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 (∼40 s, n = 11), moderate (∼2 min, n = 11) or extended (∼5 min, 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 4 min 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 (∼40 s), moderate (∼2 min) or extended (∼5 min) 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.

Evaluation of the Relationship Between Pulmonary Perfusion Via Chest Digital Dynamic Radiography System and Diffusing Capacity Test.

Non-invasive, visual, and quantitative in vivo evaluation of pulmonary blood flow is helpful in assessing gas exchange at the alveolar level. A chest digital dynamic radiography system (CDDR) has the potential to visually and quantitatively express pulmonary haemodynamics using temporal changes in radiographic transparency synchronised with the heartbeat. The lung-diffusing capacity (DLCO) test involves membranous factors comprising the alveolar membrane, interstitium, and vascular walls. Additionally, DLCO includes pulmonary blood flow factors defined by pulmonary capillary blood flow and haemoglobin levels. In individuals lacking an alveolar septum, interstitial abnormalities or anaemia leading to changes in DLCO may reflect changes in the pulmonary blood flow. Here, we investigated the usefulness of CDDR in evaluating pulmonary blood flow by comparing it with DLCO.For pulmonary blood flow, we extracted and visualised signal changes in the lung field synchronised with heart rate during CDDR imaging and created a maximum intensity projection (MIP). The DLCO was measured using the single-breath method. Among the patients who underwent CDDR, 10 with FEV/FVC (FEV1.0%) > 70% and 16 with COPD (FEV1.0% < 70%) without noticeable interstitial changes were included, with a cutoff = 70%/predicted value. MIP was compared as a pulmonary blood flow evaluation method in the DLCO≥70% group (control group: n = 15) and the DLCO<70% group (decreased DLCO group: n = 11). The mean and median values of MIP in the reduced group were lower than those in the control group (p < 0.05).Pulmonary blood flow evaluated using CDDR may be able to assess pulmonary circulatory disturbances visually and quantitatively, as indicated by decreased pulmonary diffusion capacity in patients with negligible pulmonary interstitial changes and anaemia.

Utility of Balloon Occlusion Testing in Determining Fontan Suitability Among Patients with Elevated Pulmonary Artery Pressure and Additional Antegrade Pulmonary Blood Flow.

In individuals with a single ventricle undergoing evaluation before Fontan surgery, the presence of excessive pulmonary blood flow can contribute to increased pulmonary artery pressure, notably in those who had a Glenn procedure with antegrade pulmonary flow. 28 patients who had previously undergone Glenn anastomosis with antegrade pulmonary blood flow (APBF) and with elevated mean pulmonary artery (mPAP) pressure > 15 mmHg in diagnostic catheter angiography were included in the study. After addressing other anatomical factors that could affect pulmonary artery pressure, APBF was occluded with semi-compliant, Wedge or sizing balloons to measure pulmonary artery pressure accurately. 23 patients (82% of the cohort) advanced to Fontan completion. In this group, median mPAP dropped from 20.5 (IQR 19-22) mmHg to 13 (IQR 12-14) mmHg post-test (p < 0.001). Median PVR post-test was 1.8 (IQR 1.5-2.1) WU m2. SpO2 levels decreased from a median of 88% (IQR 86%-93%) pre-test to 80% (IQR 75%-84%) post-test (p < 0.001). In five patients, elevated mPAP post-test occlusion on diagnostic catheter angiography led to non-completion of Fontan circulation. In this group, median pre- and post-test mPAP were 23 mmHg (IQR 21.5-23.5) and 19 mmHg (IQR 18.5-20), respectively (p = 0.038). Median post-test PVR was 3.8 (IQR 3.6-4.5) WU m2. SpO2 levels decreased from a median of 79% (IQR 76%-81%) pre-test to 77% (IQR 73.5%-80%) post-test (p = 0.039). Our study presents a specialized approach for patients initially deemed unsuitable for Fontan due to elevated pulmonary artery pressures. We were able to successfully complete the Fontan procedure in the majority of these high-risk cases after temporary balloon occlusion test.

