The clinical effectiveness of an integrated multidisciplinary evidence-based program to prevent intraoperative pressure injuries in high-risk children undergoing long-duration surgical procedures: A quality improvement study.

The prevention of hospital-acquired pressure injuries (HAPIs) in children undergoing long-duration surgical procedures is of critical importance due to the potential for catastrophic sequelae of these generally preventable injuries for the child and their family. Long-duration surgical procedures in children have the potential to result in high rates of HAPI due to physiological factors and the difficulty or impossibility of repositioning these patients intraoperatively. We developed and implemented a multi-modal, multi-disciplinary translational HAPI prevention quality improvement program at a large European Paediatric University Teaching Hospital. The intervention comprised the establishment of wound prevention teams, modified HAPI risk assessment tools, specific education, and the use of prophylactic dressings and fluidized positioners during long-duration surgical procedures. As part of the evaluation of the effectiveness of the program in reducing intraoperative HAPI, we conducted a prospective cohort study of 200 children undergoing long-duration surgical procedures and compared their outcomes with a matched historical cohort of 200 children who had undergone similar surgery the previous year. The findings demonstrated a reduction in HAPI in the intervention cohort of 80% (p < 0.01) compared to the comparator group when controlling for age, pathology, comorbidity, and surgical duration. We believe that the findings demonstrate that it is possible to significantly decrease HAPI incidence in these highly vulnerable children by using an evidence-based, multi-modal, multidisciplinary HAPI prevention strategy.

Is the New Infant Jarvik 2015 Suitable for Patients<8 kg? In Vitro Study Using a Hybrid Simulator.

Our aim was to study the feasibility of implanting the Infant Jarvik 2015 in patients weighing less than 8 kg. The Infant Jarvik 2015 left ventricular assist device (LVAD) was tested in a hybrid simulator of the cardiovascular system reproducing specific patients' hemodynamics for different patient weights (2-7 kg). For each weight, the sensitivity of the pump to different circulatory parameters (peripheral resistance, left ventricular elastance, right ventricular elastance, heart rate, and heart filling characteristics) has been tested repeating for each experiment a pump ramp (10 000-18 000 rpm). The increase in the pump speed causes a decrease (increase) in the left (right) atrial pressure, an increase (decrease) in the arterial systemic (pulmonary) pressure, an increase in the right ventricular pressure, a decrease (increase) in the left (right) ventricular volume, a decrease in the left ventricular cardiac output, an increase in the LVAD output and an increase in the right ventricular cardiac output (total cardiac output). Suction was observed for lower weight patients and for higher pump speed in the case of vasodilation, left ventricular recovery, bradycardia, right ventricular failure, and left ventricular hypertrophy. Backflow was observed in the case of left ventricular recovery at lower pump speed. In the hybrid simulator, the Infant Jarvik 2015 could be suitable for the implantation in patients lower than 8 kg because of the stability of the device respect to the cardio/circulatory changes (low frequency of suction and backflow) and because of the capability of the device to maintain adequate patient hemodynamics.

Evolution of Biventricular Loading Condition in Pediatric LVAD Patient: A Prospective and Observational Study.

The aim of this study was to describe the echocardiographic trend of left ventricular (LV) and right ventricular (RV) function after implantation of a pulsatile flow left ventricular assist device (LVAD) in children. From 2013 to 2016, we prospectively evaluated 13 consecutive pediatric Berlin Heart EXCOR LVAD patients. Clinical and echocardiographic data were collected at baseline, within 24 h after implantation and monthly until LVAD explant. Median age and weight at the implantation was 8 (4-23) months and 5 (4.6-8.3) kg at the time of implantation, respectively. All were affected by dilated cardiomyopathy. Average LVAD support time was 226.2 ± 121.2 days. Nine (70%) were transplanted, 4 (30%) died. LV end-systolic and end-diastolic volumes were reduced until the follow up of two months (P = 0.019 and P = 0.001). A progressive increase in RV dimensions was observed. After 4 months of follow up, RV fractional area change worsening was statistically related with the deterioration of LV unloading (P = 0.0036). Four patients needed prolonged inotropic support for RV failure. Pulsatile LVAD in pediatrics is followed by an early and mid-term LV unloading, as expressed by a decrease in LV volumes and diameters at echocardiogram. The effects of unloading do not remain stable at long term follow up. RV function improved in the acute phase, but a progressive dilatation of RV was noted over time. In some patients, RV failure might lead to the need of an increase of inotropic support at long term follow up.

