Plasma fibrin D-dimer and the risk of left atrial thrombus: A systematic review and meta-analysis

Development of a machine learning predictive model for central venous catheter-associated thrombosis in patients undergoing abdominal surgery

BACKGROUND

Central venous catheters (CVCs) are placed where the vena cava meets the right atrium. Their common use raises the risk of catheter-related thrombosis (CRT), a potentially life-threatening complication.

AIM

This study leverages machine learning to develop a CRT predictive model for abdominal surgery patients, aiming to refine clinical decisions and elevate treatment quality.

STUDY DESIGN

The data were split into training and validation sets using the caret package in R. Decision Trees (DT), Extra Trees (ET), Ada Boost, Gradient Boosting (GB), Light Gradient Boosting Machine (LGBM), K Neighbours Classifier (KNN) and Random Forest (RF) algorithms were used for model construction. Receiver operating characteristic (ROC) curve, area under curve (AUC), accuracy, recall, precision, F1 score, sensitivity and specificity were used to evaluate the performance of the model. Decision curve analysis (DCA) was used to evaluate the clinical utility of each model.

RESULTS

Among the 400 subjects, 184 had thrombosis, with an incidence of 46%. Basic characteristics analysis and univariate analysis showed that there were significant differences in the history of radiotherapy or chemotherapy, age, mobility score, retention time, D-dimer, fibrinogen and urea (p < .05). Among the models constructed by the seven algorithms, the performance of DT model was relatively balanced. The AUC of the validation set was 0.782, the sensitivity was 0.618, and the specificity was 0.781.

CONCLUSION

The predictive model for CRT developed using machine learning algorithms demonstrates good discrimination and clinical applicability among abdominal surgery patients, offering valuable guidance for CRT prevention strategies.

RELEVANCE TO CLINICAL PRACTICE

By integrating risk prediction models into the Hospital Information System (HIS), nurses can assess catheter status in a timely and accurate manner, understand the risks of thrombosis for patients, and implement targeted preventive measures. This approach can enhance the efficiency and accuracy of nursing care, holding clinical significance in critical care practice.

Antithrombotic therapy in atrial flutter: To anticoagulate or not, that is the question

Atrial fibrillation (AF) represents an arrhythmia fraught with significant morbidity, mortality, and financial burden for the health care system. Less attention is given to atrial flutter (AFL), which may occur as a stand-alone arrhythmia or coexist with AF in the same patient. Moreover, it is known that AF frequently develops after AFL ablation. Despite different pathophysiologies of AF and AFL, current guidelines provide identical indications for anticoagulation therapy in both arrhythmias, given the lack of trials in patients with AFL. This study attempts at providing an up-to-date literature review on the thromboembolic risk profile in AFL, focusing on differences between AFL and AF. Echocardiographic studies showed that the presence of spontaneous echocardiographic contrast (SEC) and thrombus are much less prevalent in patients with AFL than in those with AF. Patients with AFL had overall better left atrial appendage (LAA) function and lower coagulation marker levels than did patients with AF. Observational studies showed a significantly lower risk of stroke in patients with AFL than in those with AF. One study found a significantly higher ischemic stroke incidence in the AFL cohort only at CHA2DS2-VASc scores from 5 to 9 than in patients without AF or AFL. These findings imply that the thromboembolic risk inherent in AFL seems lower than that in AF. This should be considered in the context of a high chance of permanent AFL termination after successful cavotricuspid isthmus ablation, in contrast to the chronic clinical nature of AF. Although thromboembolic risk exists in AFL, prospective studies are warranted to establish the true prothrombotic properties of AFL, allowing the reassessment of anticoagulant treatment strategy.

