New perspectives in the assessment of cardiac chamber dimensions during development and adulthood

Factors influencing ultrasound cardiac output monitor waveform quality in patients admitted to the emergency intensive care unit

Objective

The ultrasonic cardiac output monitor (USCOM), an instrument that monitors the evolution of a patient's hemodynamic status and determines the type of shock, has become an important tool for assessing cardiac pathology and predicting changes in disease, but there are some variations in the instrumental findings for different physical conditions of patients. This article examines whether there are differences in the quality of USCOM waveforms measured in different types of critically ill patients based on clinical characteristics and test parameters.

Methods

Baseline data, diagnoses, echocardiograms, ventilation patterns, and USCOM results were retrospectively collected from patients in the emergency intensive care unit. Waveform quality was quantified using the Fremantle score to determine the extent to which age, body mass index (BMI), chronic obstructive pulmonary disease (COPD), respiratory failure, cardiac enlargement, valvular heart disease, and ventilation pattern influenced USCOM waveform quality.

Results

Age, body mass index, chronic obstructive pulmonary disease, respiratory failure, right and left heart enlargement, aortic valve disease (excluding aortic stenosis), and ventilation mode did not have a significant effect on USCOM waveform quality in critically ill patients (P > 0.05).

Conclusions

Various physical conditions of critically ill patients may have limited effect on the quality of the USCOM waveform, potentially rendering USCOM suitable for early assessment of hemodynamic status during ICU admission.

Proximal aorta dilatation in hypertension

Dilation of the proximal aorta is a common clinical manifestation in hypertensive patients. Although it is straightforward to link hypertension with proximal aortic dilation, previous studies on their interrelation have yielded controversial results. Cross-sectional design, methodology of blood pressure assessment, confounding factors like medications, and inconsistent reference values may lead to the paradoxical conclusions. Recently, advances have been made in the exploration of determinants and clinical value of proximal aortic dilatation. Thus, we reviewed these findings and summarized that aortic dilatation may be the consequence of hemodynamic and nonhemodynamic co-factors' combined action. Moreover, proximal aortic dilatation tends to be a predictor for aortic aneurysm dissection or rupture, hypertensive target organ damage as well as cardiovascular events. The present review contributes to a comprehensive understanding of the pathological process of proximal aortic dilatation in hypertension.

Assessing maternal cardiac function by obstetricians: technique and reference ranges

BACKGROUND

A strong body of evidence has now coalesced indicating that some obstetrical syndromes may result from maladaptive responses of the maternal cardiovascular system. Longitudinal studies have shown that these changes are complex and present before the clinical recognition of preeclampsia and fetal growth restriction, suggesting that hemodynamic maladaptation may play an etiologic role in obstetrical complications. Chronic hypertension is one of the most frequent complications of pregnancy, and recent evidence suggests that control of mild hypertension in early pregnancy improves outcome. The management of chronic hypertension can be improved by understanding specific cardiovascular hemodynamic abnormalities such as increased cardiac output or increased systemic vascular resistance, which can respond to either beta or calcium channel blockers, depending on the hemodynamic findings. Evaluation of maternal cardiac function has not been previously available to obstetrical healthcare providers using diagnostic ultrasound equipment used for fetal evaluation.

OBJECTIVE

Obstetrical ultrasound machines may be configured for various probes (endovaginal, abdominal, 3D/4D, and cardiac). This study used a cardiac probe placed in the suprasternal notch to image and measure the descending aorta diameter and the velocity time integral using pulsed and continuous wave Doppler ultrasound in normal pregnant women between 11 and 39 weeks of gestation. These measurements were followed by computation of maternal left ventricular preload, afterload, contractility, and blood flow.

STUDY DESIGN

This was a prospective cross-sectional study. A total of 400 pregnant women were recruited between 11 and 39 weeks of gestation. Imaging of the maternal aortic arch was performed by placing a cardiac probe in the suprasternal notch to identify the aortic arch using 2D and color Doppler ultrasound. The end-systolic diameter of the aorta was measured at the junction of the left subclavian artery with the descending aorta, which was followed by insonation of the descending aorta to obtain the Doppler waveform. Following insonation of the descending aorta, measurements of the aortic diameter, velocity time integral, ejection time, mean pressure gradient, heart rate, maternal weight and height, and systolic and diastolic blood pressures were entered into an Excel spreadsheet to compute the following: (1) preload measurements of stroke volume, stroke volume index, and stroke work index; (2) afterload measurements of systemic vascular resistance and the potential-to-kinetic energy ratio; (3) contractility measurements of inotropy and the Smith-Madigan inotropy index; and (4) blood flow measurements of cardiac output and the cardiac output index. Fractional polynomial regression analysis was performed for each of the above measurements using gestational age as the independent variable.

RESULTS

The diastolic and mean arterial blood pressure decreased from 11 to 18 weeks of gestation and then increased until term. The afterload measurements demonstrated similar characteristics, as all values decreased from 11 weeks until the mid and late second trimester, after which all values increased until term. Changes in contractility demonstrated an increase from 11 weeks to 25 to 28 weeks, followed by a decline until term. Changes in blood flow demonstrated an increase from 11 to 27 weeks and then declined until term. The continuous wave Doppler values were greater than the pulsed Doppler values except for the contractility measurements. Examples of abnormal cardiac measurements were identified in pregnant patients with hypertension and fetal growth restriction. An Excel calculator was created to provide quick computation of z-score measurements and their corresponding centiles described in this study.

CONCLUSION

The technique for evaluation of maternal cardiac function described in this study would allow screening of maternal left ventricular preload, afterload, contractility, and blood flow in the obstetrical clinical milieu once a cardiac probe is acquired for obstetrical ultrasound machines used for fetal evaluation. The above measurements would allow the clinician to select appropriate hypertensive medication on the basis of the results of the evaluation of the maternal left ventricle.

Point-of-care ultrasound in pediatric nephrology

Point-of-care ultrasound (POCUS) has evolved in recent years in clinical practice, helping in early bedside diagnosis of important etiologies. Many medical schools and training programs are integrating POCUS into their curriculum. Especially with the technological advances of newer handheld ultrasound devices, POCUS has now become a component adjunct to clinical examination, in the clinic and bedside in critical care units. The diagnostic utility of POCUS lies both in early identification of critical kidney disease, and also extra-renal pathologies from a focused cardiac ultrasound, lung ultrasound, and integrated fluid assessment. There is a need to incorporate POCUS in training in pediatric nephrology and establish competency standard criteria. This review shall cover how POCUS helps in enhancing patient care in pediatric kidney disorders and critical children, and the recent advances.

Measurement of Cardiac Output Using an Ultrasonic Cardiac Output Monitor (USCOM) in Patients with Single-Ventricle Physiology

We evaluate the validity of cardiac index (CI) measurements utilizing the Ultrasonic Cardiac Output Monitor (USCOM), a non-invasive Doppler ultrasound device, by comparing measurements to cardiac catheterization-derived CI measurements in patients with single-ventricle physiology. USCOM measurements were repeated three times for each patient at the beginning of a cardiac catheterization procedure for twenty-six patients undergoing elective pre-Glenn or pre-Fontan catheterization. CI was measured by USCOM and was calculated from cardiac catheterization data using Fick's method. Bland-Altman analysis for CI showed bias of 0.95 L/min/m² with the 95% limits of agreement of - 1.85 and 3.75. Pearson's correlation coefficient was 0.89 (p < 0.001) indicating a strong positive relationship between USCOM and cardiac catheterization CI measurements. When excluding two patients with significant dilation of the neo-aortic valve (z-score >  + 5), the bias improved to 0.66 L/min/m² with the 95% limits of agreement of - 1.38 and 2.70. Percent error of limits of agreement was 34%. There was excellent intra-operator reproducibility of USCOM CI measurements with an intra-class coefficient of 0.96. We demonstrate the use of USCOM to measure CI in patients with single-ventricle physiology for the first time, showing acceptable agreement of the CI measurements between USCOM and cardiac catheterization with a high intra-operator reproducibility.

