Publications by authors named "Arianna Di Molfetta"

49 Publications

Designing an Active Valvulated Outflow Conduit for a Continuous-Flow Left Ventricular Assist Device to Increase Pulsatility: A Simulation Study.

ASAIO J 2021 May;67(5):529-535

Institute of Biocybernetics and Biomedical Engineer, Polish Academy of Science, Warsaw, Poland.

The purpose of this work was to investigate, using a lumped parameter model, the feasibility of increasing the pulsatility of a continuous-flow ventricular assist device (VAD) by implanting an active valvulated outflow cannula. A lumped parameter model was adopted for this study. VAD was modeled, starting from its pressure-flow characteristics. The valvulated outflow conduit was modeled as an active resistance described by a square function. Starting from pathologic condition, the following simulations were performed: VAD, VAD and valvulated outflow conduit in copulsation and counterpulsation with different ratios between the VAD valve opening rate and the heart rate, and asynchrony work with the heart with different VAD valve opening intervals. The copulsation 1:1 configuration and the asynchrony 0.3s-close-0.7s-open configurations permit to maximize the hemodynamic benefits provided by the presence of the active VAD outflow valvulated conduit providing an increase of arterial pulsatility from 1.86% to 14.98% without the presence of left ventricular output. The presence of the active VAD valve in the outflow conduit causes a decrement of the left ventricular unloading and of VAD flow and, that can be counteracted by increasing the VAD speed without affecting arterial pulsatility. The valvulated outflow tube provides an increase in arterial pulsatility; it can be driven in different working modality and can be potentially applicable to all types of VADs. However, the valvulated outflow conduit causes a decrement of left ventricular unloading and of the VAD flow that can be counteracted, increasing the VAD speed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAT.0000000000001255DOI Listing
May 2021

Telemedicine for adult congenital heart disease patients during the first wave of COVID-19 era: a single center experience.

J Cardiovasc Med (Hagerstown) 2021 Apr 20. Epub 2021 Apr 20.

Dipartimento di Scienze Cardiovascolari e Toraciche, Fondazione Policlinico Universitario A. Gemelli IRCCS Catholic University of the Sacred Heart Department of Pediatric Cardiology and Cardiac Surgery - Bambino Gesù Hospital, Rome, Italy.

Aim: To summarize our experience on the implementation of a telemedicine service dedicated to adult congenital heart disease (ACHD) patients during the lockdown for the first wave of COVID-19.

Methods: This is a prospective study enrolling all ACHD patients who answered a questionnaire dedicated telematic cardiovascular examination.

Results: A total of 289 patients were enrolled, 133 (47%) were male, 25 (9%) were affected by a genetic syndrome. The median age was 38 (29-51) years, whereas the median time interval between the last visit and the telematic follow-up was 9.5 (7.5-11.5) months. Overall, 35 patients (12%) reported a worsening of fatigue in daily life activity, 17 (6%) experienced chest pain, 42 (15%) had presyncope and 2 (1%) syncope; in addition, 28 patients (10%) presented peripheral edema and 14 (5%) were orthopneic. A total of 116 (40%) patients reported palpitations and 12 had at least one episode of atrial fibrillation and underwent successful electrical (8) or pharmacological (4) cardioversion. One patient was admitted to the emergency department for uncontrolled arterial hypertension, five for chest pain, and one for heart failure. Two patients presented fever but both had negative COVID-19 nasal swab.

Conclusion: During the COVID-19 pandemic, the use of telemedicine dramatically increased and here we report a positive experience in ACHD patients. The postpandemic role of telemedicine will depend on permanent regulatory solutions and this early study might encourage a more systematic telematic approach for ACHD patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2459/JCM.0000000000001195DOI Listing
April 2021

Deciphering Genetic Variants of Warfarin Metabolism in Children With Ventricular Assist Devices.

Pediatr Cardiol 2021 Apr 10. Epub 2021 Apr 10.

Heart Failure, Transplant and Mechanical Assistance Program Unit, Bambino Gesù Children Hospital, Rome, Italy.

Warfarin is prescribed in patients with ventricular assist devices (VADs). Dosage depends on several factors including the underlying genotype. These include polymorphisms of genes encoding cytochrome P450 enzymes, the main ones being CYP2C9, VKORC1, and CYP4F2. The objectives of this study were to evaluate the prevalence of CY2CP9 1*2*3*, VKORC1, and CYP4F2 in children with VADs and the time to reach the target international normalized ratio. We performed a retrospective/prospective study in children with VADs. We recorded polymorphisms, disease, type of VAD, ethnicity, age, gender, height, weight, INR values, bleeding, and thromboembolic episodes. Informed consent was obtained. We enrolled 34 children (19 male, 15 female), with a median age of 2 years (range 0.3-17 years) and median weight of 6.9Kg. The Berlin Heart was the most commonly implanted VAD (22/34; 64%), and the most common diagnosis was dilated cardiomyopathy. Statistical analysis confirmed a significant partial correlation with VKORC1 CC (p = 0.019). The CYP2C9*2 CT genotype showed a late rise in target INR values (p = 0.06), while the CYP2C9*2 CC showed a tendency toward an early INR rise (p = 0.024). We provide new information on the contribution of the warfarin polymorphisms in children with VAD implantation. Pharmacogenomic dosing for children using warfarin has the potential to improve clinical care in VAD patients. Patients with the CYP2C9*2 CT genotype may need more time or higher doses to reach target INR, while clinicians may need to be aware of the potential for a rapid rise in INR in patients with the CYP2C9*2 CC genotype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00246-021-02585-2DOI Listing
April 2021

Increasing the pulsatility of continuos flow VAD: comparison between a valvulated outflow cannula and speed modulation by simulation.

