Tissue Doppler echocardiographic and color M-mode estimation of left atrial pressure in infants

The continuing challenge of evaluating diastolic function by echocardiography in children: developing concepts and newer modalities

PURPOSE OF REVIEW

Assessment of diastolic function by echocardiography is challenging but important. Left ventricular filling has been more extensively studied than the right ventricle, and predominantly in adult populations. Although multiple parameters exist to assess diastolic function, they all have limitations, including load and heart rate dependency, which make assessment of diastolic function particularly challenging. The purpose of this article is to review evolving concepts and modalities for echo assessment of diastolic function in children.

RECENT FINDINGS

The paradigm whereby diastolic dysfunction severity progresses in a staged fashion from impaired relaxation to increasing ventricular stiffness, may not apply in children. In addition, previous adult guidelines are not readily applicable to children with cardiomyopathy and the applicability of the newly revised adult guidelines needs to be evaluated in children. It is unlikely that any one single echocardiographic diastolic parameter will adequately reflect diastolic function. Hence, parameters derived from atrioventricular valve inflow, pulmonary venous, and tissue Doppler need to be integrated. Newer modalities such as diastolic strain rate and rotation mechanics may be useful as more sensitive markers of early ventricular dysfunction but have important limitations and require more evaluation before routine use in practice. Assessment of systolic-diastolic coupling may enhance assessment of diastolic function.

SUMMARY

Diastolic function impacts outcomes and should be part of routine echocardiographic assessment of function. An integrative approach combining different parameters, possibly with contribution of newer modalities in the future, is required.

Effects of foetal growth restriction and preterm birth on cardiac morphology and function during infancy

AIM

To investigate the effects of foetal growth restriction (FGR) and prematurity on cardiac morphology and function in infancy. We hypothesised that FGR and prematurity would both alter cardiac development.

METHODS

Cardiac morphology and function were evaluated in 24 preterm FGR infants (p-FGR) and 23 preterm and 19 term appropriately grown for gestational age infants (p-AGA and t-AGA, respectively) by conventional echocardiography and Tissue Doppler Imaging. p-FGR and p-AGA infants were studied on postnatal day 1 and all groups were studied at one-and six-months post-term age.

RESULTS

p-FGR infants demonstrated increased cardiac sphericity compared to AGA peers on postnatal day 1 (p = 0.004) and at one-month post-term age (p = 0.004). Posterior and relative wall thickness increased overtime in the p-FGR group only (p < 0.05). Systolic function was not different between groups. E/e' ratio was higher in both preterm groups compared to the term group at one-month post-term age (p = 0.01). No statistically significant group differences were found at six-months post-term age.

CONCLUSION

Foetal growth restriction was associated with subtle cardiac morphological changes, whereas both prematurity and FGR were associated with subclinical alterations in diastolic function.

Echocardiography in the Assessment of Left Atrial Pressure After Pediatric Heart Surgery: A Comparison Study With Measurements Obtained From Left Atrial Catheter

BACKGROUND

Correlation between ventricular end-diastolic pressure and pulsed Doppler and tissue Doppler-derived E/e' ratio has been widely reported in adults but scarcely studied in children with congenital heart diseases. This ratio is defined as the relationship between diastolic transmitral flow velocity (cm/s; E) and myocardial diastolic relaxation velocity (cm/s; e') in the lateral aspect of the mitral annulus. Our main objective was to ascertain whether a correlation existed between direct measurement of left atrial pressure and echocardiographic E/e' ratio in children after heart surgery.

METHODS

Prospective study including 27 consecutive children after pediatric heart surgery. Data were analyzed according to whether they were obtained within the first 72 hours following surgery or later on. Sensitivity, specificity, positive and negative predictive values, and areas under the receiver-operating characteristics curve of E/e' ratio in detection of left atrial pressure values ≥13 mm Hg were evaluated.

RESULTS

Forty-eight studies were conducted in 27 patients. Thirty-two studies were performed during the first 72 hours after heart surgery and 16 beyond the third day. Median patient age was 0.82 years (5 days-16 years). Median left atrial pressure values and E/e' measurements of the whole cohort (N = 48) were 12.0 and 10.2, respectively. Intraclass correlation index between left atrial pressure values and echocardiographic E/e' ratio was 0.35, 0.25 for studies performed within 72 hours, but 0.78 (P < .01) for those performed later. There was also a high positive predictive value, since in 13 (87%) of 15 studies with an E/e' ratio ≥13, the left atrial pressure was ≥13 mm Hg.

CONCLUSION

While echocardiographic E/e' ratio did not show a good correlation with left atrial pressure in the immediate postoperative period, the positive predictive value may suffice to aid clinicians in predicting elevated pressures.

A Novel Combined-Catheter to Monitor Left and Right Atrial Pressures: A Simple and Reliable Method for Pediatric Cardiac Surgery

OBJECTIVE

To introduce a novel combined-catheter to monitor left and right atrial pressures.

DESIGN

Prospective observational study.

SETTING

Fuwai Hospital, China.

PATIENTS

A total of 113 pediatric patients (77 men), median age 10.3 months, admitted between July 10, 2014, and February 5, 2015, were divided into two groups: the novel-catheter group and the traditional-method group.

INTERVENTIONS

All patients received routine anesthesia and surgery. Left atrial pressure and central venous pressure (an estimate of right atrial pressure), measured through a catheter needle during surgery, were identified as the "gold standard." A novel combined-catheter, composed of a reformed triple-lumen catheter with a microtube inserted within its central cavity, was used in the novel-catheter group. A traditional triple-lumen catheter to monitor central venous pressure plus another single-lumen catheter to monitor left atrial pressure were used in the traditional-method group.

MEASUREMENTS AND MAIN RESULTS

The novel combined-catheter could accurately monitor left atrial pressure and central venous pressure. Pressure values measured by the novel catheter correlated well with the gold standard (left atrial pressure, R = 0.98; central venous pressure, R = 0.99). Bland-Altman analyses revealed good agreement between pressures measured by the novel catheter and the gold standard. The absolute value of maximum difference was 0.67 mm Hg for left atrial pressure and 0.33 mm Hg for central venous pressure, which are acceptable in clinical practice. Left atrial pressure-monitoring catheter displaced into the right atrium occurred significantly less frequently in the novel-catheter group when compared with the traditional-method group (5 and 12 cases, respectively).

CONCLUSIONS

This novel combined-catheter was safe and reliable at monitoring left and right atrial pressures, and infusion involved only one catheter without the disadvantages of the traditional method. This new novel method may be particularly useful in pediatric open-heart surgery.