Follow-up aortic dilatation in patients with repaired tetralogy of Fallot using cardiovascular magnetic resonance

Purpose

The study sought to determine the rate of aortic expansion and correlation with somatic growth in patients with repaired tetralogy of Fallot (rTOF), and predictors for determining the annual growth rate of the aorta (Ao-AGR).

Methods

Ninety-four rTOF patients (mean age 14.5 ± 4.4 years) with two cardiac magnetic resonance tests (CMR) (median duration 52 months, interquartile range, IQR 24-71) were analyzed for aortic diameter (AoD) at the annulus, the sinus of Valsalva (SoV), the sinotubular junction, and the ascending aorta (AAo), and compared with the normal limit AoD (NL-AoD) values. The median age-at-repair was 60 months (IQR 36-84). Ao-AGR and its index (Ao-AGRI) were derived from changes of the AoD and AoD-index, respectively, divided by the duration between the two studies. Three potential predictors (baseline AoD, sex, and age-at-repair) for the progression of Ao-AGR were analyzed.

Results

There was a significant larger AoD than NL-AoD (p < 0.001). Slow aortic growth was encountered in 78-85 % of patients. The Ao-AGR was slow, the median AGR ranged from 0.37 mm (IQR 0.13-0.72) at annulus to 0.56 mm (IQR 0.22-0.91) at AAo. There was a regression in Ao-AGRI, ranged from -1.41 mm (IQR -1.94, -0.87) at annulus to -2.36 mm (IQR -3.09, -1.63) at SoV. The three predictors were not correlated with severity of Ao-AGR.

Conclusion

Most adolescents with rTOF show significant aortic dilatation. There is a slow Ao-AGR with regression of Ao-AGRI, which may suggest that the rate of aortic growth is slower than the somatic growth. There are no significant predictors of the progression of Ao-AGR.

Ultrasonic cardiac output monitor provides effective non-invasive bedside measurements of neonatal cardiac output

This study determined the accuracy and validity for the haemodynamic parameters of haemodynamically stable neonates after postnatal circulatory adaptation using the ultrasonic cardiac output monitor (USCOM) in comparison with echocardiography. We conducted a prospective, observational study of neonates born at 23-41 weeks of gestation. They all underwent both echocardiography and USCOM assessments for comparison purposes. The 127 neonates were examined at the median of postmenstrual age of 35 weeks and there was a very high correlation between the cardiac output measurements provided by both methods. The mean difference in cardiac output was - 12 ± 25 ml/kg/min, with percentage error of 8.3 ± 6.9%. A larger bias was observed in cases with higher left ventricular output. Bland-Altman analysis confirmed no significant bias, with acceptable limits of agreement between these two methods. There was a very good correlation between the USCOM and echocardiographic methods when we used them to measure cardiac output in neonates.

Ultrasound Cardiac Output Monitor (USCOM™) Measurements Prove Unreliable Compared to Cardiac Magnetic Resonance Imaging in Adolescents with Cardiac Disease

The purpose of this stuy is to prospectively assess the reliability of the ultrasound cardiac output monitor (USCOM™) for measuring stroke volume index and predicting left ventricular outflow tract diameter in adolescents with heart disease. Sixty consecutive adolescents with heart disease attending a tertiary medical center underwent USCOM™ assessment immediately after cardiac magnetic resonance imaging. USCOM™ measured stroke volume index and predicted left ventricular outflow tract diameter were compared to cardiac magnetic resonance imaging-derived values using Bland-Altman analysis. Ten patients with an abnormal left ventricular outflow tract were excluded from the analysis. An adequate USCOM™ signal was obtained in 49/50 patients. Mean stroke volume index was 46.1 ml/m² by the USCOM™ (range 22-66.9 ml/m²) and 42.9 ml/m² by cardiac magnetic resonance imaging (range 24.7-59.9 ml/m²). The bias (mean difference) was 3.2 ml/m²; precision (± 2SD of differences), 17 ml/m²; and mean percentage error, 38%. The mean (± 2SD) left ventricular outflow tract diameter was 0.445 ± 0.536 cm smaller by the USCOM™ algorithm prediction than by cardiac magnetic resonance imaging. Attempted adjustment of USCOM™ stroke volume index using cardiac magnetic resonance imaging left ventricular outflow tract diameter failed to improve agreement between the two modalities (bias 28.4 ml/m², precision 44.1 ml/m², percentage error 77.3%). Our study raises concerns regarding the reliability of USCOM™ for stroke volume index measurement in adolescents with cardiac disease, which did not improve even after adjusting for its inaccurate left ventricular outflow tract diameter prediction.

Outcomes of closure of doubly committed subarterial ventricular septal defects in adults

BACKGROUND

Outcome data of doubly committed subarterial ventricular septal defect closure in adults are limited.

METHODS

A review was made of the inpatients >18 years of age who underwent doubly committed subarterial ventricular septal defect closure between June 2010 and June 2017.

RESULTS

The patients were categorised into two groups: The valve intervention group consisted of 31 patients who underwent aortic valvuloplasty, aortic valve replacement, or repair of sinus Valsalva aneurysm in addition to doubly committed subarterial ventricular septal defect closure; non-valvular intervention group comprised 58 patients who underwent only doubly committed subarterial ventricular septal defect closure. The groups did not differ by sex and age. Patients in the valve intervention group, with a larger ventricular septal defect size, were shorter and tended to be lighter. The valve intervention group had more patients with pneumonia perioperatively. No infective endocarditis and reoperation were noted during the study period. At last follow-up, 91 and 96.6% of the studied patients were free from left ventricle dilation and pulmonary hypertension. In patients without pre-operative aortic regurgitation, 12 developed new mild aortic regurgitation during the follow-up.

CONCLUSIONS

About 34.8% of adult patients with doubly committed subarterial ventricular septal defect required concurrent intervention on aortic valve or sinus Valsalva aneurysm. The midterm results of doubly committed subarterial ventricular septal defect closure in adult patients were favourable. However, the incidence of new mild aortic regurgitation after ventricular septal defect closure was high (27.3%). Long-term follow-up of aortic regurgitation progression is needed.

Performance evaluation of a portable bioimpedance cardiac output monitor for measuring hemodynamic changes in athletes during a head-up tilt test

The use of impedance cardiography to monitor physiological changes in sports is rarely reported. Using head-up tilt test, we evaluated a portable noninvasive impedance cardiography device (PhysioFlow) by comparing it with a reference Doppler monitor (USCOM). Accuracy in tracking hemodynamic changes deteriorated with higher tilt, implying a gravitational influence on its performance. Stroke volume measurements were overestimated, but the changes were underestimated. Despite its convenient physical features, the suitability of PhysioFlow for sports use is questionable.

