Appropriate Use of Venous Imaging and Analysis of the D-Dimer/Clinical Probability Testing Paradigm in the Diagnosis and Location of Deep Venous Thrombosis

Cost of Low-Value Imaging Worldwide: A Systematic Review

BACKGROUND AND OBJECTIVE

Imaging with low or no benefit for the patient undermines the quality of care and amounts to vast opportunity costs. More than 3.6 billion imaging examinations are performed annually, and about 20-50% of these are of low value. This study aimed to synthesize knowledge of the costs of low-value imaging worldwide.

METHODS

This systematic review was based on the PRISMA statement. The database search was developed in Medline and further adapted to Embase-Ovid, Cochrane Library, and Scopus. Primary empirical studies assessing the costs of low-value diagnostic imaging were included if published between 2012 and March 2022. Studies designed as randomized controlled trials, non-randomized trials, cohort studies, cross-sectional studies, descriptive studies, cost analysis, cost-effectiveness analysis, and mixed-methods studies were eligible. The analysis was descriptive.

RESULTS

Of 5,567 records identified, 106 were included. Most of the studies included were conducted in the USA (n = 76), and a hospital or medical center was the most common setting (n = 82). Thirty-eight of the included studies calculated the costs of multiple imaging modalities; in studies with only one imaging modality included, conventional radiography was the most common (n = 32). Aggregated costs for low-value examinations amounts to billions of dollars per year globally. Initiatives to reduce low-value imaging may reduce costs by up to 95% without harming patients.

CONCLUSIONS

This study is the first systematic review of the cost of low-value imaging worldwide, documenting a high potential for cost reduction. Given the universal challenges with resource allocation, the large amount used for low-value imaging represents a vast opportunity cost and offers great potential to improve the quality and efficiency of care.

Assessing the efficacy of VerifyNow platelet-function testing in predicting postoperative thromboembolic complications of neuroendovascular surgery: A systematic review and meta-analysis (part 1)

BACKGROUND

Despite the heavily debated use of routine platelet-function testing, the VerifyNow Platelet Reactivity Unit (PRU) assay has been increasingly adopted as standard of care for assessing risk of postoperative thromboembolic complications of neuroendovascular surgery.

OBJECTIVE

We conducted a systematic review and meta-analysis to examine the relationship between platelet response and risk of ischemic events from neuroendovascular surgery, assess the efficacy of point-of-care platelet-function testing in predicting thromboembolic outcomes, and assess whether a clinically useful threshold for platelet response can be defined in order to standardize guidelines.

METHODS

PubMed, Embase, and Scopus were searched. Following deduplication, articles were first screened for relevance by title and abstract, followed by full text.

RESULTS

Of 735 resultant articles, 22 studies consisting of 3266 patients undergoing neuroendovascular intervention were included. Diagnoses included both intracranial and extracranial pathologies, of which 45.8% were treated with flow diversion, 16.4% with stent-assisted coil embolization, 15.8% with intracranial stenting, 12.0% with simple coil embolization, 3.4% with balloon-assisted coil embolization, 3.6% with extracranial stenting, and 3.0% with an alternate method. 54.5% (12/22) of studies determined platelet hyporesponse to be an independent predictor of postoperative thromboembolic complications, with 27.3% (6/22) of studies reporting a similar, but non-statistically significant trend. 18.2% (4/22) of studies found no relationship between platelet response and postoperative thromboembolic complications. The estimated clinical threshold for PRU to prevent thromboembolic complications varied greatly across studies (Range: > 144-295 PRU). Meta-analysis found platelet hyporesponse to have a 2.23-fold increased risk of thromboembolic complications compared to normoresponders (RR = 2.23, P = 0.03).

CONCLUSION

While PRU demonstrates a significant predictive value for postoperative thromboembolic complications of neuroendovascular surgery, the target therapeutic threshold for minimizing ischemic events remains unclear. Further studies, such as large multicenter cohorts of the existing data, are needed to standardize guidelines.

