Use of the myocardial performance index to assess right ventricular function in infants with pulmonary hypertension

Cardiac function in congenital diaphragmatic hernia

Cardiac function is known to play critical role in the pathophysiological progression and ultimate clinical outcome of patients with congenital diaphragmatic hernia (CDH). While often anatomically normal, the fetal and neonatal heart in CDH can suffer from both right and left ventricular dysfunction. Here we explore the abnormal fetal heart, early postnatal right and left ventricular dysfunction, the interplay between cardiac dysfunction and pulmonary hypertension, evaluation and echocardiographic assessment of the heart, and therapeutic strategies for managing and supporting the pathophysiologic heart and CDH. Further, we take a common clinical scenario and provide clinically relevant guidance for the diagnosis and management of this complex process.

Serial tissue Doppler imaging in the evaluation of bronchopulmonary dysplasia-associated pulmonary hypertension among extremely preterm infants: a prospective observational study

Objectives

To evaluate serial tissue Doppler cardiac imaging (TDI) in the evolution of bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) among extremely preterm infants.

Design

Prospective observational study.

Setting

Single-center, tertiary-level neonatal intensive care unit.

Patients

Infant born <28 weeks gestation.

Main outcome measures

Utility of TDI in the early diagnosis and prediction of BPD-PH and optimal timing for screening of BPD-PH.

Results

A total of 79 infants were included. Of them, 17 (23%) had BPD-PH. The mean gestational age was 25.9 ± 1.1 weeks, and mean birth weight was 830 ± 174 g. The BPD-PH group had a high incidence of hemodynamically significant patent ductus arteriosus (83% vs. 56%, p < 0.018), longer oxygen days (96.16 ± 68.09 vs. 59.35 ± 52.1, p < 0.008), and prolonged hospital stay (133.8 ± 45.9 vs. 106.5 ± 37.9 days, p < 0.005). The left ventricular eccentricity index (0.99 ± 0.1 vs. 1.1 ± 0.7, p < 0.01) and the ratio of acceleration time to right ventricular ejection time showed a statistically significant trend from 33 weeks (0.24 ± 0.05 vs. 0.28 ± 0.05, p < 0.05). At 33 weeks, the BPD-PH group showed prolonged isovolumetric contraction time (27.84 ± 5.5 vs. 22.77 ± 4, p < 0.001), prolonged isovolumetric relaxation time (40.3 ± 7.1 vs. 34.9 ± 5.3, p < 0.003), and abnormal myocardial performance index (0.39 ± 0.05 vs. 0.32 ± 0.03, p < 0.001). These differences persisted at 36 weeks after conceptional gestational age.

Conclusions

TDI parameters are sensitive in the early evolution of BPD-PH. Diagnostic accuracy can be increased by combining the TDI parameters with conventional echocardiographic parameters. BPD-PH can be recognizable as early as 33-34 weeks of gestation.

The role of point-of-care ultrasound in the management of neonates with congenital diaphragmatic hernia

In the last few years, current evidence has supported the use of point-of-care ultrasound (POCUS) for a number of diagnostic and procedural applications. Considering the valuable information that POCUS can give, we propose a standardized protocol for the management of neonates with a congenital diaphragmatic hernia (CDH-POCUS protocol) in the neonatal intensive care unit. Indeed, POCUS could be a valid tool for the neonatologist through the evaluation of 1) cardiac function and pulmonary hypertension; 2) lung volumes, postoperative pleural effusion or pneumothorax; 3) splanchnic and renal perfusion, malrotations, and/or signs of necrotizing enterocolitis; 4) cerebral perfusion and eventual brain lesions that could contribute to neurodevelopmental impairment. In this article, we discuss the state-of-the-art in neonatal POCUS for which concerns congenital diaphragmatic hernia (CDH), and we provide suggestions to improve its use. IMPACT: This review shows how point-of-care ultrasound (POCUS) could be a valid tool for managing neonates with congenital diaphragmatic hernia (CDH) after birth. Our manuscript underscores the importance of standardized protocols in neonates with CDH. Beyond the well-known role of echocardiography, ultrasound of lungs, splanchnic organs, and brain can be useful. The use of POCUS should be encouraged to improve ventilation strategies, systemic perfusion, and enteral feeding, and to intercept any early signs related to future neurodevelopmental impairment.

