Knowledge of the D-dimer test result influences clinical probability assessment of pulmonary embolism

Background: In patients with suspected pulmonary embolism (PE), an unlikely or non-high probability assessment combined with a normal D-dimer test can safely exclude the diagnosis. We studied the influence of early D-dimer knowledge on clinical probability assessment. Methods: A questionnaire was sent to 150 randomly selected pulmonologists and internists in the Netherlands, presenting six hypothetical case-descriptions of patients with suspected PE. Physicians were randomized to receive one of three versions. The version contained a normal, an abnormal or no D-dimer result with each case-description. Each version contained two cases with an abnormal D-dimer result, two cases with a normal D-dimer result and two cases with no D-dimer result. Results: A total of 71 physicians (47%) returned the questionnaire; the three versions were equally represented. Compared to the control cases in which no D-dimer was given, knowledge of an abnormal D-dimer resulted in more "likely" clinical scores using the Wells' score (absolute increase in "likely" of 25-37%, p = 0.005, 0.111 and 0.144), while knowledge of a normal D-dimer resulted in more "unlikely" scores (absolute increase in "unlikely" of 27-44%, p = 0.001 and 0.070). D-dimer knowledge did not influence the probability assessment when the clinical suspicion was very high. Conclusion: Knowledge of the D-dimer test influences the physician in how the clinical probability for PE is scored. This will have direct clinical consequences, such as unnecessary imaging testing or inappropriate exclusion of the diagnosis. Physicians should therefore make sure that they examine the patient before they take notice of the D-dimer test result. (C) 2010 Elsevier Ltd. All rights reserve

Effects of Training and Feedback on Accuracy of Predicting Rectosigmoid Neoplastic Lesions and Selection of Surveillance Intervals by Endoscopists Performing Optical Diagnosis of Diminutive Polyps

Real-time differentiation of diminutive polyps (1-5 mm) during endoscopy could replace histopathology analysis. According to guidelines, implementation of optical diagnosis into routine practice would require it to identify rectosigmoid neoplastic lesions with a negative predictive value (NPV) of over 90%, using histologic findings as a reference, and agreement with histology-based surveillance intervals for more than 90% of cases. We performed a prospective study with 39 endoscopists accredited to perform colonoscopies on participants with positive results from fecal immunochemical tests in the Bowel Cancer Screening Program at 13 centers in the Netherlands. Endoscopists were trained in optical diagnosis using a validated module (WASP). After meeting predefined performance thresholds in the training program, the endoscopists started a 1-year program (continuation phase) in which they performed narrow-band imaging analyses during colonoscopies of participants in the screening program and predicted histological findings with confidence levels. The endoscopists were randomly assigned to groups that received feedback or no feedback on the accuracy of their predictions. Primary outcome measures were endoscopists' abilities to identify rectosigmoid neoplastic lesions (using histology as a reference) with NPVs of 90% or more, and selecting surveillance intervals that agreed with those determined by histology for at least 90% of cases. Of 39 endoscopists initially trained, 27 (69%) completed the training program. During the continuation phase, these 27 endoscopists performed 3144 colonoscopies in which 4504 diminutive polyps were removed. The endoscopists identified neoplastic lesions with a pooled NPV of 90.8% (95% CI, 88.6-92.6); their proposed surveillance intervals agreed with those determined by histologic analysis for 95.4% of cases (95% CI, 94.0-96.6). Findings did not differ between the group that did versus did not receive feedback. Sixteen endoscopists (59%) identified rectosigmoid neoplastic lesions with NPVs greater than 90% and selected surveillance intervals in agreement with those determined from histology for more than 90% of patients. In a prospective study following a validated training module, we found that a selected group of endoscopists identified rectosigmoid neoplastic lesions with pooled NPVs greater than 90% and accurately selected surveillance intervals for over 90% of patients over the course of 1 year. Providing regular interim feedback on the accuracy of neoplastic lesion prediction and surveillance interval selection did not lead to differences in those endpoints. Monitoring is suggested as individual performance varied. ClinicalTrials.gov no: NCT0251674