Contrasting post-traumatic serial changes for D-dimer and PAI-1 in critically injured patients

Markers of blood coagulation and fibrinolysis in patients with early and delayed microsurgical reconstructions in the lower extremities

BACKGROUND

In this study, markers of coagulation and fibrinolysis were assessed during early and delayed microsurgical reconstruction in patients with traumatic defects of their lower legs to analyse whether an imbalance of the hemostasis after trauma might predispose the development of vascular complications.

METHODS

The prospective study included 70 patients. In 35 patients, surgery was performed within 72 hours after injury. In 35 other patients, delayed free flap transfer was performed between 14-21 days after trauma. In each group, reconstruction was performed with a fasciocutaneous anterior-lateral thigh flap (ALT, n = 18) or a myocutaneous flap (latissimus dorsi flap; n = 17). Blood samples were collected preoperatively, intraoperatively, and 3, 6, 12, 24, 36, 48, 72, 96 and 120 hours after the operation. Analysed parameters included markers of coagulation such as prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin III-complex (TAT), and antithrombin, as well as fibrinolysis markers such as plasminogenactivator inhibitor-I (PAI-1), tissue-plasminogenactivator (t-PA), and plasminogen.

RESULTS

Preoperatively, levels of F1 + 2, TAT, and PAI-1 were significantly higher in patients with delayed reconstruction (p < .05). Patients with later vascular complications in this group (n = 5) presented a significant higher concentration of TAT, F1 + 2, and PAI-1 (p < .05). Twelve and 24 hours after free flap surgery, patients with vascular complications presented significant elevated levels of these markers (p < .05).

CONCLUSIONS

Patients with delayed free flap surgery after lower leg trauma present a hypercoagulable state in their blood due to activation of the coagulation system and hypofibrinolysis. Early reconstruction might minimise the risk of flap failure caused by hypercoagulability.

Serum D-dimer concentrations are increased after pediatric traumatic brain injury

OBJECTIVE

To determine whether D-dimer would be increased in children with traumatic brain injury (TBI), specifically mild abusive head trauma.

STUDY DESIGN

D-dimer was measured using multiplex bead technology in 195 children <4 years old (n = 93 controls without TBI, n = 102 cases with TBI) using previously collected serum. D-dimer was then measured prospectively in a clinical setting in 44 children (n = 24 controls, n = 20 cases). Receiver operator curves were generated for prospective data.

RESULTS

In both the retrospective and prospective cohorts, median (25th-75th percentile) D-dimer was significantly higher in cases vs controls. A receiver operator curve demonstrated an area under the curve of 0.91 (95% CI 0.83-0.99) in the prospective cohort. At a cut-off of 0.59 μg/L, the sensitivity and specificity for identification of a case was 90% and 75%, respectively.

CONCLUSIONS

Our data suggest that serum D-dimer may be able to be used to identify which young children at risk for abusive head trauma might benefit from a head computed tomography or other additional evaluation. Additional data are needed to better identify the clinical scenarios that may result in false positive or false negative D-dimer concentrations.

The pathogenesis of traumatic coagulopathy

Over the last 10 years, the management of major haemorrhage in trauma patients has changed radically. This is mainly due to the recognition that many patients who are bleeding when they come in to the emergency department have an established coagulopathy before the haemodilution effects of fluid resuscitation. This has led to the use of new terminology: acute traumatic coagulopathy, acute coagulopathy of trauma shock or trauma-induced coagulopathy. The recognition of acute traumatic coagulopathy is important, because we now understand that its presence is a prognostic indicator, as it is associated with poor clinical outcome. This has driven a change in clinical management, so that the previous approach of maintaining an adequate circulating volume and oxygen carrying capacity before, as a secondary event, dealing with coagulopathy, has changed to haemostatic resuscitation as early as possible. While there is as yet no universally accepted assay or definition, many experts use prolongation of the prothrombin time to indicate that there is, indeed, a coagulopathy. Hypoxia, acidosis and hypothermia and hormonal, immunological and cytokine production, alongside consumption and blood loss, and the dilutional effects of resuscitation may occur to varying extents depending on the type of tissue damaged, the type and extent of injury, predisposing to, or amplifying, activation of coagulation, platelets, fibrinolysis. These are discussed in detail within the article.