Diagnosis & management of pulmonary hypertension in congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) contributes to neonatal morbidity and mortality worldwide. Pulmonary hypertension (PH) is a key component of CDH pathophysiology and critical consideration for management and therapeutic options. PH associated with CDH has traditionally been attributed to pulmonary vascular maldevelopment and associated lung parenchymal hypoplasia, leading to pre-capillary increase in pulmonary vascular resistance (PVR). However, there is increasing recognition that left ventricular hypoplasia, dysfunction and elevated end diastolic pressure may contribute to post-capillary pulmonary hypertension in CDH patients. The interplay of these mechanisms and associated dysfunction in the right and left ventricles results in variable hemodynamic phenotypes in CDH. Clinical assessment of individual phenotype may help guide personalized management strategies, including effective use of pulmonary vasodilators and extra-corporeal membrane oxygenation. Ongoing investigation of the underlying mechanisms of PH in CDH, and efficacy of physiology-based treatment approaches may support improvement in outcomes in this challenging condition.

The role of bedside functional echocardiography in the assessment and management of pulmonary hypertension

Pulmonary hypertension is an emergency in neonatal intensive care units with high morbidity and mortality. Its timely assessment and management is crucial for intact survival. Over the last couple of decades, there have been significant advances in management and techniques, which have resulted in improved survival. The use of neonatologist-performed echocardiography (NPE) is now increasingly utilized on neonatal intensive care units to understand the pathophysiology of the disease and to direct the treatment to the underlying cause. Its use is now established not only in cases of congenital diaphragmatic hernia and in the newborn with refractory hypoxemia, but also in other conditions such as bronchopulmonary dysplasia and the premature infant with difficulty in oxygenation. The use of NPE, however, requires the availability of trained personnel, equipment, and a close working relationship with pediatric cardiology.

The heart in congenital diaphragmatic hernia: Knowns, unknowns, and future priorities

There is growing recognition that the heart is a key contributor to the pathophysiology of congenital diaphragmatic hernia (CDH), in conjunction with developmental abnormalities of the lung and pulmonary vasculature. Investigations to date have demonstrated altered fetal cardiac morphology, notably relative hypoplasia of the fetal left heart, as well as early postnatal right and left ventricular dysfunction which appears to be independently associated with adverse outcomes. However, many more unknowns remain, not least an understanding of the genetic and cellular basis for cardiac dysplasia and dysfunction in CDH, the relationship between fetal, postnatal and long-term cardiac function, and the impact on other parts of the body especially the developing brain. Consensus on how to measure and classify cardiac function and pulmonary hypertension in CDH is also required, potentially using both non-invasive imaging and biomarkers. This may allow routine assessment of the relative contribution of cardiac dysfunction to individual patient pathophysiological phenotype and enable better, individualized therapeutic strategies incorporating targeted use of fetal therapies, cardiac pharmacotherapies, and extra-corporeal membrane oxygenation (ECMO). Collaborative, multi-model approaches are now required to explore these unknowns and fully appreciate the role of the heart in CDH.

Clinical Utility of Echocardiography in Former Preterm Infants with Bronchopulmonary Dysplasia

BACKGROUND

The clinical utility of echocardiography for the diagnosis of pulmonary vascular disease (PVD) in former preterm infants with bronchopulmonary dysplasia (BPD) is not established. Elevated pulmonary vascular resistance (PVR) rather than pulmonary artery pressure (PAP) is the hallmark of PVD. We evaluated the utility of echocardiography in infants with BPD in diagnosing pulmonary hypertension and PVD (PVR >3 Wood units × m²) assessed by cardiac catheterization.

METHODS

A retrospective single center study of 29 infants born ≤29 weeks of gestational age with BPD who underwent cardiac catheterization and echocardiography was performed. PVD was considered present by echocardiography if the tricuspid valve regurgitation jet peak velocity was >2.9 m/sec, post-tricuspid valve shunt systolic flow velocity estimated a right ventricular systolic pressure >35 mm Hg, or systolic septal flattening was present. The utility (accuracy, sensitivity, and positive predictive value [PPV]) of echocardiography in the diagnosis of PVD was tested. Subgroup analysis in patients without post-tricuspid valve shunts was performed. Echocardiographic estimations of right ventricular pressure, dimensions, function, and pulmonary flow measurements were evaluated for correlation with PVR.

