Pulmonary Artery Flow Research Articles

Computational Study on the Effects of Valve Orientation on the Hemodynamics and Leaflet Dynamics of Bioprosthetic Pulmonary Valves.

Pulmonary valves do not display a fibrous annulus as do other valves in the heart; thus, pulmonary valves can be implanted at multiple orientations and locations within the right ventricular outflow tract (RVOT). This gives surgeons more freedom when implanting the valve but it also results in uncertainties regarding placement, particularly with respect to valve orientation. We investigate the pulmonary artery hemodynamics and valve leaflet dynamics of pulmonary valve replacements (PVRs) with various orientations via fluid-structure interaction (FSI) models. A canonical model of the branching pulmonary artery is coupled with a dynamic model of a pulmonary valve, and from this we quantify the effect of valve implant orientation on the postvalvular hemodynamics and leaflet dynamics. Metrics such as turbulent kinetic energy (TKE), branch pulmonary artery flow distributions, projected valve opening area (PVOA), and pressure differentials across the valve leaflets are analyzed. Our results indicate that off-axis orientation results in higher pressure forces and flow and energy asymmetry, which potentially have implications for long-term durability of implanted bioprosthetic valves.

Ultrasound parameters of arteries and heart in normal fetuses

BackgroundCurrently, no normal ultrasound data of the fetuses during the 20–40 gestation have been obtained for references of fetal growth and development. If such ultrasound data existed for prenatal diagnosis of possible diseases and abnormalities, neonates would be able to get timely treatment immediately after birth. This study was thus performed to obtain ultrasound parameters of normal fetuses during the 20–40 week gestation and the distribution of ultrasound parameters with the gestational age for references of detecting potential fetal diseases and abnormalities.MethodsNormal fetuses without any abnormalities were enrolled, and the ultrasound parameters of the general biology, arteries, and aorta were measured and analyzed.Results417 normal fetuses were enrolled. A significant (P < 0.05) negative correlation with the gestational age was detected in the peak systolic velocity/peak diastolic velocity (S/D), pulsatility index (PI) and resistance index (RI) of the umbilical artery (UA). A relatively stable relationship with the gestational age was detected in the fetal weight%, S/D, PI and RI of the middle cerebral artery (MCA), peak systolic velocity (PSV) and velocity time integral (VTI) of the intra-abdominal UA, fetal heart to chest ratio, mitral valve (MV)- and tricuspid valve (TV)-E/A peak flow velocity, aortic isthmic Z-score and displacement, distance between the brachiocephalic artery-left common carotid artery (BA-LCCA) and LCCA-left subclavian artery (LSA), Z-score of aorta, ascending aorta (AAO), pulmonary artery (PA), main pulmonary artery (MPA), and descending aorta (DAO). A significant (P < 0.05) positive correlation with the gestational age was detected in the fetal biological data, MCA PSV and VTI, free-UA PSV and VTI and cardio-thoracic ratio, cardiac parameters, ductus arteriosus (DA) and isthmus diameter, aortic parameters, PA and MPA diameter, MPA PSV and VTI, isthmus flow volume and velocity and PA flow volume, DA and BA parameters, and LCCA and LSA parameters (flow volume, PSV, and VTI).ConclusionA certain correlation and distribution trend is detected in the ultrasound parameters of normal fetuses, and the ratios among different parameters remain relative stable. These findings can be used for determination of abnormal growth of the fetuses in prenatal ultrasound scan.Graphic

Evaluation of infrared thermography, arterial Doppler ultrasound, and Doppler echocardiography in healthy adult dogs exposed to a single session of Whole-body vibration at different frequencies

This study aimed to evaluate the infrared thermography, arterial Doppler ultrasound, and Doppler echocardiography in healthy adult dogs exposed to a single Whole-body vibration (WBV) at different frequencies. Sixteen (16) healthy crossbreed dogs males of ages 1 to 5 years, weighing 16.3 to 24.5 kg were enrolled in the study. The dogs were exposed to a single WBV session at frequencies of 30 Hz (5 min), 40 Hz (5 min), and 50 Hz (5 min) with intervals between each frequency exposure of 10 min. The cutaneous temperature, arterial Doppler ultrasound, and Doppler echocardiography were evaluated 10 min before the WBV session, between each frequency, and 1 min after the last frequency. The cutaneous temperature of the regions of the superficial gluteal muscle and biceps femoris muscle of both hind limbs was obtained with an infrared camera. Resistive indexes of carotid and femoral arteries were determined using Doppler ultrasound, and Doppler echocardiography was used to assess the end-systolic volume and end-diastolic volume, heart rate, aortic blood flow velocity, and pulmonary artery flow velocity. Clinical parameters, complete blood count, and serum biochemical (alanine aminotransferase, creatinine, and creatine phosphokinase) were evaluated 10 min before and 60 min after the end of the WBV session. Statistically significant differences were not found in any of the variables among the time points. In conclusion, the protocol of increasing vibration frequencies (30, 40, and 50 Hz) at short-period WBV can be considered appropriate since no change occurred in the parameters evaluated.

