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Underuse of risk assessment and overuse of CTPA in patients with suspected pulmonary thromboembolism.
Intern Med J. 2017 Jun 21;:
Authors: Perera M, Aggarwal L, Scott IA, Cocks N
Abstract
INTRODUCTION: Evidence suggests potential overuse of computerised tomography pulmonary angiography (CTPA) in patients with suspected pulmonary thromboembolism (PTE) in the absence of consistent use of pre-test clinical prediction rules and D-dimer assays.
METHODS: 344 consecutive patients undergoing CTPA at a tertiary hospital were studied for use of D-dimer assays and clinical prediction rules for PTE. For each patient, a modified Wells score (mWS), revised Geneva score (rGS) and PISA model were calculated retrospectively; performance characteristics for each rule for PTE were determined in reference to results of CTPA. Results for the mWS and D-dimer assays (when performed) were used to estimate overuse of CTPA according to risk category.
RESULTS: Use of a clinical prediction rule was documented in only 5.0 % of cases. Of 269 low risk patients who had a calculated mWS ≤4, only 64 (23.8%) had a D-dimer assay performed, with 30 (11.1%) having PTE on CTPA. Among 75 patients with a mWS >4, 23 (30.7%) had PTE on CTPA (p < 0.001). Compared to other prediction rules, a mWS>4 had the highest positive predictive value (31.0%) for PTE; all rules demonstrated similar negative predictive values for low risk scores - 87% to 89%. After adjusting for 11% false negative rate for PTE in patients with low risk mWS, overuse of CTPA was possible in up to 190 (55.2%) patients.
CONCLUSION: More than 50% of patients with suspected PTE may be subject to unwarranted use of CTPA in the absence of pre-test clinical prediction rules coupled with D-dimer assays.
PMID: 28635149 [PubMed - as supplied by publisher]