RESULTS

The duration between echocardiography and cardiac catheterization was a median of 1 day (interquartile range, 1-4 days). Accuracy, sensitivity, and PPV of echocardiography in diagnosing PVD were 72%, 90.5%, and 76%, respectively. Accuracy, sensitivity, and PPV increased to 93%, 91.7%, and 100%, respectively, when infants with post-tricuspid valve shunts were excluded. Echocardiography had poor accuracy in estimating the degree of PAP elevation by cardiac catheterization. In infants without post-tricuspid valve shunts, there was moderate to good correlation between indexed PVR and right ventricular myocardial performance index (rho = 0.89, P = .005), systolic to diastolic time index (0.84, P < .001), right to left ventricular diameter ratio at end systole (0.66, P = .003), and pulmonary artery acceleration time (0.48, P = .05).

CONCLUSIONS

Echocardiography performs well in screening for PVD in infants with BPD and may be diagnostic in the absence of a post-tricuspid valve shunt. However, cardiac catheterization is needed to assess the degree of PAP elevation and PVR. The diagnostic utility of echocardiographic measurements that correlate with PVR should be evaluated prospectively in this patient population.

The assessment of cardiac function with tissue Doppler imaging in fetuses with congenital diaphragmatic hernia

Introduction: This study aimed to evaluate the cardiac function of fetuses with congenital diaphragmatic hernia by conventional echocardiography and spectral tissue Doppler imaging (s-TDI) and to evaluate the relationship between cardiac function and the severity of pulmonary hypoplasia. We also aimed to investigate the effect of diaphragmatic hernia side on fetal cardiac function.Methods: Fetal cardiac function were evaluated in 28 fetuses (20 with left-sided and 8 with right-sided) complicated with isolated congenital diaphragmatic hernia (CDH) and 56 gestational age matched control in this single center prospective study. s-TDI measurements were obtained at the right atrioventricular valve annulus. The annular peak velocities and their ratios, the time periods of cardiac cycle and myocardial performance index were calculated.Results: In comparison to controls, significantly prolonged isovolumetric contraction time (ICT') and isovolumetric relaxation time (IRT') and, significantly shortened ejection time (ET') were observed in fetuses with CDH by s-TDI. Fetuses with CDH also had higher myocardial performance index (MPI') z-scores compared to controls. There were no significant differences in terms of s-TDI cardiac function parameters between fetuses with right- and left-sided CDH. In correlation analysis, a significant positive correlation was found between ET' value and o/e LHR.Conclusion: The signs of both systolic and diastolic altered function were observed in fetuses with CDH with s-TDI independent of the side of the hernia, and a significant positive correlation was observed between fetal cardiac systolic function and the severity of pulmonary hypoplasia.

Right ventricular myocardial performance index in pediatric patients with bronchopulmonary dysplasia-related pulmonary hypertension

INTRODUCTION

This study aims to assess the utility of right ventricular myocardial performance index (RVMPI) as a potential echocardiographic tool to evaluate and serially follow patients with bronchopulmonary dysplasia (BPD) and pulmonary hypertension (PH).

METHODS

We performed a retrospective chart review of all hemodynamic cardiac catheterizations performed January 2011 to December 2016 in patients born premature and with diagnosed BPD up to 4 years of age-excluding patients with significant congenital heart defects. Echocardiograms performed within 24 hours of the cardiac catheterization were reviewed, and a blinded RVMPI was calculated. The primary endpoint was correlation of invasive catheterization hemodynamics to noninvasive echocardiographic RVMPI measurement.

RESULTS

A total of 49 individual patients met complete study criteria, and 10 of those patients underwent repeat cardiac catheterization. Median age at the time of assessment was 8 months (25%-75%, 4-18 months), and the cohort had a calculated RVMPI mean of 0.39 (±0.19), with 73% (43/59) having a RVMPI >0.28. A statistically significant correlation was found between the RVMPI and the baseline hemodynamics during catheterization with regard to the initial mean pulmonary arterial pressure (r = 0.58; P < 0.01) as well as the calculated pulmonary vascular resistance (r = 0.34; P = 0.01).

CONCLUSIONS

This study demonstrates the utility of RVMPI for evaluation of PH in patients with prematurity and BPD. An increased RVMPI by noninvasive echocardiography was found to correlate with increased mean pulmonary arterial pressure and pulmonary vascular resistance measured during invasive cardiac catheterization. Large-scale validation of this study is being planned.

Clinical impact and efficacy of bedside echocardiography on patient management in pediatric intensive care units (PICUs): A prospective study

Objective:

To determine the indication and necessity of echocardiographic assessment and therapeutic interventions in critically ill children.

