Thrombotic Depositions on Right Impeller of Double‐Ended Centrifugal Total Artificial Heart In Vivo

The development of total artificial heart devices is a complex undertaking that includes chronic biocompatibility assessment of the device. It is considered particularly important to assess whether device design and features can be compatible long term in a biological environment. As part of the development program for the Cleveland Clinic continuous‐flow total artificial heart (CFTAH), we evaluated the device for signs of thrombosis and biological material deposition in four animals that had achieved the intended 14‐, 30‐, or 90‐day durations in each respective experiment. Explanted CFTAHs were analyzed for possible clot buildup at “susceptible” areas inside the pump, particularly the right pump impeller. Depositions of various consistency and shapes were observed. We here report our findings, along with macroscopic and microscopic analysis post explant, and provide computational fluid dynamics data with its potential implications for thrombus formation.     

Median Sternotomy or Right Thoracotomy Techniques for Total Artificial Heart Implantation in Calves

The choice of optimal operative access technique for mechanical circulatory support device implantation ensures successful postoperative outcomes. In this study, we retrospectively evaluated the median sternotomy and lateral thoracotomy incisions for placement of the Cleveland Clinic continuous‐flow total artificial heart (CFTAH) in a bovine model. The CFTAH was implanted in 17 calves (Jersey calves; weight range, 77.0–93.9 kg) through a median sternotomy (n = 9) or right thoracotomy (n = 8) for elective chronic implantation periods of 14, 30, or 90 days. Similar preoperative preparation, surgical techniques, and postoperative care were employed. Implantation of the CFTAH was successfully performed in all cases. Both methods provided excellent surgical field visualization. After device connection, however, the median sternotomy approach provided better visualization of the anastomoses and surgical lines for hemostasis confirmation and repair due to easier device displacement, which is severely limited following right thoracotomy. All four animals sacrificed after completion of the planned durations (up to 90 days) were operated through full median sternotomy. Our data demonstrate that both approaches provide excellent initial field visualization. Full median sternotomy provides larger viewing angles at the anastomotic suture line after device connection to inflow and outflow ports.     

Massive air embolism resulting in ischemic stroke after left ventricular assist device implantation

We present the first case of ischemic stroke secondary to massive air embolus during implantation of a left ventricular assist device (LVAD). The patient experienced a suction event at the time of aortic cannula removal. Despite the use of all standard deairing techniques and flooding the operative field with continuous‐flow carbon dioxide, a significant amount of air was delivered into the ascending aorta through the LVAD pump.     

Bridging to a Long‐Term Ventricular Assist Device With Short‐Term Mechanical Circulatory Support

Implanting short‐term mechanical circulatory support (MCS) devices as a bridge‐to‐decision is increasingly popular. However, outcomes have not been well studied in patients who receive short‐term MCS before receiving long‐term left ventricular assist device (LVAD) support. We analyzed outcomes in our single‐center experience with long‐term continuous‐flow (CF)‐LVAD recipients with pre‐implantation short‐term MCS. From November 2003 through March 2016, 526 patients (mean age, 54.7 ± 13.5 years) with chronic heart failure (mean ejection fraction, 21.7 ± 3.6%) underwent implantation of either the HeartMate II (n = 403) or the HeartWare device (n = 123). Before implantation, 269 patients received short‐term MCS with the TandemHeart, the Impella 2.5/5.0, an intra‐aortic balloon pump (IABP), venoarterial extracorporeal membrane oxygenation (VA‐ECMO), or the CentriMag. The short‐term MCS patients were compared with the CF‐LVAD–only patients regarding preoperative demographics, incidence of postoperative complications, and long‐term survival. The 269 patients received the following short‐term MCS devices: 57 TandemHeart, 27 Impella, 172 IABP, 12 VA‐ECMO, and 1 CentriMag. Survival at 30 days, 6 months, 1 year, and 2 years was 94.2, 87.2, 79.4, and 72.4%, respectively, for CF‐LVAD–only patients versus 91.0, 78.1, 73.4, and 65.6%, respectively, for short‐term MCS + CF‐LVAD patients (P = 0.17). Within the short‐term MCS group, survival at 24 months was poorest for patients supported with VA‐ECMO or the TandemHeart (P = 0.03 for both), and survival across all four time points was poorest for patients supported with VA‐ECMO (P = 0.02). Short‐term MCS was not an independent predictor of mortality in multivariate Cox regression models (hazard ratio = 1.12, 95% confidence interval = 0.84–1.49, P = 0.43). In conclusion, we found that using short‐term MCS therapy—except for VA‐ECMO—as a bridge to long‐term CF‐LVAD support was not associated with poorer survival.     

