Performance of a diagnostic algorithm based on a prediction rule, D-dimer and CT-scan for pulmonary embolism in patients with previous venous thromboembolism. A systematic review and meta-analysis

How to Combat Over-Testing for Patients Suspected of Pulmonary Embolism: A Narrative Review

The diagnosis of PE remains difficult in 2023 because the signs and symptoms are not sensible nor specific. The consequences of potential diagnostic errors can be dramatic, whether by default or by excess. Furthermore, the achievement of a simple diagnostic strategy, based on clinical probability assessment, D-dimer measurement and computed tomography pulmonary angiography (CTPA) leads to a new challenge for PE diagnosis: over-testing. Indeed, since the 2000s, the wide availability of CTPA resulted in a major increase in investigations with a mod I confirm erate increase in PE diagnosis, without any notable improvement in patient outcomes. Quite the contrary, the complications of anticoagulation for PE increased significantly, and the long-term consequences of imaging diagnostic radiation is an important concern, especially the risk of breast cancer for young women. As a result, several strategies have been proposed to fight over-testing. They are mostly based on defining a subgroup of patients for whom no specific exam should be required to rule-out PE and adjusting the D-dimer cutoff to allow the exclusion of PE without performing CTPA. This narrative review presents the advantages and limitations of these different strategies as well as the perspective in PE diagnosis.

d-dimer is a predictor of clot resolution in patients with pulmonary thromboembolism: A retrospective cohort study

BACKGROUND

This study assessed predictors of pulmonary thromboembolism (PE) resolution and their implications for clinical outcome.

METHOD

A total of 150 patients with acute PE diagnosed by computed tomography pulmonary angiography (CTPA) were included. All patients received anticoagulant therapy for 3-6 months and were followed-up for at least 2 years. d-dimer levels in plasma were assayed at the first admission and during follow-up.

RESULTS

The rate of CTPA-confirmed PE resolution was 48.67% at 6 months, 68% at 12 months, and 78.67% at 24 months. Thirty-nine patients had recurrent thrombosis after anticoagulation therapy was stopped, whereas 93 patients had complete resolution. The initial d-dimer level positively correlated with the pulmonary artery obstruction index (PAOI) (r = 0.21; P = 0.015), but did not significantly differ between patients experiencing resolution or recurrence. In contrast, the follow-up mean d-dimer level was significantly higher in the recurrent group (P < 0.001), and this level was an independent risk factor for recurrent PE after the termination of anticoagulation treatment (OR 1.003, 95%CI 1.002 to 1.004; P < 0.001). Higher initial thromboembolic burden measured by PAOI was associated with residual thromboemboli (P = 0.004) and recurrence (P = 0.03), but was not an independent risk factor for either.

CONCLUSIONS

Elevated d-dimer is an independent risk factor for PE recurrence. A higher initial thromboembolic burden may be associated with unresolved thromboemboli or recurrence.

Incidence of acute cerebral infarction or space occupying lesion among patients with isolated dizziness and the role of D-dimer

Background

To determine the incidence of acute cerebral infarction or space occupying lesion (SOL) among patients with isolated vertigo or dizziness (IVD) and to evaluate the role of cerebellar function test (CFT) and D-dimer to discriminate ACI/SOL and non-ACI/SOL.

Methods

A retrospective study of consecutive emergency department (ED) patients with IVD during one year was conducted. ACI was based on the diffusion-weighted magnetic resonance imaging (DW-MRI), and SOL was based on the concurrent MRI sequences. A sensitivity analysis of CFT and D-dimer was also performed.

Results

Among the 468 patients enrolled, 13 patients (2.8%) had ACI, 11 at cerebellum, 1 at occipital lobe, and 1 at centrum semiovale. Twenty-five patients (5.3%) had SOL. Aneurysm is most frequent (n = 7), followed by meningioma (n = 4) and venous anomaly (n = 4). In total, ACI/SOL was found in 8.1% (n = 38). Abnormal findings in finger-to-nose (FN), heel-to-shin (HTS), and rapid alternative movement (RAM) tests were significantly higher in ACI or ACI/SOL group, while gait disturbance, tandem gait abnormality, and Romberg’s test were not. CFT sensitivities were low for ACI as well as for ACI/SOL, but specificities were high for ACI and ACI/SOL. D-dimer level showed a sensitivity of 100% at >0.18 mg/L for ACI and >0.15 mg/L for ACI/SOL. However, specificity was low at corresponding D-dimer level. Among the subgroup (n = 411) who did not show any abnormality in CFT, 9 patients (2.2%) had ACI, and 33 patients (8.0%) had ACI/SOL.