Methods:

A total of 140 children, including 75 mechanically ventilated (MV) and 65 spontaneously breathing (SB) children, who were admitted consecutively from March to August 2013 were evaluated prospectively. Data regarding the indication for echocardiography and therapeutic approaches used were documented. For evaluating disease severity, the Pediatric Risk of Mortality Score III (PRISM) was ascertained. The correlation between PRISM score and the requirement of echocardiographic evaluations were analyzed.

Results:

Patients ages were between 45 days to 18 years. The male-to-female ratio was 1.33. In 35.4% patients who underwent echocardiographic evaluation, no definitive alteration occurred in treatment approach, whereas in the remaining 64.6% patients, decisive or supplemental information was gathered. Echocardiography was indicated in 88% MV children and 46.2% SB children. Echocardiographic evaluation was necessary in MV children and there was a positive correlation between the PRISM score and the requirement of echocardiographic assessment (p<0.001).

Conclusion:

Echocardiographic evaluation is an invaluable tool especially in MV children and the requirement of echocardiographic assessment increases according to clinical severity. Basic training for intensivists in this procedure is crucial and needs to be improved and supported in critically ill.

Cardiac dysfunction in congenital diaphragmatic hernia: Pathophysiology, clinical assessment, and management

Cardiac dysfunction is an important consequence of pulmonary hypertension in congenital diaphragmatic hernia and a determinant of disease severity. Increased afterload leads to right ventricular dilatation and diastolic dysfunction. Septal displacement and dysfunction impair left ventricular function, which may also be compromised by fetal hypoplasia. Biventricular failure contributes to systemic hypotension and hypoperfusion. Early and regular echocardiographic assessment of cardiac function and pulmonary artery pressure can guide therapeutic decision-making, including choice and timing of pulmonary vasodilators, cardiotropes, ECMO, and surgery.

Echocardiographic evaluation of right ventricular function in preterm infants with bronchopulmonary dysplasia

AIM

To evaluate right ventricular function in preterm infants with and without bronchopulmonary dysplasia.

METHODS

Eighty-nine preterm infants (<32 weeks) were divided into three groups: (1) no-bronchopulmonary dysplasia (n=32); (2) mild-bronchopulmonary dysplasia (n=35); (3) severe-bronchopulmonary dysplasia (n=15). Right ventricular echocardiographic parameters included the following: (1) pulsed-wave Doppler through the tricuspid valve (E/A ratio), pulmonary artery acceleration time, right ventricular ejection time, right ventricular velocity-time integral; (2) tissue Doppler measurements of myocardial velocities and atrioventricular conduction times; (3) pulsed-wave Doppler and tissue Doppler evaluation of myocardial performance index and E/E' ratio; and (4) M-mode detection of right ventricular end-diastolic wall diameter.

RESULTS

The severe-bronchopulmonary dysplasia group had higher mean right ventricular myocardial performance index (on the 28th day of life by pulsed-wave Doppler) than the no-bronchopulmonary dysplasia (P=.014) or mild-bronchopulmonary dysplasia (P=.031) groups; no differences were found between no-bronchopulmonary dysplasia and mild-bronchopulmonary dysplasia groups (P=.919). A reduction in right ventricular myocardial performance index at later time points was observed in all three groups (P<.05). We found no differences between preterm infants with differing bronchopulmonary dysplasia severity in other right ventricular echocardiographic parameters.

CONCLUSION

Right ventricular myocardial performance index measured by pulsed-wave Doppler indicates impaired right ventricular function in preterm infants with severe bronchopulmonary dysplasia.

A comparison of echocardiographic variables of right ventricular function with exercise capacity after bosentan treatment in patients with pulmonary arterial hypertension: Results from a multicenter, prospective, cohort study

PURPOSE

Bosentan reduces pulmonary arterial pressure and improves exercise capacity in patients with pulmonary arterial hypertension (PAH). However, there are limited data regarding the extent to which the changes in echocardiographic variables reflect improvements in exercise capacity. We aimed to assess the improvement of echocardiographic variables and exercise capacity after 6 months of bosentan treatment for PAH.

METHODS

We performed a prospective study from June 2012 to June 2015 in seven participating medical centers. Echocardiography, including tissue Doppler imaging (TDI) and the 6-minute walk test distance (6MWD), was performed at baseline and after 6 months of bosentan treatment.

