect to
the incidence of deep venous thrombosis .
(DVT:6.7% vs 0%) and the incidence of infection
during hospitalization . (40% vs 16%).
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more pationts in the splenectomy group
were regularly using aspirin or other
nonsteroidal anti_ inflammatory drugs at
follow_up (43.3 % vs 12%).
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The most significant findings of this study
were the increased incidence of
thromboembolic events and infectios in
patients who had undergone splenectomy
compared with those who had succesfull
splenic preservation.
Despite small study numbers and similar use
of chemical prophylaxis with low _ molecular
weight heparin at baseline and greater use of
asprin or other platelet_inhibiting nonst eroidal
anti _ inflammatory drugs at follow _ up ,
splenectomy patients had a 7% incidence of DVT
formation , compared with 0% in patients who
did not require splenectomy .
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Patients undergoing splenectomy were also
much more likely to develop infection during
hosptalization . this study also confirmed
persistant thrombocytosis in the splenectomy
group an average of 3 months after injury.
During the early 20th century , mortality
following splenectomy was 30% to 40%.
In contrast , attempts at nonoperative
management of splenic injuries resulted in a
90% mortality rate during the same time
frame.
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On the basis of these findings the belief that
spleen is an expendable organ and a lack of
appreciation of the spleens immunologic
importance splenectomy following injury became
the standard of care until the late 20th century.
In the 1950s infectious complications folloing
splenectomy were reported the most severe of
which is overwhelming postsplenectomy infection
(OPSI).
Recent literature quotes a 1% to 2% OPSI rate for
allsplenectomized patients. With mortalitiy in these
patients ranging from 50% to 80% .
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The OPSI rate in trauma patients undergoing
splenectomy is 1.45% . in additional to the risk OPSI ,
asplenic patients have both early and late risks for
other major infection.
Postsplenectomy thrombocytosis is a common finding
regardless of underlying diseas , and has been well
documented in humans.
Cononico et al studied blood coagulation profils in
35patients with thrombocytosis after splenectomy for
nonmalignat and nontraumatic disorders.
Seventy healty subjects served as the control group .
increased plasma levels of fibrinogen , D_dimer ,
fibrinopeptids 1and 2 , and PAI_1 were found in the
splenectomy patients compared white the control group.
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The prevalence of thrombosis following
splenectomy for hematologic disorders has
been reported to between 1.5% and 55%
with the first events occurring months to
many years after splenectomy.
Similar to nontrauma splenectomy
pationts in the study by canonico et al,
our trauma patients undergoing
splenecomy also had elevated levels of
fibrinogen and PAI_1.
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The presence of elevated PAI_1 imparts increased
thrombotic risk by decreasing active fibrinolysis through
the inhibition of tPA.
Tissue plasminogen activator is a serine protease found on
endothelial cells that catalyzes the conversion of plasminogen
to plasmin activly breaking down clot. PAI-1is also produced
in platelets themselves.
This imbalance of thrombolysis may be the larger
contributor to the thromboembolic risks of splenectomy.
In addition to more standard laboratory coagulation as
says,TEG was performed in our study patients . within 20
minutes to 30 minutes , a thromboelastographic tracing
can provide information on clotting factor activity , plattelet
function , and any clinically significant fibrinolytic process.
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TEG is aneffective instrument for the evaluation of
overal coagulation in trauma patients,and its
accuracy has been conifirmed in both
hypercoagulable hypercoagulable pattients.
Splenectomy patients had significantly higher levels
of tPA at baseline,which,plays a primary rol in
catalyzing the conversion of plasminogen to plasmin.
The splentomy patients clearly have a disruption
in the balance of their prothrombotic and
antihrombotiic mechanisms,leaving them at risk
for thromboembolic disease,as evidenced by their
higher incidenced by their higher incidence of DVT
formation.
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The risk for postsplenectomy Infectious
complications and the appreciation of the
spleens immunologic importrance have provided
an impetus to attempts spleen preservation
after trauma.
Technological advances have made
nonoperative management of splenic injery
and splenic salvage much more safe and
feasible.
These include advances in prehospital care ,
resuscitation ,diagnostic imaging , splenorrhaphy
techniques , and hemostatic agents.
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Cogbill et conducted a multicenter study
finding that 18% of pationts with splenic injury
were candidates for nonoperative management
,and 80% of these were successfully treated
nonoperativeely.
In a multi _ institutional study of blunt
splenic injury in adults , 54% of patient were
succesfully managed nonoperatively.
We believe that the results of this
prospective study , despite its limitations ,
provide further impetus to aim for splenic
preservation rather than splenectomy whenever
possible.
Zahra derakhshan deylami
Masomeh sobhani