Conclusion

The present study reports a clinically significant incidence of ACI/SOL among ED patients with IVD. D-dimer showed high sensitive and low specificity, while CFT showed low sensitivity and high specificity.

Effects of early antiplatelet therapy after splenectomy with gastro-oesophageal devascularization

BACKGROUND

This study aimed to explore the effects of early antiplatelet therapy (APT) for portal vein thrombosis (PVT) in patients with cirrhotic portal hypertension after splenectomy with gastro-oesophageal devascularization.

METHODS

We retrospectively analysed 139 patients who underwent splenectomy with gastro-oesophageal devascularization for portal hypertension due to cirrhosis between April 2010 and December 2016. Based on the post-operative platelet values, we used two different APT regimens: APT was started when platelet counts were increased to 200 × 10⁹ /L or above (group A, n = 64) or 300 × 10⁹ /L or above (group B, n = 75). We took note of the patients' clinical symptoms, operative factors and biochemical indicators.

RESULTS

Platelet count, mean platelet volume, D-dimer and pancreatic fistula were closely related to the development of PVT. Early APT was an independent protective factor for PVT. The incidence of post-operative PVT was 15.1% (21/139) overall, 4.7% (3/64) in group A and 24% (18/75) in group B; there was a significant difference between groups A and B (χ²  = 10.042, P = 0.002).

CONCLUSION

Platelet count, mean platelet volume, D-dimer and pancreatic fistula were independent risk factors for the development of PVT after splenectomy with gastro-oesophageal devascularization. Selection of the appropriate timing for early APT according to the post-operative platelet count was feasible. Moreover, the use of aspirin combined with dipyridamole was safe and effective for early prevention of PVT.

The Evaluation of D-Dimer Levels for the Comparison of Fibrinogen and Fibrin Units Using Different D-Dimer Kits to Diagnose VTE

The cutoff values of D-dimer levels for diagnosing or predicting the occurrence of deep vein thrombosis (DVT) were evaluated in preoperative patients and compared to those in non-DVT patients. The levels of 8 different D-dimers were measured using the latex agglutination method or enzyme immunoassay before surgery in 262 orthopedic surgery patients to diagnose subclinical DVT or predict postoperative DVT. There were 15 patients with subclinical DVT and 47 with postoperative DVT, but 200 patients had no DVT at all. All 8 plasma D-dimer values were significantly higher in the patients with subclinical or postoperative DVT than in those without DVT or in healthy volunteers. There were differences in the cutoff values between the assays highly sensitive for low D-dimer levels and wild-range assays of D-dimers. Some D-dimer assays might therefore be more useful than others for diagnosing low levels of D-dimer. Although the measurement of D-dimer levels was useful for diagnosing subclinical DVT and predicting the risk of DVT, the cutoff values for the diagnosis or prediction of DVT varied. The cutoff values for the prediction of postoperative DVT were ≥1.7 µg/mL (D-dimer A-D) and ≥1.0 µg/mL (D-dimer E-H).

Diagnosis of suspected venous thromboembolism

The primary goal of diagnostic testing for venous thromboembolism (VTE) is to identify all patients who could benefit from anticoagulant therapy. Test results that identify patients as having a ≤2% risk of VTE in the next 3 months are judged to exclude deep vein thrombosis (DVT) or pulmonary embolism (PE). Clinical evaluation, with assessment of: (1) clinical pretest probability (CPTP) for VTE; (2) likelihood of important alternative diagnoses; and (3) the probable yield of D-dimer and various imaging tests, guide which tests should be performed. The combination of nonhigh CPTP and negative D-dimer testing excludes DVT or PE in one-third to a half of outpatients. Venous ultrasound of the proximal veins, with or without examination of the distal veins, is the primary imaging test for leg and upper-extremity DVT. If a previous test is not available for comparison, the positive predictive value of ultrasound is low in patients with previous DVT. Computed tomography pulmonary angiography (CTPA) is the primary imaging test for PE and often yields an alternative diagnosis when there is no PE. Ventilation-perfusion scanning is associated with less radiation exposure than CTPA and is preferred in younger patients, particularly during pregnancy. If DVT or PE cannot be "ruled-in" or "ruled-out" by initial diagnostic testing, patients can usually be managed safely by: (1) withholding anticoagulant therapy; and (2) doing serial ultrasound examinations to detect new or extending DVT.

The Evaluation of Fibrin-Related Markers for Diagnosing or Predicting Acute or Subclinical Venous Thromboembolism in Patients Undergoing Major Orthopedic Surgery

OBJECTIVE

The cutoff values of fibrin-related markers (FRMs) diagnosing or predicting the occurrence of a venous thromboembolism (VTE) were evaluated.

