Positive D-dimer Research Articles

Assessment of the frequency of deep venous thromboembolism in obstructive sleep apnea syndrome

The present study aimed to investigate the frequency of deep venous thrombosis (DVT) among patients with obstructive sleep apnea syndrome (OSAS). Patients who referred the preliminary diagnosis of OSAS were included in this study. D-dimer levels of all patients were measured, and D-dimer (+) patients were evaluated by Doppler USG of the lower-extremity. Mean age of the patient group was 52 ± 12 years and 31.8% (76/239) were women. The rate of D-dimer positivity among severe-OSAS cases (15/85) was significantly higher compared to the rest (13/154) (17.6% and 8.4%, respectively; p = 0.034). The risk of D-dimer positivity was elevated by 2.3 folds in severe-OSAS cases (OR: 2,324, 95% confidence interval: 1.048–5.152). Among 28 D-dimer (+) cases, 4 (14.2%) had DVT as demonstrated by USI of the lower-extremity. All four cases with DVT had severe OSAS. D-dimer was positive in 17.6% (15/85) of all severe OSAS cases. DVT was diagnosed in 4.7% (4/85) of severe-OSAS cases. DVT frequency was 26.6% (4/15) in D-dimer (+) severe-OSAS. Findings of this study indicate that severe-OSAS can be a significant risk factor for DVT. Additionally, data obtained in this study underline the benefits of questioning severe-OSAS patients with respect to DVT symptoms, investigating D-dimer levels and evaluating D-dimer (+) severe-OSAS cases for DVT prophylaxis.

Diagnostic and prognostic value of the D-dimer test in emergency department patients: secondary analysis of an observational study.

Background D-dimer measurement improves the rule-out of thromboembolic disease. However, little is known about the risk of false positive results for the diagnosis of thromboembolic disease and its prognostic value. Herein, we investigated factors influencing the accuracy of D-dimer and its prognostic value in a large cohort of emergency department (ED) patients. Methods This is a secondary analysis of a prospective observational single center, cohort study. Consecutive patients, for whom a D-dimer test was requested by the treating physician, were included. Associations of clinical parameters on admission with false positive D-dimer results for the diagnosis of thromboembolic disease were investigated with logistic regression analysis. Results A total of 3301 patients were included, of which 203 (6.1%) had confirmed thromboembolic disease. The negative and positive predictive values of the D-dimer test at the 0.5 mg/L cut-off were 99.9% and 11.4%, respectively. Several factors were associated with positive D-dimer results potentially falsely indicating thromboembolic disease in multivariate analysis including advanced age (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.04-1.05, p < 0.001), congestive heart failure (CHF) (OR 2.79, 95% CI 1.77-4.4, p < 0.01), renal failure (OR 2.00, 95% CI 1.23-3.24, p = 0.005), history of malignancy (OR 2.6, 95% CI 1.57-4.31, p < 0.001), C-reactive protein (CRP) (OR 1.02, 95% CI 1.01-1.02, p < 0.001) and glomerular filtration rate (GFR) (OR 0.99, 95% CI 0.99-1.00, p = 0.003). Regarding its prognostic value, D-dimer was associated with a 30-day mortality (adjusted OR 1.05, 95% CI 1.02-1.09, p = 0.003) with an area under the curve (AUC) of 0.79. Conclusions While D-dimer allows an accurate rule-out of thromboembolic disease, its positive predictive value in routine ED patients is limited and largely influenced by age, comorbidities and acute disease factors. The strong prognostic value of D-dimer in this population warrants further investigation.

Relationship between Thrombosis Risk Factors, Clinical Symptoms, and Laboratory Findings with Pulmonary Embolism Diagnosis; a Cross-Sectional Study.