A Comparison of Ductal Stenting and Surgical Shunts for Infants with Duct-Dependent Pulmonary Blood Flow: The Impact of Single Versus Biventricular Repair Pathways on Outcomes.

Ductal stenting (DS) is an alternative to the Blalock-Taussig-Thomas Shunt (BTTS) as initial palliation for congenital heart disease with duct-dependent pulmonary blood flow (DDBPF). We sought to analyze the impact of intended single ventricle (SV) and biventricular (BiV) repair pathways on the outcome of DS and BTTS in infants with DDPBF. A single-center, retrospective comparison of infants with DDPBF who underwent either DS (2012-2022) or BTTS procedures (2013-2017). Primary outcomes included all-cause mortality and risk of unplanned re-intervention. Participants were divided into four groups: 1.SV with DS, 2.SV with BTTS, 3.BiV with DS, and 4.BiV with BTTS. Fifty-one DS (SV 45%) and 86 BTTS (SV 49%) procedures were undertaken. For those who had DS, mortality was lower in the BiV compared to SV patients (BiV: 0/28, versus SV: 4/23, p = 0.04). Compared to BiV DS, BiV BTTS had a higher risk of combined death or unplanned re-intervention (HR 4.28; CI 1.25-14.60; p = 0.02). In SV participants, there was no difference for either primary outcome based on procedure type. DS was associated with shorter intensive care length of stay for SV participants (mean difference 5 days, p = 0.01) and shorter intensive care and hospital stay for BiV participants (mean difference 11 days for both outcomes, p = 0.001). There is a survival benefit for DS in BiV participants compared with DS in SV and BTTS in BiV participants. Ductal stenting is associated with a shorter intensive care and hospital length of stay.

Echocardiographic measured shunt velocity does not predict pulmonary blood flow in patients with Blalock-Thomas-Taussig shunt.

INTRODUCTION: Catheterisation is the gold standard used to evaluate pulmonary blood flow in patients with a Blalock-Thomas-Taussig shunt. It involves risk and cannot be performed frequently. This study aimed to evaluate if echocardiographic measurements obtained in a clinical setting correlate with catheterisation-derived pulmonary blood flow in patients with a Blalock-Thomas-Taussig shunt as the sole source of pulmonary blood flow. METHODS: Chart review was performed retrospectively on consecutive patients referred to the catheterisation lab with a Blalock-Thomas-Taussig shunt. Echocardiographic parameters included peak, mean, and diastolic gradients across the Blalock-Thomas-Taussig shunt and forward and reverse velocity time integral across the distal transverse aorta. In addition to direct correlations, we tested a previously published formula for pulmonary blood flow calculated as velocity time integral across the shunt × heart rate × Blalock-Thomas-Taussig shunt area. Catheterisation parameters included pulmonary and systemic blood flow as calculated by the Fick principle. RESULTS: 18 patients were included. The echocardiography parameters and oxygen saturation did not correlate with catheterisation-derived pulmonary blood flow, systemic blood flow, or the ratio of pulmonary to systemic blood flow. As the ratio of reverse to forward velocity time integral across the transverse aorta increased, the probability of shunt stenosis decreased. CONCLUSION: Echocardiographic measurements obtained outside the catheterisation lab do not correlate with catheterisation-derived pulmonary blood flow. The ratio of reverse to forward velocity time integral across the transverse aortic arch may be predictive of Blalock-Thomas-Taussig shunt narrowing; this finding should be investigated further.

Two hundred and twenty-nine cases of bidirectional cavopulmonary anastomosis with and without antegrade pulmonary blood flow, a single-center experience.