Predictive Value of Inflammatory Scores for Left Atrium Thrombosis in Ischemic Stroke Without Atrial Fibrillation

Background and Objectives: Studies have shown that inflammation markers can be used as prognostic tools in predicting acute ischemic stroke. In this study, we conducted a comparison of several inflammation scores in predicting left atrial thrombosis (LAT) in patients with ischemic stroke without AF. Materials and Methods: In this single-center, retrospective study, we included 303 consecutive patients with ischemic stroke. Each patient underwent a transesophageal echocardiography (TEE) examination within 10 days of admission to detect the presence of LAT. To identify independent predictors of LAT, we conducted a multivariate logistic regression analysis. Results: In total, 303 patients who had ischemic stroke were included in the analysis. LAT was detached in 34 patients at the time of the TEE examination. The patients were categorized into two groups based on their LAT status. The Prognostic Nutritional Index (PNI), HALP score, and C-reactive Protein-Albumin Ratio (CAR) were identified as statistically significant predictors of LAT. Based on the results of the multivariate regression analysis, the CAR emerged as the only independent predictor of LAT. Conclusions: Among several inflammation scores, the PNI, HALP, and CAR were statistically significant predictors of LAT in ischemic stroke patients without AF. CAR was identified as the optimal score for the prediction of LAT in patients with stroke and without AF.

Diagnostic accuracy of D-dimer to detect left atrial thrombus in patients with atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

There is conflicting evidence about the use of biomarkers to diagnose left atrial thrombus in patients with atrial fibrillation.

OBJECTIVE

The purpose of this study was to assess the diagnostic accuracy of D-dimer to detect left atrial thrombus in patients with atrial fibrillation.

METHODS

We searched 4 electronic databases from inception to December 16, 2020. The reference standard was left atrial thrombus detected by transesophageal echocardiography. Study quality was assessed with the Quality Assessment of Diagnostic Accuracy Studies 2 tool. We used a bivariate model to calculate the pooled sensitivity and specificity with their 95% confidence intervals (CIs). The optimal cutoff and predictive values were also estimated.

RESULTS

Eleven cross-sectional studies involving 4380 patients were included. The median prevalence of left atrial thrombus was 12%. In 7 studies, the pooled sensitivity of D-dimer at 500 ng/mL was 50% (95% CI 26%-74%) and the pooled specificity was 88% (95% CI 76%-95%). The pooled sensitivity of age-adjusted D-dimer was 36% (95% CI 14%-66%) and the pooled specificity was 99% (95% CI 96%-99%) in 2 studies. The optimal cutoff of D-dimer was 390 ng/mL in 10 studies with a pooled sensitivity of 68% (95% CI 44%-85%) and a pooled specificity of 73% (95% CI 54%-86%). The positive and negative predictive values were 21.8% and 95.4%, respectively. The risk of bias was low or unclear for all domains. Concerns about applicability were low for almost all studies.

CONCLUSION

Our meta-analysis suggests that D-dimer has the potential to be useful to rule out left atrial thrombus in patients with atrial fibrillation.

d-dimer Level as a Predictor of Recurrent Stroke in Patients With Embolic Stroke of Undetermined Source

[Figure: see text].

Differences in D-dimer blood concentration in atrial fibrillation patients with left atrial thrombus or severe left atrial spontaneous echo contrast

PURPOSE

Severe left atrial spontaneous echo contrast (SLASEC) is considered the prior stage to thrombosis and a high-risk factor for thrombotic events. Studies have suggested an effect of D-dimer blood concentration on exclusion of left atrial thrombus (LAT), but it remains unclear whether D-dimer concentrations differ between atrial fibrillation (AF) patients with SLASEC or LAT.

METHODS

Nonvalvular AF patients scheduled to undergo catheter ablation or cardioversion in Shanghai Ruijin Hospital between January 2017 and July 2020 were screened for this prospective study. All patients underwent transesophageal echocardiography (TEE) to detect SLASEC or LAT. D-dimer concentrations were measured at the time of TEE. Clinical data including CHA₂DS₂-VASc score were evaluated. Major complications with thromboembolism in the SLASEC group were followed up at least 6 months after therapy.

RESULTS

Among 920 consecutively enrolled nonvalvular AF patients, 30 patients with SEC grade 0, 35 patients with SLASEC, and 22 patients with LAT were included. D-dimer concentration and CHA₂DS₂-VASc score were significantly lower in the SLASEC group compared with the LAT group (D-dimer, 0.26±0.13 vs. 0.86±0.9 mg/L, P<0.05; CHA₂DS₂-VASc score, 2.3±0.9 vs. 3.1±1.5, P=0.02). The cut-off value for D-dimer concentration (0.285 mg/L) had sensitivity of 77.3% and specificity of 80.0% for prediction of LAT. D-dimer concentration showed a decreasing trend with a significant difference (0.42±0.22 vs. 0.33±0.18 mg/L, P=0.03) for 9 patients in the LAT group after complete thrombus resolution by anticoagulation treatment. No major or fatal bleeding, ischemic stroke, or systemic thromboembolism events occurred in the SLASEC group during the 6-month follow-up.