J Artif Organs 2021 Jan 29. Epub 2021 Jan 29.

Institute of Biocybernetics and Biomedical Engineer, Polish Academy of Science, Warsaw, Poland.

To investigate by a lumped parameter model the feasibility of increasing the pulsatility of a continuous flow VAD, implanting an active valvulated outflow cannula and to compare the results with the haemodynamic outcome given by speed modulation methods. The concomitant presence of speed modulation and the active valvulated outflow conduit is also simulated. A lumped parameter model was adopted. VAD was modeled starting from its pressure flow characteristics with a second order polynomial equation. The valvulated outflow conduit was modeled as an active resistance described by a square function. Starting from pathological condition we simulated: VAD; VAD and valvulated outflow conduit in copulsation, counterpulsation and asynchrony work with the heart; VAD and active valvulated outflow tube and speed modulation. Copulsation 1:1 and asynchrony 0.3 s valve close-0.7 s valve open configurations maximised the haemodynamic benefits with the highest increment in pulsatility. The valvulated outflow conduit causes a decrement of the left ventricular unloading and of VAD flow that can be counteracted by increasing the VAD speed without affecting pulsatility. The concomitant use of the speed modulation and the active valvulated outflow conduit can further increase the pulsatility without altering left ventricular unloading and VAD flow. The valvulated outflow tube provide similar increase in pulsatility to speed modulation method but causes a decrement of left ventricular unloading and VAD flow that can be counteracted increasing the VAD speed or allowing a partial support. A valvulated outflow tube can be potentially applied to all continuous flow VADs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10047-020-01235-3DOI Listing
January 2021

Persistent myocardial atrophy despite LV reverse remodeling in Duchenne cardiomyopathy treated by LVAD.

Pediatr Transplant 2021 Mar 26;25(2):e13890. Epub 2020 Oct 26.

Pediatric Cardiology and Cardiac Arrhythmias/Syncope Unit, Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.

DCM is the leading cause of death in Duchenne patients. LVADs are considered as therapeutic options as DT in advanced HF. The aim of our study was to evaluate LV remodeling of Duchenne after LVADs and chronic therapy. Demographic and echocardiographic data of 8 Duchenne patients implanted with LVADs were reviewed and analyzed. All measures were collected before LVAD implantation, after 1 month and 1 year. All patients were affected by end-stage DCM, and mean age at implantation was 16.9 ± 2.9 years. Patients were treated with maximal medical therapy. One-year post-implantation HR decreased from a mean of 110 ± 19 bpm to 82 ± 2 bpm (P = .002), and a significant decrease in LV volumes and diameters LVEDD P = .03, LVESD P = .02, EDV P = .01, and ESV P = .02) was noticed together with a significant increase in EF (P = .0036). However, RWT did not change over time, showing an eccentric remodeling pattern pre- and post-LVADs. Our data showed that cardiac atrophy is persistent in Duchenne cardiomyopathy despite the improvement of LV function secondary to a significant ventricular unloading due to LVADs coupled with chronic therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/petr.13890DOI Listing
March 2021

Pathophysiology and molecular signalling in pediatric heart failure and VAD therapy.

Clin Chim Acta 2020 Nov 17;510:751-759. Epub 2020 Sep 17.

Institute of Clinical Physiology, CNR, Pisa, Italy. Electronic address:

Heart Failure (HF) is a progressive clinical syndrome characterized by molecular and structural abnormalities that result in impaired ventricular filling and a reduced blood ejection. In pediatric patients, HF represents an important cause of morbidity and mortality, but underlying cause, presentation and disease course remains unclear in many cases. It is evident that a child is not a "small adult" and findings are not comparable. The adoption of a standardized clinical and surgical tools as well as increased biomolecular research and therapeutic trials targeting pediatric patients with HF would greatly improve the management of this special class of patients. This review examines the most current information about the pathophysiology and molecular mechanisms related to HF in children to identify gaps in our knowledge base to further improve clinical care and outcomes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cca.2020.09.010DOI Listing
November 2020

Variations of circulating miRNA in paediatric patients with Heart Failure supported with Ventricular Assist Device: a pilot study.

Sci Rep 2020 04 3;10(1):5905. Epub 2020 Apr 3.

Institute of Clinical Physiology, CNR, Pisa, Italy.