Bidirectional cavopulmonary anastomosis is palliative surgical procedure for stepwise adaptation of the ventricle by time-phased relief of blood volume from the single functional ventricle. There still exists a controversial question regarding maintaining additional antegrade pulmonary blood flow. We retrospectively reviewed the surgical cases of 261 patients who underwent bidirectional cavopulmonary anastomosis in our institution from 2012 to 2022 with special regard to antegrade pulmonary blood flow as our preferred strategy. The mean age at the time of surgery was 33.1 months (range 2.9-192 months), and the mean weight was - 7.6 kg (range 3.9-38 kg). Furthermore, we divided all the patients into two groups: in group 1 (n = 182) - patients who underwent bidirectional cavopulmonary anastomosis with antegrade pulmonary blood flow, and in group 2 (n = 47) - patients without antegrade pulmonary blood flow. The mean follow-up time was 56 months (range 24-120 months). Mortality rate was 4.8 % (n = 11) in the past 10 years. Statistical difference between groups was in the following positions: group 2 had less ICU stay (p < 0.000125) and hospital stay (p < 0.017110); group 1 had a longer duration of pleural effusion (p < 0.000003) and amount of drainage output (p < 0.007), also demonstrated higher oxygen saturation (p < 0.000264) and Glenn shunt pressure (p < 0.002) after the surgery; but there was no difference in oxygen saturation after 6, 12, and 24 months; mortality in both groups has no statistic difference. Considering our experience, we take a stand on the controlled to antegrade pulmonary blood flow strategy during bidirectional cavopulmonary anastomosis.

Outcomes after bidirectional cavopulmonary shunt with antegrade pulmonary blood flow in high-risk patients.

OBJECTIVE: We have left antegrade pulmonary blood flow (APBF) at bidirectional cavopulmonary shunt (BCPS) only for high-risk patients. This study evaluates the indication and the outcomes of patients with APBF, compared to those without APBF. METHODS: Patients with APBF after BCPS were identified among patients who underwent BCPS between 1997 and 2022. Outcomes of patients with and without APBF after BCPS were compared. RESULTS: APBF was open in 38 (8.2%) of 461 patients. Median age (7.7 versus 6.3 months, p = 0.55) and weight (5.6 versus 6.1 kg, p = 0.75) at BCPS were similar in both groups. The most frequent indication for APBF was high pulmonary artery pressure (PAP) in 14 patients, followed by hypoxaemia in 10, and hypoplastic left pulmonary artery in 8. The source of APBF was the pulmonary trunk in 10 patients and the aortopulmonary shunt in 28. Median hospital stay after BCPS was longer (22 versus 14 days, p = 0.018) and hospital mortality was higher (10.5 versus 2.1%, p = 0.003) in patients with APBF compared to those without APBF. However, 448 hospital survivors showed similar survival after discharge following BCPS (p = 0.224). Survival after total cavopulmonary connection (TCPC) was similar between the groups (p = 0.753), although patients with APBF were older at TCPC compared to those without (3.9 versus 2.2 years, p = 0.010). CONCLUSION: APBF was left in 8% following BCPS in high-risk patients, mainly due to preoperative high PAP. Hospital survivors after BCPS demonstrated comparable survival in patients with and without APBF. Adding APBF at BCPS might be a useful option for high-risk patients.

Teaching the distribution of pulmonary blood flow using a Starling resistor model and turbine flowmeters.

The distribution of pulmonary blood flow is uneven and can be described as a three-zone model, the West zones: zone 1 occurs whenever alveolar pressure exceeds arterial pressure; zone 2 when the arterial pressure is greater than alveolar but the alveolar pressure exceeds the venous pressure; and finally zone 3 when both arterial and venous pressures exceed alveolar pressure. Consequently, the blood flow is almost determined by the difference between the arterial and venous pressures in zone 3 and between arterial and alveolar pressures in zone 2 and ceases in zone 1. The understanding of this subject may be difficult to some medical students. Therefore, to improve the learning of this topic in our physiology course, we used a didactic model to demonstrate the core concept of flow down gradients and its application to pulmonary blood flow. We modeled a Starling resistor by placing a collapsible tube inside a hermetic chamber of variable pressure. Transparent turbine flowmeters were connected to the upstream and downstream extremities of the Starling resistor, and we generated a constant airflow with a brushless motor. By maintaining the input (arterial) pressure constant and varying the chamber (alveolar) pressure, we could simulate the three zones and demonstrate the resulting flow through the turbines. In conclusion, our demonstration using a Starling resistor model combined with visible turbine flowmeters can be used to facilitate comprehension of important concepts in physiology involving flow down gradients, such as pulmonary blood flow.NEW & NOTEWORTHY The understanding of respiratory physiology is a challenge to medical students. To improve the learning of pulmonary blood flow distribution through lung vessels in our physiology course, we modeled a Starling resistor model combined with visible turbine flowmeters. Our model can significantly improve the core concept of flow down gradients teaching and its application to West zones.