CONCLUSIONS

This study demonstrated a significantly lower D-dimer concentration and CHA₂DS₂-VASc score in AF patients with SLASEC than in those with LAT. The D-dimer cut-off value (0.285 mg/L) can be used as an effective reference index to distinguish the pre-thrombotic state of LAT from LAT. D-dimer blood concentration may be a predictor of LAT thrombolysis.

Clinical characteristics and outcomes in patients with echocardiographic left ventricular spontaneous echo contrast

BACKGROUND

Spontaneous echo contrast (SEC) is a known precursor to thrombus formation and thromboembolic events. This study aims to demonstrate the clinical characteristics and outcomes of patients with left ventricular spontaneous echo contrast (LV-SEC).

METHODS

Patients with consecutive echocardiogram performed from October 2009 to September 2019 were enrolled in this retrospective, single-center study. Those with LV-SEC were included, while patients complicated by left ventricular thrombus, with history of infective endocarditis, prosthetic valves, or lost to follow-up were excluded. The clinical endpoint was 1-year thromboembolic events (i.e. stroke and peripheral embolism).

RESULTS

Among 417 patients (mean age 63.5 ± 14.7 years; 86.8% men) with LV-SEC, the incidence of 1-year embolism was 12.9%. In multivariate Cox proportional hazard model, significant risk factors for thromboembolic event were age [hazard ratio (HR) = 1.022, 95% confidence interval (CI): 1.000-1.045], atrial fibrillation (AF) (HR = 2.292, 95% CI: 1.237-4.244), hemoglobin (HR = 1.032, 95% CI: 1.017-1.047), left ventricular ejection fraction (LVEF) (HR = 1.021, 95% CI: 1.002-1.041), and anticoagulant therapy (HR = 0.310, 95% CI: 0.168-0.572). For patients with repeated measurements for echocardiography, D-dimer (HR = 1.137, 95% CI: 1.051-1.231), and △LVEF (HR = 0.961, 95% CI: 0.928-0.996) were independently associated with the persistent LV-SEC.

CONCLUSION

The present study reported a high incidence of 1-year thromboembolic event in patients with LV-SEC. Age, AF, hemoglobin, LVEF were independent risk factors for 1-year embolism and a reduced risk of embolism was observed among patients with anticoagulation therapy. Additionally, D-dimer and △LVEF are independently associated with the persistent LV-SEC.

The prevalence, predictors, and outcomes of spontaneous echocardiographic contrast or left ventricular thrombus in patients with HFrEF

AIMS

This study aimed to determine prevalence, predictors, and association with ischaemic stroke risk of spontaneous echocardiographic contrast (SEC) or left ventricular thrombus (LVT) in patients with heart failure with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

Clinical, echocardiographic, and follow-up data from January 2009 through February 2019 were retrospectively extracted from electronic medical records of patients with heart failure with left ventricular ejection fraction < 40% by echocardiography on admission, with follow-up to February 2020. Of 9485 consecutive patients with HFrEF, 123 (1.3%) presented LVT and 331 (3.5%) presented SEC. Patients with vs. those without SEC/LVT had larger left ventricular end-diastolic volume (199.5 ± 77.7 vs. 165.8 ± 61.3 mL, P < 0.001), lower left ventricular ejection fractions (29.5 ± 7.0% vs. 33.7 ± 5.5%, P < 0.001), and more often ischaemic cardiomyopathy, apical aneurysm, chronic kidney diseases, and smoking habit. In Cox regression analysis, SEC and LVT were independent predictors for ischaemic stroke occurrence [hazard ratio (HR) = 2.40, 95% confidence interval (CI): 1.74-3.31; HR = 4.52, 95% CI: 2.77-7.40, both P < 0.001]. In patients with those without SEC or LVT, stroke risk was higher among those not on anticoagulants (HR = 2.55, 95% CI: 1.85-3.53; HR = 4.71, 95% CI: 2.84-7.81, both P < 0.001), but similar among those on anticoagulants (P > 0.05). In patients with sinus rhythm, the associations between SEC/LVT and ischaemic stroke persist with HRs of 2.57 (95% CI: 1.69-3.92) and 5.74 (95% CI: 3.38-9.75).