Plasminogen activator inhibitor-type I gene deficient mice show reduced influx of neutrophils in ventilator-induced lung injury

Ventilator-induced lung injury (VILI) is associated with inhibition of the fibrinolytic system secondary to increased production of plasminogen activator inhibitor- (PAI-)1. To determine the role of PAI-1 on pulmonary coagulopathy and inflammation during mechanical ventilation, PAI-1 gene-deficient mice and their wild-type littermates were anesthetized (control), or anesthetized, tracheotomized and subsequently ventilated for 5 hours with either low tidal volumes (LV_T) or high tidal volumes (HV_T). VILI was assessed by pulmonary coagulopathy, lung wet-to-dry ratios, total protein level in bronchoalveolar lavage fluid, neutrophil influx, histopathology, and pulmonary and plasma cytokine levels. Ventilation resulted in pulmonary coagulopathy and inflammation, with more injury following ventilation with HV_T as compared to LV_T. In PAI-1 gene-deficient mice, the influx of neutrophils in the pulmonary compartment was attenuated, while increased levels of pulmonary cytokines were found. Other endpoints of VILI were not different between PAI-1 gene-deficient and wild-type mice. These data indicate that a defect fibrinolytic response attenuates recruitment of neutrophils in VILI.

D-dimer as a predictor of the need for laparotomy in patients with unclear non-traumatic acute abdomen. A preliminary study

OBJECTIVE

The acute onset of intense abdominal pain requires rapid evaluation, and since D-dimer level is reported to be useful in the diagnosis of patients with suspected acute superior mesenteric artery occlusion, our aim was to evaluate the value of D-dimer testing in the diagnosis of acute surgical abdomen with no precise diagnosis.

MATERIAL AND METHODS

Between July 2004 and June 2006, 93 patients with acute abdomen who required surgical exploration without precise diagnosis were admitted to this prospective clinical study. After surgery, the patients were divided into two groups: group 1 (n=52), patients who needed immediate laparotomy, and group 2 (n=41), patients without the need for laparotomy. Blood samples were taken to analyse D-dimer, white blood cell count and pH level. P-values of <0.05 were considered statistically significant.

RESULTS

There was a positive correlation between the plasma D-dimer level and leucocyte count. Leucocyte counts > 16,800/mm3 (p < 0.01) and D-dimer levels >4.7 microg FEU/mL were more sensitive (p < 0.001). Sensitivity was 97.6% and specificity 61.5% for D-dimer level, and 82.9% and 42.3%, respectively, for leucocyte count. Metabolic acidosis at admission was the most important factor for mortality (p < 0.001).

CONCLUSIONS

In a patient with acute abdomen without precise diagnosis, a D-dimer level above the cut-off value (4.7 microg fibrinogen equivalent units/mL) may be an indicator with high sensitivity for surgical pathology requiring laparotomy.

Hypercoagulability after trauma: hemostatic changes and relationship to venous thromboembolism

BACKGROUND

Major trauma induces a hypercoagulable state, which is frequently complicated by pathological thrombosis. However the sequential changes in coagulation markers and their relationship to clinical thrombosis have been poorly characterized.

METHODS

We measured several markers of in vivo coagulation and fibrinolysis and their regulation serially for 2 weeks after multi-system trauma in a prospective cohort of patients who received no anticoagulant prophylaxis. Asymptomatic deep vein thrombosis (DVT) was assessed by routine bilateral venography between day 12 and 14. Clinically suspected DVT and pulmonary embolism (PE) were investigated in a standardized manner.

RESULTS

Among the 135 cohort patients the overall venous thromboembolism (VTE) rate was 59%. Markers of thrombin generation were markedly increased within 24 hours of injury, remained persistently elevated for about 5 days and then decreased by day 14. No early compensatory increase in Tissue Factor Pathway Inhibitor (TFPI) or the complex of Factor Xa and TFPI (FXa-TFPI) was seen; FXa-TFPI remained depressed throughout the study. There was no inverse relationship demonstrated between markers of thrombin generation and thrombin regulation. Acquired APC resistance and hypofibrinolysis did not appear to be important contributors to hypercoagulability after trauma. None of the coagulation markers were independently predictive of VTE. Increasing age was the only significant, independent predictor of VTE.