Acute severe pulmonary hypertension during weaning from cardiopulmonary bypass for aortic valve replacement surgery: A case report.

Pulmonary arterial pressure (PAH) usually increases after cardiopulmonary bypass (CPB), but this normally does not affect weaning off CPB. Here we report a case of severe PAH in a patient with normal left atrial pressure. Prolonging CPB by 45 min did not lead to lower PAH. Given that lung injury can stimulate secretion of vasoconstrictors that trigger PAH, we decided to gradually increase blood flow into the lungs in an effort to restore the balance between pulmonary vasoconstrictors and vasodilators. Pulmonary artery pressure gradually decreased, allowing the patient to be weaned off CPB, after which she recovered uneventfully. Our experience suggests an approach for managing acute, severe PAH after CPB without the need for mechanical circulatory support.

Failing with Cyanosis-Heart Failure in End-Stage Unrepaired or Partially Palliated Congenital Heart Disease.

Heart failure in cyanotic congenital heart disease (CHD) is diagnosed clinically rather than relying solely on ventricular function assessments. Patients with cyanosis often present with clinical features indicative of heart failure. Although myocardial injury and dysfunction likely contribute to cyanotic CHD, the primary concern is the reduced delivery of oxygen to tissues. Symptoms such as fatigue, lassitude, dyspnea, headaches, myalgias, and a cold sensation underscore inadequate tissue oxygen delivery, forming the basis for defining heart failure in cyanotic CHD. Thus, it is pertinent to delve into the components of oxygen delivery in this context.

Effect of preoperative pulmonary hemodynamic and cardiopulmonary bypass on lung function in children with congenital heart disease.

In children with congenital heart disease (CHD), pulmonary blood flow (Qp) contributes to alterations of pulmonary mechanics and gas exchange, while cardiopulmonary bypass (CPB) induces lung edema. We aimed to determine the effect of hemodynamics on lung function and lung epithelial lining fluid (ELF) biomarkers in biventricular CHD children undergoing CPB. CHD children were classified as high Qp (n = 43) and low Qp (n = 17), according to preoperative cardiac morphology and arterial oxygen saturation. We measured ELF surfactant protein B (SP-B) and myeloperoxidase activity (MPO) as indexes of lung inflammation and ELF albumin as index of alveolar capillary leak in tracheal aspirate (TA) samples collected before surgery and in 6 hourly intervals within 24 h after surgery. At the same time points, we recorded dynamic compliance and oxygenation index (OI). The same biomarkers were measured in TA samples collected from 16 infants with no cardiorespiratory diseases at the time of endotracheal intubation for elective surgery. Preoperative ELF biomarkers in CHD children were significantly increased than those found in controls. In the high Qp, ELF MPO and SP-B peaked 6 h after surgery and tended to decrease afterward, while they tended to increase within the first 24 h in the low Qp. ELF albumin peaked 6 h after surgery and decreased afterwards in both CHD groups. Dynamic compliance/kg and OI significantly improved after surgery only in the High Qp.  Conclusion: In CHD children, lung mechanics, OI, and ELF biomarkers were significantly affected by CPB, according to the preoperative pulmonary hemodynamics. What is Known: • Congenital heart disease children, before cardiopulmonary run, exhibit changes in respiratory mechanics, gas exchange, and lung inflammatory biomarkers that are related to the preoperative pulmonary hemodynamics. • Cardiopulmonary bypass induces alteration of lung function and epithelial lining fluid biomarkers according to preoperative hemodynamics. What is New: • Our findings can help to identify children with congenital heart disease at high risk of postoperative lung injury who may benefit of tailored intensive care strategies, such as non-invasive ventilation techniques, fluid management, and anti-inflammatory drugs that can improve cardiopulmonary interaction in the perioperative period.