A New 2D Echocardiographic Approach to Evaluate the Membrane and Valve Movement of the Berlin Heart EXCOR VAD Chamber in Pediatric VAD Patients.

The use of Berlin Heart EXCOR VAD (BH) is a validated therapy to bridge pediatric patients to heart transplant. Serial echocardiographic (ECHO) assessment of VAD patients is necessary to support patients' management. This work aims at developing an innovative strategy to evaluate the BH device functioning by ECHO and its interaction with the native heart in a pediatric population. ECHO evaluation of BH membrane movement, and inflow and outflow valves was performed in 2D, 2D-color Doppler, M-mode, and M-mode color Doppler to assess the functioning of the device by direct positioning of the ECHO probe on the BH cannulas and membranes. Forty Berlin Heart EXCOR VAD were analyzed in 18 patients. Seven BH were placed as RVAD and 33 as LVAD. Results evidenced that 14 (21) inflow (outflow) valves presented a mild regurgitation, while 5 inflow (3 outflow) valves presented a moderate regurgitation. In three cases, we observed severe valve regurgitation with back flow in the left ventricle/right atrium. In both cases, the BH chambers were substituted, but we observed that in one case the regurgitation was due to cannulas compression, while in the other case it was due to valve malfunctioning. The M-mode and the ECHO of the membranes and valves permitted to appreciate the beat phenomenon to assess if the native heart and the BH are working in opposite or in the same phase. The membrane ECHO permits evaluation of minimal changes in membrane movement to assure the completely empty-completely fully work modality. Systematic ECHO assessment of BH chamber might support the BH programming and the detection of anomalous VAD-heart interaction.

Pediatric extracorporeal cardiopulmonary resuscitation settled in an emergency department for a propafenone intentional intoxication.

The use of drugs in suicide attempts is becoming more and more frequent among adolescents. Intentional intoxication with propafenone is very rare and mainly reported in adults associated with other drugs. The therapeutic approach is symptomatic, since there is no specific antidote for propafenone. We present a pediatric case of intentional ingestion of 1.8 g of propafenone that caused refractory cardiogenic shock. The patient was successfully rescued with extracorporeal cardiopulmonary resuscitation in the emergency department of a secondary level peripheral hospital.

Concurrent use of continuous and pulsatile flow Ventricular Assist Device on a fontan patient: A simulation study.

The aim of this work is to develop and test a lumped parameter model of the cardiovascular system to simulate the concurrent use of pulsatile (PVAD) and continuous flow (CVAD) ventricular assist device (VAD) on Fontan patients. Echocardiographic and hemodynamic data of five Fontan patients were retrospectively collected and used to simulate the patients' baseline hemodynamics. Then, for each patient, the following assistance modality was simulated for the cavopulmonary and the single ventricle (SV): (a) CVAD for cavopulmonary assistance (RCF) and PVAD assisting the SV (LCF) (RPF + LCF), (b) CVAD assisting SV and PVAD for cavopulmonary assistance (LPF + RCF). The numerical model can well reproduce patients' baseline. The cardiac output increases more importantly in the LCF + RPF configuration (35 vs. 8%). Ventricular volume decreases more evidently in the configuration LCF + RPF (28 vs. 6%), atrial pressure decreases in the LCF + RPF modality (10%), while it slightly increases in the RCF + LPF modality. The pulmonary arterial pressure slightly decreases (increases) in the configuration RCF + LPF (LCF + RPF). Ventricular external work increases in both configurations because of the total increment of the cardiac output. However, artero-ventricular coupling improves in both configurations: RCF + LPF-14%, LCF + RPF-41%. The pulsatility index decreases (increases) by 8% (13.8%) in the configuration LCF + RPF (RCF + LPF). A model could permit us to simulate extreme physiological conditions of the implantation of both CF and PF VAD on the Fontan patient and could permit to choose the proper VAD on the base of patients' condition. The configuration LCF + RPF seems to maximize the hemodynamic benefits.

