Comparison of echocardiographic measurements to invasive measurements of diastolic function in infants with single ventricle physiology: A report from the Pediatric Heart Network Infant Single Ventricle Trial

Background: While echocardiographic parameters are used to quantify ventricular function in infants with single ventricle physiology, there are few data comparing these to invasive measurements. This study correlates echocardiographic measures of diastolic function with ventricular end-diastolic pressure in infants with single ventricle physiology prior to superior cavopulmonary anastomosis.Methods: Data from 173 patients enrolled in the Pediatric Heart Network Infant Single Ventricle enalapril trial were analysed. Those with mixed ventricular types (n = 17) and one outlier (end-diastolic pressure = 32 mmHg) were excluded from the analysis, leaving a total sample size of 155 patients. Echocardiographic measurements were correlated to end-diastolic pressure using Spearman's test.Results: Median age at echocardiogram was 4.6 (range 2.5-7.4) months. Median ventricular end-diastolic pressure was 7 (range 3-19) mmHg. Median time difference between the echocardiogram and catheterisation was 0 days (range -35 to 59 days). Examining the entire cohort of 155 patients, no echocardiographic diastolic function variable correlated with ventricular end-diastolic pressure. When the analysis was limited to the 86 patients who had similar sedation for both studies, the systolic:diastolic duration ratio had a significant but weak negative correlation with end-diastolic pressure (r = -0.3, p = 0.004). The remaining echocardiographic variables did not correlate with ventricular end-diastolic pressure.Conclusion: In this cohort of infants with single ventricle physiology prior to superior cavopulmonary anastomosis, most conventional echocardiographic measures of diastolic function did not correlate with ventricular end-diastolic pressure at cardiac catheterisation. These limitations should be factored into the interpretation of quantitative echo data in this patient population.