Objectives: Previous studies evaluating light reflection rheology (LRR) in the preliminary diagnosis of suspected deep vein thrombosis (DVT) have been based on limited patient numbers. The objective of this study was to demonstrate the diagnostic value of LRR in this setting for a large patient series.
Methods: A retrospective study was carried out using prospectively collected data over a five-and-a-half year period. During the study period, 3342 limbs were assessed with LLR in 3105 patients referred with suspected DVT (both inpatients and outpatients).
Results: In total, 2396 (71.7%) of all the LRR tests carried out yielded an abnormal result. Of the remaining 946 (28.3%) with a normal result, 204 went on to have a duplex scan due to a high clinical index of suspicion, and 14 DVTs were identified on duplex scanning. Of the remaining 742 patients with a normal LRR result who were not scanned, six re-presented within three months with a confirmed DVT, and one with a confirmed pulmonary embolus (PE). These results yield a negative predictive value of 97.8%, a sensitivity of 96.4% with a three-month post-test thromboembolism incidence of 0.9%. Use of LRR allowed duplex scanning to be avoided for 22.2% of referrals.
Conclusions: Despite the increasing use of D-dimers and clinical probability scoring in the preliminary investigation of thromboembolic events, LRR remains a viable alternative in safely risk-stratifying patients with suspected DVT.