Inter-observer variability for cardiac ultrasound measurements in cats repeated at different time points in early adult life
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Published on: January 14, 2014
Ingrid van Hoek1, Jessie Rose Payne2, Alexandre Feugier1
1Royal Canin SAS. 650, Avenue de la petite Camargue, Aimargues 30470, France.
Insights
Accurate echocardiography is crucial for diagnosing feline hypertrophic cardiomyopathy (HCM). Inter-observer variability in measuring left ventricular wall thickness significantly impacts diagnosis, necessitating caution with septal measurements.
Area of Science:
- Veterinary Cardiology
- Diagnostic Imaging
- Cardiology
Background:
- Accurate echocardiography is vital for diagnosing hypertrophic cardiomyopathy (HCM) in cats.
- Small measurement variations (0.5 mm) can alter diagnostic classification.
- Inter-observer variability in veterinary cardiology assessments is a critical factor.
Purpose of the Study:
- To evaluate inter-observer variability between two veterinary cardiology specialists using echocardiography.
- To assess the impact of time and observer on cardiac measurements in cats.
- To determine the influence of measurement variability on HCM diagnosis in feline patients.
Main Methods:
- Two-dimensional echocardiographic measurements of left ventricular, aortic, and left atrial dimensions were taken in 24 cats.
- Measurements were performed by two independent, board-certified veterinary cardiologists at different time points.
- Linear mixed models were used to analyze differences in measurements, effect of time, observer, and their interaction.
Main Results:
- Significant inter-observer differences were found in septal (IVSd) and free wall (LVFWd) thickness, and left ventricular internal diameters.
- Coefficients of variation (CV) for all measurements were below 10%, but IVSd had a higher CV than LVFWd.
- Diagnosis of HCM based on IVSd differed significantly between observers, highlighting potential diagnostic challenges.
Conclusions:
- Caution is advised when interpreting septal thickness (IVSd) measurements due to significant inter-observer variability.
- Small changes in IVSd may lead to misclassification of feline hypertrophic cardiomyopathy.
- Standardization of echocardiographic techniques is important for reliable HCM diagnosis in cats.
Abstract:
A high degree of accuracy is required when using echocardiography to diagnose hypertrophic cardiomyopathy (HCM) in cats, as variation in measurements of 0.5 mm may affect classification of individuals as 'abnormal'. This study in adult cats examined at different time points inter-observer variability between two Board certified echocardiographers in veterinary cardiology. Twenty-four female European shorthair cats were examined at 12, 18 and 24 months of age by observer 1. Two dimensional (2D) echocardiographic images were collected in conscious cats to measure left ventricular, aortic and left atrial dimensions. Measurements were repeated by observer 2 on stored images, and analysed for effect of time, observer and time-observer interaction. Based on end-diastolic left ventricular wall thickness, cats were diagnosed as 'normal' or 'abnormal'. Linear mixed models (generalized when appropriate) were performed. A significant difference between observers was found for all septal (IVSd) and free wall (LVFWd) thickness measurements and left ventricular internal diameters but not for aortic or left atrial measurements. All measurement coefficients of variation (CV) were < 10%. The CV for IVSd was higher than the CV for LVFWd. There was a significant effect of time on IVSd, aortic measurements and left ventricular internal diameter measurements. No significant time-observer interaction was found for any parameter. Diagnosis of cats as 'abnormal' (>5 mm in cats > 6 kg bodyweight) was significantly different between observers for IVSd but not LVFWd. Caution is warranted when diagnosing as 'abnormal' or interpreting small changes based on IVSd, due to significant inter-observer differences in this measurement.