Rationale for using the velocity-time integral and the minute distance for assessing the stroke volume and cardiac output in point-of-care settings

Background

Stroke volume (SV) and cardiac output (CO) are basic hemodynamic parameters which aid in targeting organ perfusion and oxygen delivery in critically ill patients with hemodynamic instability. While there are several methods for obtaining this data, the use of transthoracic echocardiography (TTE) is gaining acceptance among intensivists and emergency physicians. With TTE, there are several points that practitioners should consider to make estimations of the SV/CO as simplest as possible and avoid confounders.

Main body

With TTE, the SV is usually obtained as the product of the left ventricular outflow tract (LVOT) cross-sectional area (CSA) by the LVOT velocity–time integral (LVOT VTI); the CO results as the product of the SV and the heart rate (HR). However, there are important drawbacks, especially when obtaining the LVOT CSA and thus the impaction in the calculated SV and CO. Given that the LVOT CSA is constant, any change in the SV and CO is highly dependent on variations in the LVOT VTI; the HR contributes to CO as well. Therefore, the LVOT VTI aids in monitoring the SV without the need to calculate the LVOT CSA; the minute distance (i.e., SV × HR) aids in monitoring the CO. This approach is useful for ongoing assessment of the CO status and the patient’s response to interventions, such as fluid challenges or inotropic stimulation. When the LVOT VTI is not accurate or cannot be obtained, the mitral valve or right ventricular outflow tract VTI can also be used in the same fashion as LVOT VTI. Besides its pivotal role in hemodynamic monitoring, the LVOT VTI has been shown to predict outcomes in selected populations, such as in patients with acute decompensated HF and pulmonary embolism, where a low LVOT VTI is associated with a worse prognosis.

Conclusion

The VTI and minute distance are simple, feasible and reproducible measurements to serially track the SV and CO and thus their high value in the hemodynamic monitoring of critically ill patients in point-of-care settings. In addition, the LVOT VTI is able to predict outcomes in selected populations.

Measurement of inotropy and systemic oxygen delivery in term, low- and very-low-birth-weight neonates using the Ultrasonic Cardiac Output Monitor (USCOM)

Background The aim of this study was to assess the normal values of the Smith-Madigan inotropy index (SMII) and oxygen delivery index (DO2I) in low-birth-weight (LBW) and very-low-birth-weight (VLBW) newborns on the first 3 days of life, and to identify how different degrees of maturity influence cardiovascular alterations during the transitional period compared with term neonates. Methods Twenty-eight VLBW newborns, 46 LBW newborns and 50 normal full-term newborns admitted to our department were studied. Hemodynamics of the left heart were measured in all neonates over the first 3 days using the Ultrasonic Cardiac Output Monitor (USCOM). This was combined with hemoglobin concentration and pulse oximetry to calculate DO2I. Blood pressure was combined with the hemodynamic measures and hemoglobin concentration to calculate SMII. Results SMII showed statistically significant differences among the three groups (VLBW 0.48 ± 0.11; LBW 0.54 ± 0.13; term 0.69 ± 0.17 W/m2 P < 0.001), which was in line with the following myocardial parameters: stroke volume index (SVI) and cardiac index (CI) (P < 0.001 and <0.001). For systemic oxygen delivery (DO2) parameters, significant differences were found for DO2I (P < 0.001) while hemoglobin concentration and pulse oximetry demonstrated no significant differences. In the VLBW group, SMII and DO2I showed no significant change over the 3 days. Conclusion Normal inotropy and systemic DO2I values in VLBW neonates over the first 3 days of life were assessed. SMII and DO2I were significantly lower in VLBW neonates during the first 72 h of life. With increasing birth weight, higher myocardial inotropy and DO2 were found. The addition of USCOM examination to standard neonatal echocardiography may provide further important information regarding cardiac function.

Effect of Fentanyl Boluses on Cerebral Oxygenation and Hemodynamics in Preterm Infants: A Prospective Observational Study

BACKGROUND

Fentanyl is a commonly used off-label medication for pain control and sedation in preterm infants. Yet, the effect of fentanyl on cerebral hemodynamics in preterm neonates remains unexplored.

OBJECTIVE

To evaluate the effect of a bolus dose of fentanyl on the regional cerebral oxygen saturation (RcSO2), cerebral fractional tissue oxygen extraction (cFTOE) and left ventricular output (LVO) as compared with pre-administration baseline in preterm infants.

METHODS

This was a prospective observational study conducted in a level III Canadian NICU from September 2017 to February 2019. Preterm infants born <37 weeks of gestation and scheduled to receive a fentanyl bolus (1-2 μg/kg/dose) were eligible. Infants with major congenital anomalies, medically unstable and those who had received fentanyl in the previous 48 h were excluded.

OUTCOMES

The primary outcome was the difference between RcSO2 measured 5 min prior to and RcSO2 measured at defined time points after administration of fentanyl.

RESULTS

Twenty-eight infants were enrolled during the study period (median gestational age 28 weeks; interquartile range [IQR] 25-29 weeks; median birth weight 1,035 g [IQR 830-1,292 g]; median age 4 days [IQR 3-7 days]). Mean (±standard deviation) baseline RcSO2 was 73.6% (±11.8), cFTOE was 21.9 (±11.2) and LVO was 380 (±147) mL/kg/min prior to fentanyl infusion. One-way ANOVA showed no statistically significant difference between baseline and any of the post-fentanyl cerebral oxygenation, tissue oxygen extraction or cardiac output measures (p > 0.05).

CONCLUSION

Administration of fentanyl bolus for procedural pain and sedation was not shown to significantly affect cerebral oxygenation, cerebral tissue oxygen extraction or cardiac output in stable preterm infants.

Greater Height Is Associated with a Larger Carotid Lumen Diameter

Background: Previous studies link tall stature with a reduced ischemic stroke risk. One theory posits that tall people have larger cerebral artery lumens and therefore have a lower plaque occlusion risk than those who are short. Previous studies have not critically evaluated the associations between height and cerebral artery structure independent of confounding factors. Methods: The hypothesis linking stature with cerebral artery lumen size was tested in 231 adults by measuring the associations between height and common carotid artery diameter (CCAD) and intima-media thickness (IMT) after controlling for recognized vascular influencing factors (e.g., adiposity, blood pressure, plasma lipids, etc.). Results: Height remained a significant CCAD predictor across all developed multiple regression models. These models predict a ~0.03 mm increase in CCAD for each 1-cm increase in height in this sample. This magnitude of CCAD increase with height represents over a 60% enlargement of the artery's lumen area across adults varying in stature from short (150 cm) to tall (200 cm). By contrast, IMT was non-significantly correlated with height across all developed regression models. Conclusions: People who are tall have a larger absolute CCAD than people who are short, while IMT is independent of stature. These observations potentially add to the growing cardiovascular literature aimed at explaining the lower risk of ischemic strokes in tall people.

B-Type Natriuretic Peptide Levels and Cardiac Dysfunction in Children on Peritoneal Dialysis

Background

Abnormalities in left ventricular (LV) structure and function are prevalent in patients on peritoneal dialysis (PD). The risk of cardiovascular mortality is also 10 – 20 times higher in PD patients than in age- and gender-matched healthy control subjects.

