Ventricle Assist Devices Research Articles

Abstract 18976: In-Hospital Outcomes in Patients Undergoing Protected Left Main Percutaneous Coronary Intervention With Percutaneous Left Ventricle Assist Device Protection

Introduction: Left main disease (LMCA) is a known risk factor for patients’ poor outcomes. Percutaneous revascularization of LMCA in heart failure patients is associated with a particularly high periprocedural risk. Percutaneously introduced left ventricle assist devices (pLVAD) are a potential tool to improve patient outcomes in these high-risk procedures. Hypothesis: Our study aimed to assess short-term clinical outcomes of protected left main percutaneous coronary intervention with the use of a pLVAD. Methods: A prospective registry of patients with chronic heart failure, undergoing protected LMCA PCI included 66 patients, 89% male, the median age of 71.5 y.o, 40 (60.6%) after prior myocardial infarction, 31 (47%) after prior PCI and 12 (18.2%) after CABG, with CTO RCA in 17 (25.6%) of cases. Percutaneous LVAD was used in all patients, 72% access site was the right femoral artery, additional plaque modification techniques were used in 46 (69.7%) patients, IVL was applied in 25 (37.9%) of cases and high-speed rotational or orbital atherectomy was used in 21 (31.2%) of cases. Median of 3 [2;4] DES was implanted. Results: During the in-hospital follow-up, a significant improvement of the left ventricle ejection fraction was observed (median LVEF 30% post PCI vs22% at baseline, p<0.001) as well as a significant decrease of NTproBNP levels (765 [IQR: 194, 6,370] at discharge vs 7113 pg/ml [IQR:1,945, 15,646] at baseline, p=0.01]. There was 1 in-hospital death due to cardiogenic shock. A safety monitoring revealed 11 hematomas, including 3 cases that needed vascular surgery. Bleeding according to BARC 3a was recorded in 17/66 (28%) and BARC 3b in 3/66 (5%) of cases. Conclusions: Percutaneous LVAD support is a feasible method to perform protected left main PCI with a good safety profile when applied by experienced operators A significant improvement of the LVEF can be observed after left main revascularization Further research is needed to confirm the presented results.

Daptomycin Pharmacokinetics in Blood and Wound Fluid in Critical Ill Patients with Left Ventricle Assist Devices.

Daptomycin is a cyclic lipopeptide antibiotic with bactericidal effects against multidrug-resistant Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). For critically ill patients, especially in the presence of implants, daptomycin is an important therapeutic option. Left ventricle assist devices (LVADs) can be utilized for intensive care patients with end-stage heart failure as a bridge to transplant. We conducted a single-center prospective trial with critically ill adults with LVAD who received prophylactic anti-infective therapy with daptomycin. Our study aimed to evaluate the pharmacokinetics of daptomycin in the blood serum and wound fluids after LVAD implantation. Daptomycin concentration were assessed over three days using high-performance liquid chromatography (HPLC). We detected a high correlation between blood serum and wound fluid daptomycin concentration at 12 h (IC95%: 0.64 to 0.95; r = 0.86; p < 0.001) and 24 h (IC95%: -0.38 to 0.92; r = 0.76; p < 0.001) after antibiotic administration. Our pilot clinical study provides new insights into the pharmacokinetics of daptomycin from the blood into wound fluids of critically ill patients with LVADs.

(824) Stereotactic Arrhythmia Radioablation (STAR) as Treatment for Recurrent Ventricular Tachycardia (VT) in Two Patients with Left Ventricle Assist Devices (LVAD)

(824) Stereotactic Arrhythmia Radioablation (STAR) as Treatment for Recurrent Ventricular Tachycardia (VT) in Two Patients with Left Ventricle Assist Devices (LVAD)

P38: Minimally Invasive Extracorporeal Membrane Oxygenation? Concomitant Right and Left Ventricle Assist Devices via Jugular, Subclavian, and Carotid Approaches Reduce Pressor Requirements and Lactic Acid in Cardiogenic Shock Patients, A Follow-Up Observational Study on the “Pro-Pella” Approach.

