Evaluating the Use of a Negative D-Dimer and Modified Low Wells Score in Excluding above Knee Deep Venous Thrombosis in an Outpatient Population, Assessing Need for Diagnostic Ultrasound

Characterizing and quantifying low-value diagnostic imaging internationally: a scoping review

BACKGROUND

Inappropriate and wasteful use of health care resources is a common problem, constituting 10-34% of health services spending in the western world. Even though diagnostic imaging is vital for identifying correct diagnoses and administrating the right treatment, low-value imaging-in which the diagnostic test confers little to no clinical benefit-is common and contributes to inappropriate and wasteful use of health care resources. There is a lack of knowledge on the types and extent of low-value imaging. Accordingly, the objective of this study was to identify, characterize, and quantify the extent of low-value diagnostic imaging examinations for adults and children.

METHODS

A scoping review of the published literature was performed. Medline-Ovid, Embase-Ovid, Scopus, and Cochrane Library were searched for studies published from 2010 to September 2020. The search strategy was built from medical subject headings (Mesh) for Diagnostic imaging/Radiology OR Health service misuse/Medical overuse OR Procedures and Techniques Utilization/Facilities and Services Utilization. Articles in English, German, Dutch, Swedish, Danish, or Norwegian were included.

RESULTS

A total of 39,986 records were identified and, of these, 370 studies were included in the final synthesis. Eighty-four low-value imaging examinations were identified. Imaging of atraumatic pain, routine imaging in minor head injury, trauma, thrombosis, urolithiasis, after thoracic interventions, fracture follow-up and cancer staging/follow-up were the most frequently identified low-value imaging examinations. The proportion of low-value imaging varied between 2 and 100% inappropriate or unnecessary examinations.

CONCLUSIONS

A comprehensive list of identified low-value radiological examinations for both adults and children are presented. Future research should focus on reasons for low-value imaging utilization and interventions to reduce the use of low-value imaging internationally.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO: CRD42020208072.

Evaluation of the modified Wells score in predicting venous thromboembolic disease in patients with tuberculosis or HIV in a South African setting

Background

There is paucity of data on the modified Wells score (MWS) utility on patients with venous thromboembolism (VTE) in a South African setting where there is a high burden of HIV and tuberculosis (TB). This study analyses the performance of this score in HIV/TB-infected patients compared with non-infected patients.

Objectives

To assess the performance of the MWS as an additional risk factor for VTE in hospitalised patients with a high burden of HIV/TB infections.

Method

This study was a retrospective cross-sectional cohort analysis of the utility of the MWS in 156 HIV/TB-infected and non-infected adult patients diagnosed with VTE on compression ultrasonography (CUS) or computed tomography pulmonary angiography (CTPA) in a medical inpatient setting over six months. Patients with HIV and/or TB were assessed as having an additional risk factor (1 point for each), and this was compared with the MWS. A McNeymar’s paired sample chi-squared test was used to compare the sensitivity of this score against the MWS.

Results

Of the 156 patients with VTE who were enrolled, HIV was the commonest risk factor (42.31%) with TB accounting for 10.90% of cases. When the MWS adjusted for HIV/TB was used, the sensitivity increased from 25% to 100% for the HIV–/TB+ category, it increased from 77.36% to 98.11% in the HIV+/TB– category and it increased from 84.62% to 92.95% in the HIV+/TB+ category. These differences were statistically significant at P < 0.05 in all categories.

Conclusion

The MWS performs better when the infectivity of HIV/TB is included as an additional risk factor in the score.

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.

Effects of a standardized emergency department protocol on after-hours use of venous duplex ultrasound

OBJECTIVE

Vascular laboratory (VL) venous duplex ultrasound is the "gold standard" for diagnosis of lower extremity deep venous thrombosis (DVT), which is linked to many morbid conditions. Decreasing night and weekend use of VL services in the emergency department (ED) represents a potentially viable means of reducing costs as skilled personnel must remain on call and receive a wage premium when activated. We investigated the effects of workflow changes that required ED providers to use a computerized decision-making tool, integrated into the electronic medical record, to calculate a Wells score for each patient considered for an after-hours venous duplex ultrasound study for suspected DVT.

METHODS

The rate of VL use and study positivity before and after implementation of the decision-making tool were examined in addition to measures of ED throughput, rate of concomitant pulmonary embolism, disposition of examined patients from the ED, observed thrombus distribution in duplex ultrasound studies positive for DVT, and calculated personnel costs of after-hours VL use.

RESULTS

A total of 391 after-hours, ED-initiated venous duplex ultrasound studies were obtained during the 4-year study period (n = 213 before intervention, n = 178 after intervention; P = .12). Whereas the period immediately after the start of the intervention saw a decrease in VL use, this was not sustained. Studies performed after the intervention were not more likely to be positive for acute DVT (12.2% vs 18%; P = .1179). The average Wells score was 2.8 (range, 0-6). VL personnel were called in 347 times during the 4-year period, with a total cost of $14,643.40. Nurse-ordered studies were significantly more likely to be positive, with 22% revealing acute DVT compared with 12% for physician-ordered studies (P = .042). The intervention resulted in significant improvements in ED throughput, with time between triage and study request falling from 226 minutes to 165 minutes (P < .001). Observed thrombus distribution revealed involvement of the most proximal external iliac system in a minority of cases (11%), whereas most thrombi (89%) were limited to the femoropopliteal, calf, and superficial venous systems.

CONCLUSIONS

A requirement for ED providers to document a Wells score before obtaining an after-hours venous duplex ultrasound study resulted in only a transient decrease in VL use but improved ED throughput. Studies ordered by nurses were significantly more likely to be positive, possibly as a result of consistent protocol adherence compared with the physicians. Future studies may warrant investigation into this provider variance.

[Acute mesenteric ischemia: do biomarkers contribute to diagnosis?]

Acute mesenteric ischemia is an emergency condition that requires immediate therapy. Despite advances in the fields of surgery and intensive therapy, the mortality of this condition remains high. This is due to the broad variability of clinical presentations and non-specific laboratory findings, which delay the diagnosis allowing the ischemia to progress and further worsening the patients' chances of survival. Thus, there is a significant need for reliable and enhanced serological markers of intestinal ischemia. The authors review the traditionally used and novel experimental serological markers for early diagnosis of mesenteric ischemia.