Short- and medium-term outcomes for patent ductus arteriosus stenting in neonates ≤2.5 kg with duct-dependent pulmonary circulation.

BACKGROUND: Morbidity with surgical systemic-to-pulmonary artery shunting (SPS) in infants ≤2.5 kg has remained high. Patent ductus arteriosus (PDA) stenting may be a valid alternative. The objective of this study is to evaluate outcomes following PDA stenting in patients ≤2.5 kg from four large tertiary centers. METHODS: Retrospective review of all neonates ≤2.5 kg with duct-dependent pulmonary circulation who underwent PDA stenting. Procedural details, pulmonary arterial growth, reinterventions, surgery type, and outcomes were assessed. RESULTS: PDA stents were implanted in 37 of 38 patients attempted (18 female) at a median procedural weight of 2.2 kg (interquartile range [IQR], 2-2.4 kg). Seven patients (18%) had a genetic abnormality and 16 (42%) had associated comorbidities. The median intensive care unit stay was 4 days (IQR, 2-6.75 days), and the median hospital stay was 20 days (IQR, 16-57.25). One patient required a rescue shunt procedure, with three others requiring early SPS (<30 days postprocedure). Twenty patients (54%) required reintervention with either balloon angioplasty, restenting, or both. At 6-month follow-up, right pulmonary artery growth (median z-score -1.16 to 0.01, p = 0.05) was greater than the left pulmonary artery (median z-score -0.9 to -0.64, p = 0.35). Serious adverse effects (SAEs) were seen in 18% (N = 7) of our cohort. One patient developed an SAE during planned reintervention There were no intraprocedural deaths, with one early procedure-related mortality, and three interstage mortalities not directly related to PDA stenting. CONCLUSIONS: PDA stenting in infants ≤2.5 kg is feasible and effective, promoting pulmonary artery growth. Reintervention rates are relatively high, though many are planned to allow for optimal growth before a definitive operation.

Effects of YM155 on the proliferation and apoptosis of pulmonary artery smooth muscle cells in a rat model of high pulmonary blood flow-induced pulmonary arterial hypertension.

INTRODUCTION: Proliferation and apoptosis of pulmonary artery smooth muscle cells (PASMCs) play an important role in the occurrence and development of pulmonary arterial hypertension (PAH). The purpose of this study was to investigate the effects of survivin inhibitor YM155 on the proliferation and apoptosis of PASMCs in rats with PAH induced by high pulmonary blood flow. METHODS: Thirty male Sprague-Dawley (SD) rats were randomly divided into control, model, and YM155 intervention groups. A rat model of PAH induced by high pulmonary blood flow was established, and it was confirmed by assessments of right-ventricular pressure (RVP) and right ventricular hypertrophy index (RVHI). Immunohistochemical staining and western blot analysis were used to detect the expression of survivin, and the proliferation and apoptosis of PASMCs. Lastly, the effects of in vivo treatment of YM155 were tested. RESULTS: The increased expression of survivin mRNA and protein were observed in the model group, accompanied by pulmonary arteriolar wall thickening, lumen stenosis, and perivascular inflammatory cell infiltration. Elevated expression of survivin and pulmonary vascular remodeling were significantly mitigated after YM155 treatment. Specifically, the YM155 intervention group had a significantly lower PASMC proliferation rate and a higher PASMC apoptotic rate. CONCLUSION: YM155 suppressed PASMC proliferation and promoted PASMC apoptosis by inhibiting survivin expression and thereby reducing pulmonary vascular remodeling in high pulmonary blood flow-induced PAH in vivo.