Pulmonary embolism (PE) is a potentially life threatening disease, accurate and timely diagnosis of which is still a challenge that physicians face. This study was designed with the aim of evaluating the relationship between thrombosis risk factors, clinical symptoms, and laboratory findings with the presence or absence of PE. The present retrospective cross-sectional study was performed on patients with suspected pulmonary embolism who were hospitalized in different departments of Shohadaye Tajrish Hospital, Tehran, Iran, during 1 year. All patients underwent computed tomography pulmonary angiography (CTPA) and then thrombosis risk factors, clinical symptoms, and laboratory findings of confirmed PE cases with CTPA were compared with others. 188 patients with the mean age of 61.91 ± 18.25 (20 - 101) years were studied (54.8% male). Based on Wells' score, 32 (17.2%) patients were in the low risk group, 145 (78.0%) were in the moderate risk group, and 9 (4.8%) patients were classified in the high risk group for developing PE. CTPA findings confirmed PE diagnosis for 60 (31.7%) patients (6.7% high risk, 75.0% moderate risk, 18.3% low risk). D-dimer test was only ordered for 27 patients, 25 (92.6%) of which were positive. Among the patients with positive D-dimer, 18 (72.0%) cases had negative CTPA. Inactivity (57.4%), hypertension (32.8%), and history of cancer (29.5%) were the most common risk factors of thrombosis in patients with PE. In addition, shortness of breath (60.1%) and tachypnea (11.1%) were the most common clinical findings among patients with PE. There was no significant difference between the patients with PE diagnosis and others regarding mean age (p = 0.560), sex distribution (p = 0.438), and type of thrombosis risk factors (p > 0.05), hospitalization department (p = 0.757), Wells' score (p = 0.665), electrocardiography findings, or blood gas analyses. Although attention to thrombosis risk factors, clinical symptoms, and laboratory findings, can be helpful in screening patients with suspected PE, considering the ability of CT scan in confirming or ruling out other possible differential diagnoses, it seems that a revision should be done to lower the threshold of ordering this diagnostic modality for suspected cases.

D-dimer levels during and after anticoagulation withdrawal in patients with venous thromboembolism treated with non-vitamin K anticoagulants.

BackgroundD-dimer levels measured during and after vitamin K antagonist withdrawal may be used in clinical practice to assess the individual risk of recurrent venous thromboembolism. Currently, direct oral anticoagulants (DOACs) are frequently used in venous thromboembolism treatment; however, their pharmacokinetics and pharmacodynamics characteristics are completely different than vitamin K antagonists. The present study aimed at comparing the results of D-dimer levels during and after anticoagulation withdrawal in patients with venous thromboembolism treated with DOACs or warfarin.Material and methodsD-dimer levels were measured in 527 patients (“cases”) during DOACs treatment (T0) and after 15 (T15), 30 (T30), 60 (T60) and 90 (T90) days after their discontinuation and in 527 patients (“controls”) enrolled in the DULCIS study (all treated with warfarin), matched for sex, age (+/-3 y), type of D-dimer assay and site of venous thromboembolism. Both cases and controls received anticoagulant treatment after a first venous thromboembolism event that was unprovoked or associated with weak risk factors.ResultsThe rate of positive D-dimer results was significantly higher in cases than in controls at T0 (10.8% vs 5.1%, p = 0.002) and at T30 (18.8% vs 11.8%, p = 0.019), as well as at the other time-points, though not statistically significant.ConclusionD-dimer levels during and after stopping an anticoagulant treatment for a venous thromboembolism episode differ between patients treated with a DOAC than in those treated with warfarin. Specifically designed prospective studies are warranted to reassess the use of D-dimer as predictor of the risk of recurrent venous thromboembolism in patients treated with DOACs.

Predictive value of myoglobin and D-dimer on severe heat stroke: a clinical analysis of 38 patients with severe heat stroke

To explore the clinical characteristics and early sensitive indicators of severe heat stroke patients in order to predict the development of severe heat stroke in the early stage. Thirty-eight patients with severe heat stroke admitted to emergency department of Beijing Daxing District People's Hospital from July 30th to August 5th in 2018 were enrolled. There were 18 patients suffered from exertional heat stroke (EHS), and 12 patients suffered from classical heat stroke (CHS), and 8 patients with heat spasm and heat exhaustion were selected as control group. The gender, age, onset time, body temperature, heart rate (HR), lactic acid (Lac), platelet (PLT), alanine aminotransferase (ALT), alanine aminotransferase (AST), blood urea nitrogen (BUN), serum creatinine (SCr), serum sodium at admission of hospital, as well as positive rate of myoglobin (MYO) and D-dimer (the positive threshold of MYO and D-dimer was 107 μg/L and 600 μg/L respectively) were recorded and compared among the groups. Receiver operating characteristic (ROC) curve was plotted to analyze the prognostic value of MYO and D-dimer on heat stroke. The outcome of all patients was followed up, and the 28-day mortality between EHS and CHS patients was compared. The patient's body temperature was measured again after 4 hours of active cooling treatment (T4 h), and the relationship between T4 h and 28-day mortality was discussed. The majority of severe heat stroke patients were male, especially in EHS patients. EHS patients were younger than CHS ones, and had shorter onset time, with significant differences among the groups. The body temperature and HR at admission in the EHS group and the CHS group were significantly higher than those in the control group [body temperature (centigrade): 41.34±0.67, 40.39±0.58 vs. 37.80±1.39; HR (bpm): 139.78±15.63, 113.08±17.70 vs. 92.00±15.89, all P < 0.05], PLT was significantly lowered (×109/L: 164.94±73.80, 165.78±53.49 vs. 249.50±84.22, both P < 0.05), and the positive rates of MYO and D-dimer were also significantly increased [MYO positive rate: 100.0% (18/18), 100.0% (12/12) vs. 50.0% (4/8); D-dimer positive rate: 77.8% (14/18), 100.0% (12/12) vs. 12.5% (1/8), all P < 0.05]. ROC curve analysis showed that positive MYO and D-dimer at admission had certain diagnostic value for heat stroke, the area under ROC curve (AUC) was 0.750 and 0.871, the sensitivity was 50.0% and 87.5%, and the specificity was 100% and 86.7%, respectively. The 28-day mortality of the EHS group was significantly higher than that of the CHS group [44.4% (8/18) vs. 8.3% (1/12), P < 0.05]. Furthermore, the 28-day mortality of the patients with T4 h ≥ 38 centigrade in the EHS group was significantly higher than those with T4 h < 38 centigrade [70.0% (7/10) vs. 12.5% (1/8), P < 0.05]. The decreased PLT and the increased D-dimer in the early stage of heat stroke indicate that the damage of coagulation mechanism is prominent in patients with heat stroke. EHS patients have the characteristics of acute onset, severe condition, rapid progression and poor prognosis, and the 28-day mortality is significantly higher than that of CHS patients. MYO and D-dimer are sensitive indicators in early stage of heat stroke patients, which can be used as reference for early diagnosis of heat stroke.

