Venous thrombosis and coagulation parameters in patients with pure venous malformations.

INTRODUCTION: Venous malformations (VMs) are ubiquitous, low-flow vascular anomalies known to be occasionally painful due to thrombotic episodes within the lesion. The prevalence of superficial or deep vein thrombosis is unclear. METHODS: A cross-sectional study among outpatients aged ≥ 12 years with pure VMs was performed, quantifying the prevalence of thrombosis by screening all patients with compression ultrasonography (CUS). Additionally, we evaluated whether coagulation alterations were related to thrombosis observed with CUS. RESULTS: In total, 69 patients with pure VMs were eligible, median age was 30 years (range 12-63) and 52% were female. A total of 68 patients underwent CUS. Superficial vein thrombosis was observed in 10 (15%) cases; 1 patient had a current asymptomatic deep venous thrombosis. Residual superficial or deep thrombosis was observed in 25 patients (36%). In total, 49% had either a history or current signs of a thrombotic event and overall 10% had venous thromboembolism. In approximately 50% of the patients the D-dimer level was above 0.5 mg/l. Median P-selectin and Von Willebrand factor levels were 29 ng/ml (interquartile range (IQR) 21-34) and 108% (IQR 83-132), respectively. No differences were observed in the coagulation parameters between the patients with and without current clots in their VM. CONCLUSION: This study shows that superficial or deep vein thrombosis is common among patients with a pure VM. Physicians should be aware of this high incidence, especially if other risk factors for thrombosis are present.

PO-07 - Excluding pulmonary embolism in cancer patients using the Wells rule and age-adjusted D-dimer testing: an individual patient data meta-analysis.

INTRODUCTION: Among patients with clinically suspected pulmonary embolism (PE), imaging and anticoagulant treatment can be safely withheld in approximately one-third of patients based on the combination of a "PE unlikely" Wells score and a D-dimer below the age-adjusted threshold. The clinical utility of this diagnostic approach in cancer patients is less clear. AIM: To evaluate the efficiency and failure rate of the original and simplified Wells rules in combination with age-adjusted D-dimer testing in patients with active cancer. MATERIALS AND METHODS: Individual patient data were used from 6 large prospective studies in which the diagnostic management of PE was guided by the original Wells rule and D-dimer testing. Study physicians classified patients as having active cancer if they had new, recurrent, or progressive cancer (excluding basal-cell or squamous-cell skin carcinoma), or cancer requiring treatment in the last 6 months. We evaluated the dichotomous Wells rule and its simplified version (Table). The efficiency of the algorithm was defined as the proportion of patients with a "PE unlikely" Wells score and a negative age-adjusted D-dimer, defined by a D-dimer below the threshold of a patient's age times 10 µg/L in patients aged ≥51 years. A diagnostic failure was defined as a patient with a "PE unlikely" Wells score and negative age-adjusted D-dimer who had symptomatic venous thromboembolism during 3 months follow-up. A one-stage random effects meta-analysis was performed to estimate the efficiency and failure. RESULTS: The dataset comprised 938 patients with active cancer with a mean age of 63 years. The most frequent cancer types were breast (13%), gastrointestinal tract (11%), and lung (8%). The type of cancer was not specified in 42%. The pooled PE prevalence was 29% (95% CI 25-32). PE could be excluded in 122 patients based on a "PE unlikely" Wells score and a negative age-adjusted D-dimer (efficiency 13%; 95% CI 11-15). Two of 122 patients were diagnosed with non-fatal symptomatic venous thromboembolism during follow-up (failure rate 1.5%; 95% CI 0.13-14.8). The simplified Wells score in combination with a negative age-adjusted D-dimer had an efficiency of 3.9% (95% CI 2.0-7.6) and a failure rate of 2.4% (95% CI 0.3-15). CONCLUSIONS: Among cancer patients with clinically suspected PE, imaging and anticoagulant treatment can be withheld in 1 out of every 8 patients by the original Wells rule and age-adjusted D-dimer testing. The simplified Wells rule was neither efficient nor safe in this population.

Accuracy of X-ray with perfusion scan in young patients with suspected pulmonary embolism.