Quantitative cardiopulmonary magnetic resonance imaging in neonatal congenital diaphragmatic hernia.

BACKGROUND: Pulmonary arterial hypertension, impaired cardiac function and lung hypoplasia are common in infants with congenital diaphragmatic hernia (CDH) and are associated with increased morbidity and mortality. Robust noninvasive methods to quantify these abnormalities in early infancy are lacking. OBJECTIVE: To determine the feasibility of MRI to quantify cardiopulmonary hemodynamics and function in infants with CDH and to investigate left-right blood flow and lung volume discrepancies. MATERIALS AND METHODS: We conducted a prospective MRI study of 23 neonates (isolated left CDH: 4 pre-repair, 7 post-repair, 3 pre- and post-repair; and 9 controls) performed on a small-footprint 1.5-tesla (T) scanner. We calculated MRI-based pulmonary arterial blood flow, left ventricular eccentricity index, cardiac function and lung volume. Using the Wilcoxon rank sum test for continuous data and Fisher exact test for categorical data, we made pairwise group comparisons. RESULTS: The right-to-left ratios for pulmonary artery blood flow and lung volume were elevated in pre-repair and post-repair CDH versus controls (flow: P<0.005; volume: P<0.05 pre-/post-repair). Eccentricity index at end-systole significantly differed between pre-repair and post-repair CDH (P<0.01) and between pre-repair CDH and controls (P<0.001). CONCLUSION: Cardiopulmonary MRI is a viable method to serially evaluate cardiopulmonary hemodynamics and function in critically ill infants and is useful for capturing left-right asymmetries in pulmonary blood flow and lung volume.

Patent ductus arteriosus stenting versus modified Blalock-Taussig shunt for palliation of duct-dependent pulmonary blood flow lesions.

BACKGROUND: Patent ductus arteriosus (PDA) stenting is an alternative to modified Blalock-Taussig shunt (MBTS) as first-stage palliation of duct-dependent lesions. The superiority of one approach over the other is still controversial. Our objective was to compare PDA  stent versusMBTS for palliation in regard to safety, efficacy, and efficiency. METHODS: From 2010 to 2021, 134 patients had first-stage palliation with either PDA stent (n = 83) or MBTS (n = 51). Twenty-seven patients failed the primary treatment and were converted to the other group. The study endpoints were hospital outcomes, interstage reintervention, and concomitant procedures at the second-stage palliation. RESULTS: Patients with PDA stent were significantly younger. The prevalence of antegrade pulmonary blood flow (PBF) was higher in patients who had MBTS and graft thrombosis was higher in the PDA stent. Hospital stay was significantly longer in patients who had MBTS. Predictors of prolonged mechanical ventilation were low-weight, MBTS, and conversion. Intensive care unit stay significantly increased with conversion, low-weight, and antegrade PBF. The interstage intervention was required more frequently in PDA-stent group. Predictors of reintervention were conversion and pulmonary atresia with the intact interventricular septum. Pulmonary artery plasty was required more frequently during the second-stage palliation in PDA-stent group. CONCLUSION: PDA stent is an alternative to MBTS for first-stage palliation. It is associated with shorter hospital stays and avoidance of surgery at the expense of a high rate of stent thrombosis and interstage reintervention. Conversion increased the risk of the procedure. More studies are needed to determine factors that affect PDA-stent outcomes and patient selection criteria.

Tetralogy of Fallot with pulmonary atresia and aortopulmonary window may mimic common arterial trunk.

