RV Stiffness and Relaxation in PAH

We hypothesized that the kinematic model-based parameters obtained from the transtricuspid E-wave would be useful for evaluating RV diastolic property in pediatric pulmonary arterial hypertension (PAH) patients. The model was parametrized by stiffness/elastic recoil k, relaxation/damping c, and load x. These parameters were determined as the solution of m⋅d2x/dt2 + c⋅dx/dt + kx = 0, which is based on the theory that the E-wave contour is determined by the interplay of stiffness/restoring force, damping/relaxation force, and load. The PAH group had a significantly higher k and c versus the control group (182.5 ± 72.4 g/s2 vs. 135.7 ± 49.5 g/s2, p = 0.0232 and 21.9 ± 6.5 g/s vs. 10.6 ± 5.2 g/s, p <0.0001, respectively). These results show that RV has a higher stiffness/elastic recoil and inferior cross-bridge relaxation in the PAH group. Present findings indicate the feasibility and utility of kinematic model parameters for assessing RV diastolic function

A novel index equivalent to the myocardial performance index for right ventricular functional assessment in children and adolescent patients

The aims of the present study were to develop and check the utility and feasibility of a novel right ventricular (RV) functional index (RV angular velocity; RVω, s−1) derived from the angular velocity in harmonic oscillator kinematics obtained from the RV pressure waveform. We hypothesized that RVω reflects the myocardial performance index (MPI), which represents global RV function. A total of 132 consecutive patients, ranging in age from 3 months to 34 years with various cardiac diseases were included in this prospective study. RVω was defined as the difference between the peak derivative of pressure (dP/dt_max − dP/dt_min) divided by the difference between the maximum and minimum pressure (Pmax – Pmin). RVω showed significant negative correlations with the pulsed-wave Dopplerderived myocardial performance index (PWD-MPI) and the tissue Doppler imaging-derived MPI (TDI-MPI) (r = −0.52 and −0.51, respectively; both p < 0.0001). RVω also showed significant positive correlations with RV fractional area change (RVFAC) and RV ejection fraction (RVEF) (r = 0.41 and 0.39, respectively; both p < 0.0001), as well as a significant negative correlation with tricuspid E/e′ (r = −0.19, p = 0.0283). The clinical feasibility and utility of RVω for assessing global RV performance, incorporating both systolic and diastolic function, were demonstrated

OCT for observation of vasa vasorum

Background Hypoxia and low pulmonary arterial (PA) blood flow stimulate the development of systemic-to-pulmonary collateral blood vessels, which can be an adverse factor when performing the Fontan operation. The aim of this study was to use optical coherence tomography (OCT) to elucidate the morphological changes in PA vasculature after creation of a bidirectional cavopulmonary connection (BCPC) in children. Methods This prospective study evaluated PA wall thickness and development of PA vasa vasorum (VV) in the distal PA of eight patients (BCPC group, 1.3 ± 0.3 years) and 20 age-matched children with normal pulmonary artery hemodynamics and morphology (Control group, 1.4 ± 0.3 years). VV development was defined by the VV area ratio, defined as the VV area divided by the adventitial area in cross-sectional images. Results There was no significant difference in PA wall thickness between the BCPC and control groups (0.12 ± 0.03 mm vs. 0.12 ± 0.02 mm, respectively). The VV area ratio was significantly greater in the BCPC group than in the Control group (14.5 ± 3.5% vs. 5.3 ± 1.6%, respectively; p<0.0001). Conclusion OCT is a promising new tool for evaluating PA pathology, including the development of VV in patients after BCPC

Noninvasive assessment of pulmonary arterial capacitance by pulmonary annular motion velocity in children with ventricular septal defect

