Testing the Test: The Reliability of Echocardiography in the Sequential Assessment of Valvular Regurgitation

John S. Gottdiener, MD; Julio A. Panza, MD; Martin St John Sutton, MD; Patrick Bannon, MD; Harvey Kushner, PhD; Neil J. Weissman, MD

Disclosures

Am Heart J. 2002;144(1) 

In This Article

Abstract and Introduction

Background and Objective: Substantial variability in serial echocardiographic qualitative assessment of valvular regurgitation may exist. Reader variability is generally well understood, but acquisition variability (portions of variability caused by equipment, sonographers, physiologic changes) has been less frequently assessed, particularly in combination with reader variability. We attempted to determine the relative contributions of acquisition and reader variability as components of total test-retest variability for aortic (AR) and mitral (MR) regurgitation.
Methods: Outpatient echocardiographic study was done at 2 clinical sites. Twenty-three predominantly obese middle-aged females had 3 echocardiograms, 2 performed 14 ± 3 days apart and the third performed within 1 to 2 hours of the second. Triplets of echocardiograms were evaluated for change in grade of AR and MR. Medical history, anthropometrics, and blood pressures were obtained.
Results: Average intrareader variability (percentage of reads for which there is within-reader disagreement) was 5.6% for AR and 16.7% for MR. The average total test-retest variability (percentage of reads for which there is disagreement between visits) was 29.0% for AR and 24.6% for MR. The acquisition variability for AR was 23.4% ± 7.7%; for MR, it was 7.9% ± 10.2%. A significant predictor of change for AR/MR was the initial grade. Change in diastolic blood pressure was positively associated with change in AR and MR.
Conclusions: Intrareader agreement was substantial for AR and MR. Components of total test-retest variability found were reader, biological (change in diastolic blood pressure), and regression to the mean. Recommendations for clinical practice include monitoring blood pressure changes and understanding the confidence limits of the clinical test. Test-retest variability and its components should be considered in echocardiography and other diagnostic testing.

Echocardiography is the principal diagnostic technique used for the assessment of cardiac structures and function.[1,2,3] In clinical practice and research, serial echocardiograms are used to assess the improvement or worsening of regurgitation.[4,5,6] Accurate and reproducible measurements are necessary to permit meaningful comparisons between examinations. However, variability in image acquisition and physician interpretation may be problematic for serial assessment of valvular regurgitation.[7,8]

We have previously shown that substantial variability in serial assessment of regurgitation may exist despite excellent observer reliability.[9] Test-retest variability, which is the likelihood that a repeat test shows change that actually did not occur, is pertinent to clinical practice. However, the components of test-retest variability, reader variability, and acquisition variability (nonreader variability, such as equipment variability, differences in sonographer practice, biological changes, and regression to the mean) remain undetermined. The present study was conducted to determine the relative contribution of acquisition and reader variability as components of total test-retest variability.

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