Assessment of ventricular relaxation and stiffness using early diastolic mitral annular and inflow velocities in pediatric patients with heart disease

Echocardiography to predict left ventricular filling pressure for long-term paediatric heart transplant patients

OBJECTIVES

Left ventricular diastolic dysfunction is a recognised sequela following transplantation in paediatric heart transplant patients. Traditional echocardiographic indices do not correlate well with left ventricular filling pressure immediately after transplantation. This study aimed to assess whether these indices have any long-term correlation after transplantation in paediatric patients.

METHODS

A retrospective chart review of 41 patients who had a heart transplant before the age of 24 years was performed. The median time since the transplantation was 11 years. Data obtained from surveillance cardiac catheterisation and echocardiographic examination were reviewed. Traditional echocardiographic indices of diastolic function were compared with the pulmonary capillary wedge pressure and left ventricular end-diastolic pressure obtained from cardiac catheterisation.

RESULTS

The median age at transplant was 12.1 years, and the median time since transplant was 11 years. Eighteen patients (43%) had a history of at least one rejection episode and 12 patients (29%) had a history of cardiac allograft vasculopathy. There was no correlation between mitral inflow E velocity, mitral E/A ratio, tissue Doppler velocities, mitral E/e' (mitral inflow E velocity to mitral annular velocity), and elevated pulmonary capillary wedge pressure or elevated left ventricular end-diastolic pressure. There was no correlation between mitral valve deceleration time or isovolumetric relaxation time with elevated pulmonary capillary wedge pressure or elevated left ventricular end-diastolic pressure.

CONCLUSION

Our findings suggest that traditional echocardiographic indices of diastolic function do not correlate well with elevated invasive pulmonary capillary wedge pressure or elevated left ventricular end-diastolic pressure in paediatric heart transplant patients' long-term post-transplantation.

Exploratory Study of Pharmacists' Monitoring Methods Based on Left Ventricular Function for Hypermagnesemia by Magnesium Oxide in Heart Failure

Serum magnesium (Mg) monitoring in patients with heart failure (HF) receiving magnesium oxide (MgO) is not adequately performed. Furthermore, the relationship between left ventricular function (LVF) and hypermagnesemia in HF is unknown. Here, we investigated the efficacy of serum Mg monitoring by protocol-based pharmaceutical management (PBPM) and the effect of LVF on hypermagnesemia. This protocol is for patients with an estimated glomerular filtration rate of <45 mL/min, receiving MgO, and admitted to the cardiology unit. The pharmacist includes the measurement of Mg when a blood test is ordered for a patient by their physician. Rates of serum Mg measurement and hypermagnesemia detection were compared at 2 years pre-PBPM (n = 88) and at 2 years post-PBPM (n = 55). LVF parameters and reported factors for hypermagnesemia were selected as explanatory factors on multivariate logistic regression. The measurement rate of serum Mg concentration significantly increased from 19.3% pre-PBPM to 80.0% post-PBPM (P < .001). The detection rate of hypermagnesemia also increased from 3.4% to 27.3%, respectively (P < .001). Our results suggest that serum Mg monitoring by PBPM may contribute to the early detection of hypermagnesemia and prevent its progression in HF. According to logistic regression, the adjusted odds ratio for hypermagnesemia with an exacerbation of HF was 9.57 (95% confidence interval: 1.594-57.477, P = .014), and the E/e' > 15, an index of reduced left ventricular diastolic capacity, was 6.46 (95% confidence interval: 1.291-32.364, P = .023). We propose that serum Mg monitoring should be performed during exacerbations of HF in patients with left ventricular diastolic dysfunction, with a pharmacist's assistance.

Assessment of left-ventricular diastolic function in pediatric intensive-care patients: a review of parameters and indications compared with those for adults

BACKGROUND

The incidence of diastolic heart failure has increased over time. The evaluation of left-ventricular diastolic function is complex, ongoing, and remains poorly performed in pediatric intensive-care patients. This study aimed to review the literature and to provide an update on the evaluation of left-ventricular diastolic function in adults and children in intensive care.

DATA SOURCES

We searched data from PubMed/Medline. Thirty-two studies were included. Four pragmatic questions were identified: (1) What is the physiopathology of diastolic dysfunction? (2) Which tools are required to evaluate diastolic function? (3) What are the echocardiographic criteria needed to evaluate diastolic function? (4) When should diastolic function be evaluated in pediatric intensive care?