P38: Minimally Invasive Extracorporeal Membrane Oxygenation? Concomitant Right and Left Ventricle Assist Devices via Jugular, Subclavian, and Carotid Approaches Reduce Pressor Requirements and Lactic Acid in Cardiogenic Shock Patients, A Follow-Up Observational Study on the “Pro-Pella” Approach.

Analysis of Operating Modes for Left Ventricle Assist Devices via Integrated Models of Blood Circulation

Left ventricular assist devices provide circulatory support to patients with end-stage heart failure. The standard operating conditions of the pump imply limitations on the rotation speed of the rotor. In this work we validate a model for three pumps (Sputnik 1, Sputnik 2, Sputnik D) using a mock circulation facility and known data for the pump HeartMate II. We combine this model with a 1D model of haemodynamics in the aorta and a lumped model of the left heart with valves dynamics. The model without pump is validated with known data in normal conditions. Simulations of left ventricular dilated cardiomyopathy show that none of the pumps are capable of reproducing the normal stroke volume in their operating ranges while complying with all criteria of physiologically feasible operation. We also observe that the paediatric pump Sputnik D can operate in the conditions of adult circulation with the same efficiency as the adult LVADs.

Early Aspirin Nonresponders Identification by Routine Use of Aggregometry Test in Patients With Left Ventricle Assist Devices Reduces the Risk of Pump Thrombosis

Left ventricular assist device (LVAD) management is very challenging since many adverse events can occur in ongoing patients. Inadequate anticoagulation treatment can lead to life-threatening situations like ischemic stroke or pump thrombosis. The main intention of our study was to investigate if early identification of aspirin nonresponders by using aggregometry can improve anticoagulation management, reducing the risk of pump thrombosis. MethodsFrom December 2010 to May 2018, 24 patients were implanted with a HeartMate II (HMII), 6 received a HeartWare HVAD system--full support VAD (HVAD), and 22 received a HeartMate III (HMIII). All patients were maintained with a target INR of 2.0 to 3.0. When the aggregometry test revealed a normal platelet function, 100 mg of aspirin were initiated. Only aspirin nonresponders were early identified by repeating the aggregometry after 7 days of aspirin administration. In acetylsalicylic acid nonresponder patients, 75 mg of clopidogrel was used, and the patients were tested again. Ticlopidine (250 mg) was used when clopidogrel was unsuccessful. ResultsFour patients required modification in antiplatelet therapy. Three patients (5%), 2 HVAD and 1 HMII, suffered from pump thrombosis. One patient died as a consequence of a large intracranial hemorrhagic event following thrombolytic treatment. One patient required a pump exchange; in 1 patient, thrombolytic infusion was conducted successfully. ConclusionReported rates of pump thrombosis at 12 months for patients implanted with commonly used LVADs were 6% to 12% for axial-flow pumps and 8% with centrifugal-flow devices. In our series, the reported 5% overall incidence of pump thrombosis encourages the routine use of an aggregometry test for early identification of aspirin nonresponders.

Left Ventricular Hemodynamics with an Implanted Assist Device: An In Vitro Fluid Dynamics Study.

Left ventricle assist devices (VADs) aid the heart pumping blood into the systemic circulation and grant the required cardiac output (CO) when the heart itself cannot provide it. However, it is unclear how effective these devices are at restoring not only physiological CO values but also normal intraventricular hemodynamics. In this work, the modified hemodynamics due to a VAD implantation is studied in vitro using an elastic ventricle made of silicone, which is incorporated into a pulse-duplicator setup prescribing a realistic pulsatile flow. Thereafter, a continuous axial pump is connected at the ventricle apex to mimic a VAD and its effect on the ventricular hemodynamics is investigated as a function of the pump flow suction. Using particle image velocimetry (PIV), we observe that the continuous pump flow effectively provides unloading on the ventricle and yields an increased CO. Conversely, the continuous blood suction from the ventricle apex deeply alters the hemodynamics and, in addition, the VAD obstruction in the ventricle behaves as a bluff body that affects the vorticity distribution in the LV thus creating a stagnant region at the ventricle apex. This phenomenon is rationalized by measuring in a modified set-up the benefits on the hemodynamics of a flush-mounted device. Additionally, the suction operated by the VAD reduces the ventricular pressure and yields an increase in the swirling motion around the ventricle axis, in a similar fashion as the bath-tub vortex effect, thus further modifying the intraventricular hemodynamics with respect to healthy conditions.

