The bedside investigation of pulmonary embolism diagnosis (BIOPED) study- a triple blind randomized control trial comparing initial bedside diagnostic tests to standard care (initial V/Q scan) in the investigation of patients with suspected PE

Abstract number: OC250

Rodger^* M. A., Jones† G., Rasuli† P., Raymond† F., Clement† A. M., Karovitch† A., Djunaedi† H., Makropoulos† D., Bredeson‡ C. N., Abbott- Howley^* H., Wells§ P. S.

‡IBMTR, USA; §Ottawa Health Research Institute, Canada ^*Ottawa Health Research Institute, Canada; †Ottawa Hospital, Canada;

Background  

PE is a common, potentially lethal yet treatable condition only present in a minority of those investigated for PE. Safe bedside methods to exclude PE in a large proportion of patients with PE are desirable. Wells clinical model, non ELISA D-Dimers and alveolar dead space analysis are sensitive and specific bedside tests for PE but are not safe to use alone to exclude PE. We sought to test whether using combinations of these bedside tests (2 out of 3 negative tests) to exclude PE without diagnostic imaging was as safe as the standard diagnostic strategy (i.e. beginning with a V/Q scan).

Methods  

A single center triple blind randomized control trial of two diagnostic strategies in consecutive patients with PE. Patients were randomized to the experimental arm (initial bedside tests) or standard of care (initial V/Q scan without use of bedside tests). All study patients had a Wells clinical model score, a non-ELISA D-Dimer and alveolar dead space analysis performed but this data was only used in patient management in the experimental group. Patients assigned to the experimental group (initial bedside tests) had a sham V/Q performed if 2 of 3 of the bedside tests were negative otherwise (i.e. 2 of 3 positive) they had a real V/Q scan. Sham V/Q scans were reported as ‘no evidence of PE’. All patients assigned to the V/Q scan group had a real V/Q scan. Real V/Q scans were reported as per PIOPED criteria except normal V/Q scans which were reported as ‘no evidence of PE’. Further diagnostic testing and management were dictated by a blinded physician. All patients had 90-day follow-up with blinded outcome assessment. The primary outcome was recurrent VTE over 90 days in patients not anticoagulated after the investigation of PE.

Results  

Of 458 eligible patients 399 consented to participate, 199 were randomized to initial bedside tests and 200 to initial V/Q scan. After the investigation of PE, 65 were anticoagulated and 334 were not anticoagulated (16% initial PE rate). 133 out of 399 study patients had two out of three negative bedside tests (33.3%). Of the 334 not anticoagulated patients, 4/165 (2.4%) in the experimental group and 5/169 (3.0%) in the standard care group had recurrent VTE over 3 months (P = NS).

Conclusion  

Using bedside tests (2 out of 3 negative bedside tests excludes PE) is as safe as an initial V/Q scan diagnostic approach and eliminates the need for diagnostic tests in a third of patients with suspected PE.