CONCLUSIONS

In patients with HFrEF, SEC was not uncommon and increased risk of ischaemic stroke as well as LVT. Anticoagulants could play a role in the reduction of stroke risk, suggesting that patients with SEC/LVT, even those in sinus rhythm, would benefit from systemic anticoagulation treatment.

Biomarkers in Atrial Fibrillation: Pathogenesis and Clinical Implications

Biomarkers derived from the key components of the pathophysiology of atrial fibrillation (AF) and its complications have the potential to play an important role in earlier characterization of AF phenotype and in risk prediction of adverse clinical events, which may translate into improved management strategies. C-reactive protein, natriuretic peptides, cardiac troponins, growth differentiation factor-15, and fibroblast growth factor-23 have been shown to be the most promising biomarkers in AF. Some biomarkers have already been included in clinical risk scores to predict postoperative AF, thromboembolism, major bleeding, and death. Considerably more work is needed to bring these novel biomarkers into routine clinical management of patients with AF.

Biomarkers for Predicting Left Atrial or Left Atrial Appendage Thrombus in Anticoagulated Patients with Nonvalvular Atrial Fibrillation

PURPOSE

Although atrial fibrillation (AF) is often associated with thromboembolic complications, there is no definite biomarker for detecting the presence of thrombi in the left atrial (LA) or left atrial appendage (LAA) in patients with nonvalvular atrial fibrillation (NVAF).

METHODS

NVAF patients who underwent transesophageal echocardiography (TEE) to evaluate LA/LAA thrombus and spontaneous echo contrast (SEC) before AF ablation were included. Multivariate logistic regression and receiver operating characteristic curve (ROC) analyses were performed to explore the independent risk factors of LA/LAA thrombus and indicate the best cutoff point.

RESULTS

Of the 260 consecutive subjects (mean age: 63.67 ± 9.39 years; 42% women), 45 (17.3%) patients were with LA/LAA thrombus, 131 (50.4%) were with SEC, and 84 (32.3%) were with neither thrombus nor SEC. The results of multivariate logistic regression analysis showed that N-terminal pro-B-type natriuretic peptide (NT-proBNP) (OR, 2.179; 95% CI: 1.191-3.987; p=0.012) and red cell distribution width (RDW) (OR, 2.398; 95% CI: 1.075-5.349; p=0.033) were independently correlated with the presence of LA/LAA thrombus but not D-dimer (OR, 0.999; 95% CI: 0.998-1.000; p=0.210). When all patients were divided into four groups based on the combination between RDW (cutoff value: 12.95%) and NT-proBNP levels (cutoff value: 368.9 ng/L), the rate of LA/LAA thrombus was the highest in the high RDW and NT-proBNP group.

CONCLUSION

In anticoagulation patients with NVAF, elevated NT-proBNP and RDW are related to LA/LAA thrombus. Therefore, these might be considered as useful prognostic markers in the management and treatment of NVAF patients.

Useful indices of thrombogenesis in the exclusion of intra-cardiac thrombus

Background

Cardioversion in patients with atrial fibrillation (AF) can cause cardioembolic stroke, and effective clinical management is necessary to reduce morbidity and mortality. Currently, transesophageal echocardiography (TEE) is the accepted standard to diagnose cardiogenic thromboemboli; however, a negative TEE does not eliminate the possibility of left atrial thrombus. The objective of this study was to evaluate the diagnostic value of supplementing the TEE with additional noninvasive markers to ensure thrombus absence.

Methods

A prospective study was conducted on 59 patients who underwent TEE for suspected intra‐cardiac thrombi. The TEE indications included acute ischemic stroke (45.7%) and AF or flutter (59.3%). D‐dimer level and white blood cell counts were assessed.