RIGHT VENTRICULAR PRESSURE IS ASSOCIATED WITH POST-LEFT VENTRICLE ASSIST DEVICE IMPLANTATION CHANGES IN DIFFUSION CAPACITY OF LUNGS FOR CARBON MONOXIDE (DLCO)

Pulmonary function (PF) and diffusion capacity of lungs (DLCO) do not improve following implantation of Left Ventricle Assist Devices (LVAD) despite an increase in cardiac output. We hypothesized DLCO post-surgery may be influenced by right ventricular (RV) function assessed by echo prior to LVAD

Echocardiographic dP/dt as a Novel Tool to Predict Early Right Ventricular Failure in Patients with Left Ventricle Assist Devices

Introduction Right ventricle failure (RVF) remains a major source of morbidity and mortality with Left Ventricle Assist devices (LVAD) use. Common invasive and non-invasive measurements of RV function have not been predictive of RVF post-LVAD placement. The rate of rise of intra-ventricular pressure (dP/dt) correlates with myocardial contractility and is less dependent of loading conditions. We sought to evaluate if TTE derived dP/dt predicts early RVF after LVAD implantation. Methods We retrospectively reviewed all patients who had TTE, off inotropic support within 3 months prior to LVAD implant in our center. RV dP/dt was assessed by two independent reviewers using continuous-wave TR Doppler recordings. The time required for TR velocity to increase from 0.5 to 2 m/s was measured and used to calculate dP/dt by the simplified Bernoulli equation. Baseline demographics, right heart catheterization measurements, and clinical outcomes of RVF failure and mortality were obtained by chart review. Presence and severity of RVF was based on current INTERMACS criteria. Non-parametric Mann-Whitney U test was used to compare groups that had mild or no RVF vs those that had moderate or severe RVF. Results From a total of 60 patients, 39 had TTE performed while off inotropic support and 23 had an adequate TR Doppler signal for analysis. Moderate or severe RVF was present in 10/23 (43%) of patients with average dP/dt 233 ± 58 mmHg/sec. The remaining 13/23 had mild or no RVF with an average dP/dt 314 ± 93 mmHg (p = 0.036). Pre-operative tricuspid annular plane systolic excursion (TAPSE), RV free wall tissue Doppler velocity (s’), RV fractional area change, pulmonary artery pulsatility index (PAPi), and the ratio of central venous pressure to pulmonary capillary wedge pressure (CVP/PCWP) ratio did not significantly differ between groups (Figure 1). Of note, no patients with dP/dt greater than 325 mmHg/sec had moderate or severe RVF. Conclusions TTE derived RV dP/dt strongly correlates with post LVAD RVF, and when greater than 325 mmHg/sec identifies those at low risk for RVF. Future prospective studies are needed to determine if this TTE measurement independently predicts a favorable outcome in LVAD patients.

Sleep and Life Quality with Left Ventricle Assist Devices or Transplanted Heart: Results from a Multi-Center Observational Study

Sleep and Life Quality with Left Ventricle Assist Devices or Transplanted Heart: Results from a Multi-Center Observational Study