Methods

Echocardiography was performed annually or every 6 months for children on PD; the frequency was increased if the patient had hypertension or any heart problem. We retrospectively reviewed echocardiographic findings of these children (since February 2005) by chart review. The linear regression analysis of log(B-type natriuretic peptide, BNP) was performed to evaluate the association between serum BNP and cardiac parameters on echocardiography.

Results

We enrolled 52 patients and evaluated 169 echocardiographic findings in association with serum BNP levels. Systolic blood pressure (adjusted R2 = 0.321), diastolic blood pressure (adjusted R2 = 0.292), LV posterior wall thickness at diastole (0.058), LV posterior wall thickness at systole (0.038), LV internal diameter at diastole (0.177), LV internal diameter at systole (0.132), LV mass index (0.122), thickness of interventricular septum at diastole (0.035), the left atrial (LA) diameter (0.201), LA/aorta diameter ratio (0.113), lateral E/E’ (0.229), and lateral A'/E’ (0.149) showed positive correlation with log(BNP); conversely, LV fractional shortening (FS) (0.065), LV ejection fraction (0.082), right ventricular internal diameter at diastole (0.184), right ventricular fractional shortening (0.754), lateral S’ (0.179), and lateral E’ (0.161) showed negative correlation with log(BNP).

Conclusions

Routine measurement of serum BNP is recommended in children on PD to evaluate the risk of morphological and functional cardiac problems.

Normal percentile curves for left atrial size in healthy children and adolescents

BACKGROUND

Despite the clinical utility of echocardiography to measure left atrial (LA) structure and function, there are scarcities of data about the percentiles of LA diameter (LA_D ), LA volume (LA_VOL ), and LA volume indexed by body surface area (LA_{VOL / BSA} ) from prospective population-based studies in healthy children and adolescents from the Southern Cone of Latin America.

METHODS

Echocardiographic studies were obtained in 1095 healthy subjects nonexposed to cardiovascular risk factors (5-24 years). Age- and sex-specific reference values of LA_D , LA_VOL , and LA_{VOL / BSA} were generated using parametric regression based on fractional polynomials.

RESULTS

After covariate analysis (ie, adjusting by age, body surface area), specific sex-specific percentiles were evidenced as necessaries. Age- and sex-specific 1st, 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, 97.5th, and 99th percentile and curves were reported. Our percentiles showed high concordance and complementarity with what was previously reported for the population of North American, European, and Asiatic Populations.

CONCLUSIONS

In children and adolescents, the interpretation of the LA size requires sex-related percentiles. This study provides the largest Argentinean database concerning percentile curves of LA_D , LA_VOL , and LA_{VOL / BSA} obtained in healthy children and adolescents. These data are valuable in that they provide values with which data of populations of children, adolescents, and young adults can be compared.

USCOM (Ultrasonic Cardiac Output Monitors) Lacks Agreement with Thermodilution Cardiac Output and Transoesophageal Echocardiography Valve Measurements

The USCOM (Ultrasonic Cardiac Output Monitors) device is a noninvasive cardiac output monitor, which utilises transaortic or transpulmonary Doppler flow tracing and valve area estimated using patient height to determine cardiac output. We evaluated USCOM against thermodilution cardiac outputs and transoesophageal echocardiography valve area measurements in 22 ASA PS4 cardiac surgical patients. Data collection commenced following pulmonary artery catheter insertion, with cardiac output measurements repeated after sternotomy closure. Failure to obtain transaortic Doppler readings using USCOM occurred in 5% of planned measurements. USCOM transaortic analysis was not planned for 11 patients with known aortic disease. Bias at the aortic window (n = 20) was -0.79 l/min with limits of agreement from -3.66 to 2.08 l/min. At the pulmonary window, failure to obtain Doppler readings occurred in 24% of planned measurements. Bias at the pulmonary window (n=36) was -0.17 l/min with limits of agreement from -3.30 to 2.97 l/min. The USCOM estimates of valve area based on height showed poor correlation with the echocardiographic measurements of aortic and pulmonary valves (r=0.57 and r=0.17, respectively). It was concluded that USCOM showed poor agreement with thermodilution. The estimated valve area was identified as one source of error.

Cardiac Output Measurement Using the Ultrasonic Cardiac Output Monitor: A Validation Study in Newborn Infants

OBJECTIVES

We aimed to determine the accuracy and validity of the Ultrasonic Cardiac Output Monitor (USCOM) measurements of cardiac output (CO) compared to echocardiography in newborn infants, and the inter-rater agreement of USCOM measurements.

METHODS

In a single-center study we prospectively evaluated neonates undergoing an echocardiographic evaluation. USCOM measurements of CO were obtained at the pulmonary and aortic valve by 2 physicians blinded to the echocardiographic results. All echocardiographic measurements were performed blinded to USCOM measurements. We first enrolled an ascertainment cohort which was subsequently validated in an independent new cohort. Agreement between echocardiography and USCOM methods was assessed by Bland-Altman analysis. Intra-class correlation coefficients (ICC) assessed the agreement between the 2 operators. The ascertainment cohort correction factors were applied in a second validation cohort and agreement of the calibrated measures evaluated with repeat Bland-Altman comparisons.

RESULTS

A total of 50 infants were enrolled in the initial cohort and 15 in the validation cohort. There was a high degree of correlation between the USCOM operators (ICC = 0.975). USCOM measurements of CO were significantly higher compared to echocardiography (left ventricular output bias 95 ± 52 mL/kg/min and right ventricular output bias 64 ± 30 mL/kg/min). There was no difference in the subgroup of infants with and without a ductus arteriosus. After the correction was applied to the validation cohort, there was no longer a significant difference between the measures.

CONCLUSIONS

CO measured by USCOM consistently overestimated the results obtained from echocardiography. USCOM is not adequate to provide absolute estimates of CO. However, it may allow longitudinal hemodynamic assessment of sick neonates.

Emergent stent-graft repair of a massive aortic pseudoaneurysm secondary to Behçet's disease in a child

An 11-year-old male with vasculitis was found to have a large abdominal aortic pseudoaneurysm on diagnostic angiography. This report describes endovascular repair of the pseudoaneurysm by stent-graft exclusion. The existing literature surrounding this rare and potentially fatal condition is also reviewed.

Noninvasive hemodynamic monitoring of septic shock in children

Septic shock in children is associated with high mortality and morbidity. Its management is time-sensitive and must be aggressive and target oriented. The use of clinical assessment alone to differentiate between cold and warm shock and to select the appropriate inotropic and vasoactive medications is fraught with errors. Semi-quantitative and quantitative assessment of the preload, contractility and afterload using non-invasive tools has been suggested, in conjunction with clinical and laboratory assessment, to direct shock management and select between vasopressors, vasodilators and inotropes or a combination of these drugs. This review aims to describe non-invasive tools to assess the hemodynamic status in septic shock including echocardiography, trans-thoracic/trans-esophageal Doppler and electrical cardiometry. As septic shock is a dynamic condition that changes markedly overtime, frequent or continuous measurement of the cardiac output (CO), systemic vascular resistance (SVR) and other hemodynamic parameters using the above-mentioned tools is essential to personalize the treatment and adapt it over time. The different combinations of blood pressure, CO and SVR serve as a pathophysiological framework to manage fluid therapy and titrate inotropic and vasoactive drugs. Near infrared spectroscopy is introduced as a non-invasive method to measure end organ perfusion and assess the response to treatment.

