%0 Journal Article
%T 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
%A Maryam Rahiminejad
%A Anshul Rastogi
%A Shirish Prabhudesai
%A David Mcclinton
%A Peter MacCallum
%A Sean Platton
%A Emma Friedman
%J ISRN Radiology
%D 2014
%R 10.1155/2014/519875
%X Aims. Colour doppler ultrasonography (CDUS) is widely used in the diagnosis of deep venous thrombosis (DVT); however, the number of scans positive for above knee DVT is low. The present study evaluates the reliability of the D-dimer test combined with a clinical probability score (Wells score) in ruling out an above knee DVT and identifying patients who do not need a CDUS. Materials and Method. This study is a retrospective audit and reaudit of a total of 816 outpatients presenting with suspected lower limb DVT from March 2009 to March 2010 and from September 2011 to February 2012. Following the initial audit, a revised clinical diagnostic pathway was implemented. Results. In our initial audit, seven patients (4.9%) with a negative D-dimer and a low Wells score had a DVT. On review, all seven had a risk factor identified that was not included in the Wells score. No patient with negative D-dimer and low Wells score with no extra clinical risk factor had a DVT on CDUS (negative predictive value 100%). A reaudit confirmed adherence to our revised clinical diagnostic pathway. Conclusions. A negative D-dimer together with a low Wells score and no risk factors effectively excludes a lower limb DVT and an ultrasound is unnecessary in these patients. 1. Introduction Deep venous thrombosis (DVT) is a common cause of mortality and morbidity with an estimated incidence of 67 per 100£¿000 general populations per year [1] and a cumulative lifetime incidence of 2 to 5% [2]. Accurate diagnosis of DVT is necessary because untreated DVT can result in thromboembolic disease and misdiagnosis is associated with bleeding due to the treatment with anticoagulants [3]. Diagnosis of DVT is made by varying combinations of history, physical examination, clinical probability score, blood test for D-dimer, and compression ultrasonography (CDUS). Among the patients who are referred for scanning with suspected DVT, less than 25% have the disease [4]. Over the past decades, the clinical diagnostic methods have developed considerably; however, the accurate tests are costly and the cheap ones are not reliable [5]. CDUS is still the initial approach in the diagnosis of DVT in many centres [6, 7]. It is a reliable and accurate diagnostic test to confirm or rule out DVT, but since only 17% to 24% of suspected patients have a DVT, it is not appropriate and cost-effective to request this investigation in all patients [8, 9]. Numerous studies demonstrate that a combination of a clinical probability assessment (e.g., Wells score), D-dimer, and CDUS might be a reliable means of excluding
%U http://www.hindawi.com/journals/isrn.radiology/2014/519875/