C0197: Optimization of the diagnostic management of clinically suspected pulmonary embolism in hospitalized patients

Background: Identical diagnostic algorithms for suspected pulmonary embolism (PE) [clinical decision rule (CDR) followed by D-dimer testing and/or computed tomography pulmonary angiography (CTPA)] are used for in-and outpatients, while D-dimer levels, risk factors and pre-test probability for PE differ. We firstly evaluated the efficacy of the standard algorithm in a validation cohort of inpatients and secondly aimed to optimize the algorithm in this cohort combined with a previous cohort of inpatients. Methods: Efficiency (number of CTPAs) and safety (3-month venous thromboembolism (VTE) incidence rates) of the standard algorithm were studied in a validation cohort.We further studied the potential of increasing the D-dimer threshold and/or the CDR threshold in this and a previous cohort and derived a new CDR based on a multivariate regression analysis. Results: In the validation cohort (n = 140), only 2% (3/140; 95% CI 0.4-6.1) were managed without CTPA. Combining two cohorts (n = 624), overall PE prevalence was 25%, standard management resulted in a 3-month VTE incidence rate of 0.0% (95% CI 0.0-7.3) and 92% of patients underwent CTPA. Applying an age-adjusted D-dimer threshold resulted in a-4.5 percentage points (95% CI 1.2-7.8) reduction of CTPAs with a VTE incidence rate of 1.9% (95% CI 0.9-3.6%). None of the other adjustments, nor the newly derived CDR, resulted in a higher efficiency with an acceptable failure rate. Conclusions: The standard CDR combined with the age-adjusted D-dimer threshold resulted in a limited increase of efficiency with an acceptable failure rate. Our additional attempts to safely reduce the high need for CTPA were unsuccessful.