Background: We hypothesized that longitudinal pulmonary arterial deformation during the cardiac cycle reflects pulmonary arterial capacitance. To examine this hypothesis, we assessed whether tissue Doppler-derived pulmonary annular motion could serve as a novel way to evaluate pulmonary arterial capacitance in pediatric patients with ventricular septal defect (VSD). Methods: In this prospective study, pulmonary annular velocity was measured in children (age, 6 months–5 years) with a preoperative VSD (VSD group, n = 35) and age-matched healthy children (Control group, n = 23). Pulmonary artery capacitance was calculated by two methods. Systolic pulmonary arterial capacitance (sPAC) was expressed as the stroke volume/pulmonary arterial pulse pressure. Diastolic pulmonary arterial capacitance (dPAC) was determined according to a two-element windkessel model of the pulmonary arterial diastolic pressure profile. Results: Pulmonary annular velocity waveforms comprised systolic bimodal (s1′ and s2′) and diastolic e’ and a’ waves in all participants. The peak velocities of s1′, s2′, and e’ were significantly lower in the VSD group than in the Control group. On multiple regression analysis, sPAC was an independent variable affecting the peak velocities of the s1′, s2′, and e’ waves (β = 0.41, 0.62, and 0.35, respectively). The dPAC affected the s1′ wave peak velocity (β = 0. 34). The time durations of the s1′ and e’ waves were independently determined by the sPAC (β = 0.49 and 0.27). Conclusion: Pulmonary annular motion velocity evaluated using tissue Doppler is a promising method of assessing pulmonary arterial capacitance in children with VSD

Pulmonary annular motion velocity in repaired CHD

Right ventricular (RV) dysfunction is generally evaluated using analyses of tricuspid annular motion. However, it represents only one aspect of RV performance. Whether measuring pulmonary annular motion velocity could serve as a novel way to evaluate global RV and/or RV outflow tract (RVOT) performance in pediatric congenital heart disease (CHD) patients with surgically repaired RVOT was evaluated. In this prospective study, tissue Doppler-derived pulmonary annular motion velocity was measured in children (aged 2-5 years) with RVOT reconstruction (RVOTR group, n = 48) and age-matched healthy children (Control, n = 60). The types of RVOTR procedures were as follows: pulmonary valve-sparing procedure (PVS, n = 7); transannular patch with monocusp valve reconstruction (TAP, n = 29); and RV-to-PA conduit reconstruction using a pericardial valve with expanded polytetrafluoroethylene conduit (Rastelli, n = 12). Pulmonary annular motion velocity waveforms comprised systolic bimodal (s1’ and s2’) and diastolic e’ and a’ waves in all participants. The peak velocities of s1’, s2’, e’, and a’ were significantly lower in the RVOTR group than in the control group (all p < 0.0001). Furthermore, these parameters depended significantly on the type of surgical procedure. The peak velocities of s1’, s2’, and e’ had significant correlations with RVOT ejection fraction (RVOT-EF) (r = 0.56, 0.49, and 0.34, respectively) and RVOT fractional shortening (RVOT-FS) (r = 0.72, 0.55, and 0.41, respectively), although there were no significant correlations between pulmonary annular motion and global RV function, including RV ejection fraction (RVEF) and RV fractional area change (RVFAC) in the assessment of all RVOTR group patients. The pulmonary annular motion parameters in the PVS group had significant correlations with both global RV and RVOT performance. The TAP group showed significant correlations between RVOT function and pulmonary annular motion. The Rastelli group showed almost no significant correlations between RV/RVOT function and tissue Doppler parameters. Pulmonary annular motion velocity is a simple, rapid, reproducible, and useful method of assessing RVOT function in children with surgically repaired CHD

