Importance of D-dimmer testing in ambulatory detection of atypical and 'silent' phlebothrombosis

Abstract

Deep venous thrombosis (DVT) is a life-threatening condition, which could be manifested with discrete symptoms (silent DVT). High mortality and disability of patients with DVT indicate the importance of early diagnosis, especially of "silent" DVT. The aim of this paper was to evaluate of reliability of early detection model for diagnosing DVT in ambulatory patients by using clinical probability of DVT presence, D-dimmer test (DD) and ultrasound evaluation (US). Ambulatory patients with suspected DVT were classified as "unlikely" and "likely" DVT by the Wells clinical model. The patients were randomly divided into the control and DD group. In the control group (629 patients) only US examination of lower limbs deep vein was done. All patients in the DD group (643 patients), with "unlikely" TDV, had DD, and in the positive patients US examination was done. In the "likely" patients US examination was done and negative US finding indicated DD test. Positive DD test was an indication for US examination after 7 days. The patients with initially excluded DVT were evaluated during 3 months. A total number of 1 272 patients were examined; 117 (9.19%) patients were with DVT--62 (9.640%) in the DD and 55 (8.74%) in the control group. During the follow-up periods in the DD group (with 582 initially excluded DVT) we registered DVT in only one patient (0.17%). It was significantly lower (p < 0.05) compared to the control group where we registered 7 (1.10%) DVT (a group with 581 initially excluded DVT). The applied DD diagnostic strategy for 70.7% (p < 0.001) reduced the need for US examination. The applied DD strategy in the diagnostic of DVT reduces the need for US examinations and reduces frequency of false negative results, with direct impact on cost and efficacy of procedures. DD diagnostic model should replace serial US examination in patients with suspect DVT.