RESULTS

We analyzed 19 patients with PAH: seven with congenital shunt, six with collagen vascular disease, and six with idiopathic PAH. After bosentan treatment, mean 6MWD increased by 50 meters. Right ventricle (RV) systolic pressure, tricuspid annular plane systolic excursion, myocardial performance index (MPI) derived from TDI (MPI-TDI) of RV and left ventricle (LV), RV fractional area change, and RV ejection fraction were significantly improved. In particular, the magnitude of RV and LV MPI-TDI showed good correlation with changes in the 6MWD.

CONCLUSIONS

The magnitude of RV and LV MPI-TDI was strongly associated with improvements in exercise capacity. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:28-34, 2017.

Right ventricular echocardiographic indices predict poor outcomes in infants with persistent pulmonary hypertension of the newborn

AIMS

Infants with persistent pulmonary hypertension of the newborn (PPHN) have elevated pulmonary vascular resistance that can lead to right ventricular (RV) failure and death. Clinicians must decide which infants will fail conventional therapy and require transfer to extra corporeal membrane oxygenation (ECMO) centres, but accurate echocardiographic predictors have not been identified. We assessed echocardiographic measurements of RV pressure and function in predicting progression to death or ECMO in infants with PPHN.

METHODS AND RESULTS

Echocardiograms for infants ≥35-week gestation with a clinical diagnosis of PPHN were retrospectively reviewed. Traditional and strain echocardiographic measures were compared for those with or without the primary outcome of ECMO/cardiovascular death. Receiver operator curves identified cut points for measures that were significantly different. Of the 86 subjects analysed, 25 (29%) of the patients had the primary outcome of ECMO/death. The ECMO/death group had diminished tricuspid annular plane systolic excursion (TAPSE; P = 0.002) and RV global longitudinal peak strain (GLPS; P = 0.03), a predominant right-to-left shunt across the patent ductus arteriosus (PDA; P = 0.05), and an elevated oxygenation index (OI; P < 0.001). Sensitivity/specificity for TAPSE <4 mm was 56 and 85%, and for GLPS greater than or equal to -9% was 52 and 77%.

CONCLUSION

TAPSE, GLPS, and right-to-left PDA shunting were associated with progression to death/ECMO. RV free wall strain was not associated with the outcome, suggesting that diminished global strain better reflects clinical outcomes in this group. These thresholds may assist in the decision-making to transfer high-risk infants to ECMO centres.

Echocardiographic correlates of persistent pulmonary hypertension of the newborn

AIMS

To compare echocardiographic (ECHO) measures of ventricular function and hemodynamics of infants with persistent pulmonary hypertension of the newborn (PPHN) and normal controls; and to examine their association with clinical outcomes in PPHN.

DESIGN/SUBJECTS

We performed a retrospective review of ECHOs of mechanically ventilated infants (≥ 34 weeks gestational age) with PPHN. Infants with congenital heart disease were excluded. Controls had normal ECHOs within 1 week of age.

OUTCOMES

ECHOs measures included a) right (RVO) and left ventricular output (LVO) b) RV and LV myocardial performance index (MPI) c) right ventricular systolic to diastolic duration (S/D) ratio and d) eccentricity index in systole (EIs) and diastole (EId).

RESULTS

Infants with PPHN (n = 117), 63% of whom were males, had mean (SD) GA and birth weights of 38.6 (1.9) weeks and 3.3 (0.65) kg respectively. LVO, RVO and EIs were significantly lower and heart rate, MPI and RV S/D ratio were significantly higher in infants with PPHN, compared to controls (n = 35). The mean RV S/D ratios were significantly higher in infants with PPHN who died or required ECMO (n = 61), compared to survivors without ECMO (n = 56). Increasing RV S/D ratio was independently associated with a reduction in survival without ECMO [0.21; 95% C.I. 0.06-0.74, p = 0.015]. RV S/D ratio >1.3 had a sensitivity of 93 (95% C.I. 85-99) % for death or ECMO.

CONCLUSIONS

Elevated RV S/D ratio, a marker of global RV dysfunction, was associated with adverse outcomes in PPHN. Its routine measurement in this population may aid risk-identification and targeted interventions.

Improvement in Tricuspid Annular Plane Systolic Excursion with Pulmonary Hypertension Therapy in Pediatric Patients

BACKGROUND

Tricuspid annular plane systolic excursion (TAPSE) has emerged as a novel and reliable measure of right ventricular (RV) function. The purpose of this study was to determine the effect of pulmonary hypertension (PH) therapy on TAPSE in pediatric patients and compare TAPSE to other quantitative measures of RV function.

