Variation of plasma D-dimer following surgery: implications for prediction of postoperative venous thromboembolism

Machine learning prediction of venous thromboembolism after surgeries of major sellar region tumors

PURPOSE

To describe and predict the risk of venous thromboembolism (VTE) after surgical resection of major sellar region tumors.

METHOD

Patients with sellar region tumors were identified from a database. The outcome was VTE, including deep vein thrombosis (DVT) and pulmonary embolism (PE) within 60 days after surgery. We trained regression and machine learning models to predict the outcome using baseline characteristics, surgical findings and postoperative laboratory tests.

RESULTS

Among 3818 patients included, 124 patients developed VTE after surgery. The total 60-day VTE incidence was 3.2 %, with incidence peak within ten days after the surgery. The risk increased in patients >65 years old (OR 2.96, p < 0.001), in patients with chordoma (OR 3.40, p = 0.006) or craniopharyngioma (OR 1.86, p = 0.036), in patients underwent craniotomy approach (OR 2.78, p = 0.017), in patients with high volume CSF leakage (OR 4.24, p < 0.001), and in patients with longer surgical duration (OR 1.78, p = 0.029). The linear discriminant analysis algorithm had the highest AUC (0.869, 95%CI, 0.840-0.898) in predicting the outcome. The specificity, accuracy, and sensitivity of the best model were 61.8 %, 93.6 %, and 92.8 %, respectively. Risk stratification using our best model suggested that 1.3 % and 24.5 % of the patient developed VTE in the low-risk group and in the high-risk group, respectively. We developed an online decision-support tool available on https://deepvep.shinyapps.io/VTEpred/.

CONCLUSION

The overall incidence of VTE after surgical resection of major sellar region tumors was clinically significant, especially in older patients with chordoma or craniopharyngioma.

Which serum markers predict the success of reimplantation after periprosthetic joint infection?

Purpose

In clinical practice, serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels are routinely used to screen for periprosthetic joint infection (PJI), but the effectiveness of predicting the success of reimplantation is variable. This study aimed to evaluate the diagnostic effectiveness of serum CRP, ESR, plasma D-dimer, and fibrinogen values in groups achieving treatment success or failure for PJI.

Methods

A total of 119 PJI cases between January 2012 and January 2017 were identified and included in this study. The most recent serum CRP, ESR, plasma D-dimer, and fibrinogen values obtained prior to performing second-stage revision or spacer exchange were collected for analysis. Treatment failure was defined as having been unable to undergo reimplantation due to clinically persistent infection or reinfection after reimplantation.

Results

All these tests showed significantly lower values in the treatment success group than in the treatment failure group. The optimal cutoff serum CRP, ESR, plasma D-dimer, and fibrinogen levels for predicting the success of reimplantation were 9.4 mg/L, 29 mm/h, 1740 ng/mL, and 365.6 mg/dL, respectively. All tests had the same sensitivity (72.7%) except for ESR (63.6%), while their specificities were 92.6%, 88.0%, 72.3%, and 83.2%, respectively. Plasma fibrinogen had the highest AUC value of 0.831 [95% confidence interval (CI), 0.685 to 0.978], followed by serum CRP (0.829) and ESR (0.795); plasma D-dimer had the lowest AUC value of 0.716 (95% CI, 0.573 to 0.859).

Conclusion

Plasma CRP and fibrinogen are good tests for predicting reimplantation success after two-stage revision procedures for patients with PJI.

Recent Progresses in Development of Biosensors for Thrombin Detection

Thrombin is a serine protease with an essential role in homeostasis and blood coagulation. During vascular injuries, thrombin is generated from prothrombin, a plasma protein, to polymerize fibrinogen molecules into fibrin filaments. Moreover, thrombin is a potent stimulant for platelet activation, which causes blood clots to prevent bleeding. The rapid and sensitive detection of thrombin is important in biological analysis and clinical diagnosis. Hence, various biosensors for thrombin measurement have been developed. Biosensors are devices that produce a quantifiable signal from biological interactions in proportion to the concentration of a target analyte. An aptasensor is a biosensor in which a DNA or RNA aptamer has been used as a biological recognition element and can identify target molecules with a high degree of sensitivity and affinity. Designed biosensors could provide effective methods for the highly selective and specific detection of thrombin. This review has attempted to provide an update of the various biosensors proposed in the literature, which have been designed for thrombin detection. According to their various transducers, the constructions and compositions, the performance, benefits, and restrictions of each are summarized and compared.

