Improving detection of venous thromboembolism. New technology holds promise for early, precise diagnosis

Venous thromboembolism after spinal cord injury

OBJECTIVE

To review systematically the published literature on the treatment of deep venous thromboembolism after spinal cord injury (SCI).

DATA SOURCES

MEDLINE/PubMed, CINAHL, EMBASE, and PsycINFO databases were searched for articles addressing the treatment of deep venous thromboembolism post-SCI. Randomized controlled trials (RCTs) were assessed for methodologic quality using the Physiotherapy Evidence Database Scale, while non-RCTs were assessed using the Downs and Black evaluation tool.

STUDY SELECTION

Studies included RCTs, non-RCTS, cohort, case-control, case series, pre-post, and postinterventional studies. Case studies were included only when no other studies were available.

DATA EXTRACTION

Data extracted included demographics, the nature of the study intervention, and study results.

DATA SYNTHESIS

Levels of evidence were assigned to the interventions using a modified Sackett scale.

CONCLUSIONS

Twenty-three studies met inclusion criteria. Thirteen studies examined various pharmacologic interventions for the treatment or prevention of deep venous thrombosis in patients with SCI. There was strong evidence to support the use of low-molecular-weight heparin in reducing venous thrombosis events, and a higher adjusted dose of unfractionated heparin was found to be more effective than 5000 units administered every 12 hours, although bleeding complications were more common. Nonpharmacologic treatments were also reviewed, but again limited evidence was found to support these treatments.

Management of heterotopic ossification and venous thromboembolism following acquired brain injury

OBJECTIVE

To evaluate the effectiveness of interventional strategies for the common complications of heterotopic ossification (HO) and venous thromboembolism (VTE) following acquired brain injury (ABI).

METHODS AND MAIN OUTCOMES

A systematic review of the literature from 1980-2005 was conducted focusing on interventions for HO and VTE in the ABI population. Nineteen studies examining a variety of treatment approaches were evaluated.

RESULTS

The majority of interventions are supported by limited evidence, defined as an absence of randomized controlled trials (RCTs). All of the treatment approaches for HO are supported with limited evidence. For VTE, there is moderate evidence, defined as at least one positive RCT, indicating that low-molecular-weight heparin is more effective than low-dose unfractionated heparin in preventing VTE, low-molecular-weight heparin is as effective and safe as unfractionated heparin for the prevention of pulmonary thromboembolism, low-molecular-weight heparin combined with compression stockings is more effective than compression stockings alone for the prevention of VTE and intermittent pneumatic compression devices are as effective as low-molecular-weight heparin for the prevention of VTE.

CONCLUSIONS

There are a variety of intervention and prophylactic strategies that have been postulated to treat and reduce the incidence of these complications, with the goal of improving rehabilitation outcomes. It is therefore important to investigate the efficacy of these treatment strategies to provide guidance for clinical practice based on the best available evidence.

Extensive Evaluation of the Instrumentation Laboratory IL Test D-Dimer Immunoturbidimetric Assay on the ACL 9000 Determines the D-Dimer Cutoff Value for Reliable Exclusion of Venous Thromboembolism

The clinical diagnosis of venous thromboembolism (VTE), which includes both deep vein thrombosis (DVT) and pulmonary embolism (PE), is often difficult and requires a number of imaging tests plus clinical assessment. It is now accepted that pretest clinical probability of disease plus a sensitive, quantitative D-Dimer assay can be used to reliably exclude VTE. In design of diagnostic strategies for VTE it is recommended that the D-Dimer assay be evaluated for sensitivity and specificity in well-designed, blinded studies using a cohort of patients for whom the assay will ultimately be used. Therefore we evaluated the IL Test D-Dimer on the ACL 9000 automated coagulation analyzer for its sensitivity and specificity in the diagnosis of VTE. A total of 512 patients admitted to the emergency department of Providence Hospital with suspected VTE were included in the dataset. Our aim was to find the clinically meaningful IL Test D-Dimer cutoff value, which would give us 100% sensitivity and the highest possible specificity for exclusion of VTE. Patients were categorized clinically into low, medium, or high pretest probability and had computed tomographic and/or ventilation-perfusion scans for investigation of PE and ultrasound studies for suspected DVT, with the laboratory blinded to the clinical findings. Of the 511 patients, 28 (5.4%) had confirmed VTE (PE and/or DVT) based on imaging and clinical studies. Applying receiver operating characteristic curve (ROC) analysis, we determined from our study that a cutoff value of 237 ng/mL IL Test D-Dimer gave a 100% sensitivity with a specificity of 38% for detection of VTE. The findings demonstrate that a diagnostic strategy using the IL Test D-Dimer assay as a first-line test in combination with pretest probability is safe and can be used in patients with suspected VTE. In conclusion, patient analysis results indicating low or moderate pretest probability for VTE and a negative IL Test D-Dimer (cutoff value of 237 ng/mL) assay result on the ACL 9000 reliably exclude VTE (both PE and DVT). We expect that inclusion of the rapid IL Test D-Dimer assay for assessment of suspected VTE in the emergency department at Providence will result in improved patient diagnosis and therapy, reduction in unnecessary radiological investigations, and lowering of overall costs associated with investigation of patients suspected of having VTE disease.

Use of computed tomography pulmonary angiography in the diagnosis of pulmonary embolismin patients with an intermediate probability ventilation/perfusion scan

BACKGROUND

Computed tomography pulmonary -angiography (CTPA) plays an increasingly important role in the diagnosis of pulmonary embolism (PE). Although accurate in the detection of large PE, its accuracy in other patient groups is yet to be defined.

AIM

To compare CTPA with pulmonary angiography as a second-line investigation in patients with a ventilation/perfusion (VQ) scan indicating an intermediate probability of PE.

METHODS

We recruited 25 patients over a 17-month period. Subjects were eligible if they: (i). had clinically suspected PE, (ii). had a VQ scan indicating an intermediate probability of PE and (iii). were referred for pulmonary angiography. Subjects underwent CTPA within 36 h of the VQ scan. CTPA was interpreted without knowledge of the results of the pulmonary angiogram by two of the authors.

RESULTS

PE was prevalent (i.e. embolus detected at pulmonary angiography) in seven of 25 subjects (28%). The sensitivity of CTPA was 57% and the specificity was 94%.

CONCLUSIONS

In the setting of intermediate-probability VQ scanning, CTPA may be used to clarify the diagnosis of PE. However, a negative CTPA cannot -definitely exclude PE. Conventional pulmonary angiography may be necessary to determine the presence of PE if CTPA is negative.