Uses of different D-dimer levels can reduce the need for venous duplex scanning to rule out deep vein thrombosis in patients with symptomatic pulmonary embolism

Chronic CT features in PE patients with co-existing DVT

OBJECTIVE

Clinical features may be different in patients with PE without co-existing DVT compared to those with PE with co-existing DVT. This prospective study aims to investigate the different clinical features between patients with isolated pulmonary embolism (PE) and those with PE associated with deep venous thrombosis.

METHOD

This is a prospective study conducted in 107 consecutive patients diagnosed with acute PE in the emergency department or other departments of Kırıkkale University Hospital. The diagnosis of PE was confirmed by computed tomography pulmonary angiography (CTPA), which was ordered on the basis of symptoms and findings. Bilateral lower extremity compression ultrasound with standard 7.5 MHz linear array probe was applied to all patients. According to compression ultrasound results, the patients were divided into two classes as with and without deep venous thrombosis. Embolism in the main or lobar pulmonary arteries were classified as central, and those found only in segmental or subsegmental arteries were classified as peripheral. Laboratory parameters and Oxygen saturation were assessed on admission.

RESULTS

67 of 107 (62.6%) patients with PE were isolated pulmonary embolism, and 40 (37.4%) were PE + DVT. Patients with PE with co-existing DVT have wider pulmonary artery, higher d-dimer and pro BNP level, and lower saturation than those with isolated pulmonary embolism. Central pulmonary embolism is more common in patients with deep vein thrombus than those without it. (87.5% (35/40) vs 32.8% (22/67),p = 0.001). 38.6% of central pulmonary embolism occur without deep vein thrombosis of the lower extremities. Patients with PE with co-existing DVT have 42.5% mosaic perfusion pattern,70% chronic infarct appearance such as linear band, pleural nodüle, %15.0 thickened, small arteries and, %12.5 shrunken complete artery occlusion, suggesting the chronic background.

CONCLUSION

PE patients with co-existing DVT are clinically more serious than those who do not have a DVT. An acute picture may be present in the chronic background in a significant proportion of patients with PE with co-existing DVT. In the presence of deep vein thrombosis, pulmonary embolism is usually central, but more than one-third of central pulmonary emboli occur without lower extremity deep vein thrombosis.

Deep vein sclerosis following sclerotherapy: Ultrasonic and d-dimer criteria

Objectives

The aim of sclerotherapy is to induce fibrosclerosis of superficial veins. We postulated that inadvertent entry of sclerosants into deep veins can result in sclerotic occlusion, deep vein sclerosis, a non-thrombotic process distinct from spontaneous deep vein thrombosis. The aim of this study was to assess the role of d-dimer in differentiating between deep vein sclerosis and deep vein thrombosis.

Methods

Proximal trunks of great and small saphenous veins were treated with endovenous laser ablation. Venous tributaries and perforators were treated with foam ultrasound guided sclerotherapy. Ultrasound studies of lower limb deep veins were performed before and one week after the procedures, to detect deep vein occlusions (DVOs). d-dimer levels were measured for DVOs and long-term ultrasound studies monitored the recanalisation rates.

Results

In a six-year period, 9143 procedures were performed in 1325 patients for bilateral varicose veins. This included 1124 endovenous laser ablation and 8019 foam ultrasound guided sclerotherapy procedures. A total of 259 DVOs (2.83%) were identified on ultrasound which included 251 deep vein sclerosis (2.74%), seven deep vein thrombosis (0.07%) and one endovenous heat-induced thrombosis (EHIT, 0.08%). d-dimer values <0.5 µg/mL excluded deep vein thrombosis s, 0.5–1.0 µg/mL were more likely to be associated with deep vein sclerosis and >1.0 µg/mL were a more likely to be associated with deep vein thrombosis. Lower sclerosant concentrations and higher foam volumes were associated with increased risk of DVO ( p <  .0001). No significant relationship was found between DVO and gender or thrombophilia. Deep vein thrombosis and EHIT cases but not deep vein sclerosis patients were anticoagulated. None had thromboembolic complications. Patients were followed up for a median of 299 days (37–1994 days). Recanalisation rates were 71.1% for deep vein sclerosis (92.3% competent) and 71.4% for deep vein thrombosis (60.0% competent).

Conclusions

Deep vein sclerosis is a relatively benign clinical entity distinct from deep vein thrombosis and does not require anticoagulation. Majority of affected veins on long-term follow-up regain patency and competence. d-dimer can be used to assist in differentiating deep vein sclerosis from deep vein thrombosis.