D-dimer diagnostics: can I use any D-dimer assay? Bridging the knowledge-to-action gap

A State of the Art lecture titled "D-dimer Diagnostics: Can I use any D-dimer assay? Bridging the Knowledge-to-Action gap" was presented at the International Society on Thrombosis and Haemostasis Congress in 2023, included in the session on the clinical impact of variability in commonly used coagulation assays. Here, we review the role of D-dimer, primarily in the outpatient diagnosis of patients with venous thromboembolism (VTE) when combined with clinical decision rules. We focus on the recent large management trials that have studied adjustments of VTE exclusion thresholds for D-dimer based on either prior clinical probability of VTE or patient age, and the resultant benefit of reduced imaging for VTE and improved diagnostic efficiency. In this context, we report on the significant variability between D-dimer results and the multiple D-dimer assays in use worldwide using data from international external quality assurance programs. This variability is particularly high at typical VTE exclusion thresholds. We discuss the potential clinical impact of D-dimer assay substitution on accuracy of diagnosis and risk stratification of patients with VTE. Finally, we summarize relevant new data on this topic presented during the 2023 International Society on Thrombosis and Haemostasis Congress and outline future priorities urgently needed to harmonize D-dimer results and reporting that will require international collaboration among multiple stakeholders with an overall goal to close this knowledge-to-action gap.

Obstetrics and Gynecology Acute Abdomen Clinical Diagnosis and Differential Value of Ultrasonography

Acute abdomen in obstetrics and gynecology is a common disease in clinical emergency, most of the patients have the characteristics of complex condition and rapid progress, and need to be treated through clinical diagnosis. There are many traditional diagnosis methods, but the accuracy is not ideal. Ultrasound is a widely used imaging technique in recent years, which has the characteristics of simple operation and high accuracy, so it is favored by doctors and patients in obstetrics and gynecology. In this study, 200 patients with acute abdomen in obstetrics and gynecology were selected, and the results of pathological examination were taken as the gold standard to evaluate the clinical value of ultrasound examination. As a result, the misdiagnosed ultrasound group was significantly lower after the diagnosis than in the normal group, the difference was significant (P < 0.05). Therefore, the use of ultrasound imaging, the clinical diagnosis of acute abdominal diseases in gynecology and obstetrics achieves a clear diagnostic effect, improves the diagnostic accuracy of patients with acute abdominal disease in the clinical. It is very important for the development of targeted therapeutic programmes.

A risk score for iliofemoral patients with deep vein thrombosis

OBJECTIVE

Deep vein thrombosis (DVT) is a common condition with a high risk of post-thrombotic morbidity, especially in patients with a proximal thrombus. Successful iliofemoral clot removal has been shown to decrease the severity of post-thrombotic syndrome. It is assumed that earlier thrombus lysis is associated with a better outcome. Generally, the earlier IFDVT is confirmed, the earlier thrombus lysis could be performed. d-Dimer levels and Wells score are currently used to assess the preduplex probability for DVT; however, some studies indicate that the d-dimer value varies depending on the thrombus extent and localization. Using d-dimer and other risk factors might facilitate development of a model selecting those with an increased risk of IFDVT that might benefit from early referral for additional analysis and adjunctive iliofemoral thrombectomy.

METHODS

All consecutive adult patients from a retrospective cohort of STAR diagnostic center (primary care) in Rotterdam suspected of having DVT between September 2004 and August 2016 were assessed for this retrospective study. The diagnostic workup for DVT including Wells score and d-dimer were performed as well as complete duplex ultrasound examination. Patients with objective evidence of DVT were categorized according to thrombus localization using the Lower Extremity Thrombolysis classification. Logistic regression analysis was done for a model predicting IFDVT. The cut-off value of the model was determined using a receiver operating characteristic curve.

RESULTS

A total of 3381 patients were eligible for study recruitment, of whom 489 (14.5%) had confirmed DVT. We developed a multivariate model (sensitivity of 77% and specificity of 82%; area under the curve, 0.90; 0.86-0.93) based on d-dimer, Wells score, age, and anticoagulation use, which is able to distinguish IFDVT patients from all patients suspected of DVT.

CONCLUSIONS

This multivariate model adequately distinguishes IFDVT among all suspected DVT patients. Practically, this model could give each patient a preduplex risk score, which could be used to prioritize suspected IFDVT patients for an immediate imaging test to confirm or exclude IFDVT. Further validation studies are needed to confirm potential of this prediction model for IFDVT.

In Well-Selected Patients With a Femoral Deep Vein Thrombosis Central Venous Imaging May Identify Additional Iliocaval Disease

OBJECTIVE

Patients who present acutely with a femoral deep vein thrombosis (DVT) diagnosed by ultrasound are often treated with anticoagulation and instructed to follow-up electively. This study sought to assess whether obtaining axial imaging of the central venous system results in the identification of additional iliocaval pathology warranting treatment.