CONCLUSION

Major trauma leads to significantly increased and persistent thrombin generation with disruption of its regulation. Coagulation markers do not appear to add independent predictive value in detecting VTE. Increasing age is the most important clinical predictor of VTE after trauma.

Extended monitoring of hemostatic activation after varicose vein surgery under general anesthesia

BACKGROUND

Postoperative heparin prophylaxis after stripping of the long saphenous vein is a matter of controversial discussion, and practices vary by surgeon and country.

OBJECTIVE

The aim of this study was to assess the extent of hypercoagulability by continued monitoring of activation markers of coagulation and fibrinolysis for a period of 3 weeks after stripping of the long saphenous vein and concomitant phlebectomy.

METHODS

Including 21 patients, the following markers were measured preoperatively and on postoperative day 1, 2, 3, 7, 14, and 21: Activation products of coagulation: thrombin-antithrombin complex (TAT), thrombus precursor protein (TPP), and prothrombin-fragment F1+2 (F1+2), and markers of fibrinolysis: plasmin-alpha(2)-antiplasmin complexes (PAP), D-Dimer, tissue plasminogen activator (t-PA) antigen, and plasminogen activator inhibitor 1 (PAI-1) antigen.

RESULTS

TAT levels increased significantly until day 3 (p=.008) and normalized within 14 days. TPP levels increased significantly until day 7 (p=.02), decreasing to initial values within 21 days. PAP complexes increased significantly until day 2 (p=.02) reducing to baseline within the observation period. D-Dimer levels increased immediately after surgery (p<.001) until day 14 (p<.001) and returned to baseline until day 21.

CONCLUSIONS

Significant hemostatic activation after varicose vein surgery was observed and persisted until 3 weeks postoperatively, indicating that heparin prophylaxis for 2 to 3 weeks is advisable for at-risk patients.

The role of hepatic type 1 plasminogen activator inhibitor (PAI-1) during murine hemorrhagic shock

Hemorrhagic shock (HS) followed by resuscitation (HS-R) is characterized by profound physiological changes. Even if the patient survives the initial blood loss, these poorly understood changes can lead to morbidity. One of the tissues most often affected is liver. We sought to recognize specific hepatic changes induced by this stressor to identify targets for therapeutic intervention. Gene array analyses using mouse liver mRNAs were used to identify candidate genes that contribute to hepatic damage. To verify the role of one of the genes identified using the arrays, mice were subjected to HS-R, and multiple parameters were analyzed. A profound increase in plasminogen activator inhibitor type 1 (PAI-1) mRNA was observed using hepatic mRNAs from C57Bl/6 mice after HS, both with and without resuscitation. Constitutive loss of PAI-1 resulted in notable tissue preservation and lower (P < .05) alanine aminotransferase (ALT) levels. Fibrin degradation products (FDPs) and interleukins 6 and 10 (IL-6 and IL-10) were unaffected by loss of PAI-1; however, enhanced urokinase activity, an elevation of active hepatocyte growth factor (HGF), an increase in unprocessed transforming growth factor-beta1 (TGF-beta1), and retention of ERK phosphorylation after HS-R were associated with improved hepatic function. In conclusion, PAI-1 protein is a negative effector of hepatic damage after HS-R through its influence on classic regulators of hepatic growth, as opposed to its role in fibrinolysis.

Diagnostic value of blood D-dimer level in acute mesenteric ischaemia in the rat: an experimental study

OBJECTIVE

The high mortality rate of mesenteric ischaemia is mainly due to delay in diagnosis. For this reason, it is of great importance to find a specific and rapidly elevating marker. The present study investigated the diagnostic value of blood D-dimer level as a potential marker for acute mesenteric ischaemia in a rat model.

METHODS

Thirty male Wistar albino rats were divided into three groups. Basal D-dimer and L-lactate levels were determined in the non-operative control group (I). In the operated control group (II), the superior mesenteric artery was simply manipulated, while the artery was ligated in Group III. Blood samples were drawn in all groups for D-dimer and L-lactate assays.