TRANSPLANT OUTCOMES IN PATIENTS BRIDGED WITH LVAD THERAPY AT TORONTO GENERAL HOSPITAL

Cardiac transplantation remains the standard of care for eligible patients with advanced heart failure. The advent of Left Ventricle Assist Devices (LVAD) has enabled more patients to be eligible for cardiac transplantation by normalizing pulmonary pressures and renal function. We describe the post-transplant outcomes of Toronto General Hospital’s (TGH) patient population bridged with LVAD therapy. We performed a retrospective analysis of TGH’s Transplant Program from 2000 to 2016, compared outcomes between patients who were bridged or not with LVADs. Three-hundred and eighty patients underwent heart transplantation at TGH since 2000 and 89 had previously underwent LVAD implantation. Mean age at transplant was 49 ± 12 and males accounted for 75% of the patients. Overall, the main primary diagnoses were non-ischemic myopathies (58.7%) or ischemic disease (24.2%) and did not differ between the groups. Blood group O was predominant in the LVAD group (47%), while group A was predominant in the remaining patients (49%). The rate of patients listed as status 3 or higher (LVAD 100%, No LVAD 40%; p < 0.001), as well as cold ischemic time (LVAD 157±77, No LVAD 134±72; p=0.011) were significantly greater in the LVAD group. Patient cause of death did not differ significantly between groups, with graft failure (30.7%) and multisystem organ failure (16.8%) accounting for most cases. Short-term (30-day: LVAD 87%, No LVAD 91%; Log rank test, p=0.246) and long-term post-operative survival did not differ between groups (LVAD: 1-year 85%, 5-year 81%, 10-year: 69%; No VAD: 1-year 86%, 5-year 80%, 10-year 65%; Log rank test, p=0.452). Furthermore, there was a non-significant increased 30-day survival in patients on LVAD support transplanted after 2008 (Before: 82%, After: 89%; Log rank p=0.220). This is the largest Canadian report on the outcomes of patients who underwent cardiac transplantation following LVAD therapy. As expected, higher risk patient profile and ischemic times were noted in the group bridged with LVADs; however, there was no significant difference in short and long-term survival when compared to the other patients from our program. LVAD support can successfully and safely bridge and help patients obtain candidacy for transplantation without compromising post-operative outcomes.

Particle image velocimetry tests on pediatric 45-cc and 30-cc ventricle assist devices: effects of heart rate on VAD operation.

BackgroundThis study investigated flow analysis inside pediatric ventricle assist devices (VADs) designed and manufactured at the Foundation for Cardiac Surgery Development (FRK), Zabrze, Poland. The main goal of the experiment was to define the minimal heart rate admissible in clinical practice.MethodsThe flow was directed by mechanical, single-disc valves developed at the Lodz University of Technology, Institute of Turbomachinery in Lodz, Poland. VAD operation conditions under different heart rates were analyzed. Measurements were performed on Religa PED pediatric VADs (45 cm3 and 30 cm3) with a particle image velocimetry (PIV) system.ResultsDue to the PIV method used, the measurements were made without interference of the measuring system onto the flow structure in the investigated channel, as the measurement procedure is noninvasive. During the investigations conducted in different measurement planes, the majority of the flow volume in the chamber was observable.ConclusionsThe measurements at different heart rates demonstrated a significant influence of this parameter on the flow nature in the heart ventricle. Additionally, it was found that the heart rate affected the operation of heart valves in the VAD.

AORTIC REGURGITATION EXACERBATING HEART FAILURE IN A PATIENT WITH LEFT VENTRICULAR ASSIST DEVICE

Left Ventricle Assist Devices (LVADs) have been associated with de-novo or progression of aortic regurgitation (AR) after implantation. AR leads to mechanical inefficiency of the LVAD and can worsen heart failure (HF). A range of percutaneous transcatheter or surgical strategies may be employed in

The Effect of Continuous-flow Ventricle Assist Device and Support Time on Pulmonary Artery Pressure in Bridge to Heart Transplant Patients

Introduction: The new generation continuous-flow left ventricle assist devices (LVAD) is an option for heart transplantation for end-stage heart failure. These kind of devices which developped with new technology, are implanted widely all over the world for bridge to transplantation as well as destination therapy. The effect of LVAD therapy on pulmonary artery pressure (PAP) in patients with fixed pulmonary artery hypertension (PAH) who are not good candidate for heart transplant, is an important research topic. In this study, we evaluated the course of PAP in LVAD therapy and its effect to post-transplant results. Materials-Methods: Between December 2008 and June 2013, continuous-flowLVAD implantation were performed in 73 patients. Mean age was 48.39 years and 87% was male. The common etiology for heart failure was Idiopathic dilated cardiomyopathy (69%). 9 of 73 patients (12,3%) were succesfully bridged to transplantation. 8 patients with fixed PAH were included in this study. PAP levels were retrospectively compared before LVAD, after LVAD and after heart transplantion. Results: Mean PAP before LVAD,after LVAD therapy and after heart transplant was respectively 59,6 mmHg,34.8mmHg and 32.8mmHg. The reduction of PAP was evident in patients supported with LVAD more than 60 days and consequently complications related to PAH were lower in this group. Two patients were died in early period of after heart transplant, the common feature of them was short support time after LVAD. Mean support time was 34 days. PAP was still high after LVAD and the main cause of mortality was right heart failure related multi-organ failure. Conclusion: The study is limited due to low-number of patients. But the decline of fixed PAH even it is refractory to vasodilator therapy was found in our analysis. As a conclusion we think that LVAD therapy before heart transplantation, in patients with decompansated heart failure and severe PAH, improves the results of heart transplantation.