METHODS

This study was a retrospective review of a prospectively maintained registry from November 2014 through April 2017 with follow-up through March 2020. Consecutive patients with a diagnosis of femoral DVT diagnosed by ultrasound were evaluated; those who underwent axial imaging of the iliocaval system (Group A) were compared to those who did not undergo imaging of the central veins (Group B). The primary outcome was the performance of any percutaneous central venous intervention. Secondary outcomes included the extent of DVT identified on duplex and after axial imaging, follow-up duplex patency and persistence of severe symptoms.

RESULTS

Eighty patients presented with an ultrasound diagnosis of a femoral vein DVT. Mean follow-up was 551 ± 502 days. Group A comprised 24 patients (30%) and Group B comprised 56 patients (70%). Baseline demographics did not differ significantly between the 2 groups. After duplex imaging, Group A exhibited an increased prevalence of DVT in the common femoral vein. After central imaging, Group A exhibited an increased prevalence of DVT in the iliocaval veins. The number of patients who underwent invasive treatment differed significantly between the 2 groups, Group A 16/24 (67%) vs. Group B 9/56 (16%), P < 0.0001. The number of patients that demonstrated duplex patency and had persistent symptoms on follow-up did not differ significantly.

CONCLUSIONS

Patients with an ultrasound diagnosis of femoral DVT may have additional iliocaval pathology warranting intervention. Well-selected imaging of the central veins may reveal a more complete picture, potentially altering management.

Inappropriate use of D-dimer and impact on the test characteristics for deep vein thrombosis exclusion

This study aimed to investigate the prevalence of the inappropriate use of D-dimer testing for deep vein thrombosis (DVT) exclusion, and to evaluate the diagnostic value of D-dimer testing compared between testing in appropriate and inappropriate conditions. A retrospective chart review of patients with D-dimer requests at Siriraj Hospital, Bangkok, Thailand during January-September 2017 was performed. Data relating to D-dimer requests, Wells score, imaging investigations, and coexisting conditions that cause elevated D-dimer without correlation to DVT were analyzed. From 2196 cases, there were 300 D-dimer requests for DVT diagnosis. Of those, 5 (1.7%) and 158 (53.6%) requests were considered to be absolutely inappropriate D-dimer test requests due to the absence of pre-test Wells score evaluation and testing in DVT-likely patients, respectively. One-hundred and forty-eight (49.3%) requests were considered to be the relatively inappropriate D-dimer test requests due to testing in patients with coexisting conditions that included malignancies, sepsis, surgery, trauma, arterial thrombosis, and pregnancy. Three patients had more than one of these conditions. Comparatively higher negative predictive values (NPVs) of D-dimer assay for DVT exclusion were observed when used in DVT-unlikely (100% versus 80%), and in patients without coexisting conditions (100% versus 66.7%). The present study revealed the rate of inappropriate D-dimer testing for DVT exclusion to be high and this may lead to missed DVT diagnosis, overuse of imaging study, and unnecessary cost of D-dimer testing. Appropriate patient selection before test request can improve the NPV of D-dimer for DVT exclusion.

The Diagnostic Efficacy of Age-Adjusted D-Dimer Cutoff Value and Pretest Probability Scores for Deep Venous Thrombosis

This study seeks to evaluate the diagnostic value of D-Dimer Plus and Innovance D-Dimer as well as the age-adjusted cutoff value for D-dimer detection in combination with 4 pretest probability (PTP) scores for deep venous thrombosis (DVT). A total of 688 patients referred for lower extremity vascular compression venous ultrasonography for suspected DVT from January 2016 to May 2018 in the First Affiliated Hospital of Sun Yat-sen University underwent D-dimer tests combining with 4 PTP scores. The diagnostic efficacy of the Wells score was the highest of the 4 PTP scores. The diagnostic efficacy of Innovance D-Dimer for DVT was greater than that of D-Dimer Plus, with better sensitivity and negative predictive value, which were both greater than 98%. If the cutoff values were adjusted by age, the Innovation D-Dimer could further improve both the specificity and the positive predictive value, providing better diagnostic performance. When the 2 D-dimer detections were used in combination with 4 PTP scores for DVT diagnosis, separately, both the positive predictive value and the negative predictive value significantly improved for D-Dimer Plus, and the positive predictive values significantly improved for Innovance D-Dimer. However, the sensitivity, specificity, and negative predictive values did not obviously change. For our patients, Wells score had the best diagnostic efficacy for our patients with suspected DVT among the 4 PTP scores. Innovance D-Dimer in combination with age-adjusted cutoff values exhibited increased sensitivity and negative predictive value for DVT diagnosis and was equivalent to the diagnostic efficacy of the Innovance D-Dimer in combination with PTP scores.