The Prevalence of Concomitant Deep Vein Thrombosis, Symptomatic or Asymptomatic, Proximal or Distal, in Patients With Symptomatic Pulmonary Embolism

Patients with pulmonary embolism (PE) may have symptomatic or asymptomatic concomitant deep vein thrombosis (DVT). The reported prevalence of PE-associated DVT is variable, and thus, the utility of routine testing is controversial. The aim of our study was to analyze the prevalence of DVT and the factors associated with proximal DVT/whole-leg DVT in patients with symptomatic PE. In 428 consecutive patients (mean age: 59 ± 16.4 years; 52.3% men), we performed clinical examination and complete bilateral compression ultrasound and ascertained medical history and risk factors for DVT/PE. χ² and t tests were used. Deep vein thrombosis was found in 70.6%; proximal DVT in 49.5%. Sensitivity/specificity of DVT symptoms was 42.7%/93.7% for whole-leg DVT and 47.6%/83.3% for proximal DVT. Male gender significantly prevailed among those with whole-leg DVT and with proximal DVT (58.9% and 61.8%). Active malignancy was significantly more frequent in the patients with proximal DVT than without proximal DVT (10.4% vs 3.7%). In conclusion, the prevalence of PE-associated DVT is quite high but clinical diagnosis is unreliable. In our group, male gender and active malignancy were significantly associated with the presence of concomitant proximal DVT.

The diagnosis and treatment of venous thromboembolism in asian patients

Although the incidence of venous thromboembolism (VTE) in Asian populations is lower than in Western countries, the overall burden of VTE in Asia has been considerably underestimated. Factors that may explain the lower prevalence of VTE in Asian populations relative to Western populations include the limited availability of epidemiological data in Asia, ethnic differences in the genetic predisposition to VTE, underdiagnoses, low awareness toward thrombotic disease, and possibly less symptomatic VTE in Asian patients. The clinical assessment, diagnostic testing, and therapeutic considerations for VTE are, in general, the same in Asian populations as they are in Western populations. The management of VTE is based upon balancing the treatment benefits against the risk of bleeding. This is an especially important consideration for Asian populations because of increased risk of intracranial hemorrhage with vitamin K antagonists. Non-vitamin K antagonist oral anticoagulants have shown advantages over current treatment modalities with respect to bleeding outcomes in major phase 3 clinical trials, including in Asian populations. Although anticoagulant therapy has been shown to reduce the risk of postoperative VTE in Western populations, VTE prophylaxis is not administered routinely in Asian countries. Despite advances in the management of VTE, data in Asian populations on the incidence, prevalence, recurrence, risk factors, and management of bleeding complications are limited and there is need for increased awareness. To that end, this review summarizes the available data on the epidemiology, risk stratification, diagnosis, and treatment considerations in the management of VTE in Asia.

D-dimer test for excluding the diagnosis of pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) can occur when a thrombus (blood clot) travels through the veins and lodges in the arteries of the lungs, producing an obstruction. People who are thought to be at risk include those with cancer, people who have had a recent surgical procedure or have experienced long periods of immobilisation and women who are pregnant. The clinical presentation can vary, but unexplained respiratory symptoms such as difficulty breathing, chest pain and an increased respiratory rate are common.D-dimers are fragments of protein released into the circulation when a blood clot breaks down as a result of normal body processes or with use of prescribed fibrinolytic medication. The D-dimer test is a laboratory assay currently used to rule out the presence of high D-dimer plasma levels and, by association, venous thromboembolism (VTE). D-dimer tests are rapid, simple and inexpensive and can prevent the high costs associated with expensive diagnostic tests.

OBJECTIVES

To investigate the ability of the D-dimer test to rule out a diagnosis of acute PE in patients treated in hospital outpatient and accident and emergency (A&E) settings who have had a pre-test probability (PTP) of PE determined according to a clinical prediction rule (CPR), by estimating the accuracy of the test according to estimates of sensitivity and specificity. The review focuses on those patients who are not already established on anticoagulation at the time of study recruitment.

SEARCH METHODS

We searched 13 databases from conception until December 2013. We cross-checked the reference lists of relevant studies.