Tetralogy of Fallot with pulmonary atresia is a group of congenital cardiac malformations, which is defined by the absence of luminal continuity between both ventricles and the pulmonary artery, and an interventricular communication. Pulmonary arterial supply in patients with tetralogy of Fallot with pulmonary atresia can be via the arterial duct or from collateral arteries arising directly or indirectly from the aorta (systemic-to-pulmonary artery collaterals), or rarely both. The rarest sources of pulmonary blood flow are aortopulmonary window and fistulous communication with the coronary artery.Herein, we describe an outflow tract malformation, tetralogy of Fallot with pulmonary atresia and aortopulmonary window, which was misdiagnosed as common arterial trunk. We emphasise the morphological differences.

Vascular Reactions of the Diving Reflex in Men and Women Carrying Different ADRA1A Genotypes.

The diving reflex is an oxygen-saving mechanism which is accompanied by apnea, reflex bradycardia development, peripheral vasoconstriction, spleen erythrocyte release, and selective redistribution of blood flow to the organs most vulnerable to lack of oxygen, such as the brain, heart, and lungs. However, this is a poorly studied form of hypoxia, with a knowledge gap on physiological and biochemical adaptation mechanisms. The reflective sympathetic constriction of the resistive vessels is realized via ADRA1A. It has been shown that ADRA1A SNP (p.Arg347Cys; rs1048101) is associated with changes in tonus in vessel walls. Moreover, the Cys347 allele has been shown to regulate systolic blood pressure. The aim of this work was to evaluate whether the ADRA1A polymorphism affected the pulmonary vascular reactions in men and women in response to the diving reflex. Men (n = 52) and women (n = 50) untrained in diving aged 18 to 25 were recruited into the study. The vascular reactions and blood flow were examined by integrated rheography and rheography of the pulmonary artery. Peripheral blood circulation was registered by plethysmography. The ADRA1A gene polymorphism (p.Arg347Cys; rs1048101) was determined by PCR-RFLP. In both men and women, reflective pulmonary vasodilation did occur in response to the diving reflex, but in women this vasodilation was more pronounced and was accompanied by a higher filling of the lungs with blood.. Additionally, ADRA1A SNP (p.Arg347Cys; rs1048101) is associated with sex. Interestingly, women with the Arg347 allele demonstrated the highest vasodilation of the lung vessels. Therefore, our data may help to indicate women with the most prominent adaptive reactions to the diving reflex. Our data also indicate that women and men with the Cys allele of the ADRA1A gene polymorphism have the highest risk of developing lung hypertension in response to the diving reflex. The diving reflex is an oxygen-saving mechanism which is accompanied by apnea, reflex bradycardia development, peripheral vasoconstriction, spleen erythrocyte release, and selective redistribution of blood flow to the organs most vulnerable to lack of oxygen, such as the brain, heart, and lungs. However, this is a poorly studied form of hypoxia, with a knowledge gap on physiological and biochemical adaptation mechanisms.

Impact of maternal late gestation undernutrition on surfactant maturation, pulmonary blood flow and oxygen delivery measured by magnetic resonance imaging in the sheep fetus.