RESULTS

Both Group II (p=0.016) and Group III (p=0.001) had significantly higher mean D-dimer levels in the first postoperative hour compared with the basal level in Group I. However, there was no difference between the levels in Groups II and III. The mean level in Group II in the sixth hour had dropped to a statistically insignificant level compared with the basal value, while the mean value in Group III kept rising during this period (p=0.001). Nevertheless, there was no significant difference between Groups II and III. On the other hand, the mean L-lactate level in the first postoperative hour in Group III was significantly higher than the basal level in Group I (p=0.003). No significant rises were recorded in Group II in the first and sixth postoperative hours. The difference between Groups II and III in the first hour was significant (p=0.005). Group III also had significantly higher mean serum L-lactate value in the sixth hour compared with both the basal value in Group I (p=0.001) and the sixth-hour value in Group II (p=0.003).

CONCLUSION

These results do not adequately support the use of blood D-dimer level as an independent parameter in the diagnosis of mesenteric ischaemia due to arterial thrombosis. However, this parameter can be used together with other tests in eliminating the possibility of a thromboembolic event.

The role of plasminogen activator inhibitor type 1 in the inflammatory response to local tissue injury

BACKGROUND

The plasma levels of the plasminogen activator-inhibitor type 1 (PAI-1) are consistently elevated in patients with sterile tissue injury, often accompanied by a systemic acute phase protein response. It remains unknown, however, whether and to what extent PAI-1 affects the host response to trauma.

METHODS AND RESULTS

By using the well-established murine model of turpentine-induced tissue injury we compared local and systemic inflammatory responses in PAI-1 gene-deficient (PAI-1-/-) and normal wild-type (Wt) mice. Subcutaneous turpentine injection elicited strong increases in PAI-1 protein concentration in plasma and at the site of injury, but not in liver. PAI-1 mRNA was locally increased and expressed mainly by macrophages and endothelial cells. PAI-1 deficiency greatly enhanced the early influx of neutrophils to the site of inflammation, which was associated with increased edema and necrosis at 8 h after injection. Furthermore, PAI-1-/- mice showed a reduced early interleukin (IL)-6 induction with subsequently lower acute phase protein levels and a much slower recovery of body weight loss.

CONCLUSION

These findings suggest that PAI-1 is not merely a marker of tissue injury but plays a functional role in the local and systemic host response to trauma.

Lower tidal volume ventilation and plasma cytokine markers of inflammation in patients with acute lung injury*

OBJECTIVES

To evaluate the association between interleukin-6, interleukin-8, and interleukin-10 and clinical outcomes including mortality in patients with acute lung injury and to determine whether lower tidal volume ventilation was associated with a decrease in plasma cytokines in patients with acute lung injury.

DESIGN

Multiple-center, randomized trial.

SETTING

Intensive care units in ten university centers.

PATIENTS

The study included 861 patients enrolled in the National Heart, Lung and Blood Institute Acute Respiratory Distress Syndrome Clinical Network trial of lower tidal volumes compared with traditional tidal volumes for acute lung injury.

INTERVENTIONS

Patients were randomized to a 6 mL/kg or a 12 mL/kg tidal volume strategy that has been previously described.

MEASUREMENTS AND MAIN RESULTS

Baseline plasma levels of interleukin-6, interleukin-8, and interleukin-10 were each associated with an increased risk of death in both logistic regression analyses controlling for ventilator group (odds ratio 1.63 per log-10 increment, 95% confidence interval 1.33-1.98; odds ratio 2.33 per log-10 increment, 95% confidence interval 1.79-3.03; odds ratio 2.02 per log-10 increment, 95% confidence interval 1.47-2.76, respectively) and multivariate analyses controlling for ventilation strategy, Acute Physiology and Chronic Health Evaluation III score, Pao2/Fio2 ratio, creatinine, platelet count, and vasopressor use (odds ratio 1.63 per log-10 increment, 95% confidence interval 0.93-1.49; odds ratio 1.73 per log-10 increment, 95% confidence interval 1.29-2.34; odds ratio 1.23 per log-10 increment, 95% confidence interval 0.86-1.76, respectively). Interleukin-6 and interleukin-8 levels were also associated with a significant decrease in ventilator free and organ failure free days. Patients with sepsis had the highest cytokine levels and the greatest risk of death per cytokine elevation. By day 3, the 6 mL/kg strategy was associated with a greater decrease in interleukin-6 and interleukin-8 levels. There was a 26% reduction in interleukin-6 (95% confidence interval, 12-37%) and a 12% reduction in interleukin-8 (95% confidence interval, 1-23%) in the 6 mL/kg group compared with the 12 mL/kg group.