Paradoxical Behavior of Plasma d-Dimer From Explantation to Reimplantation in a Two-Stage Revision for Periprosthetic Joint Infection

BACKGROUND

The variation of plasma d-dimer, an inflammatory marker, from pre-explantation to pre-reimplantation in two-stage revision remains unclear. Our objective was to evaluate delta-changes (Δ) in d-dimer, erythrocyte sedimentation rate (ESR), and C-reactive-protein (CRP), to ascertain whether these delta-changes are associated with the outcome of reimplantation. We hypothesized a decrease in d-dimer before reimplantation.

METHODS

A retrospective review was performed on a consecutive series of 95 two-stage revisions indicated for periprosthetic joint infection. Surgeries were performed by 3 surgeons at a single institution (2018-2020). The minimum follow-up was 1 year. The inclusion criteria comprised availability of d-dimer results at pre-explantation and pre-reimplantation. As a result, only 30 reimplantations were included. Success of reimplantation was defined by Musculoskeletal Infection Society outcome reporting tool: Tier 1/Tier 2 vs Tier 3/Tier 4. Nonparametric tests and Mann-Whitney U-tests were conducted to compare Δd-dimer% (pre-explantation value - pre-reimplantation value/pre-explantation value × 100). The bootstrapped receiver operating characteristic curve analyses with 2,000 replicates of 30 cases were conducted.

RESULTS

The median time between explantation and reimplantation was 86 days (interquartile range [IQR] = 77.7-138.5 days). Overall, a paradoxical median percent increase (Δd-Dimer% [INCREMENT] = 12.6%) in d-dimer was found from pre-explantation to pre-reimplantation (IQR = -28.06% to 77.3%). However, there was a percentage decrease in ESR (ΔESR% [DECREMENT] = -40%; IQR = -70.52% to 3.85%) and CRP (ΔCRP% [DECREMENT] = -75%; IQR = -87.43% to -61.34%). The changes in all these markers were not different between Musculoskeletal Infection Society Tier 1/2 and 3/4 outcomes (Δd-Dimer%, P = .146; ΔESR%, P = .946; ΔCRP%, P = .463). With area under curve of 0.676, Δd-dimer% (INCREMENT) appeared to be performing best in diagnosing infection control, which was nonexplanatory.

CONCLUSION

Plasma d-dimer paradoxically increases before reimplantation while other inflammatory markers (ESR/CRP) decrease, emphasizing that surgeons shall adopt caution using d-dimer to make clinical decisions.

End Tidal Carbon Dioxide as a Screening Tool for Computed Tomography Angiogram in Postoperative Orthopaedic Patients Suspected of Pulmonary Embolism

BACKGROUND

Computed tomography pulmonary angiography (CTA) is the gold standard for diagnosing pulmonary embolism (PE) but involves radiation and iodinated contrast exposure. Of orthopedic patients evaluated for PE, a minority have a positive CTA study. Herein, we evaluate end tidal carbon dioxide (ETCO2) as a method to identify patients at low risk for PE and may not require a CTA. We hypothesize that ETCO2 will be useful for predicting the absence of PE in postoperative orthopedic patients.

METHODS

In this prospective study, all patients older than 18 years who were admitted for orthopedic surgery and who had a CTA performed for PE were eligible. These patients underwent an ETCO2 measurement. Patients were determined to have PE if they had a positive PE-protocol CT.

RESULTS

Between May 2014 and April 2015, 121 patients met the inclusion criteria for the study. Of these patients, 84 had a negative CTA examination, 25 had a positive examination, and 12 had a nondiagnostic examination. We found a statistically significant difference (P = .03) when comparing the average ETCO2 values for the positive and negative CTA groups. An ETCO2 cutoff value of 43 mm Hg was 100% sensitive with a negative predictive value of 100% for absence of PE on CTA.

CONCLUSION

This study demonstrates a significant difference in ETCO2 measurements between postoperative orthopedic patients with and without CTA-detected PE. A cutoff value of >43 mm Hg may be useful in excluding patients from undergoing CTA.