MATERIALS AND METHODS

Fibrin-related markers such as fibrin monomer complex (FMC), D-dimer, and fibrinogen and fibrin degradation products (FDPs) before surgery were measured in 326 patients undergoing orthopedic surgery to diagnose subclinical VTE or predict postoperative VTE.

RESULTS

Although the FMC, D-dimer, and FDP levels were all useful for the diagnosis of acute VTE, the FDP level was not useful for diagnosing subclinical VTE or predicting postoperative VTE. The results of several D-dimer assays closely correlated with other D-dimer assays. There were various cutoff ranges for diagnosing or predicting VTE. Some D-dimer assays were useful for diagnosing low levels of D-dimer and others were useful for diagnosing moderate to high D-dimer levels. Increased D-dimer levels were useful for diagnosing acute (cutoff values: 2.0-5.9 μg/mL) or about 10% of subclinical VTE (cutoff values: 3.4-5.3 μg/mL), for predicting about 10% of postoperative VTE (cutoff values: 3.4-5.3 μg/mL), and for excluding VTE.

CONCLUSION

Although increased D-dimer levels were useful for diagnosing subclinical VTE and predicting the risk of VTE, there were various cutoff values for the diagnosis or prediction of VTE.

Current challenges in diagnostic imaging of venous thromboembolism

Because the clinical diagnosis of deep-vein thrombosis and pulmonary embolism is nonspecific, integrated diagnostic approaches for patients with suspected venous thromboembolism have been developed over the years, involving both non-invasive bedside tools (clinical decision rules and D-dimer blood tests) for patients with low pretest probability and diagnostic techniques (compression ultrasound for deep-vein thrombosis and computed tomography pulmonary angiography for pulmonary embolism) for those with a high pretest probability. This combination has led to standardized diagnostic algorithms with proven safety for excluding venous thrombotic disease. At the same time, it has become apparent that, as a result of the natural history of venous thrombosis, there are special patient populations in which the current standard diagnostic algorithms are not sufficient. In this review, we present 3 evidence-based patient cases to underline recent developments in the imaging diagnosis of venous thromboembolism.

Current challenges in diagnostic imaging of venous thromboembolism

Because the clinical diagnosis of deep-vein thrombosis and pulmonary embolism is nonspecific, integrated diagnostic approaches for patients with suspected venous thromboembolism have been developed over the years, involving both non-invasive bedside tools (clinical decision rules and D-dimer blood tests) for patients with low pretest probability and diagnostic techniques (compression ultrasound for deep-vein thrombosis and computed tomography pulmonary angiography for pulmonary embolism) for those with a high pretest probability. This combination has led to standardized diagnostic algorithms with proven safety for excluding venous thrombotic disease. At the same time, it has become apparent that, as a result of the natural history of venous thrombosis, there are special patient populations in which the current standard diagnostic algorithms are not sufficient. In this review, we present 3 evidence-based patient cases to underline recent developments in the imaging diagnosis of venous thromboembolism.

Association between D-dimer level and portal venous system thrombosis in liver cirrhosis: a retrospective observational study

OBJECTIVE

This study aimed to explore the association between D-dimer levels and presence of portal venous system thrombosis (PVST) in liver cirrhosis.

METHODS

All consecutive patients with a diagnosis of liver cirrhosis who underwent D-dimer test were retrospectively enrolled. Normal reference range of D-dimer level was 0-0.3 µg/mL. PVST was diagnosed on the basis of contrast-enhanced computed tomography and/or magnetic resonance imaging scans.

RESULTS

Of the 66 included patients, 24 were diagnosed with PVST. Mean D-dimer level was 0.51±0.72 µg/mL (range: 0.10-3.44). Mean D-dimer level was not significantly different between PVST and non-PVST groups (0.68±0.93 µg/mL versus 0.41±0.56 µg/mL, P=0.146). Area under the receiver operating curve for D-dimer level for predicting the presence of PVT was 0.606 (95% confidence interval: 0.478-0.724, P=0.1393). The optimal cut-off value for D-dimer was 0.22 with a sensitivity of 58.3% and a specificity of 69.0%. The subgroup analyses of patients without splenectomy or those with different Child-Pugh classes demonstrated no significant difference in the D-dimer level between PVST and non-PVST groups.

CONCLUSION

D-dimer might not be useful to identify the presence of PVST in liver cirrhosis. However, given the retrospective nature of this study, further well-designed prospective study should be necessary to confirm this finding.