General practitioner use of D-dimer in suspected venous thromboembolism: historical cohort study in one geographical region in the Netherlands

ObjectivesTo investigate how many general practitioner (GP)-referred venous thromboembolic events (VTEs) are diagnosed during 1 year in one geographical region and to investigate the (urgent) referral pathway of VTE diagnoses,...

SAT-593 Thyrotoxic Heart Disease: Rare but Serious Manifestation of Congestive Heart Failure

Background: Excess thyroid hormone alters the hemodynamics of the heart and vascular system resulting in a hyper-dynamic circulatory state which can lead to thyrotoxic heart disease. Clinical case: A 48-year-old male presented to the hospital with several days of rapid heart rate and weakness. He denied prior medical history, medication or supplement intake. Pertinent exam revealed a very thin, hoarse gentleman with shallow breathing and obvious hand tremors; heart exam with irregular rate and tachycardia, absent peripheral edema and bibasilar crackles bilaterally. EKG was consistent with atrial fibrillation with rapid ventricular response. Lab work revealed a pro-BNP of 4000 and positive D-dimer. CTA-Thorax was consistent with CHF with cardiomegaly, large pleural effusions, pulmonary edema and an incidental finding of thyromegaly. Echocardiogram revealed global LV hypokinesis with Ejection Fraction of 10-15%. TSH was <0.005, free Thyroxine >8.00, and Triiodothyronine was 27.04. Thyroid ultrasound showed heterogeneous enlarged gland with hypervascularity and no focal nodules. Graves’ Disease was confirmed with thyroid stimulating Immunoglobulin of 507. Methimazole and hydrocortisone were initiated along with Metoprolol and digoxin for rate control. Thyroid hormone has significant impact on cardiac function, structure and the vascular system. In the vasculature, T3 works to decrease systemic vascular resistance via direct vasodilatation. The decrease in SVR activates RAAS resulting in retention of sodium and fluid. Thyroid hormone also stimulates erythropoiesis which results in an increase in blood volume and stroke volume. In the heart, T3 enters the myocyte via specific transport proteins and via transcription-and non-transcription-mediated effects, increases contractility and relaxation of the cells. Given the increased metabolism, low SVR and increase in total blood volume, this creates a high cardiac output state. Untreated high-output state leads to ventricular dilatation, persistent tachycardia and eventual heart failure. Thus, prompt diagnosis and treatment of cardiac dysfunction is key. Of most importance is correction of thyroid dysfunction with either anti-thyroid medication, radioactive iodine ablation or thyroidectomy. This can possibly reverse and “cure” patient’s systolic heart failure. Conclusion: We present a case of thyrotoxicosis -induced cardiomyopathy with left ventricular ejection fraction of 10% secondary to undiagnosed Graves disease and emphasize the importance of thyroid disease as a possible cause of systolic heart failure.