Maternal hemodynamics in normal pregnancy: reference ranges and role of maternal characteristics

OBJECTIVES

The main aim of this study was to construct reference ranges of maternal central hemodynamic parameters during pregnancy. The second aim was to determine the maternal and pregnancy characteristics that influence these hemodynamic parameters.

METHODS

This was a prospective cohort study of low-risk pregnant women attending for routine antenatal care at St George's Hospital, London, UK. Exclusion criteria included any medical disorder present at the time of study recruitment, or development of hypertension or intrauterine fetal growth restriction following study recruitment. Stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) were obtained using non-invasive cardiac output monitoring (USCOM-1A®). USCOM-1A utilizes a non-imaging probe in the suprasternal notch to obtain velocity-time integrals of transaortic blood flow at the left ventricular outflow tract. Once the distribution of the data with respect to gestational age had been determined, maternal characteristics were added to the model to test whether they provided a significant improvement in the prediction of the median value.

RESULTS

The study included 627 women with a singleton pregnancy. The estimated median CO was constant for a maternal age above 32 years, but was around 0.5 L/min higher for women aged ≤ 25 years (P < 0.001). Maternal weight (P < 0.001) and height (P < 0.001) significantly affected CO values and there was a significant interaction (P = 0.002) between them. In women with a height of less than 1.60 m, there was no association between median CO and weight; however, in those with a height exceeding 1.60 m, an increase in weight was associated with an increase in CO. SV was primarily associated with height (P < 0.001), although some positive association with weight (P < 0.001) could also be observed within the normal body-mass-index range. Greater height (P < 0.001) was associated with lower median values of SVR, with an estimated difference of around 120 dynes × s/cm⁵ between 1.60 m and 1.80 m. Advancing maternal age was associated with higher median SVR, with an estimated difference of around 50 dynes × s/cm⁵ between 25 and 35 years. Smokers had a lower SVR by 73.5 (95% CI, 8.6-138.4) dynes × s/cm⁵ .

CONCLUSION

Maternal hemodynamics are influenced significantly by maternal age, height and weight. We provide USCOM-1A-specific reference ranges and a calculator for SV, CO and SVR in uncomplicated pregnancies that correct for maternal age, height and weight. This should enable clinical application and comparison in both uncomplicated and pathological pregnancies. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Agreement between preload reserve measured by impedance cardiography and echocardiography during pregnancy

Purpose

Accurate assessment of cardiac function is important during pregnancy. Echocardiography and impedance cardiography (ICG) are commonly used noninvasive methods to measure stroke volume (SV) and cardiac output (CO). The difference in stroke volume (ΔSV) or cardiac output (ΔCO) measured at baseline and after passive leg raising (PLR) is a measure of preload reserve that predicts volume responsiveness. However, the agreement between these two methods in measuring preload reserve during pregnancy is unclear. The aim of our study was to investigate the correlation and the agreement between Doppler echocardiography and ICG in assessing preload reserve in pregnant women.

Methods

In this prospective observational cross-sectional study, preload reserve was assessed by measuring the SV and CO during baseline and 90 s after PLR simultaneously by Doppler echocardiography and ICG in healthy pregnant women during the second and third trimesters. Bland–Altman analysis was used to determine the agreement between the two methods. Bias was calculated as the mean difference between two methods and precision as 1.96 SD of the difference.

Results

A total of 53 pregnant women were included. We found a statistically significant correlation between ΔSV (R = 0.56, p < 0.0001) and ΔCO (R = 0.39, p = 0.004) measured by ICG and Doppler echocardiography. The mean bias for ΔSV was 2.52 ml, with a precision of 18.19 ml. The mean bias for ΔCO was 0.21 l/min, with a precision of 1.51 l/min.

Conclusion

There was a good agreement and a statistically significant correlation between ICG and Doppler echocardiography for measuring preload reserve.

Racial Variation in Echocardiographic Reference Ranges for Left Chamber Dimensions in Children and Adolescents: A Systematic Review

Echocardiography plays a critical role in the assessment of cardiac disease. Important differences in echocardiographically derived cardiac chamber dimensions have been previously highlighted in different population groups in adult studies, but this has not been systematically studied in children, whose body size changes throughout childhood. The aim of this study was to review the distribution of available reference ranges for the left cardiac chamber dimensions in older children and adolescents. The following electronic data bases were searched: Medline, Embase and Web of Science were searched to identify studies which have established echocardiographic reference ranges of left heart parameters in children and adolescents from 1975 to December 2017. There was no geographical limitation. All results were imported into Endnote. Retrieved articles were screened and data extracted by two independent reviewers. A total of 4398 studies were retrieved, with 36 studies finally included in this review. 29 (81%) references were from North America and European (Caucasians) populations, with only one study each from Africa and South America. Two-dimensional and M-mode techniques were the most commonly used echocardiography techniques. There were methodological variations in techniques and normalisation of references. Comparison of selected cardiac measures showed significant differences for interventricular septal thickness among Black African, Indian, German and US American children. Available echocardiographic references cannot be generalised to all settings and therefore, there is need for locally relevant reference ranges. Africa and South America are particularly under-represented. Future studies should focus on developing comprehensive echocardiographic reference ranges for children from different racial backgrounds and should use standardised techniques.

Echocardiographic Evaluation of Ventricular Function-For the Neonatologist and Pediatric Intensivist

In the neonatal and pediatric intensive care setting, bedside cardiac ultrasound is often used to assess ventricular dimensions and function. Depending upon the underlying disease process, it is necessary to be able to evaluate the systolic and diastolic function of left and or right ventricles. The systolic function of left ventricle is mostly assessed qualitatively on visual inspection "eye-balling" and quantitatively by measuring circumferential fraction shortening or calculating the ejection fraction by Simpson's planimetry. The assessment of left ventricular diastolic function relies essentially on the mitral valve and pulmonary venous Doppler tracings or tissue Doppler evaluation. The right ventricular particular shape and anatomical position does not permit to use the same parameters for measuring systolic function as is used for the LV. Tricuspid annular plane systolic excursion (TAPSE) and S' velocity on tissue Doppler imaging are more often used for quantitative assessment of right ventricle systolic function. Several parameters proposed to assess right ventricle systolic function such as fractional area change, 3D echocardiography, speckle tracking, and strain rate are being researched and normal values for children are being established. Diastolic function of right ventricle is evaluated by tricuspid valve and hepatic venous Doppler tracings or on tissue Doppler evaluation. The normal values for children are pretty similar to adults while normal values for the neonates, especially preterm infants, may differ significantly from adult population. The normal values for most of the parameters used to assess cardiac function in term neonates and children have now been established.

Stroke Volume Monitoring: Novel Continuous Wave Doppler Parameters, Algorithms and Advanced Noninvasive Haemodynamic Concepts

PURPOSE OF REVIEW

Adequate oxygen delivery is essential for life, with hypoxia resulting in dysfunction, and ultimately death, of the cells, organs and organism. Blood flow delivers the oxygen bound in the blood, while haemodynamics is the science of blood flow. Stroke volume (SV) is the fundamental unit of blood flow, and reflects the interdependent performance of the heart, the vessels and the autonomic nervous system. However, haemodynamic management remains generally poor and predominantly guided by simple blood pressure observations alone.

RECENT FINDINGS

Doppler ultrasound measures SV with unequalled clinical precision when operated by trained personnel. Combining SV with BP measurements allows calculation of flow-pressure based measures which better reflect cardiovascular performance and allows personalised physiologic and pathophysiologic modelling consistent with Frank's and Starling's observations.