Circulating miRNAs (c-miRNAs) are promising biomarkers for HF diagnosis and prognosis. There are no studies on HF pediatric patients undergoing VAD-implantation. Aims of this study were: to examine the c-miRNAs profile in HF children; to evaluate the effects of VAD on c-miRNAs levels; to in vitro validate putative c-miRNA targets. c-miRNA profile was determined in serum of HF children by NGS before and one month after VAD-implant. The c-miRNA differentially expressed were analyzed by real time-PCR, before and at 4 hrs,1,3,7,14,30 days after VAD-implant. A miRNA mimic transfection study in HepG2 cells was performed to validate putative miRNA targets selected through miRWalk database. Thirteen c-miRNAs were modified at 30 days after VAD-implant compared to pre-VAD at NSG, and, among them, six c-miRNAs were confirmed by Real-TimePCR. Putative targets of the validated c-miRNAs are involved in the hemostatic process. The in vitro study confirmed a down-regulatory effect of hsa-miR-409-3p towards coagulation factor 7 (F7) and F2. Of note, all patients had thrombotic events requiring pump change. In conclusion, in HF children, the level of six c-miRNAs involved in the regulation of hemostatic events changed after 30 days of VAD-treatment. In particular, the lowering of c-miR-409-3p regulating both F7 and F2 could reflect a pro-thrombotic state after VAD-implant.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-62757-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7125126PMC
April 2020

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

Int J Artif Organs 2020 Oct 22;43(10):663-670. Epub 2020 Feb 22.

Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital Bambino Gesù, Rome, Italy.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0391398820906840DOI Listing
October 2020

Effects of levosimendan on ventriculo-arterial coupling and cardiac efficiency in paediatric patients with single-ventricle physiology after surgical palliation: retrospective study.

Interact Cardiovasc Thorac Surg 2020 04;30(4):623-629

Pediatric Cardiac Intensive Care Unit, Department of Cardiology and Cardiac Surgery, Bambino Gesù Children's Hospital, Rome, Italy.

Objectives: The use of levosimendan for paediatric patients with low cardiac output after congenital heart surgery has been recently described. We sought to evaluate ventriculo-arterial coupling (VAC) and other ventricular energetic parameters before and after 72 h from levosimendan start in infants with single-ventricle physiology and cardiac failure after palliation with Norwood or hybrid procedures.

Methods: In this single-centre retrospective study, 9 consecutive patients affected by hypoplastic left heart syndrome-like anatomy were retrospectively analysed. Systolic elastance, diastolic elastance, arterial elastance, VAC and cardiac mechanical efficiency were calculated by measuring, through 2-dimensional echocardiography, end-systolic volume and end-diastolic volume and by recording mean arterial pressure and central venous pressure.

Results: The median (range) weight and age were 2.8 (2.3-6) kg and 16.5 (6-116) days, respectively. After 72 h from levosimendan start, end-systolic volume significantly decreased (-1 ml, -3.2 to -0.1, P = 0.007), whereas mean arterial pressure and end-diastolic volume remained stable. Heart rate showed a significant decrease (-28 beats/min, -41 to 22, P = 0.008). Systolic elastance (2.9 mmHg/ml, 0.4-5.4, P = 0.008), arterial elastance (-5.9, -24 to -0.5, P = 0.038), VAC (-0.86, -1.5 to -0.16, P = 0.009) and cardiac mechanical efficiency (0.18, 0.03-0.22, P = 0.008) differences also showed significant modifications.

Conclusions: In a small case series of patients with single-ventricle physiology, levosimendan showed to improve contractility and optimize VAC, with a reduction of heart rate. Monitoring of VAC and ventricular energetics can be an interesting aspect to improve the management of heart failure in infants with univentricular anatomy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/icvts/ivz319DOI Listing
April 2020

Predicting the pressure of the total cavopulmonary connection: clinical testing of a mathematical equation.

Cardiol Young 2019 Aug 23;29(8):1066-1071. Epub 2019 Jul 23.

Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital Bambino Gesù, Rome, Italy.

Introduction: Some authors advocate the use of a dedicated formula to predict the Fontan pressure starting from pre-Fontan catheterisation data. This paper aims at testing the predictive value of the mentioned formula through a retrospective clinical study.

Methods And Results: Pre-Fontan catheterisation data and Fontan pressure measured at the completion were retrospectively collected. Pre-Fontan data were used to calculate the predicted pressure in the Fontan system. The predicted values were compared to the Fontan pressure measured at the Fontan completion and with the needs for fenestration. One hundred twenty-four Fontan patients were retrospectively enrolled (At Fontan: median age 30.73 [24.70-37.20] months, median weight 12.00 [10.98-14.15] kg). Fontan conduit was fenestrated in 78 patients. A poor correlation (r2 = 0.05128) between the measured and predicted data for non-fenestrated patients was observed. In the case of Fontan-predicted pressure <17.59 mmHg, the formula identified a good short-term clinical outcome with a sensitivity of 92%.