METHODS

A retrospective review of medical records and echocardiograms of patients in the PH clinic from January 2011 to August 2013 was done. Echocardiograms were analyzed prior to initiation or addition of a PH drug and at least 8 weeks later. Following quantitative measures of RV function were compared: TAPSE, TAPSE age-based z-score, RV fractional area change (RVFAC), tricuspid annular S', tricuspid inflow E/tricuspid annular E' velocity (TV E/E'), and RV myocardial performance index (RVMPI).

RESULTS

Of the 37 patients included in this study (median age 0.6 years), 23 (62.2%) were treatment naive and others had a new PH drug added to their regimen at the time of the baseline echocardiogram. The median duration between the baseline and follow-up echocardiogram was 8 (2-25) months. There was a significant improvement in TAPSE and TAPSE age-based z-score on the follow-up echocardiogram. RVFAC, tricuspid S', TV E/E', and RVMPI did not show a statistically significant change.

CONCLUSION

In contrast to the other echocardiographic markers of RV function, TAPSE, and TAPSE age-based z-score significantly improve after initiation or addition of PH therapy and can be used for serial noninvasive monitoring of RV function in pediatric PH patients.

Echocardiography in pediatric pulmonary hypertension

Pulmonary hypertension (PH) can be a rapidly progressive and fatal disease. Although right heart catheterization remains the gold standard in evaluation of PH, echocardiography remains an important tool in screening, diagnosing, evaluating, and following these patients. In this article, we will review the important echocardiographic parameters of the right heart in evaluating its anatomy, hemodynamic assessment, systolic, and diastolic function in children with PH.

Mid-term differences in right ventricular function in patients with congenital diaphragmatic hernia compared with controls

BACKGROUND

Patients with congenital diaphragmatic hernia (CDH) may have abnormal lung development, which may cause detrimental effects on right ventricular (RV) function. This study aimed to determine if there are persistent echocardiographic differences in RV function in patients with CDH years after repair versus control patients.

METHODS

Patients who underwent repair for CDH were recruited. RV function was evaluated by strain analysis and tissue Doppler imaging (TDI). Wilcoxon's rank-sum test was used for analysis.

RESULTS

Seven CDH patients and 16 control patients were studied. There was no difference in age between the CDH and control groups (6.2±1.7 years vs. 5.7±1.7 years). TDI demonstrated significantly lower values in the RV early diastolic wave (12.8±1.5 cm/s vs. 16.1±3.1 cm/s) and RV systolic wave (10.2± 0.8cm/s vs. 13.4±1.3 cm/s) when comparing the CDH group and the control group. Interventricular apical septal strain was signifi cantly lower in the CDH group than in the control group (-20.1±4.6% vs. -25.4±4.1%). There was a trend towards lower strain values in the RV mid-lateral segment in the CDH group (-30.8±9.9% versus -39.7±6.0%, P=0.06) and a lower global RV strain (-27.8±3.0% vs. -31.1±3.1%, P=0.06).

CONCLUSIONS

Patients who underwent CDH repair continue to have differences in RV function years after repair. Follow-up is needed to determine how these differences impact cardiac function in adult survivors of CDH.

Impact of sildenafil on echocardiographic indices of myocardial performance after the Fontan operation

The objective of this study was describe the impact of sildenafil on echocardiographic measures of myocardial performance in children and young adults with a functional single-ventricle physiology late after Fontan surgery. A double-blind, placebo-controlled, crossover trial was conducted in children and young adults after the Fontan operation at a single pediatric center. Subjects were randomized to receive placebo or sildenafil (20 mg tid) for 6 weeks. After a 6-week washout period, subjects were crossed for an additional 6 weeks. Each subject underwent an echocardiogram at the start and finish of each phase. A total of 27 subjects completed study testing at a mean age of 14.9 years and a mean time from Fontan surgery of 11.3 years. After sildenafil, subjects demonstrated improvement in their myocardial performance index (MPI; -0.051; 95% CI -0.095, -0.0077; p 0.02) and in the product of the velocity time integral (VTI) of the dominant outflow tract and the heart rate (HR; 110 cm × bpm; 95% CI 7.5, 220; p = 0.04). Measures of diastolic performance, including inflow velocities, myocardial velocities, and the ratio of blood pool velocity to myocardial velocity during passive inflow, did not change. In this cohort, there were significant improvements in both the MPI and the product of the VTI × HR after 6 weeks of treatment with sildenafil. These findings suggest that sildenafil may be a useful therapy to improve or maintain ventricular performance in select patients after the Fontan operation.