Perinatal Cardiac Functional Adaptation in Hypoplastic Left Heart Syndrome: A Longitudinal Analysis

The perinatal transition is characterized by acute changes in cardiac loading. Compared with normal newborn combined cardiac output (CCO), single right ventricular (RV) output of neonates with hypoplastic left heart syndrome (HLHS) is markedly greater. The aim of this study was to examine the mechanisms of cardiac adaptation that facilitate this perinatal transition from late fetal to early neonatal life in HLHS. Prospectively recruited pregnancies complicated by fetal HLHS (n=35) and healthy control subjects (Ctrl; n=17) underwent serial echocardiography in late gestation (38±1weeks) and 6, 24, and 48hours after birth. Cardiac function was assessed using conventional, Doppler tissue, and speckle-tracking echocardiography. Term fetuses with HLHS had RV output comparable with Ctrl CCO via higher stroke volume. Compared with both left ventricular and RV indices of Ctrl, they exhibited globular and dilated right ventricles with reduced relative wall thickness (0.40±0.08 vs 0.49±0.10, P<.01), increased Tei index' (HLHS vs Ctrl left ventricle/Ctrl right ventricle: sphericity index, 0.9±0.25 vs 0.5±0.10/0.6±0.11; RV area index, 28±6 vs 15±3/17±5cm2/m2; Tei index', 0.65±0.11 vs 0.43±0.07/0.45±0.09; P<.0001 for all). Neonates with HLHS generated elevated RV cardiac output compared with Ctrl CCO via higher heart rate and stroke volume, with further RV dilatation, increased longitudinal systolic strain at 48hours (-17±4% vs -14±3%/14±5%) with reduced circumferential and rotational myocardial deformation and altered diastolic function. Neonates with HLHS also demonstrated right atrial enlargement with increased longitudinal strain: 6hours (33±12% vs 26±6%), 24hours (37±15% vs 26± 13%), and 48hours (38±11% vs 24±13%) (P<.0001). Term fetuses with HLHS exhibit altered RV geometry and RV systolic and diastolic functional parameters. After birth, further alterations in these cardiac parameters likely reflect adaptation to acutely altered RV loading from increasing cardiac output and pulmonary artery flow demands.

Porcine lungs perfused with three different flows using the 8-h open-atrium cellular ex vivo lung perfusion technique.

The number of lung transplantations is limited due to the shortage of donor lungs fulfilling the standard criteria. The ex vivo lung perfusion (EVLP) technique provides the ability of re-evaluating and potentially improving and treating marginal donor lungs. Accordingly, the technique has emerged as an essential tool to increase the much-needed donor lung pool. One of the major EVLP protocols, the Lund protocol, characterized by high pulmonary artery flow (100% of cardiac output [CO]), an open atrium, and a cellular perfusate, has demonstrated encouraging short-EVLP duration results. However, the potential of the longer EVLP duration of the protocol is yet to be investigated, a duration which is considered necessary to rescue more marginal donor lungs in future. This study aimed to achieve stable 8-h EVLP using an open-atrium cellular model with three different pulmonary artery flows in addition to determining the most optimal flow in terms of best lung performance, including lung electrolytes and least lung edema formation, perfusate and tissue inflammation, and histopathological changes, using the porcine model. EVLP was performed using a flow of either 40% (n = 6), 80% (n = 6), or 100% (n = 6) of CO. No flow rate demonstrated stable 8-h EVLP. Stable 2-h EVLP was observed in all three groups. Insignificant deterioration was observed in dynamic compliance, peak airway pressure, and oxygenation between the groups. Pulmonary vascular resistance increased significantly in the 40% group (p < .05). Electrolytes demonstrated an insignificant worsening trend with longer EVLP. Interleukin-8 (IL-8) in perfusate and tissue, wet-to-dry weight ratio, and histopathological changes after EVLP were insignificantly time dependent between the groups. This study demonstrated that stable 8-h EVLP was not feasible in an open-atrium cellular model regardless of the flow of 40%, 80%, or 100% of CO. No flow was superior in terms of lung performance, lung electrolytes changes, least lung edema formation, minimal IL-8 expression in perfusate and tissue, and histopathological changes.