D-dimer plasma level: a reliable marker for venous thromboembolism after elective craniotomy

OBJECT

The incidence of deep venous thrombosis (DVT) after craniotomy is reported to be as high as 50%. In outpatients, D-dimer levels of more than 0.5 mg/L indicate venous thromboembolism (VTE, which subsumes DVT and pulmonary embolism [PE]) with a sensitivity of 99.4% and a specificity of 38.2%. However, D-dimer levels are believed to be unreliable in postoperative patients. The authors undertook the present study to test the hypothesis that D-dimer levels would be systematically raised in a postoperative population and to define a feasible threshold for identification of VTE.

METHODS

Doppler ultrasonography of the lower extremity was performed pre- and postoperatively to evaluate for DVT in 101 patients who underwent elective craniotomy. D-dimer levels were assessed preoperatively and on the 3rd, 7th, and 10th days after surgery. Statistical analysis was carried out to define a feasible threshold for D-dimer levels.

RESULTS

D-dimer plasma levels were found to be systematically raised postoperatively, and they differed between patients with and without VTE in a highly significant way. On the 3rd day after surgery, D-dimer levels of more than 2 mg/L indicated VTE with a sensitivity of 95.3% and a specificity of 74.1%, allowing for the definition of a feasible threshold. D-dimer levels of more than 4 mg/L were observed in all patients who had PE during the postoperative period (n = 9). Ventilation time and duration of surgery were identified as highly significant risk factors for the development of VTE.

CONCLUSIONS

Using a threshold of 2 mg/L, D-dimer levels will indicate VTE with a high degree of sensitivity and specificity in patients who have undergone craniotomy. Pulmonary embolism seems to be indicated by even higher D-dimer levels. Given that the development of D-dimer plasma levels in the postoperative period follows a principle that can be predicted and that deviations from it indicate VTE, this principle might be applicable to other types of surgery.

D-dimer: Simple Test, Tough Problems

Context.—D-dimer is widely used for exclusion, or as an aid in diagnosis, of venous thromboembolism (VTE); however, the D-dimer assay methods available from manufacturers and the laboratory application of those methods vary widely.

Objectives.—To describe the current laboratory practice regarding the assay and reporting of D-dimer.

Design.—Laboratories' D-dimer proficiency testing data were analyzed and laboratory practices regarding the performance and reporting of D-dimer were surveyed.

Results.—Initial grading of D-dimer proficiency testing demonstrated high variability within and among methods. This variability continued to be present for several years after attempts to intervene. The number of laboratories using D-dimer to exclude VTE grew from 1500 in 2004 to more than 3500 in 2012. Survey and proficiency testing data demonstrated that 33% of laboratories changed the type or magnitude of units from that recommended by the manufacturer, a practice associated with as much as a 20-fold increase in the failure of proficiency testing. Many laboratories used a threshold for the exclusion of VTE that is higher than that recommended by the manufacturer. Many laboratories continue to use qualitative assays with insufficient sensitivity for exclusion of VTE.

Conclusions.—There is considerable variability both within and among quantitative methods used to assay D-dimer by laboratories. Laboratory practice continues to vary widely regarding the type and magnitude of units reported and the setting of the threshold for the exclusion of VTE. Although improved, the variability continues despite initial efforts to intervene.

Subclinical activation of coagulation and fibrinolysis in laparoscopic cholecystectomy: do risk factors exist?

PURPOSES

This study examines whether inherent patient-related risk factors (age, gender) modify the effect of laparoscopic cholecystectomy (LC) upon the coagulation and fibrinolysis cascades.

METHODS

This observational study included 119 low-risk for deep vein thrombosis (DVT) patients undergoing elective LC, without thromboprophylaxis. Pre-operatively and 24 h post-operatively we measured PT-INR, aPTT, FDP, d-dimer, and fibrinogen. Color Doppler scan of the lower extremity was performed the 1st post-operative day. Differences before and after surgery were analyzed with respect to risk factors.

RESULTS

No clinically or ultrasound evident DVT was observed. INR (1.04 ± 0.06 vs. 1.12 ± 0.11, p < 0.0001), d-dimer (0.38 ± 0.36 vs. 0.9 ± 0.64, p < 0.0001), plasma fibrinogen (380.8 ± 74.9 vs. 403.8 ± 78.8, p = 0.0001) and FDP positivity exhibited statistically significant increase after surgery. The levels of aPTT did not exhibit any significant change. Concerning d-dimer, older age was associated with higher pre-operative concentrations; older patients accordingly exhibited more intense increase in d-dimer and FDP positivity after surgery. Male sex was associated with higher PT-INR and aPTT before surgery, as well as with more pronounced increase in PT- INR postoperatively; similarly, older age was associated only with higher PT-INR before surgery.