Noninvasive assessment of the early transitional circulation in healthy term infants

BACKGROUND

The early neonatal circulatory transition usually occurs smoothly but occasionally it is incomplete or reverts to the fetal state of high pulmonary vascular resistance, resulting in significant neonatal morbidity.

OBJECTIVE

To define the normal values for echocardiographic parameters during the early transitional circulation in term infants.

METHODS

Two-dimensional, M-mode, pulsed and color flow Doppler echocardiography was used to assess healthy term infants in the first 4 h of life. Left and right ventricular outputs (LVO and RVO) and myocardial performance indices (MPI), left ventricular fractional shortening, end-systolic diameter and end-diastolic diameter, ductal size, shunt and peak velocities, tricuspid regurgitation and left pulmonary artery diastolic velocities were documented.

RESULTS

A total of 21 normal term infants were assessed with median gestation of 39 weeks, birth weight of 3,470 g and postnatal age of 3 h and 22 min. The median echocardiographic values were LVO 193 ml/kg/min, RVO 216 ml/kg/min, left MPI 0.41, right MPI 0.63, and fractional shortening 29%. The ductus was patent in all 21 infants with a median size of 2.3 mm; ductal flow was bidirectional in 86% with median peak left-to-right velocity of 1.07 m/s. The median left pulmonary artery diastolic velocity was 0.31 m/s and physiological tricuspid regurgitation was present in all infants.

CONCLUSION

This study defines normal values for echocardiographic measurements in healthy term infants during the first 4 h after birth. These normative data may be useful in early identification of infants with abnormal circulatory transition, allowing more rapid determination of cardiovascular dysfunction.

Echocardiographic measures of ventricular function and pulmonary artery size: prognostic markers of congenital diaphragmatic hernia?

OBJECTIVE

To compare echocardiographic measures of biventricular function and pulmonary artery size in infants with congenital diaphragmatic hernia (CDH) and normal controls, and examine their correlation, if any, with outcomes in CDH.

STUDY DESIGN

We included consecutive neonates (<1 month old) with CDH and term controls without structural heart defects. Clinical and outcomes data were recorded and echocardiograms evaluated for right ventricular (RV) and left ventricular (LV) myocardial performance index (MPI), cardiac output index (CI) and McGoon index, among others. Statistical analyses (SPSS version 17, SPSS, Chicago, IL, USA) included between-group comparisons, using analysis of variance and χ(2)-test and binary regression, with significance set at P<0.05.

RESULT

Infants with CDH (n=34) were comparable with controls (n=35) in their age, weight, gestational age and gender. CDH was left sided in 24 (70%) neonates. Extracorporeal membrane oxygenation (ECMO) was required in 15 (45%) neonates; 18 (53%) infants survived. MPIs, CI and eccentricity index in systole were significantly worse in the CDH group, compared with controls and among CDH infants who died, compared with survivors. Infants with CDH who died or needed ECMO had significantly impaired MPIs and CI than survivors. On regression analyses, LV CI and MPIs were independently associated with mortality.

CONCLUSION

Infants with CDH had significantly impaired ventricular function and pulmonary hypertension, compared with controls. In the CDH group, LV dysfunction was associated with death and adverse outcomes. Further studies incorporating echocardiographic indices as prognostic markers of CDH are warranted.

Comparison of Doppler Flow Tei-Indexes With Pulmonary Artery Thermodilution Measurement of Cardiac Output in an Experimental Porcine Model

The objective of our study was to compare Doppler echocardiography imaging with pulmonary artery thermodilution measurement during mechanical ventilation. Total 78 piglets (6 weeks old, average weight 24 kg, under general anesthesia) were divided into 4 groups under different cardiac loading conditions (at rest, with increased left ventricular afterload, with increased right ventricular preload, and with increased afterload of both heart ventricles). At 60 and 120 min the animals were examined by echocardiography and simultaneously pulmonary artery thermodilution was used to measure cardiac output. Tei-indexes data were compared with invasively monitored hemodynamic data and cardiac output values together with calculated vascular resistance indices. A total of 224 parallel measurements were obtained. Correlation was found between values of right Tei-index of myocardial performance and changes in right ventricular preload (p<0.05) and afterload (p<0.01). Significant correlation was also found between left index values and changes of left ventricular preload (p<0.001), afterload (p<0.001), stroke volume (p<0.01), and cardiac output (p<0.01). In conclusion, echocardiographic examination and determination of the global performance selectively for the right and left ventricle can be recommended as a suitable non-invasive supplement to the whole set of methods used for monitoring of circulation and cardiac performance.