Effects of Pterostilbene on Heart and Lung Oxidative Stress Parameters in 2 Experimental Models of Cardiovascular Disease: Myocardial Infarction and Pulmonary Arterial Hypertension.

Myocardial infarction (MI) and pulmonary arterial hypertension (PAH) are 2 prevalent cardiovascular diseases. In both conditions, oxidative stress is associated with a worse prognosis. Pterostilbene (PTE), an antioxidant compound, has been studied as a possible therapy for cardiovascular diseases. This study aims to evaluate the effect of PTE on oxidative stress in the hearts of animals with MI and in the lungs of animals with PAH. Male Wistar rats were used in both models. In the MI model, the experimental groups were sham, MI, and MI + PTE. In the PAH model, the experimental groups were control, PAH, and PAH + PTE. Animals were exposed to MI through surgical ligation of the left coronary artery, or to PAH, by the administration of monocrotaline (60 mg/kg). Seven days after undergoing cardiac injury, the MI + PTE animals were treated with PTE (100 mg/kg day) for 8 days. After this, the heart was collected for molecular analysis. The PAH + PTE animals were treated with PTE (100 mg/kg day) for 14 days, beginning 7 days after PAH induction. After this, the lungs were collected for biochemical evaluation. We found that PTE administration attenuated the decrease in ejection fraction and improved left ventricle end-systolic volume in infarcted animals. In the PAH model, PTE improved pulmonary artery flow and decreased reactive oxygen species levels in the lung. PTE administration promoted protective effects in terms of oxidative stress in 2 experimental models of cardiac diseases: MI and PAH. PTE also improved cardiac function in infarcted rats and pulmonary artery flow in animals with PAH.

Increased left atrial pressure distorts pulmonary arterial impedance estimates in the low-range of frequency in rats

BACKGROUD: Post-capillary pulmonary hypertension (PH), characterized as increased downstream pressure such as left atrial pressure (LAP), is the most prevalent type of PH and a significant contributor to right heart failure. Accurate estimation of pulmonary arterial characteristics, serving as right ventricular afterload, is crucial for management of PH. These characteristics can be captured comprehensively through pulmonary arterial impedance (PAZ), which elucidates pulmonary arterial pressure-flow relationship within the frequency domain. Although LAP waveforms are potential to affect the contours of pulmonary arterial pressure (PAP) and flow (PAF) waveforms, it remains unknown whether increased LAP affects the accuracy of PAZ measurement. This study aimed to investigate the impact of LAP on the accuracy of PAZ using an acute rodent model. METHODS: We measured pulmonary arterial blood flow (PAF), PAP, and LAP simultaneously in eight male Sprague-Dawley rats. PAZ was calculated as a reciprocal of admittance. Admittance was calculated in the following two ways: 1) one-input (PAP) and one-output (PAF) analysis (I1O1 analysis): the ratio of PAP(f) to PAF(f) at each frequency, where PAP(f) and PAF(f) are frequency spectra of PAP and PAF, respectively, and 2) two-input (PAP and LAP) and one-output (PAF) analysis (I2O1 analysis): excluding the potential effect of LAP from PAP and PAF. We measured PAZ under both normal physiological condition and post-capillary PH condition. To induce acute post-capillary PH by raising LAP &gt;15 mmHg, we ligated aortic arch at the site between brachiocephalic artery and left common carotid artery and performed blood transfusion from a donor rat (TAL/BT). The accuracy of PAZ was examined as the coherence function representing the linearity between the input and output signals. Results: TAL/BT significantly increased LAP from 3 ± 1mmHg to 21 ± 4 mmHg and PAP from 17 ± 3 mmHg to 34 ± 3 mmHg (p&lt;0.01 for both). The I2O1 analysis provided a consistently accurate estimation of PAZ under both normal and elevated LAP conditions with high coherence function (&gt;0.9) in the wide range of frequency between 0.12 and 10.7 Hz. The I1O1 analysis also estimated the PAZ accurately in normal condition with high coherence function (&gt;0.9) in the wide range of frequency, however, the I1O1 analysis overestimated PAZ in the low-range frequency between 0.12 and 1.0 Hz compared with the I2O1 analysis (I1O1: 0.32±0.10 vs. I2O1 0.23±0.06 mmHg/ml/min, p&lt;0.01), with significantly lower coherence function (I1O1: 0.77±0.05 vs. I2O1: 0.96±0.01, p&lt;0.01). CONCLUSION: Increased LAP may have the impact on the accuracy of PAZ estimation in the low-range frequency. The I2O1 analysis can lead to more accurate assessment of right ventricular afterload in post-capillary PH, compared with the I1O1 analysis. Grant-in-Aid for Young Scientists of the Japanese Society of Cardiovascular Anesthesiologists Project Number 2271000048. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Quantitative evaluation of pulmonary hypertension using 4D flow MRI: A retrospective study