CONCLUSIONS

Despite no DVT, significant increase in PT-INR, d-dimer, FDP and fibrinogen appeared after LC. This may be attributed to surgical trauma and pneumoperitoneum effects on the portal vein flow. Elderly subjects and males seem particularly vulnerable, demonstrating more sizeable changes.

Kinetics of D-dimer after general surgery

D-dimers may be elevated after surgery. However, the kinetics of postoperative D-dimers remains unknown hampering the use of D-dimer testing in surgical patients with suspected venous thromboembolism. D-dimer levels were prospectively measured in 154 patients after general surgery at predefined time points (kinetics were determined in an initial cohort of 108 patients; for validation, these findings were applied to a second cohort of 46 patients). Clinical factors influencing the peak of D-dimers were analyzed using multivariate regression. Surgical operations were stratified based on severity (type I: not entering abdominal cavity; type II: intraabdominal; type III: retroperitoneal/liver surgery). D-dimer levels increased postoperatively reaching a peak on day 7. After type I surgery, peak D-dimer levels did not exceed normal range (300 ng/ml, 100-500). After type II procedures, peak D-dimer level was 1500 ng/ml (200-7800) and returned to normal values after 25 days (+/-14). Peak level was 4000 ng/ml (500-14 400) after type III surgery normalizing within 38 days (+/-11). Clearance of D-dimer was exponential after having reached the peak with 6.0% per day (95% confidence interval 4.8-7.1%). By this clearance, D-dimer values could be adequately predicted in the validation cohort after day 7 (r2 = 0.63). Peak D-dimer levels were independently influenced by the type of surgery (P < 0.001), the operation time (P < 0.001) and by preoperatively elevated D-dimer levels (P < 0.001). Based on this data, duration of postoperative D-dimer elevation after abdominal surgery is predictable. This study indicates for the first time when D-dimers may be used again in the diagnostic algorithm for venous thromboembolism exclusion after surgery in patients with low or moderate clinical probability.

Inflammatory response in patients undergoing hip surgery due to osteoarthrosis or different types of hip fractures

OBJECTIVE

Hip surgery represents a major intervention associated with significant inflammatory response. The objective of our study was to compare markers of systemic inflammation and soluble adhesive molecules in patients undergoing elective hip replacement to those with hip fracture either intracapsular (IC) or extracapsular (EC).

DESIGN

We included 65 consecutive patients undergoing hip surgery--17 patients with elective hip replacement (EL group), 29 patients with EC fracture (EC group) and 11 patients with IC fracture (IC group). Fibrinogen (FBG), orosomucoid (ORM), C-reactive protein (CRP), transferrin (TRF) and white blood cells count (WBC), sP-selectin, sE-selectin, and soluble intercellular adhesion molecule-1 (sICAM-1) were measured before surgery 4h, 48h, and 7 days after surgery.

RESULTS

IC patients had preoperatively highest values of inflammatory markers including FBG, CRP, ORM, WBC and lowest values of TRF, as compared to intermediate values found in EC and lowest values in EL groups. The surgery has led in all three subgroups to significant elevation in CRP, ORM and decrease in TRF. In IC group, the subsequent recovery of inflammatory markers was very slow. We noted a significant suppression of sP-selectin and sE-selectin values in all subgroups after surgery. The decrease of sE-selectin but not of sP-selectin correlated with changes in hemoglobin and blood transfusions' administration.

CONCLUSIONS

Hip surgery is associated with significant inflammatory reaction. In patients with hip fractures, inflammatory markers are elevated already preoperatively, more so in IC than in EC fractures. The unexpected observation of a significant postoperative decrease in sE-selectin and sP-selectin will require further research for elucidation.

Help me, Doctor! My D-dimer is raised

Although optimal strategy for management of patients with suspected venous thromboembolism depends on local expertise and cost, diagnostic algorithms including clinical assessment and D-dimer have been validated in several trials. However, a new paradigm shift is emerging, giving an extended role of D-dimer measurement in clinical practice. D-dimer is a useful biomarker to help determine initial anticoagulant therapy in patients with thrombosis. Emerging evidence also endorses a 'predictive' role for raised D-dimer levels, since its measurement provides prognostic indications for a variety of conditions, including venous thromboembolism, disseminated intravascular coagulation, cardiovascular disease, infectious diseases, and cancer. Additional investigation is needed to clarify whether raised D-dimer is an epiphenomenon or it is actively involved in pathophysiology. Further studies are also required to establish whether D-dimer testing, alone or combined with other prognostic indicators, can be used to identify patient candidates for further triage and treatment. Nevertheless, the hazard(s) associated with raised D-dimer in plasma requires re-emphasis in the teaching of post-graduates, junior doctors and medical students, including the most effective treatments to inhibit clot spread and decrease the probability of further significant thrombotic incidents even in the absence of any 'detectable' thrombosis.