Hospital costs fell as numbers of LVADs were increasing: experiences from Oslo University Hospital

BackgroundThe current study was undertaken to examine total hospital costs per patient of a consecutive implantation series of two 3rd generation Left Ventricle Assist Devices (LVAD). Further we analyzed if increased clinical experience would reduce total hospital costs and the gap between costs and the diagnosis related grouped (DRG)-reimbursement.MethodCost data of 20 LVAD implantations (VentrAssist™) from 2005-2009 (period 1) were analyzed together with costs from nine patients using another LVAD (HeartWare™) from 2009-June 2011 (period 2). For each patient, total costs were calculated for three phases - the pre-LVAD implantation phase, the LVAD implantation phase and the post LVAD implant phase. Patient specific costs were obtained prospectively from patient records and included personnel resources, medication, blood products, blood chemistry and microbiology, imaging and procedure costs including operating room costs. Overhead costs were registered retrospectively and allocated to the specific patient by predefined allocation keys. Finally, patient specific costs and overhead costs were aggregated into total hospital costs for each patient. All costs were calculated in 2011-prices. We used regression analyses to analyze cost variations over time and between the different devices.ResultsThe average total hospital cost per patient for the pre-LVAD, LVAD and post-LVAD for period 1 was $ 585, 513 (range 132, 640- 1 247, 299), and the corresponding DRG- reimbursement (2009) was $ 143, 192 . The mean LOS was 54 days (range 12- 127). For period 2 the total hospital cost per patient was $ 413, 185 (range 314, 540- 622, 664) and the corresponding DRG- reimbursement (2010) was $ 136, 963. The mean LOS was 49 days (range 31- 93).The estimates from the regression analysis showed that the total hospital costs, excluding device costs, per patient were falling as the number of treated patients increased. The estimate from the trend variable was -14, 096 US$ (CI -3, 842 to -24, 349, p < 0.01).ConclusionThere were significant reductions in total hospital costs per patient as the numbers of patients were increasing. This can possibly be explained by a learning effect including better logistics, selection and management of patients.

Extracorporeal life support in pediatric cardiac dysfunction

BackgroundLow cardiac output (LCO) after corrective surgery remains a serious complication in pediatric congenital heart diseases (CHD). In the case of refractory LCO, extra corporeal life support (ECLS) extra corporeal membrane oxygenation (ECMO) or ventricle assist devices (VAD) is the final therapeutic option. In the present study we have reviewed the outcomes of pediatric patients after corrective surgery necessitating ECLS and compared outcomes with pediatric patients necessitating ECLS because of dilatated cardiomyopathy (DCM).MethodsA retrospective single-centre cohort study was evaluated in pediatric patients, between 1991 and 2008, that required ECLS. A total of 48 patients received ECLS, of which 23 were male and 25 female. The indications for ECLS included CHD in 32 patients and DCM in 16 patients.ResultsThe mean age was 1.2 ± 3.9 years for CHD patients and 10.4 ± 5.8 years for DCM patients. Twenty-six patients received ECMO and 22 patients received VAD. A total of 15 patients out of 48 survived, 8 were discharged after myocardial recovery and 7 were discharged after successful heart transplantation. The overall mortality in patients with extracorporeal life support was 68%.ConclusionAlthough the use of ECLS shows a significantly high mortality rate it remains the ultimate chance for children. For better results, ECLS should be initiated in the operating room or shortly thereafter. Bridge to heart transplantation should be considered if there is no improvement in cardiac function to avoid irreversible multiorgan failure (MFO).