SELECTION CRITERIA

Two review authors independently applied exclusion criteria to full papers and resolved disagreements by discussion.We included cross-sectional studies of D-dimer in which ventilation/perfusion (V/Q) scintigraphy, computerised tomography pulmonary angiography (CTPA), selective pulmonary angiography and magnetic resonance pulmonary angiography (MRPA) were used as the reference standard.•

PARTICIPANTS

Adults who were managed in hospital outpatient and A&E settings and were suspected of acute PE were eligible for inclusion in the review if they had received a pre-test probability score based on a CPR.•

INDEX TESTS

quantitative, semi quantitative and qualitative D-dimer tests.• Target condition: acute symptomatic PE.• Reference standards: We included studies that used pulmonary angiography, V/Q scintigraphy, CTPA and MRPA as reference standard tests.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed quality using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). We resolved disagreements by discussion. Review authors extracted patient-level data when available to populate 2 × 2 contingency tables (true-positives (TPs), true-negatives (TNs), false-positives (FPs) and false-negatives (FNs)).

MAIN RESULTS

We included four studies in the review (n = 1585 patients). None of the studies were at high risk of bias in any of the QUADAS-2 domains, but some uncertainty surrounded the validity of studies in some domains for which the risk of bias was uncertain. D-dimer assays demonstrated high sensitivity in all four studies, but with high levels of false-positive results, especially among those over the age of 65 years. Estimates of sensitivity ranged from 80% to 100%, and estimates of specificity from 23% to 63%.

AUTHORS' CONCLUSIONS

A negative D-dimer test is valuable in ruling out PE in patients who present to the A&E setting with a low PTP. Evidence from one study suggests that this test may have less utility in older populations, but no empirical evidence was available to support an increase in the diagnostic threshold of interpretation of D-dimer results for those over the age of 65 years.

Risk assessment of deep-vein thrombosis after acute stroke: a prospective study using clinical factors

AIMS

Deep-vein thrombosis (DVT) represents a serious complication in acute stroke patients with pulmonary embolus (PE) as a potential outcome. Prediction of DVT may help with formulating a proper prevention strategy. To assess of the risk of deep venous thrombosis (DVT) in acute stroke patients, we developed and validated a clinical score in a cohort study.

METHODS

Incidence of Deep Venous Thrombosis after Acute Stroke in China (INVENT-China) is a multicenter prospective cohort study. The potential predictive variables for DVT at baseline were collected, and the presence of DVT was evaluated using ultrasonography on the 14 ± 3 days. Data were randomly assigned to either a training data set or a test data set. Multivariate logistic regression analysis was used to develop risk scores to predict DVT in the training data set and the area under the receiver operating characteristic curve to validate the score in the test data set.

RESULTS

From 2006-2007, 862 hospital-based acute stroke patients were enrolled in China. The overall incidence of DVT after acute stroke within two weeks was 12.4% (95%CI 10.3-14.7%). A seven-point score derived in the training data set (age [≥65 years = 1], sex [female gender = 1]), obesity [BMI ≥ 25 kg/m(2) = 1], active cancer [yes = 2], stroke subtype [cerebral hemorraghe = 1], muscle weakness [≥2 on Lower limb NIHSS score = 1] was highly predictive of 14-day risk of DVT(c statistic = 0.70, 95% CI, 0.64-0.76, P < 0.001), in the overall study population(c statistic = 0.65, 95% CI 0.59-0.70, P < 0.001).

CONCLUSIONS

This clinical score may help identify acute stroke patients with high risk of DVT. In addition, it also serves as a platform to develop further models of DVT prediction in stroke patients based on clinical factors.

Cost-effectiveness of strategies for diagnosing pulmonary embolism among emergency department patients presenting with undifferentiated symptoms

STUDY OBJECTIVE

Symptoms associated with pulmonary embolism can be nonspecific and similar to many competing diagnoses, leading to excessive costly testing and treatment, as well as missed diagnoses. Objective studies are essential for diagnosis. This study evaluates the cost-effectiveness of different diagnostic strategies in an emergency department (ED) for patients presenting with undifferentiated symptoms suggestive of pulmonary embolism.

METHODS

Using a probabilistic decision model, we evaluated the incremental costs and effectiveness (quality-adjusted life-years gained) of 60 testing strategies for 5 patient pretest categories (distinguished by Wells score [high, moderate, or low] and whether deep venous thrombosis is clinically suspected). We performed deterministic and probabilistic sensitivity analyses.

