Is stand-alone D-dimer testing safe to rule out acute pulmonary embolism?

Current use of D-dimer for the exclusion of venous thrombosis in hospitalized patients

D-dimer assay’s utility for excluding venous thromboembolism (VTE) in hospitalized patients is debatable. We aimed to assess the current use of D-dimer as a diagnostic tool for excluding VTE in hospitalized patients and examine a mandatory age-adjusted D-dimer (AADD) threshold for diagnostic imaging. Retrospective cohort study between 2014 to 2019 that included patients from medical and surgical wards with a positive AADD result drawn during their hospitalization. The outcomes were determining a D-dimer threshold requiring further evaluation and assessing the prognostic value of D-dimer in predicting clinically relevant VTE in hospitalized patients. The cohort included 354 patients, 56% of them underwent definitive diagnostic imaging, and 7.6% were diagnosed with VTE after a positive AADD within 90 days of follow-up. Mortality rates were higher in patients diagnosed with VTE (33.3% vs. 15.9%, p = 0.03). Patients with pneumonia and other infectious etiologies were less likely to be further evaluated by definitive imaging (p = 0.001). Patients with a respiratory complaint (p = 0.02), chest pain (p < 0.001), or leg swelling (p = 0.01) were more likely to undergo diagnostic imaging. Patients with D-dimer levels > X2 the AADD were at increased risk of VTE [OR 3.87 (1.45–10.27)]. At 90 days of follow-up, no excess mortality was observed for patients without diagnostic evaluation following elevated AADD. D-dimer may be used in hospitalized patients to exclude VTE using the traditional AADD thresholds, with a high negative predictive value. D-dimer levels > X2 the AADD usually mandates further diagnostic imaging, while lower levels, probably do not require additional workup, with a sensitivity of almost 80% and no excess mortality.

Prevalence of preoperative Deep Venous Thrombosis (DVT) following elderly intertrochanteric fractures and development of a risk prediction model

Background

This study aimed to investigate the prevalence of preoperative deep venous thrombosis (DVT) following intertrochanteric fractures in the elderly and identify the associated factors, based on which a risk prediction model was developed.

Method

This was a retrospective single-center study of elderly patients presenting with intertrochanteric fractures between our institution between January 2017 and December 2020. Patients' duplex ultrasound (DUS) or venography results were retrieved to evaluate whether they had a preoperative deep venous thrombosis (DVT) of bilateral extremities, whereby patients were dichotomized. Various variables of interest on demographics, comorbidities, injury and biomarkers were extracted and their relationship between DVT were investigated. Statistically significant variables tested in multivariate logistics regression analyses were used to develop a risk prediction model.

Results

There were 855 patients eligible to be included in this study, and 105 were found to have preoperative DVT, with a prevalence rate of 12.3%. Ten factors were tested as significantly different and 2 marginally significant between DVT and non-DVT groups in the univariate analyses, but only 6 demonstrated the independent effect on DVT occurrence, including history of a VTE event (OR, 4.43; 95%CI, 2.04 to 9.62), time from injury to DVT screening (OR, 1.19; 95%CI, 1.13 to 1.25), BMI (OR, 1.11; 95%CI, 1.04–1.18), peripheral vascular disease (OR, 2.66; 95%CI, 1.10 to 6.40), reduced albumin (2.35; 95%CI, 1.48 to 3.71) and D-Dimer > 1.0 mg/L(OR, 1.90; 95%CI, 1.13 to 3.20). The DVT risk model showed an AUC of 0.780 (95%CI, 0.731 to 0.829), with a sensitivity of 0.667 and a specificity of 0.777.

Conclusion

Despite without a so high prevalence rate of DVT in a general population with intertrochanteric fracture, particular attention should be paid to those involved in the associated risk factors above. The risk prediction model exhibited the improved specificity, but its validity required further studies to verify.

Beyond the d-dimer - Machine-learning assisted pre-test probability evaluation in patients with suspected pulmonary embolism and elevated d-dimers

INTRODUCTION

Acute pulmonary embolism (PE) is a leading cardiovascular cause of death, resembling a common indication for emergency computed tomography (CT). Nonetheless, in clinical routine most CTs performed for suspicion of PE excluded the suspected diagnosis. As patients with low to intermediate risk for PE are triaged according to the d-dimer, its relatively low specifity and widespread elevation among elderly might be an underlying issue. Aim of this study was to find potential predictors based on initial emergency blood tests in patients with elevated d-dimers and suspected PE to further increase pre-test probability.

METHODS

In this retrospective study all patients at the local university hospital's emergency room from 2009 to 2019 with suspected PE, emergency blood testing and CT were included. Cluster analysis was performed to separate groups with distinct laboratory parameter profiles and PE frequencies were compared. Machine learning algorithms were trained on the groups to predict individual PE probability based on emergency laboratory parameters.