SUMMARY

Doppler SV monitoring and novel flow-pressure parameters may improve our understanding of the cardiovascular system and lead to improved diagnosis and therapy. This review examines the physics and practice of Doppler SV monitoring and its application in advanced haemodynamics.

Factors associated with aortic root dilatation after surgically repaired ventricular septal defect

BACKGROUND

Aortic root dilatation (ARD) in congenital heart disease is related to aortic aneurysm, rupture, and dissection. This study aimed to investigate the factors associated with ARD in patients with surgically repaired ventricular septal defect (VSD).

METHODS

This cross-sectional study included 152 patients with surgically repaired VSD. Two definitions of ARD were used: (1) observed Valsalva diameter to body surface area (BSA) ratio >2.1 cm/m² and (2) absolute value of Valsalva diameter ≥4.0 cm. Odds ratios (ORs) and 95% confidence intervals (CIs) of ARD presence were calculated using multivariate logistic regressions.

RESULTS

The prevalence of ARD ranged between 8.6% and 32.9%. Using the definition of observed aortic root diameter/BSA >2.1 cm/m² , patients with nonsubarterial VSD type were more likely to have ARD (OR 5.65, 95% CI; 1.83-17.44, P=.003) than those with subarterial type, and patients with preoperative right- or noncoronary cusp prolapse (R/NCCP) were more likely to have ARD (OR 3.68, 95% CI; 1.20-11.23, P=.022) than patients without preoperative R/NCCP after adjustment for sex, age at repair (ie, shunt duration), VSD size, and postoperative follow-up period. Using the definition of absolute Valsalva diameter ≥4 cm, nonsubarterial VSD type and presence of R/NCCP were also significantly associated with ARD after adjustment for the same covariates.

CONCLUSIONS

Anatomical and morphological features (nonsubarterial type and presence of preoperative R/NCCP) are independently correlated with ARD in patients with VSD regardless of the different definitions of ARD. Patients with surgically repaired VSD may need careful monitoring for potential ARD development.

Myocardial Rotation and Torsion in Child Growth

Background

The speckle tracking echocardiography can benefit to assess the regional myocardial deformations. Although, previous reports suggested no significant change in left ventricular (LV) torsion with aging, there are certain differences in LV rotation at the base and apex. The purpose of this study was to evaluate the change and relationship of LV rotation for torsion with aging in children.

Methods

Forty healthy children were recruited and divided into two groups of twenty based on whether the children were preschool-age (2–6 years of age) or school-age (7–12 years of age). After obtaining conventional echocardiographic data, apical and basal short axis rotation were assessed with speckle tracking echocardiography. LV rotation in the basal and apical short axis planes was determined using six myocardial segments along the central axis.

Results

Apical and basal LV rotation did not show the statistical difference with increased age between preschool- and school-age children. Apical radial strain showed significant higher values in preschool-age children, especially at the anterior (52.8 ± 17.4% vs. 34.7 ± 23.2%, p < 0.02), lateral (55.8 ± 20.4% vs. 36.1 ± 22.7%, p < 0.02), and posterior segments (57.1 ± 17.6% vs. 38.5 ± 21.7%, p < 0.01). The torsion values did not demonstrate the statistical difference between two groups.

Conclusion

This study revealed the tendency of higher rotation values in preschool-age children than in school-age children. The lesser values of rotation and torsion with increased age during childhood warrant further investigation.

A comparison of the non-invasive ultrasonic cardiac output monitor (USCOM) with the oesophageal Doppler monitor during major abdominal surgery

BACKGROUND

Perioperative interventions, targeted to increase global blood flow defined by explicit measured goals, reduce postoperative complications. Consequently, reliable non-invasive estimation of the cardiac output could have far-reaching benefit.

METHODS

This study compared a non-invasive Doppler device - the ultrasonic cardiac output monitor (USCOM) - with the oesophageal Doppler monitor (ODM), on 25 patients during major abdominal surgery. Stroke volume was determined by USCOM (SV_USCOM) and ODM (SV_ODM) pre and post fluid challenges.

RESULTS

A ≥ 10% change (Δ) SV_USCOM had a sensitivity of 94% and specificity of 88% to detect a ≥ 10% Δ SV_ODM; the area under the receiver operating curve was 0.94 (95% CI 0.90-0.99). Concordance was 98%, using an exclusion zone of <10% Δ SV_ODM. 135 measurements gave median SV_USCOM 80 ml (interquartile range 65-93 ml) and SV_ODM 86 ml (69-100 ml); mean bias was 5.9 ml (limits of agreement -20 to +30 ml) and percentage error 30%.

CONCLUSIONS

Following fluid challenges SV_USCOM showed good concordance and accurately discriminated a change ≥10% in SV_ODM.

The effects of malnutrition on cardiac function in African children

OBJECTIVE

Cardiac dysfunction may contribute to high mortality in severely malnourished children. Our objective was to assess the effect of malnutrition on cardiac function in hospitalised African children.

DESIGN

Prospective cross-sectional study.

SETTING

Public referral hospital in Blantyre, Malawi.

PATIENTS

We enrolled 272 stable, hospitalised children ages 6-59 months, with and without WHO-defined severe acute malnutrition.

MAIN OUTCOME MEASURES

Cardiac index, heart rate, mean arterial pressure, stroke volume index and systemic vascular resistance index were measured by the ultrasound cardiac output monitor (USCOM, New South Wales, Australia). We used linear regression with generalised estimating equations controlling for age, sex and anaemia.

RESULTS

Our primary outcome, cardiac index, was similar between those with and without severe malnutrition: difference=0.22 L/min/m(2) (95% CI -0.08 to 0.51). No difference was found in heart rate or stroke volume index. However, mean arterial pressure and systemic vascular resistance index were lower in children with severe malnutrition: difference=-8.6 mm Hg (95% CI -12.7 to -4.6) and difference=-200 dyne s/cm(5)/m(2) (95% CI -320 to -80), respectively.

CONCLUSIONS

In this largest study to date, we found no significant difference in cardiac function between hospitalised children with and without severe acute malnutrition. Further study is needed to determine if cardiac function is diminished in unstable malnourished children.

The Relationship Between Aortic Root Size and Hypertension: An Unsolved Conundrum