BackgroundPulmonary hypertension (PH) is a severe vascular disorder that may affect 50 % of patients with heart failure. Currently, right-sided heart catheterization is required to definitively diagnose PH. However, this method is invasive and thus may not be appropriate for repeated, long-term monitoring of PH patients. This retrospective study's aim was to evaluate whether 4D flow magnetic resonance imaging (MRI) can be used to quantitively measure flow parameters to identify patients with PH. MethodsThe study cohort included 97 patients recruited from a single institution and divided into three groups based on echocardiographic estimate of pulmonary artery systolic pressure (PASP): normal group with PASP<36 mmHg, borderline PH group with PASP of 37–50 mmHg, and PH group with PASP>50 mmHg. 4D flow MRI was used to quantitively assess blood flow and velocity, regurgitation, wall shear stress (WSS) and kinetic energy in the pulmonary artery trunk, right main pulmonary artery, and left pulmonary artery. Two experienced radiologists independently analyzed the MR images, blinded to clinical details. ResultsWe found a significant difference in WSS in the pulmonary artery trunk, right main pulmonary artery and left main pulmonary artery among the three patient groups. We also found significant differences in the kinetic energy and average through velocity in the pulmonary artery trunk and right main pulmonary artery, and significant differences in the flow rate in the right main pulmonary artery. ConclusionThese data suggest that 4D flow MRI can quantitate pulmonary artery flow parameters and distinguish between patients with and without PH.

Impact of respiratory cycle during mechanical ventilation on beat-to-beat right ventricle stroke volume estimation by pulmonary artery pulse wave analysis.

The same principle behind pulse wave analysis can be applied on the pulmonary artery (PA) pressure waveform to estimate right ventricle stroke volume (RVSV). However, the PA pressure waveform might be influenced by the direct transmission of the intrathoracic pressure changes throughout the respiratory cycle caused by mechanical ventilation (MV), potentially impacting the reliability of PA pulse wave analysis (PAPWA). We assessed a new method that minimizes the direct effect of the MV on continuous PA pressure measurements and enhances the reliability of PAPWA in tracking beat-to-beat RVSV. Continuous PA pressure and flow were simultaneously measured for 2-3min in 5 pigs using a high-fidelity micro-tip catheter and a transonic flow sensor around the PA trunk, both pre and post an experimental ARDS model. RVSV was estimated by PAPWA indexes such as pulse pressure (SVPP), systolic area (SVSystAUC) and standard deviation (SVSD) beat-to-beat from both corrected and non-corrected PA signals. The reference RVSV was derived from the PA flow signal (SVref). The reliability of PAPWA in tracking RVSV on a beat-to-beat basis was enhanced after accounting for the direct impact of intrathoracic pressure changes induced by MV throughout the respiratory cycle. This was evidenced by an increase in the correlation between SVref and RVSV estimated by PAPWA under healthy conditions: rho between SVref and non-corrected SVSD -0.111 (0.342), corrected SVSD 0.876 (0.130), non-corrected SVSystAUC 0.543 (0.141) and corrected SVSystAUC 0.923 (0.050). Following ARDS, correlations were SVref and non-corrected SVSD -0.033 (0.262), corrected SVSD 0.839 (0.077), non-corrected SVSystAUC 0.483 (0.114) and corrected SVSystAUC 0.928 (0.026). Correction also led to reduced limits of agreement between SVref and SVSD and SVSystAUC in the two evaluated conditions. In our experimental model, we confirmed that correcting for mechanical ventilation induced changes during the respiratory cycle improves the performance of PAPWA for beat-to-beat estimation of RVSV compared to uncorrected measurements. This was demonstrated by a better correlation and agreement between the actual SV and the obtained from PAPWA.