D-DIMER AS A NOVEL MARKER OF INFLAMMATION IN PERICARDITIS

Positive D-dimer, a fibrin degradation product, is non-specific for thromboembolism and may be seen with inflammation. To study its prevalence and significance in pericarditis, we hypothesized that elevated D-dimer correlates with traditional biomarkers such as C-reactive protein (CRP) as a marker

D-dimer increase: an unfavorable factor for patients with primary liver cancer treated with TACE.

To explore the clinical significance of plasma D-dimer increase for transcatheter arterial chemoembolization (TACE) in patients with primary liver cancer (PLC). The clinical data of 80 PLC patients who underwent TACE in our hospital from January 2015 to January 2017 were collected, including the plasma D-dimer level 1 week before TACE (D0), D-dimer level 1 month after TACE (D1) and D-dimer level when the disease begins to progress (D2). 1 Month after TACE, these patients were divided into two groups according to the mRecist criteria: disease-controlled group (CR + PR + SD) and disease-progressing group (PD). In all subjects, progression-free survival (PFS) was recorded. D0 and D1 were compared between the two groups by the rank sum test; and the relation between D-dimer level and PFS was assessed by the Kaplan-Meier test and Breslow test. In the disease-controlled group, there was no significant difference between D0 and D1 (P > 0.05); in the disease-progressing group, D1 was significantly higher than D0 (P < 0.05) and the D1 is higher than that in disease-controlled group. In the patients with a negative D1 or D2, PFS was longer than those with a positive level (both P < 0.05), but such difference was not statistically significant in D0 (P > 0.05). In the patients witha D-dimer level increase after TACE (group 3), PFS was shorter than that in those witha D-dimer level decrease after TACE (Group 1) and that in those with a relatively stable D-dimer level before and after TACE (Group 2) (P < 0.05); survival in Group 1 was slightly but not significantly longer than that in Group 2 (P > 0.05). The change in plasma D-dimer level can be used as a biological index to assess the efficacy of TACE and prognosis for PLC patients, and thus, a positive D-dimer level or D-dimer increase after TACE is an unfavorable factor.

Diagnostic de l’embolie pulmonaire

The diagnosis of pulmonary embolism (PE) is nowadays based on the sequential use of several diagnostic tests rather than on a single test. These diagnostic strategies are safe and have been prospectively validated. The first step after identifying patients with suspicion of PE is to establish the pre-test clinical probability. Several scores are available in order to make a standardised and reproducible assessment of the clinical probability, and therefore represent precious diagnostic tools. Indeed, clinical probability guides further investigations. Indeed, in patients with a low or an intermediate clinical probability or an “unlikely” probability, PE can be safely ruled out by negative D-dimers in approximately one third of outpatients without additional imaging. In case of positive D-dimers and a high clinical probability or a “likely” clinical probability, CT pulmonary angiography is now the recommended imaging technique. However, lower limb venous compression ultrasound and ventilation/perfusion scans remain useful in patients with contra-indications to CT, mainly those with renal insufficiency. Finally, some novel diagnostic tests seem promising. For example, V/Q SPECT has arisen as a highly accurate test and a potential alternative to CTPA. However, prospective management outcome studies are still lacking and are warranted before its implementation in routine clinical practice.

Role of hemogram parameters in diagnosis and assessing severity of pulmonary embolism

Introduction To investigate the changes in platelets indices in patients with pulmonary embolism (PE) and to examine the correlation of these parameters with the extent of vascular occlusion. Patients and methods The present study was conducted on 70 patients who were admitted because of clinical suspicion of PE. For all patients, complete history taking and examination, routine laboratory investigations, chest radiography, ECG, and transthoracic echocardiography were done. For patients with low and intermediate clinical probability, assessment of d-dimer level was done. For patients with high clinical probability and those with positive d-dimer finding, pulmonary computed tomography angiography was performed with measurement of pulmonary artery obstructive index (PAOI) and right ventricle to left ventricle (RV/LV) ratio. Results Fifty patients were confirmed to have PE and the remaining 20 patients were negative for PE. The group of patients without PE served as a control group. The differences in platelet count, mean platelet volume (MPV), platelet distribution width (PDW), red cell distribution width, and other parameters were compared between both the groups. MPV and PDW were significantly higher in patients with acute PE than in other patients (P=0.0002 and 0.0001). A significant correlation was found between MPV and both PAOI (P=0.049) and RV/LV ratio (P=0.0004). Moreover, significant correlation between PDW and PAOI (P=0.001) and between PDW and RV/LV (P=0.044) was found. The best cutoff value for MPV for the prediction of RV dysfunction was more than 9.4 fl (sensitivity 46.7%; specificity 94.7%). The best cutoff value for PDW for the prediction of RV dysfunction was more than 15.85 fl (sensitivity 75%; specificity 65.9%; P=0.006).