Conclusion: The proposed formula showed a poor capability in estimating the actual pressure into the Fontan system and in identifying patients needing fenestration. As the pressure into the Fontan system is determined by multiple factors, the tested formula could be an additional data in a multi-parametric approach.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1017/S1047951119001513DOI Listing
August 2019

Changes in left and right ventricular two-dimensional echocardiographic speckle-tracking indices in pediatric LVAD population: A retrospective clinical study.

Int J Artif Organs 2019 Dec 26;42(12):711-716. Epub 2019 Jun 26.

Department of Cardiology and Cardiac Surgery, Bambino Gesù Pediatric Hospital, Rome, Italy.

Echocardiographic strain and strain-rate imaging is a promising tool for the evaluation of myocardial segmental function, for the early detection of myocardial dysfunction, and for the prediction of reverse remodeling. We aimed at studying the changes in left and right ventricular function in pulsatile left ventricular assist device pediatric patients by two-dimensional echocardiography and two-dimensional speckle-tracking echocardiography. Echocardiographic and clinical data of patients implanted with a pulsatile-flow left ventricular assist device from 2011 to 2018 were retrospectively reviewed before and after implantation at 1, 3, and 6 months. A total of 18 patients were enrolled. Median age and weight at implantation were 9 months (5-23 months) and 5.85 kg (4.85-8.75 kg), respectively; median left ventricular assist device support was 181 (114.5-289.5) days. 13 patients (73%) were transplanted and 5 patients (27%) died. At follow-up: left ventricular ejection fraction increase at 1 month (p = 0.001) and 3 months (p = 0.01), left ventricular global longitudinal strain improvement at 1 month (p = 0.0008) and 3 months (p = 0.02), and right ventricular free-wall longitudinal strain increase at 1 month (p = 0.01). At short term after left ventricular assist device implantation, both left ventricular and right ventricular mechanics improved. The temporary benefit seems to decrease over time. The worsening of left ventricular function has been followed by a worsening of right ventricular function probably due to the ventricular interdependence.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0391398819857446DOI Listing
December 2019

The "Heart Valve Clinic" Pathway for the Management of Frail Patients With Valvular Heart Disease: From "One for All" to "All for One".

Crit Pathw Cardiol 2019 06;18(2):61-65

From the Cardiovascular Sciences Department, Agostino Gemelli Foundation Polyclinic IRCSS, Catholic University of The Sacred Heart, Rome, Italy.

Valvular heart disease (VHD) is frequently diagnosed in old patients with clinical evidence of heart failure. This elderly population typically presents a high prevalence of frailty and comorbidities, which are associated with increased operative risk for surgical and percutaneous procedures. Recently, the Euro Heart Survey reported a clear gap between treatment guidelines and their application in the "real world". A more realistic approach to the treatment of older VHD patients treatment, mostly if associated with heart failure, is advocated. A multidisciplinary approach, as obtained with the Heart Valve Clinic methodology (intended to put the patient in the "center" of the scene and the specialists "around him"), has been applied in a group of 79 patients, aged >70 years, with symptomatic VHD, divided in 2 groups according to their frailty status (58 robust and 21 frail). No in-hospital mortality and no difference in late mortality and complications were observed. Infections were more frequent (14.3 vs. 1.7 %; P = 0.02) in frail patients. In patients with postoperative complications, serum levels of interleukin 6 (67.6 vs. 49.6; P = 0.01) and of CAF (C-terminal agrin fragment) as sarcopenia marker (67.9 vs. 62.0; P = 0.04) were higher than that in uncomplicated patients. This study was designed to determine the outcomes of the multidimensional geriatric assessment in the management of older patients with heart failure eligible for heart valve surgery. Geriatric assessment and measurement of inflammatory and sarcopenia markers may represent valid tools for a more realistic evaluation of elderly patients with VHD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/HPC.0000000000000179DOI Listing
June 2019

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

Artif Organs 2019 Jan 6;43(1):E1-E8. Epub 2018 Nov 6.

Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital Bambino Gesù, Rome, Italy.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/aor.13302DOI Listing
January 2019

Time-course of circulating cardiac and inflammatory biomarkers after Ventricular Assist Device implantation: Comparison between paediatric and adult patients.

Clin Chim Acta 2018 Nov 21;486:88-93. Epub 2018 Jul 21.

CNR, Institute of Clinical Physiology, Laboratory of Biochemistry and Molecular Biology, Pisa, Italy. Electronic address:

Background: Ventricular Assist Device (VAD) as bridge to transplantation is a common therapy for adult with heart failure (HF), but VAD use is increasing also in children. Cardiac and inflammatory biomarkers have an important role in the diagnosis and prognosis of HF in adults, but their role in paediatric setting is unknown. The aim of this study was to examine changes in cardiac and inflammatory biomarkers, both in HF paediatric and adult patients, before and following VAD.

Methods: Cardiac (NT-proBNP, cTnI, sST2,Gal-3) and inflammatory (IL-6,IL-8) biomarkers were determined in plasma collected from 12 paediatric patients and 7 adult patients with HF, before and at 4 h,1,3,7,14 and 30 days after VAD implant.