The value of the D-Dimer assay for predicting vein thrombosis in rehabilitation patients receiving prophylactic low molecular weight heparin doses

PURPOSE

Early diagnosis and treatment of venous thrombosis biocontact="no" are essential in preventing pulmonary embolism (PE) and reducing the risk of recurrence. The objective was to assess the usefulness of the D-Dimer testing to rule out symptomatic VT in populations of patients receiving heparin in prophylactic doses.

METHODS

One hundred and twenty-three rehabilitation patients with medium or high risk for VT were investigated. Patients were affected by acquired cerebral diseases (n=31), severe brain damage (n=32) or orthopaedic surgical sequelae for major joint replacement or multiple limb fractures (n=60). All patients were receiving prophylactic heparin doses. D-Dimer levels were assessed using Dimertest Latex Agglutination Assay in citrated plasma. Single blinded compression Doppler Ultrasound (DUS) examination was performed in conformity with international standards.

RESULTS

In this specific setting, good sensitivity and specificity of the D-Dimer test was confirmed in patients with acquired cerebral diseases during rehabilitation, whereas false positive results were found in most patients who had undergone major joint replacement, until several weeks after surgery.

CONCLUSIONS

In rehabilitation patients receiving prophylactic heparin doses, the D-Dimer test seems to confirm high sensitivity and high negative predictive value for VT and PE. Relevant clinical variables seem to reduce the usefulness of the D-Dimer test as a screening tool for VT, at least in orthopaedic patients with joint prosthesis.

Surveillance biologique après chirurgie orthopédique. Quel apport au diagnostic des complications infectieuses et thromboemboliques ?

OBJECTIVES

To determine the modification in postoperative D-dimer level as a function of the surgical act and to assess the relevance of this measure for diagnosing thromboembolism.

METHOD

A cohort of 179 patients was followed: group 1 comprised 128 patients undergoing lower limb arthroplasty, group 2 comprised 29 patients undergoing lower limb surgery without implant, and group 3 comprised 22 patients undergoing spinal or upper limb surgery. D-dimer level was systematically measured on admission and then once a week for 4 weeks. Doppler ultrasonography was performed on clinical suspicion of deep vein thrombosis. D-dimer levels were compared between patients with and without deep vein thrombosis.

RESULTS

D-dimer levels were constantly elevated postsurgery (2- to 6-fold above normal) and returned to normal by week 4 in groups 2 and 3 but remained elevated in group 1 (3-fold above normal). Deep vein thrombosis was suspected in 45 cases and confirmed by Doppler ultrasonography in 10 cases. D-dimer level was not significantly different between patients with deep vein thrombosis and those without.

DISCUSSION AND CONCLUSIONS

In the postoperative period, measurement of D-dimer level does not aid in diagnosing thromboembolism since its constant high level obviates any negative predictive value.

Assessment of red blood cell and coagulation laboratory data

Critically ill patients present with a myriad of hematologic problems of various etiologies. The astute advanced practice nurse carefully reviews laboratory data incorporating principles of diagnostic reasoning and critical thinking while developing the plan of care. An in-depth understanding of hematology including red blood cells, red blood cell indices, and coagulation laboratory data is essential in the quest to understand the patient's pathophysiology. With every decade, nurses and physicians learn more about diseases that have plagued mankind for centuries--learning in greater detail about the deleterious effects and subsequent outcomes that often begin as subtle changes in traditional laboratory data. Greater focus on interpreting hematologic data and seeking support for diagnoses in clinical correlates will serve nurses well. This article intends to move advanced practice nurses beyond their current understanding of hematologic values--enabling them to understand that how and why we measure is as important as what we measure. No longer is it enough to simply measure physiologic data to develop a care plan driven by the patient's diagnoses. The contemporary nurse understands the importance of assigning meaning to data. Meaningful data are manageable data.