CONCLUSIONS

In patients with acute lung injury, plasma interleukin-6 and interleukin-8 levels are associated with morbidity and mortality. The severity of inflammation varies with clinical risk factor, suggesting that clinical risk factor should be considered when both developing and testing therapeutic interventions. Low tidal volume ventilation is associated with a more rapid attenuation of the inflammatory response.

Venous thromboembolism in trauma: a local manifestation of systemic hypercoagulability?

BACKGROUND

The purpose of this study was to evaluate the relative importance of systemic hypercoagulability, preexisting and acquired risk factors, and specific injury patterns in the development of venous thromboembolism (VTE) after injury.

METHODS

Injured patients with an Injury Severity Score > or = 15 were followed with lower extremity venous duplex ultrasonography, prothrombin fragment 1 + 2, and quantitative D-dimer levels at 1 and 3 days and then weekly until discharge.

RESULTS

Among 101 patients with a mean Injury Severity Score of 27.3 +/- 10.5 followed for 12.4 +/- 8.7 days, 28 (27.7%) developed a lower extremity thrombosis, 2 (1.9%) sustained a pulmonary embolism, and 1 (0.9%) had a symptomatic upper extremity thrombosis. Although admission fragment 1 + 2 and D-dimer levels were elevated in 81.4% and 100% of patients, respectively, mean levels were not significantly different in those with or without VTE. VTE was more common (p < 0.05) among those with obesity, age > 40 years, immobilization for > 3 days, spine fractures, and lower extremity fractures. However, only obesity (p = 0.004) and immobilization > 3 days (p = 0.05) were independent predictors of VTE in a multivariate analysis.

CONCLUSION

Although elevated in seriously injured patients, neither markers of activated coagulation nor specific injury patterns are predictive of VTE. Associations with immobilization and obesity suggest that VTE after injury is a systemic hypercoagulable disorder with local manifestations of thrombosis related to lower extremity stasis.

Preliminary study of D-dimer as a possible marker of acute bowel ischaemia

BACKGROUND

Occlusion of the superior mesenteric artery (SMA) demands prompt recognition and diagnosis. No accurate diagnostic method is available. The aim of this study was to determine whether the fibrinolytic marker D-dimer is a useful early marker of acute bowel ischaemia.

METHODS

Fourteen patients suspected of having acute bowel ischaemia were analysed for an increase in plasma D-dimer level.

RESULTS

Six patients had embolic or thrombotic occlusion of the SMA and all had significantly higher D-dimer levels than those without thromboembolic occlusion (P < 0.05). Four patients with strangulation of the small bowel due to adhesions and one with a ruptured aortic aneurysm also had raised D-dimer values.

CONCLUSION

In patients with suspected thromboembolic occlusive disease of the SMA, a raised level of D-dimer indicated the presence of acute bowel ischaemia, whatever the cause. A more extensive prospective study is needed to evaluate a potential survival benefit using the test as a marker of the need for urgent laparotomy.

Hemostatic imbalance in active and quiescent ulcerative colitis

OBJECTIVE

In healthy conditions, factors inducing or inhibiting coagulation and factors inducing or inhibiting fibrinolysis are in balance. In ulcerative colitis, hypercoagulation is presumed, which may explain part of the clinical features of this disease. Therapy strategies affecting hemostasis may improve the course of ulcerative colitis. This study was conducted to evaluate the balance of coagulation and fibrinolysis in the course of treatment of active ulcerative colitis.

