USE OF THE VALVE VISUALIZATION ON ECHOCARDIOGRAPHY GRADE (VVEG) TOOL IMPROVES NEGATIVE PREDICTIVE VALUE OF TRANSTHORACIC ECHOCARDIOGRAM FOR RULING OUT VALVULAR VEGETATION

Abstract

Transesophageal echocardiography (TEE) remains the preferred diagnostic test to rule out infective endocarditis (IE), but is resource intensive and carries risk. Studies reporting low sensitivity of transthoracic echocardiography (TTE) for detection of IE did not use modern echo techniques, and do not take into account TTE quality. A good quality TTE may be sufficient to rule out IE in the absence of high risk clinical features. Reported technical adequacy of a TTE is variable amongst interpreters. No standardized method exists to assess TTE quality for ruling out valvular vegetation. Sequential patients who underwent TTE and TEE to rule out IE at an academic teaching hospital from 2011-2015 were identified. All studies were performed with modern echo machines. Patients with prosthetic valves and pacemaker wires were excluded. The Valve Visualization on Echocardiography Grade(VVEG) tool was developed by expert consensus after a thorough literature review. The score assigns each valve a score from 0-3 for mitral, tricuspid and aortic valves, and 0-1 for pulmonic, reflecting leaflet visibility and presence of orthogonal views, for a total score from 0-10. Each TTE was blindly graded using the tool. Reported technical difficulty and presence of vegetation was obtained from the TTE report. The TEE report was used as a gold standard for vegetation. 511 patients were identified, 316 TTE/TEE pairs were evaluated after exclusions. The average age was 65 and 67% had positive blood cultures. The average VVEG score was 4.5(SD+/-2.8). Overall, 20%(65) of TTEs were positive for vegetation, 69%(219) were negative, 10%(32) were indeterminate. Of the negative TTEs, 9%(19) went on to have positive TEEs. Overall, TTE had a sensitivity of 72%, a specificity of 93%, and a negative predictive value (NPV) of 91%. TTEs reported technically adequate had a sensitivity of 85% and NPV of 94% for detecting vegetation. Receiver operator characteristic analysis determined a cut off of >6 on the VVEG score was optimal for sensitivity. 24%(77) of patients had VVEG scores > 6; 38%(29) had positive TTEs for vegetation, 52%(40) had negative TTEs, and 10%(8) were indeterminate. A TTE with a VVEG score of > 6 had a sensitivity of 96% and an NPV of 98%. Applying the VVEG score increased the sensitivity of TTE from 72% to 96%. While this tool requires further validation, this demonstrates that when TTE quality is assessed by an objective measure, a high quality TTE can safely rule out vegetation.View Large Image Figure ViewerDownload Hi-res image Download (PPT)