Repeated bedside echocardiography in children with respiratory failure

BACKGROUND

The aim of this study was to verify the benefits and limitations of repeated bedside echocardiographic examinations in children during mechanical ventilation. For the purposes of this study, we selected the data of over a time period from 2006 to 2010.

METHODS

A total of 235 children, average age 3.21 (SD 1.32) years were included into the study and divided into etiopathogenic groups. High-risk groups comprised: Acute lung injury and acute respiratory distress syndrome (ALI/ARDS), return of spontaneous circulation after cardiopulmonary resuscitation (ROSC), bronchopulmonary dysplasia (BPD), cardiomyopathy (CMP) and cardiopulmonary disease (CPD). Transthoracic echocardiography was carried out during mechanical ventilation. The following data were collated for statistical evaluation: right and left ventricle myocardial performance indices (RV MPI; LV MPI), left ventricle shortening fraction (SF), cardiac output (CO), and the mitral valve ratio of peak velocity of early wave (E) to the peak velocity of active wave (A) as E/A ratio. The data was processed after a period of recovery, i.e. one hour after the introduction of invasive lines (time-1) and after 72 hours of comprehensive treatment (time-2). The overall development of parameters over time was compared within groups and between groups using the distribution-free Wilcoxons and two-way ANOVA tests.

RESULTS

A total of 870 echocardiographic examinations were performed. At time-1 higher average values of RV MPI (0.34, SD 0.01 vs. 0.21, SD 0.01; p < 0.001) were found in all groups compared with reference values. Left ventricular load in the high-risk groups was expressed by a higher LV MPI (0.39, SD 0.13 vs. 0.29, SD 0.02; p < 0.01) and lower E/A ratio (0.95, SD 0.36 vs. 1.36, SD 0.64; p < 0.001), SF (0.37, SD 0.11 vs. 0.47, SD 0.02; p < 0.01) and CO (1.95, SD 0.37 vs. 2.94, SD 1.03; p < 0.01). At time-2 RV MPI were lower (0.25, SD 0.02 vs. 0.34, SD 0.01; p < 0.001), but remained higher compared with reference values (0.25, SD 0.02 vs. 0.21, SD 0.01; p < 0.05). Other parameters in high-risk groups were improved, but remained insignificantly different compared with reference values.

CONCLUSION

Echocardiography complements standard monitoring of valuable information regarding cardiac load in real time. Chest excursion during mechanical ventilation does not reduce the quality of the acquired data.

Functional echocardiography in assessment of the cardiovascular system in asphyxiated neonates

Perinatal asphyxia commonly results in multi-organ damage, and cardiovascular dysfunction is a frequent association. Myocardial damage, right ventricular dysfunction, abnormal circulatory transition, and impaired autoregulation may all contribute to postnatal neurological damage. Adequate monitoring and appropriate targeted treatment therefore are essential after an asphyxial insult. Standard methods of cardiovascular monitoring in the neonate have limitations. Point of care ultrasound scanning or functional echocardiography offers extra information to assist the clinician in identifying when there is significant cardiovascular impairment, classifying the underlying abnormal physiology and potentially targeting appropriate therapy, thereby optimizing the post-insult cerebral blood flow and oxygen delivery.

Functional echocardiography; from physiology to treatment

Functional echocardiography (fECHO) is the bedside use of ultrasound to longitudinally assess myocardial function, systemic and pulmonary blood flow, and intra and extracardiac shunts. This review will focus on fECHO as a tool for the clinician to assess the hemodynamic condition of sick neonates and describe situations where fECHO can help determine a pathophysiological choice for cardiovascular support. The very low birth weight infant with hypotension during the first 24h of life, assessment and monitoring of the ductus arteriosus, assessment and response to treatment of infants with pulmonary hypertension, the infant with perinatal asphyxia and the infant with sepsis and cardiovascular compromise are reviewed. Close cooperation with pediatric cardiology, proper logistics and training programs are mandatory to achieve a 24h a day fECHO service run by bedside clinicians.