Results

A negative D‐dimer level (<200 ng/mL) excluded the presence of intra‐cardiac thrombi. Groups with either negative (n = 14) or positive (n = 45) D‐dimer levels had comparable clinical characteristics. Comparing positive D‐dimer–level patients with thrombus (n = 7) and without thrombus (n = 33), patients with thrombus had reduced left atrial appendage (LAA) velocity (P = .0024), reduced left ventricular ejection fraction (LVEF) (P = .0263), increased neutrophil percent (P = .0261), decreased lymphocyte percent (P = .0216), and increased monocyte counts (P = .0220). The area under the receiver operating characteristic (ROC) curve for thrombus diagnostics was larger for combinations of clinical and biochemical data than for each parameter individually.

Conclusions

Supplementing the gold standard TEE with the analysis of LAA velocity, noninvasive LVEF, D‐dimer, and hemostatic markers provided additional useful diagnostic information. Larger studies are needed to further validate the efficacy of supplementing the TEE to better assess patients for intra‐cardiac thrombi.

The emerging value of serum D-dimer measurement in the work-up and management of ischemic stroke

Background

Elevated D-dimer levels are a marker of both thrombin formation and fibrinolysis. Currently D-dimer measurement is routinely used for ruling out venous thromboembolism and diagnosis/monitoring of disseminated intravascular coagulation. Recent emerging data suggest that D-dimer may become an important biomarker in ischemic stroke as well as in cardiovascular diseases.

Aims

To outline the clinical utility of D-dimer in work-up and management of ischemic stroke.

Summary

D-dimer measurement is most useful in stroke with active cancer as it can confirm etiologic diagnosis, predict recurrent stroke risk, and aid treatment decision in cancer-associated stroke. In cryptogenic stroke, high D-dimer levels can also provide clues for the cause of stroke as occult cancer and undetected cardiac embolic source as occult atrial fibrillation and may be helpful in treatment decision making of secondary stroke prevention. Serial D-dimer measurements should be further studied to monitor antithrombotic therapy effectiveness in both cardiogenic and cryptogenic etiologies.

Conclusion

Accumulating data suggests the utility of D-dimer test in the management of ischemic stroke, although the evidence is still limited. Future studies would clarify the role of D-dimer measurement in ischemic stroke.

Baseline D-Dimer Levels as a Risk Assessment Biomarker for Recurrent Stroke in Patients with Combined Atrial Fibrillation and Atherosclerosis

Background: We investigated the effect of D-dimer levels and efficacy of different antithrombotic therapies according to the baseline D-dimer levels on recurrent stroke in patients with atrial fibrillation (AF)-related stroke and atherosclerosis. Methods: We enrolled 1441 patients with AF-related stroke and atherosclerosis in this nationwide multicenter study. The primary outcome measure was the occurrence of recurrent ischemic stroke over a 3-year period. Results: High D-dimer levels (≥2 μg/mL) were significantly associated with higher risk of recurrent ischemic stroke (adjusted hazard ratio (HR), 1.80; 95% confidence interval (CI), 1.13–2.84; p = 0.012). The risk of recurrent stroke was similar between the anticoagulant and the antiplatelet groups in all subjects (adjusted HR, 0.78; 95% CI, 0.46–1.32; p = 0.369). However, in patients with high D-dimer levels (≥2 μg/mL), risk of recurrent stroke was significantly lower in the anticoagulant group than in the antiplatelet group (adjusted HR, 0.40; 95% CI, 0.18–0.87; p = 0.022). Conclusion: Our findings suggested that baseline D-dimer levels could be used as a risk assessment biomarker of recurrent stroke in patients with AF-related stroke and atherosclerosis. High D-dimer levels would facilitate the identification of patients who are more likely to benefit from anticoagulants to ensure secondary prevention of stroke.