Saddle Pulmonary Embolus Treated With Bilateral Emergent Aspiration Pulmonary Thrombectomy

A 77 year old man with recurrent lower extremity thrombosis presented with acute onset shortness of breath and new onset hypoxemia three days after prostatectomy for adenocarcinoma of the prostate. He had been off anticoagulation during the perioperative period. In addition to his new diagnosis of prostate cancer he also had a remote history of treated non-invasive melanoma. Based on this presentation he was at high risk of developing thromboembolic disease. Computed tomography angiogram (CTA) of his chest confirmed a large saddle pulmonary embolus, echocardiogram was positive for new right ventricular wall motion dyskinesis and lower extremity ultrasound revealed bilateral acute and chronic deep vein thrombosis. Given his high bleeding risk, hypoxia and elevated troponin I, he underwent emergent successful aspiration pulmonary thrombectomy. This case is of interest to hospitalists and intesivists as it provides an overview of the current invasive management of pulmonary embolus in the acute setting when systemic anticoagulation is contraindicated. Emergent Aspiration Pulmonary Thrombectomy can restore pulmonary artery flow and cardiopulmonary hemodynamics. A collaborative team based approach that involves the emergency department, intensive care unit, interventional teams and hospitalists is favored.

Extended period of ventilation before delayed cord clamping augments left-to-right shunting and decreases systemic perfusion at birth in preterm lambs.

Previous studies have suggested that an extended period of ventilation before delayed cord clamping (DCC) augments birth-related rises in pulmonary arterial (PA) blood flow. However, it is unknown whether this greater rise in PA flow is accompanied by increases in left ventricular (LV) output and systemic arterial perfusion or whether it reflects enhanced left-to-right shunting across the ductus arteriosus and/or foramen ovale (FO), with decreased systemic arterial perfusion. Using an established preterm lamb birth transition model, this study compared the effect of a short (∼40s, n=11), moderate (∼2min, n=11) or extended (∼5min, n=12) period of initial mechanical lung ventilation before DCC on flow probe-derived perinatal changes in PA flow, LV output, total systemic arterial blood flow, ductal shunting and FO shunting. The LV output was relatively stable during initial ventilation but increased after DCC, with similar responses in all groups. Systemic arterial flow patterns displayed only minor differences during brief and moderate periods of initial ventilation and were similar after DCC. However, an increase in PA flow was augmented with an extended initial ventilation (P < 0.001), owing to an earlier onset of left-to-right ductal and FO shunting (P < 0.001), and was accompanied by a pronounced reduction in total systemic arterial flow (P=0.005) that persisted for 4min after DCC (P ≤ 0.039). These findings suggest that, owing to increased left-to-right shunting and a greater reduction in systemic arterial perfusion, an extended period of ventilation before DCC does not result in greater perinatal circulatory benefits than shorter periods of initial ventilation in the birth transition. KEY POINTS: Previous studies suggest that an extended period of initial ventilation before delayed cord clamping (DCC) augments birth-related rises in pulmonary arterial (PA) blood flow. It is unknown whether this greater rise in PA flow is accompanied by an increased left ventricular output and systemic arterial perfusion or whether it reflects enhanced left-to-right shunting across the ductus arteriosus and/or foramen ovale, with decreased systemic arterial perfusion. Anaesthetized preterm fetal lambs instrumented with central arterial flow probes underwent a brief (∼40s), moderate (∼2min) or extended (∼5min) period of ventilation before DCC. Perinatal changes in left ventricular output were similar in all groups, but extended initial ventilation augmented both perinatal increases in PA flow, owing to earlier onset and greater left-to-right ductal and foramen ovale shunting, and perinatal reductions in total systemic arterial perfusion. Extended ventilation before DCC does not confer a greater perinatal circulatory benefit than shorter periods of initial ventilation.

Surgical Modulation of Pulmonary Artery Shear Stress: A Patient-Specific CFD Analysis of the Norwood Procedure.