Is Bedside End-Tidal CO2 Measurement a Screening Tool to Exclude Pulmonary Embolism in Emergency Department?

BackgroundPulmonary embolism (PE) is among the most difficult conditions to diagnose in emergency department. The majority of patients thought to have PE are tested positive for D-dimer and subsequently tested with advanced diagnostic modalities. Novel noninvasive tests capable of excluding PE may obviate the need for advanced imaging tests. We studied the role of combined clinical probability assessment and end-tidal carbon dioxide (ETCO2) measurement for diagnosis of possible PE in emergency department.MethodsWe included 100 consecutive subjects suspected to have PE and a positive D-dimer test to study clinical probability of PE and ETCO2 levels. ETCO2 > 34 mm Hg was found to be the best cut-off point for diagnosing PE. PE was ultimately eliminated or diagnosed by spiral computed tomography (CT).ResultsDiagnostic performances of tests were as follows: ETCO2 and D-dimer had a sensitivity of 100% and a negative predictive value (NPV) of 100% at the cut-off levels of 34 mm Hg and 500 ng/mL, respectively; Wells score had a sensitivity of 80% and NPV of 69.7% at a score of 4.ConclusionsETCO2 alone cannot reliably exclude PE. Combining it with clinical probability, however, reliably and correctly eliminates or diagnoses PE and prevents further testing to be done.

Prevalence of acute deep vein thrombosis according to HIV status following major orthopaedic surgery at the University Teaching Hospital, Lusaka, Zambia

Background: Hypercoagulable states and immobilization following lower limb, pelvic, and spinal surgery increases the risk of deep vein thrombosis (DVT). It is also suggested that HIV alone increases the risk of deep vein thrombosis. However no study has been done to determine the prevalence of deep vein thrombosis in HIV seropositive individuals who have undergone lower limb orthopaedic surgery in the Zambian context. We therefore conducted this study to determine the prevalence of deep vein thrombosis in patients who are HIV seropositive in comparison to those who are HIV seronegative after undergoing lower limb orthopaedic surgery. Methods: A total of 42 Patients were enrolled. Of these 23 (54 %) were HIV negative controls and 19 (46 %) were HIV positive patients who underwent lower limb surgery or spinal surgery. Demographic and HIV status data was collected prior to surgery. After surgery a blood sample was tested for fibrinogen degradation products (D-dimer) levels. The patients were then monitored for the development of clinical DVT and those that developed clinical DVT had an ultrasound to confirm the diagnosis. Results: The majority (81%) of the study population were under the age of 50 years. The mean values of D-dimers were 2.33 ± 1.65 μg/ml for the HIV negative group and 2.55 ±1.50 μg/ml for the HIV positive group. The number of positive D-dimer results was similar in the two groups, 94.7% for the HIV cohort and 95.7% in the negative group (X 2 0.19 p=0.89). There was a positive correlation between the D-dimer value and the type of surgery done in both the HIV positive group (R 0.390 p = 0.049) and the HIV negative group (R 0.398 at p = 0.03). In both group’s hip and knee surgeries gave higher values of D-dimers. There was no statistical difference in the occurrence of a positive D-dimer and CD4 count (X2 0.95 p=0.89). The combined prevalence of clinical DVT confirmed by compression ultrasonography in the entire study population was 4.8%. The prevalence in the HIV seropositive group and HIV seronegative groups were 5.3% and 4.3% respectively (X2 0.19 p= 0.89). None of the patients received preoperative DVT prophylaxis due to cost but both patients that developed DVT received antithrombotic treatment. Conclusions: There was no significant difference in the prevalence of DVT between patients who were HIV seronegative and seronegative following major lower limb and spinal orthopaedic surgery. Both groups had raised D-dimer values. Keywords: deep vein thrombosis; HIV; D-dimer; Doppler ultrasound

Order Indication Solicitation to Assess Clinical Laboratory Test Utilization: D-Dimer Order Patterns as an Illustrative Case