Application of a Lumped Parameter Model to Study the Feasibility of Simultaneous Implantation of a Continuous Flow Ventricular Assist Device (VAD) and a Pulsatile Flow VAD in BIVAD Patients.

The aim of this work is to develop and test a lumped parameter model of the cardiovascular system to simulate the simultaneous use of pulsatile (P) and continuous flow (C) ventricular assist devices (VADs) on the same patient. Echocardiographic and hemodynamic data of five pediatric patients undergoing VAD implantation were retrospectively collected and used to simulate the patients' baseline condition with the numerical model. Once the baseline hemodynamic was reproduced for each patient, the following assistance modalities were simulated: (a) CVAD assisting the right ventricle and PVAD assisting the left ventricle (RCF + LPF), (b) CVAD assisting the left ventricle and PVAD assisting the right ventricle (LCF + RPF). The numerical model can well reproduce patients' baseline. The cardiac output increases in both assisted configurations (RCF + LPF: +17%, LCF + RPF: +21%, P = ns), left (right) ventricular volumes decrease more evidently in the configuration LCF + RPF (RCF + LPF), left (right) atrial pressure decreases in the LCF + RPF (RCF + LPF) modality. The pulmonary arterial pressure slightly decreases in the configuration LCF + RPF and it increases with RCF + LPF. Left and right ventricular external work increases in both configurations probably because of the total cardiac output increment. However, left and right artero-ventricular coupling improves especially in the LCF + RPF (-36% for the left ventricle and -21% for the right ventricle, P = ns). The pulsatility index decreases by 8.5% in the configuration LCF + RPF and increases by 6.4% with RCF + LPF (P = 0.0001). A numerical model could be useful to tailor on patients the choice of the VAD that could be implanted to improve the hemodynamic benefits. Moreover, a model could permit to simulate extreme physiological conditions and innovative configurations, as the implantation of both CVAD and PVAD on the same patient.

Use of Ventricular Assist Device in Univentricular Physiology: The Role of Lumped Parameter Models.

Failing single-ventricle (SV) patients might benefit from ventricular assist devices (VADs) as a bridge to heart transplantation. Considering the complex physiopathology of SV patients and the lack of established experience, the aim of this work was to realize and test a lumped parameter model of the cardiovascular system, able to simulate SV hemodynamics and VAD implantation effects. Data of 30 SV patients (10 Norwood, 10 Glenn, and 10 Fontan) were retrospectively collected and used to simulate patients' baseline. Then, the effects of VAD implantation were simulated. Additionally, both the effects of ventricular assistance and cavopulmonary assistance were simulated in different pathologic conditions on Fontan patients, including systolic dysfunction, diastolic dysfunction, and pulmonary vascular resistance increment. The model can reproduce patients' baseline well. Simulation results suggest that the implantation of VAD: (i) increases the cardiac output (CO) in all the three palliation conditions (Norwood 77.2%, Glenn 38.6%, and Fontan 17.2%); (ii) decreases the SV external work (SVEW) (Norwood 55%, Glenn 35.6%, and Fontan 41%); (iii) increases the mean pulmonary arterial pressure (Pap) (Norwood 39.7%, Glenn 12.1%, and Fontan 3%). In Fontan circulation, with systolic dysfunction, the left VAD (LVAD) increases CO (35%), while the right VAD (RVAD) determines a decrement of inferior vena cava pressure (Pvci) (39%) with 34% increment of CO. With diastolic dysfunction, the LVAD increases CO (42%) and the RVAD decreases the Pvci. With pulmonary vascular resistance increment, the RVAD allows the highest CO (50%) increment with the highest decrement of Pvci (53%). The single ventricular external work (SVEW) increases (decreases) increasing the VAD speed in cavopulmonary (ventricular) assistance. Numeric models could be helpful in this challenging and innovative field to support patients and VAD selection to optimize the clinical outcome and personalize the therapy.