PA compliance using harmonic oscillator kinematics

We hypothesized that KPA, a harmonic oscillator kinematics-derived spring constant parameter of the pulmonary artery pressure (PAP) profile, reflects PA compliance in pediatric patients. In this prospective study of 33 children (age range=0.5–20 years) with various cardiac diseases, we assessed the novel parameter designated as KPA calculated using the pressure phase plane and the equation KPA=(dP/dt_max)2/([Pmax – Pmin])/2)2, where dP/dt_max is the peak derivative of PAP, and Pmax – Pmin is the difference between the minimum and maximum PAP. PA compliance was also calculated using two conventional methods: systolic PA compliance (sPAC) was expressed as the stroke volume/Pmax – Pmin; and diastolic PA compliance (dPAC) was determined according to a two-element Windkessel model of PA diastolic pressure decay. In addition, data were recorded during abdominal compression to determine the influence of preload on KPA. A significant correlation was observed between KPA and sPAC (r=0.52, P=0.0018), but not dPAC. Significant correlations were also seen with the time constant (τ) of diastolic PAP (r=-0.51, P=0.0026) and the pulmonary vascular resistance index (r=-0.39, P=0.0242). No significant difference in KPA was seen between before and after abdominal compression. KPA had a higher intraclass correlation coefficient than other compliance and resistance parameters for both intra-observer and inter-observer variability (0.998 and 0.997, respectively). These results suggest that KPA can provide insight into the underlying mechanisms and facilitate the quantification of PA compliance

Intrapulmonary venous anastomosis after PV obstraction

Pulmonary venous (PV) obstruction is associated with a poor prognosis, as well as a high risk of recurrence, following surgical treatment. It can also interfere with the successful completion of Fontan circulation in patients with complex congenital heart disease. A case of a patient who had right isomerism (also known as asplenia syndrome), total anomalous pulmonary venous connection (TAPVC), and a single right ventricle is presented. Although bilateral total occlusion of the inferior PVs was identified postoperatively, the formation of the anastomosis and collateral vessels into the superior and middle PVs enabled successful completion of Fontan circulation. Anastomoses and collateral flow of the PVs were found largely in the interlobar pleura and not in the lung parenchyma

RV Stiffness and Relaxation in PAH

Background The rate of left ventricular pressure decrease during isovolumic relaxation is traditionally assessed algebraically via 2 empirical indices: the monoexponential and logistic time constants (τE and τL). Since the pattern of right ventricular (RV) pressure decrease is quite different from that of the left ventricular, we hypothesized that novel kinematic model parameters are more appropriate and useful to evaluate RV diastolic dysfunction. Methods and Results Eight patients with pulmonary arterial hypertension (age 12.5±4.8 years) and 20 normal subjects (control group; age 12.3±4.4 years) were enrolled. The kinematic model was parametrized by stiffness/restoring Ek and damping/relaxation μ. The model predicts isovolumic relaxation pressure as a function of time as the solution of d2P/dt2+(1/μ)dP/dt+EkP=0, based on the theory that the pressure decay is determined by the interplay of inertial, stiffness/restoring, and damping/relaxation forces. In the assessment of RV diastolic function, τE and τL did not show significant differences between the pulmonary arterial hypertension and control groups (46.8±15.5 ms versus 32.5±14.6 ms, and 19.6±5.9 ms versus 14.5±7.2 ms, respectively). The pulmonary arterial hypertension group had a significantly higher Ek than the control group (915.9±84.2 s−2 versus 487.0±99.6 s−2, P<0.0001) and a significantly lower μ than the control group (16.5±4.3 ms versus 41.1±10.4 ms, P<0.0001). These results show that the RV has higher stiffness/elastic recoil and lower cross‐bridge relaxation in pulmonary arterial hypertension. Conclusions The present findings indicate the feasibility and utility of kinematic model parameters for assessing RV diastolic function

NGS utility for diagnosis of MCA/ID

Background : In clinical practice, a large proportion of patients with multiple congenital anomalies and/or intellectual disabilities (MCA/ID) lacks a specific diagnosis. Recently, next-generation sequencing (NGS) has become an efficient strategy for genetic diagnosis of patients with MCA/ID. Objective : To review the utility of NGS for the diagnosis of patients with MCA/ID. Method : Patients with MCA/ID were recruited between 2013 and 2017. Molecular diagnosis was performed using NGS-based targeted panel sequencing for 4,813 genes. Promising causative variants underwent confirmation by Sanger sequencing or chromosomal microarray. Results : Eighteen patients with MCA/ID were enrolled in this study. Of them, 8 cases (44%) were diagnosed by targeted panel sequencing. Most of diagnosed patients were able to receive better counseling and more appropriate medical management. Conclusion : NGS-based targeted panel sequencing seems to be an effective testing strategy for diagnosis of patients with MCA/ID