RESULTS

In the base case, for all patient pretest categories, the most cost-effective diagnostic strategy is to use an initial enzyme-linked immunosorbent assay D-dimer test, followed by compression ultrasonography of the lower extremities if the D-dimer is above a specified cutoff. The level of the preferred cutoff varies with the Wells pretest category and whether a deep venous thrombosis is clinically suspected. D-dimer cutoffs higher than the current recommended cutoff were often preferred for patients with even moderate and high Wells categories. Compression ultrasonography accuracy had to decrease below commonly cited levels in the literature before it was not part of a preferred strategy.

CONCLUSION

When pulmonary embolism is suspected in the ED, use of an enzyme-linked immunosorbent assay D-dimer assay, often at cutoffs higher than those currently in use (for patients in whom deep venous thrombosis is not clinically suspected), followed by compression ultrasonography as appropriate, can reduce costs and improve outcomes.

Prevalence of venous thromboembolism in neurosurgical patients

This study was conducted to clarify the prevalence of venous thromboembolism (VTE) in neurosurgical patients. Prospective study for venous thromboembolism screening after neurosurgery was conducted. Thirty-seven patients were screened by ultrasonography for deep vein thrombosis in the lower extremities at an average of 12 days postoperatively. All patients received standard thromboprophylaxis using graded compression stocking with/without intermittent pneumatic compression following the VTE prevention guidelines. Definitive diagnosis of venous thromboembolism was made by contrast-enhanced whole-body computed tomography. Prevalence of deep vein thrombosis of the lower legs was 13.5% (5/37). Incidence of pulmonary embolism was 60% (3/5) in patients having deep vein thrombosis. All patients having venous thromboembolism were asymptomatic. In high-risk patients, VTE prevalence after neurosurgery was high even under mechanical prophylaxis. Additional pharmacological prophylaxis should be considered for patients with high risk of VTE.

Combined use of pretest clinical probability score and latex agglutination D-dimer testing for excluding acute deep vein thrombosis

OBJECTIVE

Currently, the latex agglutination D-dimer assay is widely used for excluding deep vein thrombosis (DVT) but is considered less sensitive than the enzyme-linked immunosorbent assay-based D-dimer test. The purpose of the present study was to determine if a combination of different cutoff points, rather than a single cutoff point of 1.0 microg/mL, on the latex agglutination D-dimer assay and the pretest clinical probability (PTP) score would be able to reduce the use of venous duplex ultrasound (DU) scanning in patients with suspected DVT.

METHODS

The PTP score and D-dimer testing were used to evaluate 989 consecutive patients with suspected DVT before venous DU scanning. After calculating the clinical probability scores, patients were divided into low-risk (< or =0 points), moderate-risk (1-2 points), and high-risk (> or =3 points) pretest clinical probability groups. Receiver operating characteristic (ROC) curve analysis was used to determine the appropriate D-dimer cutoff point for each PTP with a negative predictive value of >98% for a positive DU scan.

RESULTS

There were 886 patients enrolled. The study group included 609 inpatients (68.7%) and 277 outpatients (31.3%). The prevalence of DVT in this series was 28.9%. There were 508 patients (57.3%) classified as low-risk, 237 (26.8%) as moderate-risk, and 141 (14.9%) as high-risk PTP. DVT was identified in 29 patients (5.7%) with low-risk, 118 (49.8%) with moderate-risk, and 109 (77.3%) with high-risk PTP scores. ROC curve analysis was used to select D-dimer cutoff points of 2.6, 1.1, and 1.1 microg/mL for the low-, moderate- and high-risk PTP groups, respectively. In the low-risk PTP group, specificity increased from 48.9% to 78.2% (P < .0001) with use of the different D-dimer cutoff value. In the moderate- and high-risk PTP groups, however, the different D-dimer levels did not achieve substantial improvement. Despite this, the overall use of venous DU scanning could have been reduced by 43.0% (381 of 886) if the different D-dimer cutoff points had been used.

CONCLUSIONS

Combination of a specific D-dimer level with the clinical probability score is most effective in low-risk PTP patients for excluding DVT. In moderate- and high-risk PTP patients, however, the recommended cutoff points of 1.0 microg/mL may be preferable. These results show that different D-dimer levels for patients differing in risk is feasible for excluding DVT using the latex agglutination D-dimer assay.