478: Ethical Considerations for Cardiac Ventricular Assist Device Support: A 12 Point Protocol

While cardiac ventricle assist devices (VAD) as bridges to transplant (BTT) and destination therapies (DT) are advancing technical, medical and surgical supports for end stage heart disease collateral ethical advances have not occurred. The increasing use of elective or emergent VADs are creating unique ethical issues. This is a 12 point patient protocol to reduce potential ethical dilemmas.

BLOOD COAGULATION TIME CONTROL, DURING IN VIVO TESTS WITH THE AUXILIARY TOTAL ARTIFICIAL HEART (ATAH) IMPLANTED IN CALVES AS LEFT VENTRICLE ASSIST DEVICE

Many research groups are studding new designs for Ventricle Assist devices (VAD) and Total Artificial Hearts (TAH). Common problems encountered by those groups are the device dimension, thrombus formation and the TAH control system. A miniaturized artificial heart is being tested in our laboratories, the Auxiliary Total Artificial Heart (ATAH). The ATAH is an electromechanically driven artificial heart with reduced dimensions (outer diameter is 85 mm and the thickness is 65 mm). Eighteen In Vivo tests were performed in calves with 80 ± 5 Kg of weight. The device was implanted as Left Ventricle Assist Device (LVAD) in their abdominal cavities in series with their native hearts to verify the device performance and operating functions. The implantations were performed connecting a flexible polymeric graft from the left ventricle apex to the artificial ventricle inlet port. From the LVAD outlet port, the blood was pumped to the descending aorta through another polymeric graft. During all the tests, heparin was administrated and the blood Activated Coagulation Time (ACT) was maintained in 400 ± 100 s by adjusting the heparin infusion flow. Important data were obtained with those tests. A strong relationship between the polymeric area and the heparin dosage was observed. The polymeric materials initiate the blood coagulation process that must be reversed by the anticoagulant (heparin). A relationship between the blood flow through the LVAD and the heparin infusion flow was observed.

Coupling Pediatric Ventricle Assist Devices to the Fontan Circulation: Simulations with a Lumped-Parameter Model

In pediatric ventricular assist device (VAD) design, the process of matching device characteristics and dimensions to the relevant disease conditions poses a formidable challenge because the disease spectrum is more highly varied than for adult applications. One example arises with single-ventricle congenital defects, which demand palliative surgeries that create elevated systemic venous pressure and altered pulmonary hemodynamics. Substituting a mechanical pump as a right ventricle has long been proposed to eliminate the associated early and postoperative anomalies. A pulsatile lumped-parameter model of the single-ventricle circulation was developed to guide the preliminary design studies. Two special modules, the pump characteristics and the total cavopulmonary connection (TCPC) module, are introduced. The TCPC module incorporates the results of three-dimensional patient-specific computational fluid dynamics calculations, where the pressure drop in the TCPC anastomosis is calculated at the equal vascular lung resistance operating point for different cardiac outputs at a steady 60/40 inferior vena cava/superior vena cava flow split. Preliminary results obtained with the adult parameters are presented with no ventricle remodeling or combined larger-size single ventricle. A detailed literature review of single-ventricle function is provided. Coupling a continuous pump to the single-ventricle circulation brought both the pulmonary and systemic venous pressures back to manageable levels. Selected VADs provided an acceptable cardiac output trace of the single left ventricle, after initial transients. Remodeling of the systemic venous compliance plays a critical role in performance and is included in this study. Pulsatile operation mode with rotational speed regulation highlighted the importance of TCPC and pulmonary artery compliances. Four different pumps and three patient-specific anatomical TCPC pathologies were studied. Magnitudes of the equivalent TCPC resistances were found to be comparable to the vascular resistances of the normal baseline circulation, significantly affecting both the VAD design and hemodynamics.

Impact of nutritional status on mortality of 34 patients supported by ventricle assist devices (VAD)

Desseigne, P.; Bizouarn, P.; Treilhaud, M.; Videcoq, M.; Blanloeil, Y.; Duveau, D. Author Information