BACKGROUND: Computed tomography pulmonary angiogram (CTPA) has become the standard test in the diagnostic workup of patients with suspected pulmonary embolism (PE). However, young patients may have an increased risk of cancer with CTPA. Perfusion scanning combined with chest X-ray (X/Q) may offer an adequate alternative, but has never been prospectively validated. We directly compared this strategy with CTPA in patients aged ≤50years with suspected PE. METHODS: Consecutive patients with a likely clinical probability or an abnormal D-dimer level underwent both CTPA and X/Q. Two trained and experienced nuclear physicians independently analyzed the X/Q-scans. The accuracy of X/Q according to the PISAPED criteria was calculated in terms of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). RESULTS: Seventy-six patients were included, with a PE rate of 33%. The inter-observer agreement for X/Q-scan reading was high (κ=0.89). After consensus reading, 21 patients (28%) were categorized as 'PE present', 53 (70%) as 'PE absent', and two (2.6%) as 'non-diagnostic'. In 22%, there was a discrepancy between the X/Q-scan and CPTA for the diagnosis or exclusion of PE. The PPV and NPV were 71% and 83%, respectively. CONCLUSION: In patients with a high risk of PE, a diagnostic strategy of chest X-ray and perfusion scanning using the PISAPED criteria seems less safe than CTPA. Additional studies should further investigate this diagnostic algorithm.

A simple decision rule including D-dimer to reduce the need for computed tomography scanning in patients with suspected pulmonary embolism.

BACKGROUND: An 'unlikely' clinical decision rule with a negative D-dimer result safely excludes pulmonary embolism (PE) in 30% of presenting patients. We aimed to simplify this diagnostic approach and to increase its efficiency. METHODS: Data for 723 consecutive patients with suspected PE were analyzed (prevalence of PE, 22%). After constructing a logistic regression model with the D-dimer test result and items from the Wells' score, we identified the most prevalent combinations of influential items and selected new D-dimer positivity thresholds. The performance was separately validated with data from 2785 consecutive patients with suspected PE. RESULTS: Three Wells items significantly added incremental value to the D-dimer test: hemoptysis, signs of deep vein thrombosis and 'PE most likely'. Based on the most frequent combinations of these three items, we identified two groups: (i) none of these three items positive (41%); (ii) one or more of these items positive (59%). When applying a 1000 µg/L D-dimer threshold in group 1 and 500 µg/L in group 2, PE could be excluded without CT scanning in 36%, at a false-negative rate of 1.2% (95%, 0.04-3.3%). In the validation set, these proportions were 46% and 1.9% (95% CI, 1.2-2.7%), respectively. Using the conventional Wells score with a normal D-dimer result, these rates were, respectively, 22% and 0.6% (95% CI, 0.10-2.4%). CONCLUSION: Combining Wells items with the D-dimer test resulted in a simplified decision rule, which reduces the need for CT scanning in patients with suspected PE. A prospective validation is required before it can be implemented in clinical practice.

Clot resolution after 3 weeks of anticoagulant treatment for pulmonary embolism: comparison of computed tomography and perfusion scintigraphy.

INTRODUCTION: Little is known about the natural history of clot resolution in the initial weeks of anticoagulant therapy in patients with acute pulmonary embolism (PE). Clot resolution of acute PE was assessed with either computed tomography pulmonary angiography scan (CT-scan) or perfusion scintigraphy scan (Q-scan) after 3 weeks of treatment. METHODS: This was a predefined safety analysis of the Einstein PE study, including PE patients, randomized to either enoxaparin with vitamin K antagonist (VKA) or rivaroxaban. A similar scan as at baseline was repeated after 3 weeks. The percentage of vascular obstruction (PVO) was calculated on the basis of a weighted semiquantitative estimation of obstruction. Clot resolution was assessed blindly by calculating the relative change after 3 weeks. RESULTS: PE was diagnosed in 264 patients with CT-scan and in 83 with Q-scan. Baseline characteristics were similar. At baseline, the mean PVO assessed with CT-scan (PVO-CT) and the mean PVO assessed with Q-scan (PVO-Q) were both 21% (standard deviation [SD] 13%) (P = 0.9). The mean relative decrease in PVO was 71% (SD 33%) for PVO-CT, and 62% (SD 36%) for PVO-Q (P = 0.02); complete resolution was observed in 44% (116/264; 95% confidence interval [CI] 38-50%) and 31% (26/83; 95% CI 22-42%) with CT-scan and Q-scan, respectively (P = 0.04). No difference in clot resolution between enoxaparin/VKA and rivaroxaban was found. CONCLUSION: In patients with acute PE, only 3 weeks of anticoagulant treatment leads to complete clot resolution in a considerable proportion of patients, and normalization is more often observed with CT-scan than with Q-scan.