This study created 3D CFD models of the Norwood procedure for hypoplastic left heart syndrome (HLHS) using standard angiography and echocardiogram data to investigate the impact of shunt characteristics on pulmonary artery (PA) hemodynamics. Leveraging routine clinical data offers advantages such as availability and cost-effectiveness without subjecting patients to additional invasive procedures. Patient-specific geometries of the intrathoracic arteries of two Norwood patients were generated from biplane cineangiograms. "Virtual surgery" was then performed to simulate the hemodynamics of alternative PA shunt configurations, including shunt type (modified Blalock-Thomas-Taussig shunt (mBTTS) vs. right ventricle-to-pulmonary artery shunt (RVPAS)), shunt diameter, and pulmonary artery anastomosis angle. Left-right pulmonary flow differential, Qp/Qs, time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) were evaluated. There was strong agreement between clinically measured data and CFD model output throughout the patient-specific models. Geometries with a RVPAS tended toward more balanced left-right pulmonary flow, lower Qp/Qs, and greater TAWSS and OSI than models with a mBTTS. For both shunt types, larger shunts resulted in a higher Qp/Qs and higher TAWSS, with minimal effect on OSI. Low TAWSS areas correlated with regions of low flow and changing the PA-shunt anastomosis angle to face toward low TAWSS regions increased TAWSS. Excellent correlation between clinically measured and CFD model data shows that 3D CFD models of HLHS Norwood can be developed using standard angiography and echocardiographic data. The CFD analysis also revealed consistent changes in PA TAWSS, flow differential, and OSI as a function of shunt characteristics.

Flow pattern analysis of right ventricular outflow tract in repaired tetralogy of Fallot through 4D flow MRI.

Cardiac magnetic resonance imaging (CMR) often shows discrepancies between right ventricular outflow tract (RVOT) flow and left ventricular outflow tract flow in patients with late-stage repaired tetralogy of Fallot (rTOF), leading to potential errors in pulmonary regurgitation fraction (PRF) assessment. This study aimed to identify the conditions under which RVOT flow can be acutely evaluated using four-dimensional (4D) flow CMR. Twenty-seven consecutive patients with rTOF underwent both two-dimensional phase-contrast (2D PC) and 4D flow CMR between 2016 and 2018, excluding those with peripheral pulmonary artery stenosis, RVOT conduit replacement, unknown surgical method, and an aortic valve regurgitation greater than 20%. Seven healthy controls also underwent only 4D Flow CMR. All healthy controls and fifteen patients with rTOF showed laminar RVOT flow, while seven patients exhibited helical, and four patients exhibited vortical RVOT flow in 4D flow CMR visualization. Flow-volume concordance between the pulmonary artery and aortic flow was significantly lower in patients with rTOF and PRF > 40% in 2D PC CMR. This concordance rate in the suprapulmonary valve was high in both the TOF and control groups, comparing at five RVOT locations in 4D flow CMR. Regarding RVOT flow regurgitation in 4D flow, the whole bulk evaluation exhibited greater variation depending on the flow type compared to the whole pixel-wise evaluation. The study confirmed the flow volume at the upper section of the pulmonary valve as the most accurate correlate of aortic flow volume. Furthermore, the 4D flow CMR using the pixel-wise method demonstrated superior accuracy compared to the traditional bulk flow method.

Morphometrics predicts the differential regurgitant fraction in bilateral pulmonary arteries of patients with repaired tetralogy of fallot.

In patients with repaired tetralogy of Fallot (rTOF), the regurgitant fraction (RF) in left pulmonary artery (LPA) and right pulmonary artery (RPA) is usually unequal. The morphometrics may play a crucial role in this RF discrepancy. Cardiovascular MR of 79 rTOF patients and 20 healthy controls were retrospectively enrolled. Forty-four from the 79 patients were matched in age, sex and body surface areato the 20 controls andwere investigated for: (1) phase-contrast flow of main pulmonary artery (MPA), LPA, and RPA; (2) vascular angles: the angles between the thoracic anterior-posterior line (TAPL) with MPA (θM-AP), MPA with RPA (θM-R), and MPA with LPA (θM-L); (3) cardiac angle, the angle between TAPL and the interventricular septum; (4) area ratio of bilateral lung and hemithorax regions. Compared with the 20 controls, the 44 rTOF patients exhibited wider θM-AP, sharper θM-L angle, and a smaller θM-L/θM-R ratio. In the 79 rTOF patients, LPA showed lower forward, backward, and net flow, and greater RF as compared with RPA. Multivariate analysis showed that the RF of LPA was negatively associated with the θM-L/θM-R ratio and the age at surgery (R2 = 0.255). Conversely, the RF of RPA was negatively associated with the left lung/left hemithorax area ratio and cross-sectional area (CSA) of LPA, and positively associated with CSA of RPA and MPA (R2 = 0.366). In rTOF patients, the RF of LPA is more severe than that of RPA, which may be related to the vascular morphometrics. Different morphometric parameters areindependently associated with the RF of LPA or RPA, which may offer potential insights for surgical strategies.

Pulmonary blood flow in children with univentricular heart and unilateral diaphragmatic paralysis.