Hemodynamic Effects of Ventricular Assist Device Implantation on Norwood, Glenn, and Fontan Circulation: A Simulation Study.

The growing population of failing single-ventricle (SV) patients might benefit from ventricular assist device (VAD) support as a bridge to heart transplantation. However, the documented experience is limited to isolated case reports. Considering the complex and different physiopathology of Norwood, Glenn, and Fontan patients and the lack of established experience, the aim of this work is to realize and test a lumped parameter model of the cardiovascular system able to simulate SV hemodynamics and VAD implantation effects to support clinical decision. Hemodynamic and echocardiographic data of 30 SV patients (10 Norwood, 10 Glenn, and 10 Fontan) were retrospectively collected and used to simulate patients' baseline. Then, the effects of VAD implantation were simulated. Simulation results suggest that the implantation of VAD: (i) increases the cardiac output and the mean arterial systemic pressure in all the three palliation conditions (Norwood 77.2 and 19.7%, Glenn 38.6 and 32.2%, and Fontan 17.2 and 14.2%); (ii) decreases the SV external work (Norwood 55%, Glenn 35.6%, and Fontan 41%); (iii) decreases the pressure pulsatility index (Norwood 65.2%, Glenn 81.3%, and Fontan 64.8%); (iv) increases the pulmonary arterial pressure in particular in the Norwood circulation (Norwood 39.7%, Glenn 12.1% and Fontan 3%); and (v) decreases the atrial pressure (Norwood 2%, Glenn 10.6%, and Fontan 8.6%). Finally, the VAD work is lower in the Norwood circulation (30.4 mL·mm Hg) in comparison with Fontan (40.3 mL·mm Hg) and to Glenn (64.5 mL·mm Hg) circulations. The use of VAD in SV physiology could be helpful to bridge patients to heart transplantations by increasing the CO and unloading the SV with a decrement of the atrial pressure and the SV external work. The regulation of the pulmonary flow is challenging because the Pap is increased by the presence of VAD. The hemodynamic changes are different in the different SV palliation step. The use of numerical models could be helpful to support patient and VAD selection to optimize the clinical outcome.

Mechanically Assisted Total Cavopulmonary Connection With an Axial Flow Pump: Computational and In Vivo Study.

A relevant number of patients undergoing total cavopulmonary connection (TCPC) experience heart failure (HF). Heart transplant is then the final option when all other treatments fail. The axial flow blood pumps are now the state of the art; however, there is little experience in low-pressure circuits, such as support of the right ventricle or even a TCPC circulation. A new T-shaped model of mechanically assisted TCPC using the "Jarvik Child 2000" axial pump, (flow rates between 1 and 3 L/m in a range of 5000-9000 rpm) was designed, simulated numerically, and then tested in animals. Eight sheep (42-45 kg) were studied: two pilot studies, four pump-supported (PS) TCPC for 3 h, and two not pump-supported (NPS) TCPC. In the PS, the axial pump was set to maintain the baseline cardiac output (CO). Pressures, CO, systemic and pulmonary vascular resistance, lactate levels, and blood gases were recorded for 3 h. Computational fluid dynamics (CFD) study allows us to set the feasible operating condition and the safety margins to minimize the venous collapse risk. In the NPS animals, a circulatory deterioration, with increasing lactate level, occurred rapidly. In the PS animals, there was a stable cardiac index of 2.7 ± 1.4 L/min/m(2), central venous pressure of 12.3 ± 1 mm Hg, and a mean pulmonary artery pressure (PAP) of 18.1 ± 6 after 3 h of support up to 9000 rpm. systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), blood gasses, and arterial lactate levels remained stable to baseline values. No caval collapse occurred. A new pediatric axial flow pump provides normal CO and physiologic stability in a new T-shaped model of TCPC in sheep, in vivo. CFD and in vivo data showed that this experimental arrangement will allow us to evaluate the potential for mechanical support in patients with Fontan failure avoiding major adverse events.

The use of a numerical model to simulate the cavo-pulmonary assistance in Fontan circulation: a preliminary verification.

