Isovolumetric relaxation time of the right ventricle assessed by tissue Doppler imaging

Clinical Utility of Echocardiography for the Diagnosis and Prognosis in Children with Bronchopulmonary Dsyplasia

Background

Bronchopulmonary dysplasia (BPD) may result in chronic pulmonary artery hypertension and right ventricular (RV) dysfunction. Various echocardiographic assessments of RV dysfunction have been used to determine whether echocardiographic measurements of premature infants with BPD could provide sensitive measures of RV function that correlates with BPD severity.

Methods

Twenty-eight control subjects without BPD (non BPD group), 28 patients with mild BPD, 11 patients with moderate BPD, and six patients with severe BPD underwent echocardiograms with standard measurement such as ejection fraction by M-mode, tricuspid regurgitation pressure gradient, myocardial performance index (MPI) derived from pulse Doppler, and tissue Doppler imaging (TDI) measurements. BPD severity was classified by the NICHD/NHLBI/ORD workshop rating scale. Twenty-eight control subjects without BPD (non BPD group), 28 patients with mild BPD, 11 patients with moderate BPD, and six patients with severe BPD underwent echocardiograms with standard measurement such as ejection fraction by M-mode, tricuspid regurgitation pressure gradient, myocardial performance index (MPI) derived from pulse Doppler, and TDI measurements. BPD severity was classified by the NICHD/NHLBI/ORD workshop rating scale.

Results

None of the standard echocardiographic findings was significantly different between the control group and BPD groups. However, mean septal TDI-MPI of the severe BPD group (0.68 ± 0.06) was significantly (p < 0.01) higher than that of the non-BPD (0.58 ± 0.10) or the mild BPD group (0.59 ± 0.12). In addition, mean RV TDI-MPI of the severe BPD group (0.71 ± 0.13) was significantly (p < 0.05) higher than that of the non-BPD group (0.56 ± 0.08) or the mild BPD group (0.60 ± 0.125). Linear regression showed a good correlation between the severity of BPD and RV TDI-MPI (p = 0.01, R = 0.30) or septal TDI-MPI (p = 0.04, R = 0.24).

Conclusion

Echocardiographic evaluation of RV function based on an assessment of RV TDI-MPI can provide RV dysfunction parameter in premature infants with BPD.

Different functional cardiac characteristics observed in term/preterm neonates by echocardiography and tissue doppler imaging

BACKGROUND AND AIM

To establish, using echocardiography, color-flow Doppler and tissue doppler imaging (TDI), physiological values of systolic/diastolic indexes in healthy term/pre-term newborns, and to identify how different degrees of maturity influence morpho-functional cardiac alterations during the transitional period.

STUDY DESIGN AND SUBJECTS

33 term newborns (M = 19, F = 14; gestational ages: 37th-41st week), and 20 pre-term infants (M = 11, F = 9; gestational ages: 31st-36th week) admitted to our department were studied. All infants underwent to clinical and Doppler ultrasound evaluations, carried out by the third to fourth day. Investigations included: M-mode echocardiography, color-flow Doppler and TDI.

OUTCOME MEASURES AND RESULTS

Term and preterm neonates differed for: interventricular septum and left systolic/diastolic ventricle diameters (p<0.01 and <0.05 respectively); left ventricle posterior wall in systole (p<0.01); shortening and ejection fraction (p<0.05). Color-flow Doppler parameters on the tricuspid (peak E, peak A, ratio E/A; p<0.05) and on the mitral (peak E and E/A ratio; p<0.01) significantly differed between the two groups. Significant differences were also present for basal left ventricular lateral wall and right ventricular lateral wall in the Ew (p<0.01 and <0.05 respectively), Sw peak (p<0.01 and <0.05 respectively), and Ew/Aw (p<0.05). The isovolumetric relax time and the E/Ew measured on the medial mitral annulus also demonstrated significant differences (p<0.01) between the two groups.