An age-adapted approach for the use of D-dimers in the exclusion of deep venous thrombosis

A normal D-dimer (DD) concentration for the exclusion of deep venous thrombosis (DVT) has a low specificity in older patients and compression ultrasonography is often required. Three D-dimer assays, STA Liatest, Tina-quant, and Innovance, are evaluated in symptomatic outpatients suspected for DVT with emphasis on its performance in older patients by using different cut-off levels. This study includes 466 outpatients suspected for having DVT. The diagnostic accuracy, measured as sensitivity and area under the curve of the receiver operation characteristic curve is good for all DD assays. The specificity of the DD assays combined with a low pretest probability varies from 42.6 to 51.5%. The specificity of the three DD assays in patients > or = 60 years varies, however, between 24.6 and 40.9%. Several cut-off values in different age-subgroups are studied. For patients < 60 years, the most accurate cut-off value is 500 microg/L for all DD assays. For patients > or = 60 years, a threshold of 750 microg/L has the best results with NPV of 100% for all assays and specificity of 48.5% (STA Liatest), 60.6% (Tina-quant), and 49.2% (Innovance), respectively. For the three assays, the number needed to test (NNT) decreases in both subgroups of patients compared to the standard algorithm. A cut-off level of 750 microg/L for patients > or = 60 years improves the clinical performance of DD assays in combination with the PTP score without the loss of NPV. The NNT improves substantially with an age-adapted algorithm.

Pulmonary embolism in the elderly: a review on clinical, instrumental and laboratory presentation

Objective

Diagnosis of pulmonary embolism (PE) remains difficult and is often missed in the elderly due to nonspecific and atypical presentation. Diagnostic algorithms able to rule out PE and validated in young adult patients may have reduced applicability in elderly patients, which increases the number of diagnostic tools use and costs. The aim of the present study was to analyze the reported clinical presentation of PE in patients aged 65 and more.

Materials and Methods

Prospective and retrospective English language studies dealing with the clinical, instrumental and laboratory aspects of PE in patients more than 65 and published after January 1987 and indexed in MEDLINE using keywords as pulmonary embolism, elderly, old, venous thromboembolism (VTE) in the title, abstract or text, were reviewed.

Results

Dyspnea (range 59%–91.5%), tachypnea (46%–74%), tachycardia (29%–76%), and chest pain (26%–57%) represented the most common clinical symptoms and signs. Bed rest was the most frequent risk factor for VTE (15%–67%); deep vein thrombosis was detected in 15%–50% of cases. Sinus tachycardia, right bundle branch block, and ST-T abnormalities were the most frequent ECG findings. Abnormalities of chest X-ray varied (less than 50% in one-half of the studies and more than 70% in the other one-half). Arterial blood gas analysis revealed severe hypoxemia and mild hypocapnia as the main findings. D-Dimer was higher than cut-off in 100% of patients in 75% of studies. Clinical usefulness of D-Dimer measurement decreases with age, although the strategies based on D-Dimer seem to be cost-effective at least until 80 years.

Conclusion

Despite limitations due to pooling data of heterogeneous studies, our review could contribute to the knowledge of the presentation of PE in the elderly with its diagnostic difficulties. A diagnostic strategy based on reviewed data is proposed.

Presence of lower limb deep vein thrombosis and prognosis in patients with symptomatic pulmonary embolism: preliminary report

OBJECTIVES

To investigate the presence of lower limb deep vein thrombosis (DVT) and prognosis in patients with symptomatic pulmonary embolism (PE).

MATERIALS AND METHODS

A total of 203 consecutive referral patients with PE were included. The distribution of DVT was evaluated with compression ultrasound (CUS), and all patients were then followed for 12 months for investigation of recurrence of venous thromboembolism (VTE) and fatal events as adverse outcome.

RESULTS

The mean age of the patients was 62.8 years, and 78 (38.4%) were males. DVT was found in 118 (58.1%) patients. Of these patients, 61 (30.0%) had proximal DVT. Multivariate analysis demonstrated that active cancer, inadequate anticoagulation, leg symptoms, male gender, presence of DVT, presence of proximal DVT, and previous DVT were independent risk factors for adverse outcome. A clinical risk score ranging from 0 to 10 points was generated on the basis of multivariate regression coefficients. Receiver operating characteristic curve analysis showed that an appropriate cut-off point for discriminating between the presence and the absence of an adverse event was 4. Using this category, 166 (81.8%) patients were classified as low risk and 37 (18.2%) as high risk for adverse outcome. The adverse event rates were 6.0% for the low-risk group and 59.5% for the high-risk group.

CONCLUSIONS

This study has confirmed the clinical significance of surveillance CUS in patients with a first episode of PE. Furthermore, a simple risk score on the basis of available variables can identify patients at risk of an adverse outcome in patients with PE.