Background: A common challenge in the development of laboratory clinical decision support (CDS) and laboratory utilization management (UM) initiatives stems from the fact that many laboratory tests have multiple potential indications, limiting the ability to develop context-specific alerts. As a potential solution, we designed a CDS alert that asks the ordering clinician to provide the indication for testing, using D-dimer as an exemplar. Using data collected over a nearly 3-year period, we sought to determine whether the indication capture was a useful feature within the CDS alert and whether it provided actionable intelligence to guide the development of an UM strategy. Methods: We extracted results and ordering data for D-dimer testing performed in our laboratory over a 35-month period. We analyzed order patterns by clinical indication, hospital service, and length of hospitalization. Results: Our final data set included 13,971 result-order combinations and indeed provided actionable intelligence regarding test utilization patterns. For example, pulmonary embolism was the most common emergency department indication (86%), while disseminated intravascular coagulation was the most common inpatient indication (56%). D-dimer positivity rates increased with the duration of hospitalization and our data suggested limited utility for ordering this test in the setting of suspected venous thromboembolic disease in admitted patients. In addition, we found that D-dimer was ordered for unexpected indications including the assessment of stroke, dissection, and extracorporeal membrane oxygenation. Conclusions: Indication capture within a CDS alert and correlation with result data can provide insight into order patterns which can be used to develop future CDS strategies to guide appropriate test use by clinical indication.

Post-Anticoagulation Cessation D-Dimer Testing and VTE Recurrence in Real-World Australian Audit

AimElevated D-dimer post-anticoagulation cessation is a recognised risk factor for recurrent venous thromboembolic events (VTE). In particular, raised D-dimer post cessation has been associated with increased risk of recurrence in unprovoked major VTE. Currently in Australia, D-dimer has not been widely used in practice to stratify the risk of VTE recurrence. This study aims to retrospectively analyse the effect of routine D-dimer testing and it's association with VTE recurrence.MethodsA retrospective evaluation was performed on 1024 patients with a diagnosis of VTE at a tertiary hospital in Australia between January 2013 and December 2016. Data collected included demographics, results and timing of D-dimer testing and serial imaging results.Results1024 patients were reviewed with a total median follow up of 12 months (range 0-59 months). D-dimer was tested in 189 patients (18.5%) within 90 days after cessation of anticoagulation. Of these patients, median age was 58 (18-92) and 55.3% (n=105) were female. 33.3% (n=63) had isolated distal deep vein thrombosis (IDDVT), 66.3% (n=126) had above knee DVT (AKDVT)/pulmonary embolus (PE), 54.5% (n=103) of VTE were provoked.Abnormal post cessation D-dimer (>500) was found in 72 patients (37.9%). Of these, 25 patients were restarted on anticoagulation; one had recurrent VTE whilst on low dose apixaban 2.5mg BD and one had recurrence after cessation of anticoagulation at a later date. Patients with elevated D-dimer post cessation had a higher rate of recurrence with the highest risk in patients with D-dimer >1000 (RR 7.38, p=<0.01) outlined in Table 1.Of the 164 patients with post cessation D-dimer testing who remained off anticoagulation there were a total of 24 (12.6%) episodes of recurrent VTE. Elevated D-dimer post anticoagulation cessation was a significant risk factor for recurrence in both provoked VTE (RR 4.21, p=0.01) and unprovoked VTE cohorts (RR 4.55, p=0.008) outlined in Table 2. When provoked VTE were sub-categorised, raised D-dimer demonstrated the most statistical significance in VTE provoked by travel (RR 13.5 p=0.06).Of the patients with post anticoagulation cessation D-dimer testing 170 patients (89.9%) had repeat imaging to assess for residual thrombus. In the subgroup of patients with no residual thrombus, elevated D-dimer was a significant risk factor for VTE recurrence (RR 6.4, p=<0.01). Patients with normal D-dimer and no residual thrombus had the lowest rate of recurrence 5.4% (n=4) see Table 3.When stratified by type of VTE, elevated D-dimer post anticoagulation cessation was significantly related to risk for recurrence in the overall IDDVT sub-cohort (RR 4.09, p=0.007). This was not significant for the AKDVT/PE sub cohort (RR 3.24, p=0.079). However, for patients with unprovoked AKDVT or PE, having D-dimer tested post anticoagulation, regardless of result, was associated with lower rates of VTE recurrence RR 0.30 (p=0.02) compared to those who had no D-dimer testing as part of follow-up.ConclusionPost treatment D-dimer testing may have a clinical role in stratifying the risk of VTE recurrence along with repeat imaging to detect residual thrombus. Elevated D-dimer post anticoagulation cessation is associated with increased risk of VTE recurrence for both provoked and unprovoked VTE with highest risk in patients with D-dimer >1000. Patients with no residual thrombus and a negative D-dimer post anticoagulation cessation had the lowest rate of recurrence. In the subgroup of patients with provoked VTE and IDDVT a positive D-dimer post cessation was associated with 4.21 and 4.09 relative risk of recurrence respectively, suggesting that the role of D-dimer testing can be extended to these subpopulations. Interestingly, in patients with unprovoked AKDVT or PE, having post-cessation D-dimer testing performed, regardless of result, was associated with a significantly lower rate of VTE recurrence compared to patients without D-dimer testing, which may be related to specialist review and recommencement of anticoagulation in high-risk patients. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Safety of D-Dimer As a Stand-Alone Test for the Exclusion of Deep Vein Thrombosis Compared to Other Strategies

