Observer‐dependent variability of quantitative clinical endpoints: the example of canine echocardiography

Abstract

The objective of this study was to determine the intra- and inter-observer variability of echocardiographic measurements in dogs. Four observers with different levels of experience in echocardiography performed 192 echocardiographic examinations of six dogs on four different days. The lowest within- and between-day coefficients of variation (CV) (%) were 13.8 and 5.2 for the right ventricle in diastole, 8.9 and 4.5 for the interventricular septal thickness in diastole (6.3 and 7.0 in systole), 7.7 and 9.4 for the left ventricular free-wall thickness in diastole (8.1 and 5.2 in systole), 3.1 and 5.0 for the left ventricular end-diastolic diameter (6.2 and 7.0 for end-systolic diameter), 10.2 and 10.8 for the left ventricular shortening fraction, and 8.2 and 9.8 for the left atrium/aorta ratio, respectively. Most of these lowest CVs were observed by the two most experienced observers. Conversely, all maximum values were obtained with the two less experienced observers. These differences in observer-dependent variability may considerably influence the minimum number of animals required to detect a treatment-associated change in echocardiographic variables.

Comparative Adverse Cardiac Effects of Pimobendan and Benazepril Monotherapy in Dogs with Mild Degenerative Mitral Valve Disease: A Prospective, Controlled, Blinded, and Randomized Study

“…Moreover, at the end of the study period, glomerular filtration rate (GFR) was assessed in all dogs using the plasma exogenous creatinine clearance test as previously validated by our group because of potential renal safety issues due to the observed hemodynamic effects. 18 To perform an adequate analysis of imaging data, all variations after drug administration were interpreted according to the involved investigator's variability, which has already been published for all of the conventional echocardiographic 19 and TDI 20 variables except for the maximal thickness of the mitral valve leaflet. A validation protocol was performed during the study period to assess the intraobserver variability of the latter variable and of all the conventional Doppler variables (see validation of Conventional Echo-Doppler Variables section).…”

“…19 The left ventricular myocardial walls and diameters were measured, as were fractional shortening (%FS) using the 2D-guided M-mode 21 and maximal thickness of the anterior mitral valve leaflet using the right parasternal 4-chamber view. Left atrial diameter/aortic diameter ratio (LA/Ao) also was assessed.…”

“…Left atrial diameter/aortic diameter ratio (LA/Ao) also was assessed. 19 Mitral regurgitant jet area was assessed by the Doppler color flow mapping method as previously described, 22 and the maximum area of the regurgitant jet signal/left atrium area ratio (ARJ/LAA) was calculated. The peak velocity and the velocity time integral of the regurgitant jet were measured by continuous-wave Doppler using the left apical 4-chamber view.…”

Azotemia and Glomerular Filtration Rate in Dogs with Chronic Valvular Disease

“…11 Ventricular measurements were taken from the right parasternal location by means of the 2-dimensional (2D)-guided M-mode according to the standard published veterinary recommendations. 12 Left ventricular enddiastolic and end-systolic diameters (LVDD, LVSD), left ventricular free-wall and interventricular septal thickness in diastole and systole (LVFWD, LVFWS, IVSD, IVSS) were measured.…”

Dépistage de la cardiomyopathie dilatée et de la fibrillation atriale chez le Lévrier Irlandais

“…-il existe une variabilité des résultats entre les manipulateurs qui peut même se manifester entre deux examens réalisés par le même opérateur (Chetboul et al 2004). …”