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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.
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.
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.
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.
A few studies have evaluated the impact of clinical trial results on practice in paediatric cardiology. The Infant Single Ventricle (ISV) Trial results published in 2010 did not support routine use of the angiotensin-converting enzyme inhibitor enalapril in infants with single-ventricle physiology. We sought to assess the influence of these findings on clinical practice.
A web-based survey was distributed via e-mail to over 2000 paediatric cardiologists, intensivists, cardiothoracic surgeons, and cardiac advance practice nurses during three distribution periods. The results were analysed using McNemar’s test for paired data and Fisher’s exact test.
The response rate was 31.5% (69% cardiologists and 65% with >10 years of experience). Among respondents familiar with trial results, 74% reported current practice consistent with trial findings versus 48% before trial publication (p<0.001); 19% used angiotensin-converting enzyme inhibitor in this population “almost always” versus 36% in the past (p<0.001), and 72% reported a change in management or improved confidence in treatment decisions involving this therapy based on the trial results. Respondents familiar with trial results (78%) were marginally more likely to practise consistent with the trial results than those unfamiliar (74 versus 67%, p=0.16). Among all respondents, 28% reported less frequent use of angiotensin-converting enzyme inhibitor over the last 3 years.
Within 5 years of publication, the majority of respondents was familiar with the Infant Single Ventricle Trial results and reported less frequent use of angiotensin-converting enzyme inhibitor in single-ventricle infants; however, 28% reported not adjusting their clinical decisions based on the trial’s findings.
Purpose: The aim of this study was to compare associations between generic versus disease-specific functional health status assessments and patient and clinical characteristics for patients with severe congenital heart disease. Methods: This was a cross-sectional observational study involving 325 single ventricle patients, aged 10–18 years, after Fontan procedure. Enrolled patients underwent a medical history review, laboratory testing, and assessment of the functional health status by completion of the generic Child Report Child Health Questionnaire and the disease-specific Congenital Heart Adolescent and Teenage questionnaire. Correlated conceptually equivalent domains from both questionnaires were identified and their associations with patient and clinical variables were compared. Results: From the generic assessment, patients perceived marginally lower physical functioning (p = 0.05) but greater freedom from bodily pain compared with a normal population (p < 0.001). The equivalent physical functioning/limitations domain of the generic instrument, compared with the disease-specific instrument, had similar associations (higher multi-variable model R2) with medical history variables (R2 = 0.14 versus R2 = 0.12, respectively) and stronger associations with exercise testing variables (R2 = 0.22 versus R2 = 0.06). Similarly, the corresponding freedom from bodily pain/symptoms domains from both questionnaires showed a greater association for the generic instrument with medical history variables (R2 = 0.15 versus R2 = 0.09, respectively) and non-cardiac conditions (R2 = 0.13 versus R2 = 0.06). The associations of each questionnaire with echocardiographic results, cardiac magnetic resonance imaging results, and serum brain natriuretic peptide levels were uniformly weak (R2 range <0.01 to 0.04). Conclusions: Assessment of the physical functional health status using generic and disease-specific instruments yields few differences with regard to associations between conceptually similar domains and patient and clinical characteristics for adolescents after Fontan procedure.
Rheological testing has been developed to predict the extrudability of ceramic pastes. Inorganic batches containing cellulosic binders were mixed in a twin screw extruder prior to characterization in a capillary rheometer. Various die lengths were used to separate viscosity from wall slip parameters. A power law model was fit to the paste viscosity. The wall shear stress, assuming 100% slip, was a linear function of the wall velocity. The resulting rheological models were used in fluid flow finite element analysis for determination of extrusion pressure, and the evaluation of binders.
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