The lack of an established experience on the use of VAD for the cavo-pulmonary assistance leads to the need of dedicated VADs development and animal experiments. A dedicated numerical model could support clinical and experimental strategies design and new VADs testing. The aim of this work is to perform a preliminary verification of a lumped parameter model of the cardiovascular system to simulate Fontan physiology and the effect of cavo-pulmonary assistance. Literature data of 4 pigs were used to simulate animals' baseline, and then the model was tested in simulating Fontan circulation and cavo-pulmonary-assisted condition comparing the simulation outcome (Sim) with measured literature data (Me). The results show that the numerical model can well reproduce experimental data in all three conditions (baseline, Fontan and assisted Fontan) [cardiac output (l/min): Me = 2.8 ± 1.7, Sim = 2.8 ± 1.8; ejection fraction (%): Me = 57 ± 17, Sim = 54 ± 17; arterial systemic pressure (mmHg): Me = 41.8 ± 18.6, Sim = 43.8 ± 18.1; pulmonary arterial pressure (mmHg): Me = 15.4 ± 8.9, Sim = 17.7 ± 9.9; caval pressure (mmHg): Me = 6.8 ± 4.1, Sim = 7 ± 4.6]. Systolic elastance, arterial systemic and arterial pulmonary resistances increase (10, 69, and 100 %) passing from the biventricular circulation to the Fontan physiology and then decrease (21, 39, and 50 %) once the VAD was implanted. The ventricular external work decreases (71 %) passing from the biventricular circulation to the Fontan physiology and it increases three times after the VAD implantation in parallel with the VAD power consumption. A numerical model could support clinicians in an innovative and challenging field as the use of VAD to assist the Fontan physiology and it could be helpful to personalize the VAD insertion on the base of ventricular systo-diastolic function, circulatory parameters and energetic variables.

Vacuum-assisted closure system in newborns after cardiac surgery.

OBJECTIVE: To analyze the effectiveness and the results of the use of a vacuum-assisted closure (VAC) system for the treatment of complex sternal wounds in newborns after cardiac surgery. METHODS: From May 2008 until December 2012, six patients developed post-sternotomy wound problems (large defects of epithelialization or mediastinitis), which were treated with a VAC system. Median age at the time of institution of VAC was 24.5 days (range 16 to 65 days). Median time of treatment was 14 days (range 3 to 42 days). RESULTS: All patients were newborns and all underwent delayed sternal closure after cardiac surgery. The indications for using the VAC system were: mediastinitis in two patients (33.3%) and impairment of healing without signs of infection in four (66.7%). All children after VAC therapy achieved healing of the sternal wound. VAC therapy was started with high negative pressures (-125 mmHg) continuously then switched to an intermittent modality in all patients. CONCLUSION: VAC system with high negative pressure is safe, effective, and is a well-tolerated therapy in newborns with complex sternal wounds.

Surgical management of a neonate with congenitally corrected transposition of the great vessels, hypoplastic right aortic arch, and Ebstein anomaly.

We report a neonate with a primary diagnosis of congenitally corrected transposition (ccTGA) of the great vessels, hypoplastic right aortic arch, and a severely regurgitant Ebstein tricuspid valve (TV). During the fetal period, she was listed for heart transplantation, and two weeks after birth due to a deterioration of her general condition, we performed a Norwood-Sano modified procedure. After 58 days a donor heart became available and the baby successfully received a orthotopic heart transplantation.

Surgical repair of an unusual type of supra-cardiac total anomalous pulmonary venous connection to the superior vena cava.

Anomalies of the pulmonary venous drainage vary widely in their anatomic spectrum and clinical presentation. We describe an unusual case of supra-cardiac total anomalous pulmonary venous connection (TAPVC), where the pulmonary veins drained directly in the posterior aspect of proximal right superior vena cava (SVC) through separate ostia. The veins were re-routed with a patch to the left atrium via the secundum atrial septal defect (ASD). The continuity between distal SVC and right atrium was re-established by re-implanting the SVC to the right atrial appendage (Warden Procedure).

Ascending aortic extension to increase aortopulmonary space after comprehensive stage II palliation.