RESULTS

Early diastole allows characterization of relaxation, whereas compliance assessments and filling pressures are evaluated during late diastole. The evolution of diastolic function differs between adults and children. Unlike in adults, decreased compliance occurs at the same time as delayed relaxation in children. Diastolic function can be evaluated by Doppler echocardiography. The echocardiographic criteria for ventricular relaxation include the E wave, E/A wave ratio, and isovolumic relaxation time. Ventricular compliance can be assessed by the E/e' wave ratio, atrial volume, and Ap wave duration during pulmonary vein flow. In adult intensive-care patients, the E/e' ratio can be used as an index of tolerance for volume expansion in septic patients and to adjust the inotropic support.

CONCLUSION

Clinical studies would allow some of these parameters to be validated for use in children in intensive care.

Atrial Function and Its Role in the Non-invasive Evaluation of Diastolic Function in Congenital Heart Disease

Diastolic dysfunction has correlated with adverse outcomes in various forms of unrepaired and repaired or palliated congenital heart disease (CHD). The non-invasive assessment of diastolic function in pediatric and adult patients with CHD remains challenging. Atrial size has a pivotal role in the evaluation of diastolic function; however, a growing body of evidence supports the additional role of atrial function as a more sensitive parameter of ventricular diastolic dysfunction. While the importance of atrial function is becoming clearer in adult acquired heart disease, it remains ambiguous in those with CHD. In this review we set the stage with the current understanding of diastolic function assessment in CHD, followed by insight into atrial form and function including its non-invasive assessment, and conclude with the current knowledge of atrial function in CHD. A general pattern of decrease in reservoir and conduit function with compensatory increase followed by decompensatory decrease in contractile function seems to be the common pathway of atrial dysfunction in most forms of CHD.

Indexing peak rapid filling velocity to both relaxation and filling volume to estimate left ventricular filling pressures

AIMS

The peak transmitral velocity/peak mitral annular velocity (E/e') ratio has been used as a left ventricular (LV) filling pressure (LVFP) correlate. However, the E/e' and its changes with haemodynamic alterations have not always correlated with changes in LVFP's. We hypothesized that indexing E/e' to a measure of LV filling volume may enhance the correlation with LVFP and LVFP changes.

METHODS AND RESULTS

We summarized previously obtained haemodynamic and Doppler echo data in 137 dogs with coronary microsphere embolization induced-chronic LV dysfunction prior to and following haemodynamic induced alterations in LVFP's. E/e' values were obtained as E*tau where tau is the inverse logarithmic LV pressure decay. E*tau was indexed to LV filling volume by dividing by the diastolic time velocity integral (DVI) and correlated with LV mean diastolic pressure (LVmDP). Similarly, the relationship of E/e' and E/e'/DVI to LV pre A wave pressure was evaluated in 84 patients by invasive haemodynamics and Doppler echo. Combining data from all interventions, LVmDP correlated with E*tau (r = 0.408) but more strongly with E*tau/DVI (r = 0.667, z = 3.03, P = 0.0008). The change in LVmDP correlated with the change in E*tau/DVI (r = 0.742) more strongly than E*Tau (r = 0.187, Z = 4.01, P < 0.0001). In the patient cohort, E/e' was modestly correlated with LV pre A wave pressure (r = 0.301) but more strongly correlated with E/e'/DVI (r = 0.636, z = 2.36, P = 0.0161).

CONCLUSION

Indexing E to both LV relaxation and filling volume results in a more robust relation with LVFP's and with LVFP changes.

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.

Ventricular-vascular dynamics in pediatric patients with heart failure and preserved ejection fraction

OBJECTIVE

The details of the ventricular-vascular dynamics of heart failure with preserved ejection fraction (HFpEF) in children remain poorly understood. We tested the hypothesis that pediatric HFpEF patients have ventricular systolic, diastolic, and arterial stiffening at rest as well as impaired reserve function associated with coronary supply/demand imbalance.

METHODS

We studied the ventricular pressure-area relationship in 22 pediatric HFpEF patients and 22 control subjects before and after dobutamine infusion and during abdominal compression. Coronary supply/demand balance was assessed by subendocardial viability ratio (SEVR) calculated from the aortic pressure waveform.