Results: All biomarkers increased up to 1 day after VAD implant and then decreased at pre-VAD levels in 1 month in both groups. Only in children, NT-proBNP decreased significantly after 30 days Post-VAD treatment compared to pre-VAD levels. During the post-operative time-course, NT-proBNP and sST2 were significantly higher in children than adults, while IL-6 was lower.

Conclusions: Cardiac and inflammatory biomarkers were differently modified by VAD implant in children compared to adults. These preliminary data could suggest that different molecular pathways may underlie HF patho-physiology of the two groups, possibly paving the way to a specific and targeted therapeutic intervention in the near future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cca.2018.07.036DOI Listing
November 2018

Percutaneous treatment of aneurysmatic right coronary fistula in an infant, pediatric cardiology.

J Cardiovasc Med (Hagerstown) 2018 09;19(9):505-508

Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital Bambino, Gesù, Rome, Italy.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2459/JCM.0000000000000683DOI Listing
September 2018

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

Artif Organs 2018 Apr;42(4):451-456

Department of Pediatric Cardiology and Cardiac Surgery, -Ospedale Pediatrico Bambino Gesù, Rome, Italy.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/aor.13122DOI Listing
April 2018

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

Artif Organs 2018 Apr 12;42(4):386-393. Epub 2017 Dec 12.

Department of Pediatric Cardiology and Cardiac Surgery-Pediatric Hospital Bambino Gesù, Rome, Italy.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/aor.13050DOI Listing
April 2018

Exercise physiology with a left ventricular assist device: Analysis of heart-pump interaction with a computational simulator.

PLoS One 2017 24;12(7):e0181879. Epub 2017 Jul 24.

KU Leuven, Department of Cardiac Surgery, Leuven, Belgium.

Patients with a Ventricular Assist Device (VAD) are hemodynamically stable but show an impaired exercise capacity. Aim of this work is to identify and to describe the limiting factors of exercise physiology with a VAD. We searched for data concerning exercise in heart failure condition and after VAD implantation from the literature. Data were analyzed by using a cardiorespiratory simulator that worked as a collector of inputs coming from different papers. As a preliminary step the simulator was used to reproduce the evolution of hemodynamics from rest to peak exercise (ergometer cycling) in heart failure condition. Results evidence an increase of cardiac output of +2.8 l/min and a heart rate increase to 67% of the expected value. Then, we simulated the effect of a continuous-flow VAD at both rest and exercise. Total cardiac output increases of +3.0 l/min (+0.9 l/min due to the VAD and +2.1 l/min to the native ventricle). Since the left ventricle works in a non-linear portion of the diastolic stiffness line, we observed a consistent increase of pulmonary capillary wedge pressure (from 14 to 20 mmHg) for a relatively small increase of end-diastolic volume (from 182 to 189 cm3). We finally increased VAD speed during exercise to the maximum possible value and we observed a reduction of wedge pressure (-4.5 mmHg), a slight improvement of cardiac output (8.0 l/min) and a complete unloading of the native ventricle. The VAD can assure a proper hemodynamics at rest, but provides an insufficient unloading of the left ventricle and does not prevent wedge pressure from rising during exercise. Neither the VAD provides major benefits during exercise in terms of total cardiac output, which increases to a similar extend to an unassisted heart failure condition. VAD speed modulation can contribute to better unload the ventricle but the maximal flow reachable with the current devices is below the cardiac output observed in a healthy heart.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0181879PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5524292PMC
September 2017

Control of a Pediatric Pulsatile Ventricular Assist Device: A Hybrid Cardiovascular Model Study.

Artif Organs 2017 Dec 16;41(12):1099-1108. Epub 2017 Jun 16.

Nałecz Institute of Biocybernetics and Biomedical Engineering, PAS, Warsaw, Poland.

The aim of this work is to study pediatric pneumatic ventricle (PVAD) performance, versus VAD rate (VADR) and native heart rate (HR) ratio Rr (VADR/HR). The study uses a hybrid model of the cardiovascular system (HCS). HCS consists of a computational part (a lumped parameter model including left and right ventricles, systemic and pulmonary arterial and venous circulation) interfaced to a physical part. This permits the connection of a VAD (15 mL PVAD). Echocardiographic and hemodynamic data of a pediatric patient (average weight 14.3 kg, HR 100 bpm, systemic pressure 75/44 mm Hg, CO 1.5 L/min) assisted apically with asynchronous PVAD were used to set up a basal condition in the model. After model tuning, the assistance was started, setting VAD parameters (ejection and filling pressures, systole duration) to completely fill and empty the PVAD. The study was conducted with constant HR and variable VADR (50-120, step 10, bpm). Experiments were repeated for two additional patients' HRs, 90 and 110 bpm and for two values of systemic arterial resistance (R ) and E . Experimental data were collected and stored on disk. Analyzed data include average left and right ventricular volumes (LVV, RVV), left ventricular flow (LVF), VAD flow (VADF), and total cardiac output (COt). Data were analyzed versus Rr. LVV and RVV are sensitive to Rr and a left ventricular unloading corresponds in general to a right ventricular loading. In the case of asynchronous assistance, frequency beats are always present and the beat rate is equal to the difference between HR and VADR. In the case of pulsatile asynchronous LVAD assistance, VADR should be chosen to minimize frequency beat effects and right ventricular loading and to maximize left ventricular unloading.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/aor.12929DOI Listing
December 2017

Ventricular Energetics in Pediatric Left Ventricular Assist Device Patients: A Retrospective Clinical Study.