Spontaneous breathing has an important effect on pulmonary arterial blood flow in patients with Glenn/Fontan circulation. Unilateral diaphragmatic paralysis (DP) is a frequent complication after heart surgery in congenital heart disease. The aim of this study was to investigate the influence of unilateral DP on blood flow distribution in the pulmonary arteries with Glenn/Fontan circulation. Magnetic resonance phase-contrast imaging was used to evaluate stroke volume index (SVI) in the left and right pulmonary arteries in patients with Glenn/Fontan circulation with unilateral DP. Data for 18 patients with univentricular heart and unilateral DP were analysed, 8 in the Glenn stage and 10 in the Fontan stage. Ten patients had right-sided DP, and 8 had left-sided DP. A diaphragmatic plication was performed in 7 patients. The control group consisted of 36 patients with Glenn (n = 16)/Fontan (n = 20) circulation without DP. In both left- and right-sided DP, the SVI to the ipsilateral side was significantly lower than in controls [2.81 (1.45-4.50) ml/m2 left vs 11.97 (7.36-16.37) ml/m2 in controls, P < 0.0002; 8.2 (4.49-12.64) ml/m2 with right vs 12.64 (9.66-16.61) ml/m2 in controls; P = 0.0284]. The SVI to the contralateral side showed a slight but non-significant increase in the presence of unilateral DP. Unilateral DP in patients with Glenn/Fontan circulation has a negative impact on pulmonary arterial SVI on the side of the paralysis.

Pulmonary artery diameter ratio as a prognostic indicator of congenital diaphragmatic hernia

BackgroundFollowing on from an earlier study published in 2008 about left pulmonary artery (LPA) flow measured on serial echocardiography being strongly prognostic in left-sided congenital diaphragmatic hernia (CDH) and the...

Meta-analysis of the correlation between pulmonary hypertension and echocardiographic parameters in patients with chronic kidney disease.

To investigate the correlation between pulmonary hypertension (PH) and echocardiographic parameters in patients with chronic kidney disease (CKD). PubMed, Embase, Web of Science, Cochrane, VIP, CNKI, and Wanfang databases were systematically searched for articles published from inception to 19 May 2023. Study quality was estimated using the Quality Assessment of Case-Control Studies tool. Forest plots were drawn using R language software. The "metacor" function in the "meta" package was utilized for meta-analysis of the r-values and their standard errors. Heterogeneity and sensitivity analyses were carried out, with the main outcomes as r-value, p-value, and I2 value. Eleven studies were included, with 1,809 CKD patients. The correlations between 12 echocardiographic parameters and PH were analyzed. Except for FS and LVEF which were negatively correlated with CKD-PH, the other 10 parameters were positively correlated with CKD-PH. Among them, LA was highly correlated with CKD-PH (0.70 < r < 0.89); LVDD, RA, RV, LVMI, and LVDS were moderately correlated with CKD-PH (0.40 < r < 0.69); while PA, IVS, LVPW, SV, FS, and LVEF were lowly correlated with CKD-PH (0.20 < r < 0.39). The synthesized estimates were stable against heterogeneity. CKD-PH patients may have large cardiac chambers, thickened septal tissue on both sides of the chambers, reduced pulmonary artery flow rates, and decreased left ventricular function.

Feasibility of a Composite Measure of Pulmonary Vascular Impedance and Application to Patients with Chronic RV Failure Post LVAD Implant.

Pulmonary vascular impedance (PVZ) describes RV afterload in the frequency domain and has not been studied extensively in LVAD patients. We sought to determine (1) feasibility of calculating a composite (c)PVZ using standard of care (SoC), asynchronous, pulmonary artery pressure (PAP) and flow (PAQ) waveforms; and (2) if chronic right ventricular failure (RVF) post-LVAD implant was associated with changes in perioperative cPVZ.PAP and PAQ were obtained via SoC procedures at three landmarks: T(1), Retrospectively, pre-operative with patient conscious; and T(2) and T(3), prospectively with patient anesthetized, and either pre-sternotomy or chest open with LVAD, respectively. Additional PAP's were taken at T(4), following chest closure; and T(5), 4-24h post chest closure. Harmonics (z) were calculated by Fast Fourier Transform (FFT) with cPVZ(z) = FFT(PAP)/FFT(PAQ). Total pulmonary resistance Z(0); characteristic impedance Zc, mean of cPVZ(2-4); and vascular stiffness PVS, sum of cPVZ(1,2), were compared at T(1,2,3) between +/-RVF groups.Out of 51 patients, nine experienced RVF. Standard hemodynamics and changes in cPVZ-derived parameters were not significant between groups at any T.In conclusion, cPVZ calculated from SoC measures is possible. Although data that could be obtained were limited it suggests no difference in RV afterload for RVF patients post-implant. If confirmed in larger studies, focus should be placed on cardiac function in these subjects.