RESULTS

Overall, PE frequency among the 2045 analyzed patients was 41%. Three clusters with significant differences (p ≤ 0.05) in PE frequency were identified: C1 showed a PE frequency of 43%, C2 40% and C3 33%. Laboratory parameter profiles (e.g. creatinine) differed significantly between clusters (p ≤ 0.0001). Both logistic regression and support-vector machines were able to predict clusters with an accuracy of over 90%.

DISCUSSION

Initial blood parameters seem to enable further differentiation of patients with suspected PE and elevated d-dimers to raise pre-test probability of PE. Machine-learning-based prediction models might help to further narrow down CT indications in the future.

Safety of D-dimer testing as a stand-alone test for the exclusion of deep vein thrombosis as compared with other strategies

Essentials The aim of deep vein thrombosis (DVT) diagnostic work-up is to maximize both safety and efficiency. We explored whether D-dimer is safe and efficient as a stand-alone test to exclude DVT. Our findings suggest it is a safe, efficient and simplified diagnostic strategy. The safety of age-adjusted D-dimer as a stand-alone test requires further investigation. SUMMARY: Background Several strategies for safely excluding deep vein thrombosis (DVT) while limiting the number of imaging tests have been explored. Objectives To determine whether D-dimer testing could safely and efficiently exclude DVT as a stand-alone test, and evaluate its performance as compared with strategies that incorporate the Wells score and age-adjusted D-dimer. Patients/Methods We included consecutive outpatients referred with suspected DVT to the Emergency Department at Østfold Hospital, Norway. STA-Liatest D-Di PLUS D-dimer was analyzed for all patients. Patients with a D-dimer level of ≥ 0.5 μg mL-1 were referred for compression ultrasonography (CUS). In patients with a D-dimer level of < 0.5 μg mL-1 , no further testing was performed and anticoagulation was withheld. Patients were followed for 3 months for venous thromboembolism (VTE). Results Of the 913 included patients, 298 (33%) had a negative D-dimer result. One hundred and seventy-three patients (18.9%) were diagnosed with DVT at baseline. One of 298 patients had DVT despite having a negative D-dimer result, resulting in a failure rate of 0.3% (95% confidence interval [CI] 0.1-1.9%). Adding the modified Wells score would have yielded a failure rate of 0.0% (95% CI 0.0-1.8%) while necessitating 87 more CUS examinations. Age-adjusted D-dimer as a stand-alone test would have necessitated 80 fewer CUS examinations than fixed D-dimer as a stand-alone test, at the cost of a failure rate of 1.6% (95% CI 0.7-3.4%). Conclusions This outcome study shows that a negative high-sensitivity D-dimer result safely excludes DVT in an outpatient population, and necessitates fewer CUS than if used in combination with Wells score. The safety of stand-alone age-adjusted D-dimer needs further assessment in prospective outcome studies.

Deep Vein Thrombosis of the Upper Extremity

BACKGROUND

Deep venous thrombosis (DVT) arises with an incidence of about 1 per 1000 persons per year; 4-10% of all DVTs are located in an upper extremity (DVT-UE). DVT-UE can lead to complications such as post-thrombotic syndrome and pulmonary embolism and carries a high mortality.

METHODS

This review is based on pertinent literature, published from January 1980 to May 2016, that was retrieved by a systematic search, employing the PRISMA criteria, carried out in four databases: PubMed (n = 749), EMBASE (n = 789), SciSearch (n = 0), and the Cochrane Library (n = 12). Guidelines were included in the search.

RESULTS

DVT-UE arises mainly in patients with severe underlying diseases, especially cancer (odds ratio [OR] 18.1; 95% confidence interval [9.4; 35.1]). The insertion of venous catheters-particularly central venous catheters-also elevates the risk of DVT-UE. Its clinical manifestations are nonspecific. Diagnostic algorithms are of little use, but ultrasonography is very helpful in diagnosis. DVT-UE is treated by anticoagulation, with heparin at first and then with oral anticoagulants. Direct oral anticoagulants are now being increasingly used. The thrombus is often not totally eradicated. Anticoagulation is generally continued as maintenance treatment for 3-6 months. Interventional techniques can be used for special indications. Patients with DVT-UE have a high mortality, though they often die of their underlying diseases rather than of the DVT-UE or its complications.

CONCLUSION

DVT of the upper extremity is becoming increasingly common, though still much less common than DVT of the lower extremity. The treatment of choice is anticoagulation, which is given analogously to that given for DVT of the lower extremity.

Prophylaxis of Postoperative Venous Thromboembolism Using Enoxaparin After Esophagectomy: A Prospective Observational Study of Effectiveness and Safety

BACKGROUND

The incidence of venous thromboembolism (VTE) after esophagectomy is higher than in other gastroenterological cancer surgery. Although the effectiveness and safety of thromboprophylaxis using enoxaparin have been established in orthopedic, abdominal, and pelvic surgeries, no studies regarding esophagectomy are available.