ASAIO J 2017 Nov/Dec;63(6):815-823

From the *Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital Bambino Gesù, Rome, Italy; and †Department of Cardiovascular Engineer-Institute of Clinical Physiology-CNR, Pisa, Italy.

The aim of this study is to estimate the trend of right and left energetic parameters in left ventricular assist device (LVAD) pediatric patients. Echocardiographic data were retrospectively collected at the baseline, in the acute phase after and at the monthly follow-ups till the LVAD explantation to estimate left and right ventricular energetic parameters. A significant relationship between the left and right ventricular energetic parameter trends was found along all the study period. Left ventricular end-systolic pressure-volume relationship improved till the follow-up of 2 months and then progressively decreases. Left arteroventricular coupling decreases after the LVAD, and right arteroventricular coupling decreases at the short-term follow-up. Left ventricular external work, potential energy, and pressure-volume area decrease at the short-term follow-up and then increase progressively. Right ventricular external work, potential energy, and pressure-volume area increase after the LVAD implantation. Left (right) cardiac mechanical efficiency is improved (worsened) by the LVAD. Energetic variables show that the LVAD benefits could decrease over time. A continuous and patient tailored LVAD setting could contribute to prolong LVAD benefits. The introduction of energetic parameters could lead to a more complete evaluation of LVAD patients' outcome which is a multiparametric process.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAT.0000000000000595DOI Listing
May 2018

Acute and Long-Term Effects of LVAD Support on Right Ventricular Function in Children with Pediatric Pulsatile Ventricular Assist Devices.

ASAIO J 2018 Jan/Feb;64(1):91-97

From the Department of Cardiology and Cardiac Surgery, Bambino Gesù Pediatric Hospital, Rome, Italy.

Right ventricular failure (RVF) is a significant issue when considering left ventricular assist device (LVAD) implantation in pediatrics. The aim of this study was to evaluate the effects of LVAD on right ventricular (RV) function in children. We retrospectively reviewed clinical and echocardiographic data of children who underwent Berlin Heart EXCOR LVAD focusing on RV function before and after implantation (1, 3, and 6 month follow-up). An isolated LVAD was used in 27 patients. Median age was 11 months (interquartile range [IQR]: 5-24 months), with a median weight of 6.3 kg (IQR: 5-9 kg). Median time on ventricular assist device (VAD) support was 147 days (IQR: 86-210 days). Twenty patients were successfully bridged to orthotopic heart transplantation (OHT) (74%), six patients died (22%), and also heart function recovered in one patient (4%). Before LVAD implantation, nine patients (33%) showed a RV fractional area change (RVFAC) less than or equal to 30%. After implantation, mean RVFAC increased up until the 3 month follow-up (43.13%; p = 0.033) and then slightly decreased. In a subgroup of 18 patients, the average strain value increased after the 1 month follow-up (p = 0.022). Right ventricular failure developed in 33% of patients before the 1 month follow-up, and 7.4% experienced RVF at the 6 month follow-up. No patient required biventricular assist device (BiVAD). In our population, pulsatile-flow LVAD in children allows optimal RV decompression and function post-LVAD as measured by improvement in RV function at echo particularly at 1 and 3 month follow-up. At long-term follow-up, the beneficial effects of LVAD on RV function seem to be reduced as signs and symptoms of late RVF may develop in some patients despite LVAD support.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAT.0000000000000596DOI Listing
July 2018

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.

Artif Organs 2017 Mar;41(3):242-252

Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital, Bambino Gesù.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/aor.12911DOI Listing
March 2017

Concomitant pulsatile and continuous flow VAD in biventricular and univentricular physiology: a comparison study with a numerical model.

Int J Artif Organs 2017 Mar 11;40(2):74-81. Epub 2017 Feb 11.

Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Pediatric Hospital, Rome - Italy.

Introduction: To develop and test a lumped parameter model to simulate and compare the effects of the simultaneous use of continuous flow (CF) and pulsatile flow (PF) ventricular assist devices (VADs) to assist biventricular circulation vs. single ventricle circulation in pediatrics.

Methods: Baseline data of 5 patients with biventricular circulation eligible for LVAD and of 5 patients with Fontan physiology were retrospectively collected and used to simulate patient baselines. Then, for each patient the following simulations were performed: (a) CF VAD to assist the left ventricle (single ventricle) + a PF VAD to assist the right ventricle (cavo-pulmonary connection) (LCF + RPF); (b) PF VAD to assist the left ventricle (single ventricle) + a CF VAD to assist the right ventricle (cavo-pulmonary connection) (RCF + LPF).