CONCLUSIONS

TDI is feasible in preterm neonates and enables assessment of myocardial velocities. With increasing gestational age, higher myocardial velocities and lower E/E' Πratios were found. TDI addition to standard neonatal echocardiography may provide further important information about cardiac function.

Myocardial tissue Doppler changes in patients with bronchopulmonary dysplasia

OBJECTIVE

To determine whether tissue Doppler measurements provide sensitive measures of right ventricular function that correlate with the severity of bronchopulmonary dysplasia (BPD).

STUDY DESIGN

21 subjects (6 control subjects with no/mild BPD, 7 patients with moderate BPD, and 8 patients with severe BPD) underwent limited echocardiograms with standard M-mode, mitral and tricuspid inflow velocities, and tissue Doppler features measured. BPD severity was scored by using the NICHD/NHLBI/ORD workshop rating scale by physicians blinded to the echocardiogram results. Groups were compared by using 1-way analysis of variance with post-hoc testing and linear regression.

RESULTS

Patients with moderate BPD had a higher early Doppler inflow velocity to the early tissue Doppler velocity ratio (E/E' ratio; P = .03), corresponding to increased end diastolic pressure, compared with patients with no/mild BPD. Patients with severe BPD had a higher E/E' ratio (P = .004) than patients with no/mild BPD. Linear regression demonstrated a correlation between BPD category and right ventricle E/E' (P = .007, R(2) = 0.33) and left ventricular myocardial performance index (P = .02, R(2) = 0.28).

CONCLUSION

Increasing right ventricle E/E' ratio correlates with clinical severity of BPD. Abnormal left ventricular myocardial performance index was noted to correlate with the grade of BPD. Further longitudinal studies of tissue Doppler echocardiographic assessment of cardiac function in premature infants with BPD are needed.

Right Ventricular Diastolic Dysfunction and the Acute Effects of Sildenafil in Pulmonary Hypertension Patients

AIMS

This study investigated whether right ventricular (RV) diastolic function is impaired in pulmonary hypertension (PH) patients, and whether it is related to RV mass and afterload. In addition, the effects of an acute reduction of RV afterload by the oral intake of sildenafil were studied. Finally, we assessed whether diastolic function is related to cardiac parameters of disease severity.

METHODS AND RESULTS

Twenty-five PH patients and 11 control subjects were studied. Right-heart catheterization and N-terminal pro-brain natriuretic peptide (NT-proBNP) sampling were performed in patients. MRI measured RV ejection fraction, mass, and diastolic function. Isovolumic relaxation time (IVRT), normalized early peak filling rate (E), atrium-induced peak filling rate (A), and E/A ratio described diastolic function. Compared to control subjects, patients had prolonged mean (+/- SD) IVRT (133.5 +/- 53.2 vs 29.3 +/- 20.8 ms, respectively; p < 0.001), decreased E (3.0 +/- 1.6 vs 6.4 +/- 2.5 s(-1), respectively; p < 0.001) and E/A ratio (1.1 +/- 0.7 vs 5.3 +/- 4.9, respectively; p < 0.001), and increased A (3.0 +/- 1.4 vs 1.5 +/- 0.9 s(-1), respectively; p = 0.001). IVRT was related to RV mass (r(25) = 0.56; p = 0.005) and pulmonary vascular resistance (r(25) = 0.74; p < 0.0001). Sildenafil therapy reduced RV afterload and improved RV diastolic and systolic function. IVRT was correlated with NT-proBNP level (r = 0.70; p < 0.001), and was inversely related to cardiac index (r = -0.70; p < 0.001) and RV ejection fraction (r = -0.69; p < 0.001).

CONCLUSION

In PH patients, RV diastolic dysfunction is related to RV mass and afterload. RV diastolic function improves by reducing afterload. The correlations between diastolic function and prognostic parameters showed that diastolic function is most impaired in patients with severe disease.