Abstract 19104: Hemodynamic Analysis of Pulmonary Artery for Congenital Right-Side Heart Disease in Adulthood by 4d-Flow MRI

Introduction: Using 4D-flow MRI, we evaluated hemodynamics in the pulmonary artery of congenital right-side heart disease in adulthood. Hypothesis: We hypothesize that 4D flow MRI may be used to assess pulmonary artery flow hemodynamics in adults with congenital right heart disease. Methods: In 20 adults, we measured energy loss (EL) and helicity of the main pulmonary artery (MPA) by cardiovascular MRI. The maximum value (peak EL) in one heartbeat and the total value were obtained for EL. Helicity was defined as a vector quantity, with clockwise rotation being positive and counterclockwise rotation being negative, and the total value was calculated. Results: The mean age was 27.9 years. The cases included 15 cases of postoperative tetralogy of Fallot without pulmonary arterial hypertension (TOF) and 5 cases of congenital heart diseases with pulmonary arterial hypertension (CHD-PAH). Peak EL, time to peak EL, and total helicity were higher in the CHD-PAH group than TOF group. Peak EL values were significantly higher during systole but were observed during diastole in 8 patients (40%). The combined mean value of helicity was positive, with clockwise predominance in 12 cases (60%). A strong correlation was found between peak EL and clockwise helicity (r=0.68) and counterclockwise helicity (r=-0.73). In addition, a correlation was observed between diastolic EL/BSA and diastolic clockwise helicity (r=0.51) and diastolic counterclockwise helicity (r=-0.52). A correlation was also observed with the pulmonary regurgitant fraction (r=0.49). Conclusions: In this study, helicity in the MPA was dominant clockwise in congenital right-side heart disease in adulthood. It was suggested that EL was involved in helicity throughout the entire cardiac cycle and that peak EL had a particularly large effect.

Abstract 14032: Transcatheter Palliation With Pulmonary Artery Flow Restrictors in Neonates With Congenital Heart Disease: Feasibility, Outcomes, and Comparison With a Historical Hybrid Stage 1 Cohort

Introduction: Neonates with complex congenital heart disease (CHD) and pulmonary overcirculation have been historically treated surgically. However, sub-cohorts may benefit from less invasive procedures. Data on transcatheter palliation are limited to case reports. Hypothesis: Transcatheter palliation with pulmonary flow restrictors (PFR) may represent an effective palliation strategy in neonates with CHD, especially those at high surgical risk. Methods: We present our experience of PFR palliation in neonates with CHD, including procedural feasibility, technical details, and outcomes. We then compared our sub-cohort of high-risk single ventricle (SV) neonates palliated with PFRs with a historical cohort of high-risk SV neonates palliated with a hybrid Stage 1. Cox regression was used to evaluate the association between palliation strategy and mortality at 6 months. Results: From 2021 to 2023, 17 neonates (median age 4 d [IQR 2-8]; median weight 2.5 kg [IQR 2.1-3.3]) underwent a PFR procedure; 15 (88%) had SV physiology, 15 (88%) were high-risk surgical candidates. All procedures were technically successful. At a median follow-up of 5.2 mo (IQR 2.7-9.9), 13 patients (76%) were either successfully bridged to surgery (n=12, 71%) or are awaiting surgery (n=1, 6%). Patients underwent target surgery at a median of 2.5 mo (IQR 1.1-3.4) since the PFR procedure (median weight 4.6 kg [IQR 3.3-5.6]). Pulmonary arteries were found to have grown adequately for age. All PFR devices were easily removed with no need for arterioplasty. The all-cause mortality rate before target surgery was 24% (n=4). Compared to a historical cohort of high-risk SV neonates palliated with a hybrid Stage 1 (n=23), after adjustment for main confounding (age, weight, intact atrial septum/severely restrictive foramen ovale or left ventricle to coronary fistulae), the PFR procedure was associated with a significantly lower all-cause 6-month mortality risk (adjHR=0.30 [95% CI 0.10-0.93]). Conclusions: Transcatheter PFR palliation in high-risk neonates with CHD is feasible, safe, and may represent an effective alternative strategy to bridge such high-risk neonates to surgical palliation, complete repair, or transplant while allowing for clinical stabilization and somatic growth.