Thoracic aortic aneurysms rupture and dissection are among the most devastating vascular diseases, being characterized by elevated mortality, despite improvements in diagnostic imaging and surgical techniques.An increased aortic root diameter (ARD) represents the main risk factor for thoracic aortic dissection and rupture and for aortic valve regurgitation.Even though arterial hypertension is commonly regarded as a predisposing condition for the development of thoracic aorta aneurysms, the role of blood pressure (BP) as determinant of aortic root enlargement is still controversial. The use of different methods for indexation of ARD may have in part contributed to the heterogeneous findings obtained in the investigations exploring the relationships between ARD and BP. Indeed, the best methods for ARD indexation, as well as the normal values of aortic root size, are still a matter of debate.Several non-hemodynamic factors influence ARD, including age, gender, and anthropometric variables, such as height, weight and their derivatives body surface area (BSA) and body mass index. Of these factors, anthropometric variables have the greatest impact.Several studies documented an association between ARD enlargement, assessed by echocardiography, and some indices of hypertensive target organ damage such as left ventricular hypertrophy, diastolic dysfunction, and carotid intima-media thickening. Recently, we found that ARD, expressed either as absolute values or normalized for BSA (ARD/BSA) or height (ARD/H), was significantly greater in hypertensive subjects with chronic kidney disease (CKD) when compared to their counterparts with normal renal function. Moreover, at univariate analyses estimated glomerular filtration rate (eGFR) showed significant inverse correlations with ARD not indexed and with ARD/BSA and ARD/H. Taking into account the effect of age, sex, duration of hypertension and other potentially confounding factors, in multiple regression analyses, only the association of GFR with ARD/H and that between GFR and ARD/BSA remained statistically significant. The receiver-operating characteristic curve analysis revealed that an estimated GFR of about 50 ml/min/1.73 m² represents the better threshold to distinguish hypertensive patients with dilated aortic root from those with a normal one.Some population-based studies showed that an enlarged ARD might predict an adverse prognosis, even in absence of aneurysmatic alterations.In the Cardiovascular Health Study, a dilated aortic root was independently associated with an increased risk for stroke, cardiovascular and total mortality in both sexes and with incident congestive heart failure only in men. The relationship between ARD and heart failure has been observed also in the Framingham Heart Study. More recently, the PAMELA (Pressioni Arteriose Monitorate E Loro Associazioni) study demonstrated an independent relationship of ARD/H with incident cardiovascular morbidity and mortality.Although the relationship between BP and aortic root size is still a matter of debate, increasing evidence seems to support the notion that aortic root dilatation, even in absence of aneurysmatic alterations, may be regarded as an hypertensive organ damage paralleling other preclinical markers whose unfavourable prognostic significance is firmly established. Future studies are needed to assess whether or not antihypertensive therapy is able to reduce aortic root dimension and the increased risk associated with its enlargement.

Measuring the cardiac output in acute emergency admissions: use of the non-invasive ultrasonic cardiac output monitor (USCOM) with determination of the learning curve and inter-rater reliability

Traditionally, assessment of the cardiac output has been limited to theatre or the intensive care unit. However, non-invasive cardiac output estimation is now readily available, and its application may have wider benefit in the emergency setting. The non-invasive ultrasonic cardiac output monitor (USCOM) was investigated to determine its learning curve and inter-rater reliability. Four trainee operators each performed stroke volume measurements on 25 volunteers, compared to an experienced operator pre- and post-passive leg raise. Inter-rater reliability was then assessed on 24 acute emergency in-patients. Mean percentage difference in stroke volume decreased from 19% (95% confidence intervals 14-23) across volunteers 1-5, to 6% (4-8) for the last 5 volunteers scanned. Consequently, on acute emergency in-patients, excellent inter-rater reliability (Lin's concordance correlation coefficient (ρ_c) 0.96 (0.92-0.98)) and agreement of a change ≥10% in stroke volume following passive leg raise on 23/24 cases were found. Following a training period of less than 5 h, USCOM stroke volume measurements demonstrated excellent inter-rater reliability.

Five algorithms that calculate cardiac output from the arterial waveform: a comparison with Doppler ultrasound

BACKGROUND

Different mathematical approaches are used to calculate arterial pulse pressure wave analysis (PPWA) cardiac output. The CardioQ-Combi is a research oesophageal Doppler (COODM) monitor that includes these five fundamental PPWA algorithms. We compared these PPWA cardiac output readings to COODM and suprasternal USCOM Doppler (COUS) over a range of cardiac output values induced by dopamine infusion in patients undergoing major surgery. USCOM acted as a control.

METHODS

Serial sets of cardiac output data were recorded at regular intervals as cardiac output increased. Formulae included: cardiac output calculated form systemic vascular resistance (COMAP), pulse pressure (COPP), Liljestrand-Zander formula (COLZ), alternating current power (COAC) and systolic area with Kouchoukos correction (COSA). The reference method for comparisons was COODM. Statistical methods included: Scatter plots (correlation), Bland-Altman (agreement) and concordance (trending) and polar (trending).

RESULTS

From 20 patients 255 sets of cardiac output comparative data were collected. Mean cardiac output for each method ranged between 5.0 and 5.5 litre min(-1). For comparisons between COUS and the five PPWA algorithms with COODM: Correlation was best with COUS (R(2)=0.81) followed by COLZ (R(2)=0.72). Bias ranged between 0.1 and 0.5 litre min(-1). Percentage error was lowest with COUS (26.4%) followed by COLZ (35.2%), others (40.7 to 56.3%). Concordance was best with COUS (92%), followed by COLZ (71%), others (64 to 66%). Polar analysis (mean(standard deviation)) were best with COUS (-2.7 (21.1)), followed by COLZ (+4.7 (26.6).

CONCLUSIONS

The Liljestrand-Zander PPWA formula was most reliable compared with oesophageal Doppler in major surgical patients under general anaesthesia, but not better than USCOM.

Diseases of the Aorta in Elite Athletes

Sudden cardiovascular deaths in athletes are rare and only a fraction are due to aortic events. There has been concern that the hemodynamic load during exercise may lead to aortic dilation, but aortic dimensions in endurance and strength-trained athletes are only slightly larger than those in sedentary comparison subjects. The presence of a bicuspid aortic valve without significant valvular dysfunction and normal aortic dimensions should not influence eligibility to practice sport. Patients with genetic syndromes associated with aortopathy generally should be restricted from vigorous sports participation. This article reviews the diagnosis and management of diseases of the aorta in athletes.

Effect of Preload Alterations on Left Ventricular Systolic Parameters Including Speckle-Tracking Echocardiography Radial Strain During General Anesthesia

OBJECTIVES

Frequently used parameters for evaluation of left ventricular systolic function are load-sensitive. However, the impact of preload alterations on speckle-tracking echocardiographic parameters during anesthesia has not been validated. Therefore, two-dimensional (2D) speckle-tracking echocardiography radial strain (RS) was assessed during general anesthesia, simulating 3 different preload conditions.

DESIGN

Single-center prospective observational study.

SETTING

University hospital.

PARTICIPANTS

Thirty-three patients with normal left ventricular systolic function undergoing major surgery.

INTERVENTIONS

Transgastric views of the midpapillary level of the left ventricle were acquired at 3 different positions.

MEASUREMENTS AND MAIN RESULTS

Fractional shortening (FS), fractional area change (FAC), and 2D speckle-tracking echocardiography RS were analyzed in the transgastric midpapillary view. Considerable correlation above 0.5 was found for FAC and FS in the zero and Trendelenburg positions (r = 0.629, r = 0.587), and for RS and FAC in the anti-Trendelenburg position (r = 0.518). In the repeated-measures analysis, significant differences among the values measured at the 3 positions were found for FAC and FS. For FAC, there were differences up to 2.8 percentage points between the anti-Trendelenburg position and the other 2 positions. For FS, only the difference between position zero and anti-Trendelenburg was significant, with an observed change of 1.66. Two-dimensional RS was not significantly different at all positions, with observed changes below 1 percentage point.

CONCLUSIONS

Alterations in preload did not result in clinically relevant changes of RS, FS, or FAC. Observed changes for RS were smallest; however, the variation of RS was larger than that of FS or FAC.

The effect of L-thyroxine treatment on left ventricular functions in children with subclinical hypothyroidism

OBJECTIVE

The aim of this study was to search for evidence suggesting treatment for childhood subclinical hypothyroidism (SH) by evaluating left ventricular (LV) functions of children with SH by using M-mode and tissue Doppler echocardiography (TDE).

