Intraoperator, intraobserver and interoperator variability of echocardiographic measurements in healthy foals.

The research study investigated the variability in echocardiographic measurements on healthy foals, taken by multiple operators and observers. Variabilities were generally low, leading to a conclusion that such measurements can be reliably used in serial clinical evaluations or experimental studies. However, caution is advised for certain measurements like Right Ventricular Internal Diameter (RVID), E-point to septal separation (EPSS), Left Ventricular Ejection Time (LVET), and Left Atrial Appendage (LAA) as they showed higher variability.

Methodology

• The study used echocardiographic examinations conducted on six healthy foals. The measurements were obtained by three distinct, experienced echocardiographers.
• Intraoperator variability was determined by having a single echocardiographer conduct and measure images from the same six foals scanned on three subsequent days.
• Interoperator and intraobserver variabilities were determined by having three different echocardiographers each obtain images from an additional set of six sedated foals.
• Within a day, the interoperator variability was determined by having each echocardiographer measure their own images while the intraobserver variability was ascertained by having a single echocardiographer measure all images obtained by the three echocardiographers.
• The coefficient of variation (CV) and standard error were computed for each measure to estimate the variability.

Results

• Most measurements exhibited either very low (CV < 5%) or low (CV = 5-15%) variability.
• However, measurements of Right Ventricular Internal Diameter (RVID) in systole and E-point to septal separation (EPSS) displayed moderate (CV 15-25%) to high variability (CV > 25%) across all three categories of variability.
• Measures for Left Ventricular Ejection Time (LVET) and velocity time integral from the right parasternal long axis view of right outflow tract in the fourth intercostal space showed moderate intraoperator variability.
• The measurements for the LVET, RVID in diastole, and Left Atrial Appendage (LAA) revealed moderate interoperator variability.
• The measurements for the RVID in diastole and acceleration time from the short axis view of the right outflow tract in the right third intercostal space showed moderate interobserver variability.

Conclusions

• The study concludes that most echocardiographic measurements in foals show low levels of intraoperator, intraobserver, and interoperator variabilities. This means these measurements can be relied upon for consistency.
• Such measurements are sufficiently reliable to be used in sequential clinical evaluations or experimental research involving foals.
• However, the research advises caution when interpreting repeated measurements of RVID, EPSS, LVET, and LAA, because these demonstrated higher levels of variability.