Aortic reconstruction at the time of the comprehensive stage II (CSII) procedure can be complicated by compression within the aortopulmonary space resulting in airway or pulmonary artery narrowing. We describe our experience with 2 patients with hypoplastic left heart syndrome and pulmonary artery stenosis after the CSII procedure. Both patients underwent an aortic extension with a Hemashield interposition graft to open up the aortopulmonary space. The patients were discharged from the hospital. In all cases the aortopulmonary space was enlarged, and the pulmonary arteries and airway were free from compression. Aortic extension is an option to be considered in children with pulmonary artery compression who previously had a CSII procedure.

Use of Transcarotid IMPELLA 2.5 Axial-Flow Pump Device for Left Ventricle Unloading During VA-ECMO Support in Pediatric Acute Heart Failure.

An alternative strategy for left ventricular (LV) venting during short-term mechanical circulatory support is use of Impella axial-flow pump. We present our transcarotid Impella 2.5 implantation technique using a polytetrafluoroethylene graft, in two children with acute heart failure treated primarily with venoarterial ECMO. The venoarterial extracorporeal membrane oxygenator and Impella support were maintained for 5 and 17 days, respectively. Transcarotid Impella implantation might be an alternative and feasible option in pediatrics patients affected by severe LV failure, as a bridge to decision or bridge to candidacy. Potentially, the Impella 2.5 device provides less invasive support for children with heart failure.

Use of carotid artery cannulation during redo sternotomy in congenital cardiac surgery: a single-centre experience.

OBJECTIVES: Management of resternotomy is often a difficult challenge in patients with congenital diseases who have undergone multiple sternotomies. Our goal was to report our single-centre experience with carotid cannulation using a graft interposed during redo sternotomy in complex cardiac reintervention procedures. METHODS: We performed a retrospective review of all patients who had undergone complex redo sternotomies between January 2019 and May 2020 utilizing a cervical cannulation technique with a Gore-Tex graft interposed on the carotid artery. We classified our population study on the basis of the primary diagnosis and the type of surgery. The primary outcomes of our analysis were the evaluation of the safety of the procedure in terms of survival and freedom from neurological events. RESULTS: We analysed 22 patients who had undergone previous complex operations. The median age and weight at the time of reintervention were 130.35 (range 0.46-435) months and 31.5 (range 2.2-85) kg, respectively. Composite graft carotid cannulation provided adequate arterial flow in all patients with a median arterial flow of 3.5 l/min/m2 (range 0.6-6). One major cardiac injury occurred during sternotomy when emergency cardiopulmonary bypass (CPB) was initiated. Moreover, during their hospital stays, all patients had an uneventful recovery without neurological or vascular complications and no cervical wound infections. CONCLUSIONS: Carotid cannulation using interposition of a side graft on the common carotid artery for arterial inflow is a reliable and safe method for initiation of CPB in complex redo surgeries in patients with congenital disease. Complications directly associated with this type of cannulation are uncommon and allow surgical re-entry with overall low risks.

Impact of COVID-19 Pandemic on the Italian Humanitarian Congenital Cardiac Surgery Activity: What No One Tells You.

More than 4 millions of children with congenital heart disease (CHD) are waiting for cardiac surgery around the world. Few of these patients are treated only thanks to the support of many non-governmental organizations (NGOs). Starting in December 2019, the so-called coronavirus disease 2019 (COVID-19) has rapidly become a worldwide pandemic and has dramatically impacted on all the international humanitarian activities for congenital heart disease. We analyzed data from all the Italian congenital cardiac surgery centers with the aim to quantify the impact of the pandemic on their charities. Fifteen Italian centers participated in the study and contributed to data collection. We analyzed and compared data regarding humanitarian activities carried out abroad and on site from two periods: year 2019 (pre-COVID-19) and year 2020 (COVID-19 pandemic). In 2019, 53 international missions were carried out by Italian congenital cardiac surgeons, resulting in the treatment of 471 CHD patients. In the same period 11 Italian cardiac centers operated on 251 foreign patients in Italy. In 2020, the pandemic led to a reduction of this activity by 96% for the surgery performed overseas and 86% for the interventions carried out in Italy. In conclusion our study shows the important quantitative impact of the pandemic on the Italian humanitarian cardiac surgical activity overseas and in Italy. This shocking result highlights the failure of the systems adopted so far to solve the problem of CHD in developing countries.