Results: In biventricular circulation, the following results were found: cardiac output (17% RCF + LPF, 21% LCF + RPF), artero-ventricular coupling (-36% for the left ventricle and -21.6% for the right ventricle), pulsatility index (+6.4% RCF + LPF, p = 0.02; -8.5% LCF + RPF, p = 0.00009). Right (left) atrial pressure and right (left) ventricular volumes are decreased by the RCF + LPF (by RPF + LCF). Pulmonary arterial pressure decreases in the LCF + RPF configuration. In Fontan physiology: cardiac output (LCF + RPF 35% vs. 8% in RCF + LPF), ventricular preload (+4% RCF + LPF, -10% LCF + RPF), Fontan conduit pressure (-5% RCF + LPF, +7% LCF + RPF), artero-ventricular coupling (-14% RCF + LPF vs. -41% LCF + RPF) and pulsatility (+13% RCF + LPF, - 8% LCF + RPF).

Conclusions: A numerical model supports clinicians in defining and innovating the VAD implantation strategy to maximize the hemodynamic benefits. Results suggest that the hemodynamic benefits are maximized by the LCF + RPF configuration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5301/ijao.5000562DOI Listing
March 2017

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

Artif Organs 2017 Jan 26;41(1):32-39. Epub 2016 Dec 26.

Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital Bambino Gesù.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/aor.12859DOI Listing
January 2017

The Use of Berlin Heart EXCOR VAD in Children Less than 10 kg: A Single Center Experience.

Front Physiol 2016 6;7:614. Epub 2016 Dec 6.

Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital Bambino Gesù Rome, Italy.

Despite the improvement in ventricular assist device (VAD) therapy in adults and in adolescents, in infant population only Berlin Heart EXCOR (BHE) is licensed as long term VAD to bridge children to Heart Transplantation (HTx). Particularly demanding in terms of morbidity and mortality are smallest patients namely the ones implanted in the first year of life or with a lower body surface area. This work aims at retrospective reviewing a single center experience in using BHE in children with a body weight under 10 kg. Data of all pediatric patients under 10 kg undergoing BHE implantation in our institution from March 2002 to March 2016 were retrospectively reviewed. Of the 30 patients enrolled in the study, 53% were male, 87% were affected by a dilated cardiomyopathy with an average weight and age at the implantation of 6.75 ± 2.16 Kg and 11.57 ± 10.12 months, respectively. Three patients (10%) required a BIVAD implantation. After the implantation, 7 patients (23%) required re-intervention for bleeding and 9 patients (30%) experienced BHE cannulas infection. A total of 56 BHE pump were changed for thrombus formation (1.86 BHE pump for patient). The average duration of VAD support was 132.8 ± 94.4 days. Twenty patients (67%) were successfully transplanted and 10 patients (33%) died: 7 for major neurological complication and 3 for sepsis. Mechanical support in smaller children with end stage heart failure is an effective strategy for bridging patients to HTx. The need for BIVAD was relegated, in the last years, only to restrictive cardiomiopathy. Further efforts are required in small infants to improve anticoagulation strategy to reduce neurological events and BHE pump changes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphys.2016.00614DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5138210PMC
December 2016

Berlin Heart EXCOR Ventricular Assist Device: Multilayer Membrane Rupture in a Pediatric Patient.

Ann Thorac Surg 2016 Aug;102(2):e129-30

Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital Bambino Gesù, Rome, Italy.

A 2-year-old child was implanted with an Berlin Heart EXCOR Ventricular Assist Device (Berlin Heart, Berlin, Germany) as a bridge to heart transplantation for idiopathic dilated cardiomyopathy. At postoperative day 296, a significant reduction of membrane movement was observed. The device was explanted and tested on a hydronumerical circulation simulator. Findings suggested that the integrity of the multilayered membrane had been compromised. This was confirmed by a computed tomography scan of the device. The computed tomography evidenced a detachment of the 3-layered membrane, with a thinner, convex layer on the side of the air chamber and an opposite convexity of the remaining membranes. These showed an additional air space within the layers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.athoracsur.2016.01.022DOI Listing
August 2016

A Model of the Cardiorespiratory Response to Aerobic Exercise in Healthy and Heart Failure Conditions.

Front Physiol 2016 8;7:189. Epub 2016 Jun 8.

Institute of Clinical Physiology, National Research Council Rome, Italy.