METHODS

A prospective observational study was conducted to elucidate the usefulness of enoxaparin for VTE prophylaxis after esophagectomy. The study enrolled 30 patients who underwent elective esophagectomy for esophageal cancer between April 2015 and October 2016. During postoperative days 2-11, the patients received a subcutaneous injection of enoxaparin (2000 IU) twice daily. The primary end point for the study was the incidence of postoperative VTE. In addition, the incidence of all enoxaparin treatment- and operation-related adverse events was investigated. The study identified VTE by VTE protocol-enhanced computed tomography, performed routinely during and after enoxaparin treatment.

RESULTS

One pulmonary embolism (PE) (3.3%) and two deep vein thromboses (DVTs) (6.7%) were observed during enoxaparin treatment. In addition, one PE (3.6%) and four DVTs (14.3%) (one patient experienced both) were observed after treatment. All VTEs were asymptomatic. Regarding enoxaparin-related adverse events, four minor bleeds occurred but did not require discontinuation of enoxaparin. The incidence of postoperative morbidity was acceptable. In blood tests related to coagulation, no significant differences were observed between patients with and without VTE.

CONCLUSIONS

The authors believe that thromboprophylaxis using enoxaparin is safe and can prevent VTE after esophagectomy. However, its effectiveness is limited to the period of treatment, so additional prophylaxis may be recommended.

Age-adjusted D-dimer cut-off leads to more efficient diagnosis of venous thromboembolism in the emergency department: a comparison of four assays

Essentials Age-adjusted D-dimer cut-offs decrease the false positives in the elderly. Four D-dimer assays were compared in venous thromboembolism outpatients in an emergency ward. Age-adjusted cut-off resulted in improved specificity with maintained sensitivity for all assays. There was a substantial decrease in false positive results, especially in the older population.

SUMMARY

Background The study compares different D-dimer assays and age-adjusted cut-offs in outpatients with suspected venous thromboembolism (VTE). The plasma concentration of this sensitive biomarker is increased by activated coagulation, but also by several conditions that are linked to an increased risk of VTE. One such condition is old age, which poses a common clinical problem where many prefer not to analyze D-dimer in elderly patients. Age-adjusted cut-offs have been validated for both deep venous thrombosis (DVT) and pulmonary embolism, aiming to increase specificity without notably decreasing sensitivity. Objectives We evaluated four common D-dimer assays in parallel, with and without applying age-adjusted cut offs for VTE. Patients/methods The prospective single-center study was conducted in 940 outpatients attending the emergency department with clinically suspected pulmonary embolism or DVT. Four automated D-dimer assays were compared (Siemens INNOVANCE® , Roche Tina-quant, Medirox MRX and STA® -Liatest® D-Di PLUS). Results All assays performed with areas under the ROC curve (AUC) > 0.9 and maintained their sensitivities after implementation of age-adjusted cut-offs. Specificities increased by 6-7% and number needed to test decreased by < 0.3. The rate of false positive results decreased by 6% overall and by 10-20% for patients ≥ 70. Conclusions Age-adjusted cut-offs resulted in maintained high sensitivity and a modest improvement in specificity and number needed to test for all evaluated D-dimer assays. There was a significant reduction in false positive results, which reflects avoidable unnecessary imaging without any compromise of clinical safety. This suggests a potential to benefit the management of VTE in elderly patients, both clinically and economically.

Efficacy and safety of postoperative anticoagulation prophylaxis with enoxaparin in patients undergoing pancreatic surgery: A prospective trial and literature review

BACKGROUND

/Objectives: Enoxaparin is low-molecular-weight heparin that is used for postoperative thromboprophylaxis. The purpose of this study was to evaluate the efficacy and safety of enoxaparin after pancreatic resection. We additionally carried out a literature review regarding venous thromboembolism (VTE) and postoperative bleeding mainly after hepatobiliary-pancreatic surgery.

METHODS

This was a prospective, single-arm study. Patients aged 20-79 years who planned to undergo pancreatic resection followed by postoperative anticoagulation therapy with enoxaparin were enrolled from 2013 to 2016. The exclusion criteria were low renal function, active bleeding, clinical signs of VTE at screening, or evidence of thromboembolic disease before surgery. The primary endpoint was the incidence of postoperative VTE. The secondary endpoint was the incidence of postoperative complications. For the literature review, PubMed was searched for relevant articles and the PRISMA guidelines were used.

RESULTS

In total, 103 patients were analyzed. Two patients (1.9%) developed asymptomatic VTE, and no patients developed symptomatic VTE. No in-hospital mortality occurred. Morbidities (Clavien-Dindo grade ≥ IIIa) occurred in 29 patients (28.1%). Three patients (2.9%) developed intra-abdominal hemorrhage due to pseudoaneurysm formation after pancreaticoduodenectomy or distal pancreatectomy. The literature review included nine articles, and all indicated that the results of this study were feasible.

CONCLUSION

This is the first prospective trial to focus on pharmacologic prophylaxis with enoxaparin after pancreatic surgery. Postoperative anticoagulant therapy with enoxaparin was used in patients who underwent pancreatic surgery with a low incidence of VTE and no increase in postoperative bleeding events compared with existing evidence.