METHODS

Patients with active ulcerative colitis were studied by serial determination of markers of the coagulation cascade (thrombin-antithrombin complexes and fibrin degradation products [FbDP]) and the fibrinolytic cascade (fibrinogen degradation products [FgDP]). Parameters of inflammation were also measured (C-reactive protein [CRP], erythrocyte sedimentation rate [ESR], albumin, platelet count, and fibrinogen). Disease activity was assessed by endoscopic and histopathological scores. Follow-up measurement was performed in the course of treatment at the third or fourth month after baseline. Measurements were compared with healthy controls.

RESULTS

Thirty-three patients and 22 healthy controls were included. During active ulcerative colitis, inflammatory parameters (CRP, ESR, platelet count) and hemostatic parameters (thrombin-antithrombin complexes, fibrinogen, FgDP, and FbDP) were elevated in comparison with healthy controls. Albumin was decreased and antithrombin-III remained unchanged. During treatment, disease activity decreased significantly endoscopically and histopathologically (p < 0.001). CRP, ESR, platelet count, and fibrinogen also decreased significantly. The hemostatic balance, expressed as the ratio between the plasmin-dependent generation of FgDP and coagulation-dependent generation of FbDP, increased from 0.69 to 1.12 during treatment, mainly because of a decrease of FbDP. In healthy controls, this ratio was

CONCLUSIONS

The coagulation and fibrinolytic cascades were activated in active ulcerative colitis, with a hemostatic imbalance in favor of coagulation. This hypercoagulability persisted in 20% (7/33) of patients with ulcerative colitis in remission. The decrease of FbDP and the increase in the FgDP/FbDP ratio during reconvalescence of ulcerative colitis showed that the coagulation cascade was more activated than the fibrinolytic cascade in active disease.

The risk assessment profile score identifies trauma patients at risk for deep vein thrombosis

BACKGROUND

The identification of trauma patients at risk for the development of deep venous thrombosis (DVT) at the time of admission remains difficult. The purpose of this study is to validate the risk assessment profile (RAP) score to stratify patients for DVT prophylaxis.

METHODS

All patients admitted from November 1998 thru May 1999 were evaluated for enrollment. We prospectively assigned patients as low risk or high risk for DVT using the RAP score. High-risk patients received both pharmacologic and mechanical prophylaxis. Low-risk patients received none. Surveillance duplex Doppler scans were performed each week of hospitalization or if symptoms developed. Hospital charges for prophylaxis were used to determine the savings in the low-risk group. Statistical differences between the risk groups for each factor of the RAP and development of DVT were determined by the chi-squared test, with significance at a probability value of less than .05.

RESULTS

There were 102 high-risk (64%) and 58 low-risk (36%) individuals studied. Eleven of the high-risk group (10.8%) experienced the development of DVT (asymptomatic, 64%). None of the low-risk group was diagnosed with DVT. Five of the 16 RAP factors were statistically significant for DVT. Eliminating prophylaxis and Doppler scans in low-risk patients resulted in a total savings of $18,908 in hospital charges.

CONCLUSIONS

The RAP score correctly identified trauma patients at increased risk for the development of DVT. Despite prophylaxis, the high-risk group warrants surveillance scans. Withholding prophylaxis in low-risk patients can reduce hospital charges without risk.

D-dimer for the diagnosis of venous thromboembolism

D-dimer, a breakdown product of cross-linked fibrin has been extensively evaluated as a diagnostic test for acute venous thromboembolism. Rapid, highly sensitive D-dimer assays are now available that are suitable for testing in the emergency setting. Preliminary studies suggest that when using a highly sensitive D-dimer assay, a negative test result may,be sufficient to exclude the diagnosis of venous thromboembolism without need for further testing. Less sensitive, but more specific D-dimer assays are also available. The negative predictive value of these latter assays is insufficient to exclude venous thromboembolism on the basis of a negative test result alone. However, their utility is increased by identifying patient populations at low risk for venous thromboembolism using consideration of clinical probability or radiographic testing. Further, large multicenter management studies are required to confirm the safety of relying on a negative D-dimer result to exclude the diagnosis of venous thromboembolism.