The physiological response to physical exercise is now recognized as an important tool which can aid the diagnosis and treatment of cardiovascular diseases. This is due to the fact that several mechanisms are needed to accommodate a higher cardiac output and a higher oxygen delivery to tissues. The aim of the present work is to provide a fully closed loop cardiorespiratory simulator reproducing the main physiological mechanisms which arise during aerobic exercise. The simulator also provides a representation of the impairments of these mechanisms in heart failure condition and their effect on limiting exercise capacity. The simulator consists of a cardiovascular model including the left and right heart, pulmonary and systemic circulations. This latter is split into exercising and non-exercising regions and is controlled by the baroreflex and metabolic mechanisms. In addition, the simulator includes a respiratory model reproducing the gas exchange in lungs and tissues, the ventilation control and the effects of its mechanics on the cardiovascular system. The simulator was tested and compared to the data in the literature at three different workloads whilst cycling (25, 49 and 73 watts). The results show that the simulator is able to reproduce the response to exercise in terms of: heart rate (from 67 to 134 bpm), cardiac output (from 5.3 to 10.2 l/min), leg blood flow (from 0.7 to 3.0 l/min), peripheral resistance (from 0.9 to 0.5 mmHg/(cm(3)/s)), central arteriovenous oxygen difference (from 4.5 to 10.8 ml/dl) and ventilation (6.1-25.5 l/min). The simulator was further adapted to reproduce the main impairments observed in heart failure condition, such as reduced sensitivity of baroreflex and metabolic controls, lower perfusion to the exercising regions (from 0.6 to 1.4 l/min) and hyperventilation (from 9.2 to 40.2 l/min). The simulator we developed is a useful tool for the description of the basic physiological mechanisms operating during exercise. It can reproduce how these mechanisms interact and how their impairments could limit exercise performance in heart failure condition. The simulator can thus be used in the future as a test bench for different therapeutic strategies aimed at improving exercise performance in cardiopathic subjects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fphys.2016.00189DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4896934PMC
July 2016

Acute Biventricular Interaction in Pediatric Patients Implanted with Continuous Flow and Pulsatile Flow LVAD: A Simulation Study.

ASAIO J 2016 Sep-Oct;62(5):591-9

From the *Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital Bambino Gesù, Rome, Italy; †Cardiovascular Engineering Laboratory, Institute of Clinical Physiology, Rome, Italy; and ‡ Department of Cardiac Surgery, KU Leuven, Leuven, Belgium.

Left ventricular assist devices (LVADs) are used to bridge pediatric patients till transplantation. However, the LVADs effects on right ventricular (RV) function are controversial. This work aims at studying the ventricular interdependency in the presence of continuous (c-) and pulsatile (p-) flow LVAD in pediatric patients using a lumped parameter model including the representation of the septum. Five pediatric patients' data were used to simulate patients' baseline. The effects on LV and RV functions, energetics, preloads and afterloads of different c-LVAD speeds, p-LVAD rate, p-LVAD systole duration, p-LVAD filling and ejection pressures were simulated. c-LVAD and p-LVAD unload the LV decreasing the LV external work and improving the LV ventriculo-arterial coupling and these effects are more evident increasing the c-LVAD speed and the p-LVAD rate. Continuous-LVAD and p-LVAD decrease the RV afterload, increase the RV ejection fraction and improve the RV ventriculo-arterial coupling. The changes in RV function are inversely proportional to the degree of the interventricular septum leftward shift that increased by increasing the LVAD contribution. The study of the interventricular interaction could lead to the development of a dedicated algorithm to optimize LVAD setting in pediatric population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAT.0000000000000396DOI Listing
November 2017

Simulation of acute haemodynamic outcomes of the surgical strategies for the right ventricular failure treatment in pediatric LVAD.

Int J Artif Organs 2015 Dec 30;38(12):638-45. Epub 2016 Jan 30.

Department of Pediatric Cardiology and Cardiac Surgery, Pediatric Hospital Bambino Gesù, Rome - Italy.

Background: Right ventricular failure (RVF) is one of the major complications during LVAD. Apart from drug therapy, the most reliable option is the implantation of RVAD. However, BIVAD have a poor prognosis and increased complications. Experiments have been conducted on alternative approaches, such as the creation of an atrial septal defect (ASD), a cavo-aortic shunt (CAS) including the LVAD and a cavo-pulmonary connection (CPC). This work aims at realizing a lumped parameter model (LPM) to compare the acute hemodynamic effects of ASD, CPC, CAS, RVAD in LVAD pediatric patients with RVF.

Methods: Data of 5 pediatric patients undergoing LVAD were retrospectively collected to reproduce patients baseline hemodynamics with the LPM. The effects of continuous flow LVAD implantation complicated by RVF was simulated and then the effects of ASD, CPC, CAS and RVAD treatments were simulated for each patient.

Results: The model successfully reproduced patients' baseline and the hemodynamic effects of the surgical strategies. Simulating the different surgical strategies, an unloading of the right ventricle and an increment of left ventricular preload were observed with an improvement of the hemodynamics (total cardiac output: ASD +15%, CPC +10%, CAS +70% RVAD +20%; right ventricular external work: ASD -19%, CPC -46%, CAS -76%, RVAD -32%; left ventricular external work: ASD +12%, CPC +28%, RVAD +64%).

Conclusions: The use of numerical model could offer an additional support for clinical decision-making, also potentially reducing animal experiments, to compare the outcome of different surgical strategies to treat RVF in LVAD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5301/ijao.5000462DOI Listing
December 2015

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

J Artif Organs 2016 Jun 6;19(2):105-13. Epub 2015 Nov 6.

Institute of Clinical Physiology, CNR, Pisa, Italy.

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.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10047-015-0874-5DOI Listing
June 2016