Pneumatic pulsatile ventricular assist device as a bridge to heart transplantation in pediatric patients.

Despite the remarkable advances with the use of ventricular assist devices (VAD) in adults, pneumatic pulsatile support in children is still limited. We report on our experience in the pediatric population. A retrospective review of 17 consecutive children offered mechanical support with Berlin Heart as a bridge to heart transplant from February 2002 to April 2010 was conducted. The median patient age was 3.9 years (75 days to 13.3 years). The median patient weight was 14.1 kg (2.9-43kg). Before VAD implantation, all children were managed by multiple intravenous inotropes and mechanical ventilation (14) or extracorporeal membrane oxygenation (3). All patients had right ventricular dysfunction. Nine patients required biventricular mechanical support (BVAD), but in all other cases a single left ventricular assist device proved sufficient (47%). The median duration of VAD support was 47 days (1-168 days). The median pre-VAD pulmonary vascular resistance index (Rpi) was 5.7 WU/m(2) (3.5 to 14.4WU/m(2) ). Eleven patients (65%) were successfully bridged to heart transplantation after a median duration of mechanical support of 68 days (6-168 days). Six deaths occurred (35%), three for neurological complications, one for sepsis, and two others for device malfunctioning. Since 2007, the survival rate of our patients has increased from 43% to 80%, and the need for BVAD has decreased from 86% to 30%. In two patients with Rpi >10WU/m(2) , unresponsive to pulmonary vasodilatator therapy, Rpi dropped to 2.2 and 2WU/m(2) after 40 and 23 days of BVAD support, respectively. Seven patients (41%) required at least one pump change. Of 11 patients undergoing heart transplant, four developed an extremely elevated (>60%) panel reactive antibody by enzyme-linked immunosorbent assay, confirmed by Luminex. All of them experienced at least one acute episode of rejection in the first month after heart transplant, needing plasmapheresis. The survival rate after heart transplantation was 100% with a median follow-up of 25.4 months (6 days to 7.7 years). Mechanical support in children with end-stage heart failure is an effective strategy as a bridge to heart transplantation with a reasonable morbidity and mortality. BVAD support may offer an additional means to reverse extremely elevated pulmonary vascular resistance.

Left ventricular unloading during extracorporeal membrane oxygenation - Impella versus atrial septal defect: A simulation study.

BACKGROUND: Atrial septal defect and Impella have been proposed for left ventricular unloading in venoarterial extracorporeal membrane oxygenation patients. This work aims at evaluating the haemodynamic changes in venoarterial extracorporeal membrane oxygenation patients after Impella implantation or atrial septal defect realization by a simulation study. METHODS: A lumped parameter model of the cardiovascular system was adapted to this study. Atrial septal defect was modelled as a resistance between the two atria. Venoarterial extracorporeal membrane oxygenation and Impella were modelled starting from their pressure-flow characteristics. The baseline condition of a patient undergoing venoarterial extracorporeal membrane oxygenation was reproduced starting from haemodynamic and echocardiographic data. The effects of different atrial septal defect size, Impella and venoarterial extracorporeal membrane oxygenation support were simulated. RESULTS: Impella caused an increment of mean arterial pressure up to 67%, a decrement in mean pulmonary arterial pressure up to 8%, a decrement in left ventricular end systolic volume up to 11% with a reduction up to 97% of left ventricular cardiac output. Atrial septal defect reduces left atrial pressure (19%), increases right atrial pressure (22%), increases mean arterial pressure (18%), decreases left ventricular end systolic volume (11%), increases right ventricular volume (33%) and decreases left ventricular cardiac output (55%). CONCLUSION: Impella has a higher capability in left ventricular unloading during venoarterial extracorporeal membrane oxygenation in comparison to atrial septal defect with a lower right ventricular overload.