RESULTS

Compared with controls, the HFpEF patients had significantly higher end-systolic (Ees) and arterial (Ea) elastance. Increased ventricular diastolic stiffness also occurred in the HFpEF patients, resulting in modest elevation of end-diastolic pressure (EDP) at rest (13.6±4.3 vs. 7.3±2.3mmHg, P<0.0001). The difference in EDP became more evident with a preload increase through abdominal compression, indicating a limited diastolic reserve in HFpEF patients (EDP changes; 11.3±6.2 for HFpEF vs. 3.4±0.6mmHg for controls, P=0.016). The HFpEF patients exhibited impaired beta-adrenergic reserve in ventricular contractility and ventricular-arterial coupling in response to dobutamine infusion. SEVR was significantly lower in the HFpEF (0.64±0.11) than in the control (0.79±0.07, P<0.0001) and was significantly correlated with LV diastolic stiffness and dobutamine-induced changes in ventricular contractility.

CONCLUSIONS

HFpEF in children involves higher ventricular-arterial stiffness at rest as well as impaired systolic and diastolic reserve, which closely correlate with impaired coronary supply/demand balance.

Patients with left ventricular ejection fraction greater than 58 % have fewer incidences of future acute decompensated heart failure admission and all-cause mortality

Based on our previous observation, inertia stress (IS) of late systolic aortic flow was often observed in left ventricles with relatively higher left ventricular (LV) ejection fraction (EF). Most left ventricles with relatively lower LVEF did not have IS. Accordingly, lack of IS may correlate with LV diastolic dysfunction through the loss of LV elastic recoil and may contribute to the pathogenesis of heart failure (HF) and reduced survival. We enrolled 144 consecutive patients that underwent cardiac catheterization for the diagnosis of coronary artery disease. Left ventricular ejection fraction (LVEF) was obtained from left ventriculography. The IS was calculated from the LV pressure (P)-dP/dt relation. The study endpoint of this retrospective outcome-observational study was combined subsequent acute decompensated heart failure (ADHF) and all-cause mortality. During the follow-up period (median 6.1 years), seven unscheduled hospitalizations for ADHF and nine all-cause deaths were observed. The event-free survival rate was significantly higher among patients with IS than among patients without IS (log-rank, p = 0.001). On a multivariate Cox regression analysis, lack of IS was a prime predictor of the endpoint during follow-up (hazard ratio: 6.98; 95 % confidence interval: 1.48-33.03; p = 0.01). An LVEF ≥ 58 % was a surrogate indicator for the presence of IS, and patients with LVEF ≥ 58 % had fewer incidences of the endpoint than patients with LVEF < 58 %. In conclusion, lack of IS or LVEF < 58 % should be a predictor of future ADHF and all-cause mortality.

A novel technique to predict pulmonary capillary wedge pressure utilizing central venous pressure and tissue Doppler tricuspid/mitral annular velocities

Assessing left ventricular (LV) filling pressure (pulmonary capillary wedge pressure, PCWP) is an important aspect in the care of patients with heart failure (HF). Physicians rely on right ventricular (RV) filling pressures such as central venous pressure (CVP) to predict PCWP, assuming concordance between CVP and PCWP. However, the use of this method is limited because discordance between CVP and PCWP is observed. We hypothesized that PCWP can be reliably predicted by CVP corrected by the relationship between RV and LV function, provided by the ratio of tissue Doppler peak systolic velocity of tricuspid annulus (S(T)) to that of mitral annulus (S(M)) (corrected CVP:CVP·S(T)/S(M)). In 16 anesthetized closed-chest dogs, S T and S M were measured by transthoracic tissue Doppler echocardiography. PCWP was varied over a wide range (1.8-40.0 mmHg) under normal condition and various types of acute and chronic HF. A significantly stronger linear correlation was observed between CVP·S(T)/S(M) and PCWP (R2 = 0.78) than between CVP and PCWP (R2 = 0.22) (P < 0.01). Receiver-operating characteristic (ROC) analysis indicated that CVP·S(T)/S(M) >10.5 mmHg predicted PCWP >18 mmHg with 85% sensitivity and 88% specificity. Area under ROC curve for CVP·S T/S M to predict PCWP >18 mmHg was 0.93, which was significantly larger than that for CVP (0.66) (P < 0.01). Peripheral venous pressure (PVP) corrected by S T/S M (PVP·S(T)/S(M) also predicted PCWP reasonably well, suggesting that PVP·S(T)/S (M) may be a minimally invasive alternative to CVP·S(T)/S(M) In conclusion, our technique is potentially useful for the reliable prediction of PCWP in HF patients.