METHODS

Children with SH and euthyroid healthy children (control group) were enrolled in the study. At baseline and 6 months after euthyroidism was achieved, M-mode and TDE were performed and LV functions were evaluated. Pretreatment parameters of the SH group were compared with those of controls and post-treatment parameters.

RESULTS

31 children with SH and 32 euthyroid healthy children were enrolled in the study. The groups had similar age, gender, puberty and body mass index. Interventricular septum thickness and LV mass index, which are the parameters for LV morphology, were slightly increased in the SH group than in the controls (p<0.05). In TDE, children with SH had significant changes in LV diastolic (lower E'm, higher E/E'm ratio and longer isovolumic relaxation time) and systolic functions (lower isovolumic contraction time) compared with controls (p<0.05). Six months after euthyroidism was achieved, TDE showed a significant improvement of some of the diastolic and systolic parameters (p<0.05).

CONCLUSIONS

The results of this study showed that SH is associated with subclinical alterations in LV function, and LT4 replacement may improve LV systolic and diastolic parameters. However, since SH is usually a self-limiting process, these improvements in LV functions may simply be associated with the natural course of the disease and/or physiological linear growth of the children.

Coronary artery dilation and left ventricular hypertrophy do not predict morbidity in children with sickle cell disease

BACKGROUND

Little is known about the clinical significance of coronary artery dilation (CAD) and left ventricular hypertrophy (LVH) in patients with sickle cell disease (SCD).

PROCEDURE

In a retrospective cohort, we studied the prevalence of CAD and LVH in 101 children with SCD in comparison to 93 healthy African-American patients without SCD. Hospital days, number of admissions, and intensive care unit admission after the echocardiogram were assessed as measures of morbidity.

RESULTS

Multivariable analysis of echocardiographic measures of LVH and CAD did not predict subsequent intensive care unit admission, hospital days/year or number of hospital admissions/year during a median follow-up time of 6.1 years. LVH as measured by left ventricular mass index was present in 46% of children with SCD and was inversely related to age (P = 0.0004). Height-indexed dimensions in children with SCD demonstrated that the prevalence of dilation was 49% for the left main coronary artery (LMCA), 29% for the left anterior descending (LAD), and 6% for the right coronary artery (RCA). LMCA dilation was related to relative wall thickness (P = 0.006), inversely to age (P < 0.0006) and weakly to disease severity as determined by hemoglobin (P = 0.03). CAD and LVH were not related to a clinical history of vaso-occlusive pain episode, acute chest syndrome, or cerebrovascular accident.

CONCLUSION

LVH and CAD are common findings in children with SCD; however, they are not associated with need for subsequent hospital or intensive care unit admission.

Age-specific non-invasive transcutaneous Doppler ultrasound derived haemodynamic reference ranges in elderly Chinese adults

Background

Whilst there is a presumption in medicine that ageing adversely affects cardiovascular function, it is unknown if resting haemodynamics are compromised in the elderly, and if so, to what degree. This study was intended to answer several questions; whether age-related changes in haemodynamics occur; whether there was a difference between the haemodynamics of ageing subjects with and without mild chronic disease; whether there was a difference in haemodynamics as measured from either the aortic or the pulmonary valve; and to establish reference ranges for this population.

Methods

Chinese adults aged over 60 years were divided into three age bands of 61–70, 71–80 and over 80 years. The haemodynamic parameters were measured using a non-invasive Doppler ultrasound-based instrument, the Ultrasonic Cardiac Output Monitor (USCOM).

Results

One hundred and sixty-five subjects (48.5% males) were recruited. 78 (47.3%) had no known disease whilst 87 (52.7%) had mild chronic illness. A total of 21 individual haemodynamic parameters were measured or calculated for each subject. There were no significant differences in stroke volume (SV), cardiac output (CO), systemic vascular resistance (SVR) or in body surface area (BSA)-indexed parameters, SV index (SVI), cardiac index (CI) and SVR index (SVRI) across age groups, or in other indexed haemodynamic parameters. No significant differences in indexed haemodynamics were found between those subjects with and those without mild chronic disease. Small, statistically significant, but clinically insignificant, differences (< 5%) were found between the aortic and pulmonary valve measurements for SV, SVI and heart rate.

Conclusions

Ageing does not have any significant effect on resting haemodynamics in the elderly population studied. Mild chronic disease does not adversely affect resting haemodynamics in this population.

General Significance

Reference ranges were established for 21 haemodynamic parameters, as measured by USCOM, for an elderly Chinese population but not for non-Chinese populations.

•

Ageing has no significant effect on resting haemodynamics in the population studied.

•

Mild chronic disease does not adversely affect resting haemodynamics in this population.

•

Reference ranges were established for 21 haemodynamic parameters in Chinese elderly.

Hirschsprung's Disease and Associated Congenital Heart Defects: A Prospective Observational Study from a Single Institution

OBJECTIVE

To define the prevalence and characteristics of associated congenital heart diseases (CHDs) in patients with Hirschsprung's disease (HSCR).

METHOD

All patients with a histological diagnosis of HSCR admitted to our hospital between January 2010 and December 2013 were included in this prospective observational study and underwent cardiovascular screening. Cardiac anatomy was assessed by a segmental echocardiographic approach. Measurements of aortic root and left ventricular dimensions, wall thickness, and function were obtained. CHDs requiring a percutaneous or surgical intervention were described as major heart diseases.

RESULTS

One hundred thirty-three consecutive patients were enrolled at median age of 2.3 years. Eleven patients (8.3%) presented an associated heart disease. Moreover, five patients had mild dilatation of aortic root. Six out of 11 (4.5%) patients had a major CHDs requiring surgical repair.

CONCLUSION

Prevalence of associated CHDs was slightly higher than in previous papers, and mostly represented by septal defects. Four out of six patients with major heart disease had also a chromosomal anomaly. If we do not consider the subpopulation of patients with a chromosomal anomaly, cardiac defects were present in 3.8% of the patients. Based on these results, we suggest to perform routine echocardiogram in all Hirschsprung patients, with or without associated chromosomal syndromes.

An assessment of two Doppler-Based Monitors to Track Cardiac Output Changes in Anaesthetised Patients Undergoing Major Surgery

Minimally-invasive cardiac output (CO) monitoring to follow changes in CO would be helpful in anaesthesia practice. Two Doppler systems marketed for this purpose include the CardioQ (Deltex Medical Group, Chichester, United Kingdom), which uses an oesophageal probe, and the USCOM (USCOM Ltd., Sydney, NSW, Australia), which uses a hand-held probe. The aim of the study was to assess the ability of these two methods to track CO during major surgery and to determine their relationship. Twenty patients, age 58 (26 to 81) years, (m/f) 15/5, requiring abdominal surgery were studied. The surgical procedures lasted between 128 and 408 minutes and a total of 285 data pairs (8 to 22 per case) were collected. Time plots showed good tracking ability across a wide range of CO in most patients. Correlation between the two devices was excellent in 14 patients (R2 >0.85), good in another four (R2 >0.64) and poor in two. Regression line data supported the hypothesis that CardioQ under-reads at low CO and over-reads at high CO in respect to the USCOM. However, the precision between the two CO readings was poor with wide limits of agreement and a percentage error of ± 37%. These findings indicate that these devices individually track changes in CO in many patients but cannot be relied upon to provide the same values.