Restriction of fetal substrate supply has an adverse effect on surfactant maturation in the lung and thus affects the transition from in utero placental oxygenation to pulmonary ventilation ex utero. The effects on surfactant maturation are mediated by alteration in mechanisms regulating surfactant protein and phospholipid synthesis. This study aimed to determine the effects of late gestation maternal undernutrition (LGUN) and LGUN plus fetal glucose infusion (LGUN+G) compared to Control on surfactant maturation and lung development, and the relationship with pulmonary blood flow and oxygen delivery ( DO2 ) measured by magnetic resonance imaging (MRI) with molecules that regulate lung development. LGUN from 115 to 140 days' gestation significantly decreased fetal body weight, which was normalized by glucose infusion. LGUN and LGUN+G resulted in decreased fetal plasma glucose concentration, with no change in fetal arterial PO2 compared to control. There was no effect of LGUN and LGUN+G on the mRNA expression of surfactant proteins (SFTP) and genes regulating surfactant maturation in the fetal lung. However, blood flow in the main pulmonary artery was significantly increased in LGUN, despite no change in blood flow in the left or right pulmonary artery and DO2 to the fetal lung. There was a negative relationship between left pulmonary artery flow and DO2 to the left lung with SFTP-B and GLUT1 mRNA expression, while their relationship with VEGFR2 was positive. These results suggest that increased pulmonary blood flow measured by MRI may have an adverse effect on surfactant maturation during fetal lung development. KEY POINTS: Maternal undernutrition during gestation alters fetal lung development by impacting surfactant maturation. However, the direction of change remains controversial. We examined the effects of maternal late gestation maternal undernutrition (LGUN) on maternal and fetal outcomes, signalling pathways involved in fetal lung development, pulmonary haemodynamics and oxygen delivery in sheep using a combination of molecular and magnetic resonance imaging (MRI) techniques. LGUN decreased fetal plasma glucose concentration without affecting arterial PO2 . Surfactant maturation was not affected; however, main pulmonary artery blood flow was significantly increased in the LGUN fetuses. This is the first study to explore the relationship between in utero MRI measures of pulmonary haemodynamics and lung development. Across all treatment groups, left pulmonary artery blood flow and oxygen delivery were negatively correlated with surfactant protein B mRNA and protein expression in late gestation.

Detection of Pulmonary Embolism Using a Novel Dynamic Flat-Panel Detector System in Monkeys.

BACKGROUND: Recently, dynamic chest radiography (DCR) was developed to evaluate pulmonary function using a flat-panel detector (FPD), which can evaluate blood flow in the pulmonary artery without injection of contrast agents. This study investigated the ability of a FPD to measure physiological changes in blood flow and to detect pulmonary embolism (PE) in monkeys.Methods and Results:DCR was performed in 5 monkeys using a FPD. Regions of interest (ROI) were placed in both lung fields of the image, and maximum changes in pixel value (∆pixel value) in the ROI were measured during 1 electrocardiogram cardiac cycle. Next, a PE model was induced using a Swan-Ganz catheter and additional images were taken. The ∆pixel value of the lungs in normal and PE models were compared in both supine and standing positions. The lung ∆pixel value followed the same cycle as the monkey electrocardiogram. ∆pixel values in the upper lung field decreased in the standing as compared to the supine position. In the PE model, the ∆pixel value decreased in the area of pulmonary blood flow occlusion and increased in the contralateral lung as compared to the normal model (normal model 1.287±0.385, PE model occluded side 0.428±0.128, PE model non-occluded side 1.900±0.431). CONCLUSIONS: A FPD could detect postural changes in pulmonary blood flow and its reduction caused by pulmonary artery occlusion in a monkey model.

Outcome after surgery for pulmonary atresia with ventricular septal defect, a long-term follow-up study.

AIM: To study the long-term outcome after surgery for pulmonary atresia and ventricular septal defect (PA-VSD), and to determine association between the contribution of major aorto-pulmonary collateral arteries (MAPCAs) to the pulmonary blood flow, comorbidity and cause of death. METHODS: Patients who had undergone surgery for PA-VSD from January 1st 1994 to December 31st 2017 were studied retrospectively. Survival was cross-checked against the Swedish National Population Register. RESULTS: Seventy patients were identified, giving an incidence of 5.3 newborns per 100 000 live births. In 41 patients (59%) the pulmonary blood flow originated from a patent ductus arteriosus (PDA), while 29 patients (41%) had contribution of the pulmonary blood flow from MAPCAs. Extracardiac disease was found in 34 patients (49%), 16 of whom had 22q11-microdeletion syndrome (23%). Survival at follow-up was similar in patients with and without MAPCAs (72.4% vs. 75.6%, n.s.), with a median follow-up time of 14.3 years (3.2-41.8 years). No difference was found in mortality in patients with or without any syndrome or extracardiac disease. CONCLUSION: Long-term survival did not differ between those with and without MAPCAs and no difference in mortality was seen in patients with and without concomitant extracardiac disease or any kind of syndrome.