BackgroundTogether with clinical decision rules, D-dimer testing has long been the mainstay of diagnostic work-up of suspected deep vein thrombosis (DVT). Advantages of D-dimer measurement include wide availability, low costs and high sensitivity. Age-adjusted D-dimer cut-off values have been suggested to improve specificity of D-dimer testing, defining a positive D-dimer as age multiplied by 0.01 mg/L at or over fifty years of age. Age-adjusted cut-off values have been found to increase specificity without compromising safety in the setting of acute pulmonary embolism, but have not been extensively evaluated in DVT.In this study, we aimed to evaluate and compare the diagnostic performance of fixed versus age-adjusted D-dimer thresholds in patients with suspected DVT, as a stand-alone test or in combination with pre-test probability assessment.MethodsWe included 973 consecutive outpatients referred to Østfold Hospital, Norway, with suspected first or recurrent lower extremity DVT, between 2015 and 2017. STA®-Liatest® Plus D-Dimer assay was performed and Wells clinical score assessed in all patients. Patients with positive fixed D-dimer (≥0.5 mg/L) were referred for whole-leg compression ultrasonography (CUS), whereas patients with negative D-dimer were not, irrespective of the clinical pre-test probability. Failure rate was defined as patients with negative D-dimer at baseline remaining untreated and diagnosed with symptomatic venous thromboembolism during 3-month follow-up. We compared diagnostic indices of both D-dimer thresholds with or without initial pre-test probability assessment.ResultsDVT was diagnosed in 177 out of 973 patients (18%).The fixed D-dimer cut-off was associated with a sensitivity of 99.4% (95% CI 96.9 to 99.9%) for one diagnostic failure (0.3%) (not adjudicated as of print). Adding the Wells score would have detected this one case at a cost of 90 additional CUS examinations. Age-adjusted D-dimer as a stand-alone test was associated with 6 diagnostic failures (1.5%) for a sensitivity of 96.6% (95% CI 92.8 to 98.8%). Age-adjusted D-dimer combined with Wells score yielded a sensitivity of 99.4% (95% CI 96.9 to 99.9%), with one diagnostic failure (0.4%) and 714 patients referred for CUS.ConclusionOur results suggest that the fixed D-dimer as a stand-alone test without Wells score is a safe and efficient diagnostic strategy. Combining age-adjusted D-dimer with Wells score was equally safe, but was not associated with a lower number of necessary CUS examinations. DisclosuresFronas:Bayer AG: Other: Bayer AG contributed with financial support in conducting the study; South-Eastern Norway Regional Health Authority: Other: Grant in conducting the study. Tøvik Jørgensen:Bayer AG: Other: Bayer AG contributed with financial support in conducting the study; South-Eastern Norway Regional Health Authority: Other: Grant for conducting the study. Ghanima:Bayer, BMS, Novartis: Research Funding; Amgen, Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees.

A9612 The combination therapy of Xa inhibitor and antihypertensive therapy improved anticoagulant activity and hypertensive target organ damage in nonvalvular atrial fibrillation patients.

Objectives: The anticoagulant activity and blood pressure increase in morning. The aim of this study was to evaluate the change of anticoagulant activity, blood pressure and target organ damage in combination therapy of Xa inhibitor and antihypertensive therapy in nonvalvular atrial fibrillation patients. Methods: We enrolled 72 NVAF patients. Rivaroxaban (10–15 mg) was continuously administered once daily over 8 weeks (study period I). To subjects who have shown early-morning hypertension in the study period I (N = 50), nifedipine was additionally administered at bedtime, and the rivaroxaban administration was continued for additional 8 weeks. We assessed prothrombin fragment 1 + 2, optimal range of prothrombin fragment 1 + 2 was defined 69–229pmol/L, D-Dimer, positive D-dimer measurement (≥1.0 μg/mL), and evaluated urinary albumin creatinine ratio (UACR) as hypertensive target organ damage. Results: The percentage of optimal range of prothrombin fragment 1 + 2 was significantly increased from baseline at 4 weeks (70.8 vs. 86.1%, p = 0.033). Clinic systolic blood pressure was reduced at 12 weeks (134.7 ± 9.6 vs. 118.7 ± 9.6mmHg, p < 0.003) and 16weeks (134.7 ± 9.6 vs. 118.7 ± 9.6mmHg, p < 0.003)). UACR was significantly reduced from 8 weeks at 12 weeks (median UACR: 13.7 vs. 8.8 mg/gCR, p = 0.006). The percentage of positive D-dimer reduced from baseline to 8 weeks (8% vs. 0%, p = 0.044), and remained 0% at 16 weeks. Conclusion: The combination therapy of Xa inhibitor and antihypertensive therapy improved anticoagulant activity and hypertensive target organ damage in nonvalvular atrial fibrillation patients.

