The american journal of surgery (2010)

Splenectomy leads to a persistent hypercoagulable state after trauma

• 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.

• 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 .

• 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%)

• 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.

• 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.

methods

• 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.

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) .

• 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.

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 .

result

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.

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%).

more pationts in the splenectomy

group were regularly using aspirin or other nonsteroidal anti_ inflammatory drugs at follow_up (43.3 % vs 12%).

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 .

comments

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.

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% .

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.

• 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.

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.

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.

• 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.

• 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

Thank you for your attention