Left atrial spontaneous echo contrast: relationship with clinical and echocardiographic parameters

Spontaneous echo contrast (SEC) indicates blood stasis in cardiac chambers and major vessels, and is a known precursor of thrombus formation. Transesophageal echocardiography plays a pivotal role in detecting and grading SEC in the left atrial (LA) cavity. Assessing LA SEC can identify patients at increased risk for thromboembolic events. LA SEC also develops in patients who have sinus rhythm, especially in those with heart failure. Detection of LA SEC is not uncommon in subjects who have multiple cardiovascular comorbidities, although mechanisms behind this association are not fully understood. In patients with atrial fibrillation, the role of mitral regurgitation in counteracting LA SEC and subsequent thromboembolism is controversial. Moreover, alterations of blood coagulability and elevated levels of certain biological markers in the blood contribute to occurrence of LA SEC. This review describes the pathogenesis and assessment of SEC, in addition to the relationship between LA SEC and clinical, biological and echocardiographic parameters.

Evidence-Based Case Report: The Use of D-Dimer Assay to Exclude Left Atrial Thrombus in Patient with Atrial Fibrillation >48 Hours

INTRODUCTION

Patients with atrial fibrillation (AF) for >48 hours who are a candidate for cardioversion should have transesophageal echocardiography (TEE) performed to exclude left atrial thrombus (LAT) that may cause systemic thromboembolism upon conversion to sinus rhythm. However, TEE facilities were limited, especially in developing countries.

CASE ILLUSTRATION

A 50 years-old man presented with exertional dyspnea and palpitation for 72 hours prior to admission. Electrocardiography showed AF with a ventricular rate of 140x/minute. Cardioversion was decided to be the best approach. This patient has an AF >48 hours of onset, hence, LAT should be excluded by the use of TEE. Unfortunately, there was no TEE facility nearby.

DISCUSSION

Upon comprehensive search on the use of D-Dimer assay to exclude the LAT in AF patients, we found seven studies showed increased D-dimer level in those with left atrial thrombus. In 4 studies, AUC was > 0.70, sensitivity and specificity varied from 75.9% to 89% and 73.1% to 95% respectively. However, there is no single cut-off point, due to the heterogeneity of cut-off points.

CONCLUSION

D-dimer assay combined with other variables of atrial thrombus exclusion score is valuable in excluding LAT. Previously, weeks of anticoagulation is more advisable before attempting cardioversion in the absence of nearby TEE facilities. With current evidence, a low D-dimer and ATE score of 0 is safe for cardioversion.

The diagnostic efficacy of cardiac CTA combined with D-dimer assay for the detection of left atrial thrombus in patients with atrial fibrillation

PURPOSE

We aimed to evaluate a combination diagnostic method of single-phased, single-contrast injection cardiac computed tomography angiography CTA combined with age-adjusted D-dimer assay for diagnosis of left atrial/left atrial appendage (LA/LAA) thrombus in comparison to transesophageal echocardiography (TEE) in patients with atrial fibrillation. The addition of D-dimer to the CTA is to increase specificity, since CTA is part of the combined method.

MATERIALS AND METHODS

Between October 2016 and December 2017, 113consective patients with non-valvular or valvular AF (male: 72.6%; mean age: 57.9 ± 11.5 y) underwent diagnostic work-up, included TEE, single-phased, single contrast injection cardiac CTA, and age-adjusted D-dimer assay, for the evaluation of LA/LAA thrombus formation.

RESULTS

Cardiac CTA identified 32 patients with filling defects in LA or LAA. Of these patients, 17 had an elevated D-dimer value according to age-adjusted cut-off. TEE detected definitive thrombus formation in 15 patients. Using TEE as the reference standard, the combination diagnostic method had a sensitivity of 100.0%, specificity of 97.9%, positive predictive value (PPV) of 88.2, and negative predictive value of 100.0%. Further, compared to cardiac CTA alone, the combination diagnostic method had significantly better specificity (82.7% vs. 97.9%, respectively; p < 0.01) and PPV (46.9% vs. 88.2%, respectively; p < 0.01).

CONCLUSION

The combination diagnostic method comprising single-phase, single-contrast injection cardiac CTA and age-adjusted D-dimer assay had good diagnostic efficacy for the detection of LA/LAA thrombus in patients with AF. The combination diagnostic method had significantly better specificity and PPV than cardiac CTA alone. The presented diagnostic approach could potentially facilitate rapid diagnosis or exclusion of left atrial thrombus under emergency situation or when TEE is un-available, with good diagnostic efficacy and no TEE related risks.