Hemostatic changes in patients with chronic renal failure

Background: Renal disease results in significant disorder of hemostasis (bleeding diathesis orhypercoagulable state).Objectives: This study is to determine the changes in some hemostasis parameters in patients withchronic renal failure and identify the effect of dialysis on these changes.Patients and Methods: seventy five patients with end stage chronic renal failure were collected fromBaghdad hospital, a full detailed history and clinical examination were performed, 50 patients were onmaintenance weekly hemodialysis, and 25 patients were without dialysis.Result: Bleeding time was significantly higher in patients with chronic renal failure who didn’t needany type of dialysis, positive D-Dimer test. In some patients, Platelet count, prothrombin time, thrombintime, fibrinogene level, activated partial thromboplastin time; all did not reach significant level betweenboth groups of patients.Conclusion: hemostatic changes are not uncommon in patients with chronic renal failure, affecting thedifferent parameter hemostasis so it should be consider in the management of these patients.

Hemostatic changes in patients with chronic renal failure

Background: Renal disease results in significant disorder of hemostasis (bleeding diathesis orhypercoagulable state).Objectives: This study is to determine the changes in some hemostasis parameters in patients withchronic renal failure and identify the effect of dialysis on these changes.Patients and Methods: seventy five patients with end stage chronic renal failure were collected fromBaghdad hospital, a full detailed history and clinical examination were performed, 50 patients were onmaintenance weekly hemodialysis, and 25 patients were without dialysis.Result: Bleeding time was significantly higher in patients with chronic renal failure who didn’t needany type of dialysis, positive D-Dimer test. In some patients, Platelet count, prothrombin time, thrombintime, fibrinogene level, activated partial thromboplastin time; all did not reach significant level betweenboth groups of patients.Conclusion: hemostatic changes are not uncommon in patients with chronic renal failure, affecting thedifferent parameter hemostasis so it should be consider in the management of these patients.

D-dimer in Adolescent Pulmonary Embolism.

D-dimer is used to aid in diagnosing adult pulmonary embolism (PE). D-dimer has not been validated in adolescents. Clinicians must balance the risk of overtesting with that of a missed PE. D-dimer may be useful in this context. This study evaluates D-dimer in PE-positive and PE-negative adolescents. PE-positive patients<22 years were diagnosed with PE by computed tomography (CT) or high-probability ventilation/perfusion, seen at emergency departments (EDs)/hospitals within a 16-hospital system across two states, January 1998 through December 2016. Of the 189 PE-positive patients, 88 (46.5%) had a D-dimer and were matched 1:1 by age, sex, and race to patients suspected of PE but confirmed negative by CT angiogram. Ages of PE-positive patients ranged from 13 to 21 years, 64 (73%) were female, and 52 (60%) were Caucasian. Mean D-dimer was significantly higher (3,256 ng/mL, 95% confidence interval [CI]= 2,505-4,006 ng/mL) in PE-positive versus PE-negative patients (1,244 ng/mL, 95% CI= 493-1,995 ng/mL; p<0.001). Mean D-dimer was higher in patients with massive or submassive PE (8,742 ng/mL, 95% CI= 5,994-11,491 ng/mL), followed by PE in central (4,795 ng/mL [95% CI= 3,465-6,125 ng/mL), lobar (3,758 ng/mL [95% CI= 1,841-5,676), and distal (2,327 ng/mL [95% CI= 1,273-3,381 ng/mL]) arteries. When comparing thresholds of positive D-dimer (≥500, ≥750, and ≥1,000 ng/mL), D-dimer had sensitivities of 90, 82, and 67% and specificities of 16, 53, and 67%, respectively. Negative predictive values were 61, 75, and 71% while positive likelihood ratios were 1.1, 1.8, and 2.2, respectively. This study represents the largest available cohort of adolescent patients examining the diagnostic value of D-dimer for PE. Our results indicate that depending on the threshold selected, D-dimer can be a sensitive test for PE in adolescents and that discriminative value is higher for a cutoff of 750 ng/mL than that for 500 ng/mL. Prospective studies investigating the diagnostic value of D-dimer and a clinical decision rule for PE in pediatrics are needed.