Third Generation Ventricular Assist Device: Mid‐Term Outcomes of the HeartWare HVAD in Pediatric Patients

The HeartWare HVAD is a small, third generation continuous flow pump that is intracorporeally placed for support of a failing ventricle in adult patients. This device is small in size when compared to other left ventricular assist devices and can therefore be used in smaller sized pediatric patients. We present our initial experience using the HVAD as a bridge to heart transplantation in the pediatric population. We performed a retrospective, single center, nonrandomized review of 17 pediatric patients who underwent HVAD implantation between June 2013 and March 2016. The primary endpoints evaluated in this study were overall survival to heart transplantation, ongoing device support, or death. In this patient cohort, nine (53%) of 17 patients were male. The median age of the patients was 13.4 ± 3.8 (range 5–17) years. The median body surface area was 1.4 ± 0.4(0.7–2) m². Etiologies of heart failure requiring HVAD support were dilated cardiomyopathy (n = 8), myocarditis (n = 5) and noncompaction cardiomyopathy (n = 4). The overall mean length of HVAD support was 254 ± 298 (range 2–804) days. A successful outcome (bridge to transplant and ongoing mechanical support) was achieved in 13 patients (76.5%). Of the 13 patients, nine (69.2%) were bridged to heart transplantation and four continue to receive support (30.7%) and are eligible for transplantation. Post‐transplant survival has been 100%, with a mean follow‐up of 296 ± 264.5 (range 18–785) days. The most common complication was pump thrombosis (23.5%) in follow‐up. Four patients (23.5%) experienced no complications. The HVAD continuous flow ventricular assist device can be safely used to bridge pediatric patients to cardiac transplantation. Favorable outcomes of this device are comparable to the adult population. This analysis demonstrated safe and effective implantation of the HVAD System in a child with a BSA of 0.7 m².     

Analysis of Cleveland Clinic continuous-flow total artificial heart performance using the Virtual Mock Loop: Comparison with an in vivo study

The Virtual Mock Loop (VML) is a mathematical model designed to simulate mechanism of the human cardiovascular system interacting with mechanical circulatory support devices. Here, we aimed to mimic the hemodynamic performance of Cleveland Clinic’s self-regulating continuous-flow total artificial heart (CFTAH) via VML and evaluate the accuracy of the VML compared with an in vivo acute animal study. The VML reproduced 124 hemodynamic conditions from three acute in vivo experiments in calves. Systemic/pulmonary vascular resistances, pump rotational speed, pulsatility, and pulse rate were set for the VML from in vivo data. We compared outputs (pump flow, left and right pump pressure rises, and atrial pressure difference) between the two systems. The pump performance curves all fell in the designed range. There was a strong correlation between the VML and the in vivo study in the left pump flow (r² = 0.84) and pressure rise (r² = 0.80), and a moderate correlation in right pressure rise (r² = 0.52) and atrial pressure difference (r² = 0.59). Although there is room for improvement in simulating right-sided pump performance of self-regulating CFTAH, the VML acceptably simulated the hemodynamics observed in an in vivo study. These results indicate that pump flow and pressure rise can be estimated from vascular resistances and pump settings.     

Building a Better Neonatal Extracorporeal Life Support Circuit: Comparison of Hemodynamic Performance and Gaseous Microemboli Handling in Different Pump and Oxygenator Technologies

Neurologic complications during neonatal extracorporeal life support (ECLS) are associated with significant morbidity and mortality. Gaseous microemboli (GME) in the ECLS circuit may be a possible cause. Advances in neonatal circuitry may improve hemodynamic performance and GME handling leading to reduction in patient complications. This study compared hemodynamic performance and GME handling using two centrifugal pumps (Maquet RotaFlow and Medos Deltastream DP3) and polymethylpentene oxygenators (Maquet Quadrox‐iD and Medos Hilite 800LT) in a neonatal ECLS circuit model. The experimental circuit was primed with Lactated Ringer's solution and packed human red blood cells (hematocrit 40%) and arranged in parallel with the RotaFlow and DP3 pump, Quadrox‐iD and Hilite oxygenator, and Better‐Bladder. Hemodynamic trials evaluating pressure drops and total hemodynamic energy (THE) were conducted at 300 and 500 mL/min at 36°C. GME handling was measured after 0.5 mL of air was injected into the venous line using the Emboli Detection and Classification Quantifier System with unique pump, oxygenator, and Better‐Bladder combinations. The RotaFlow pump and Quadrox oxygenator arrangement had lower pressure drops and THE loss at both flow rates compared to the DP3 pump and Hilite oxygenator (P < 0.01). Total GME volume and counts decreased with Better‐Bladder at both flow rates with all combinations (P < 0.01). Hemodynamic performance and energy loss were similar in all of the circuit combinations. The Better‐Bladder significantly decreased GME. All four combinations of pumps and oxygenators also performed similarly in terms of GME handling.     

Hydrogen Gas Does Not Ameliorate Renal Ischemia Reperfusion Injury in a Preclinical Model

In renal transplantation, ischemia reperfusion injury impairs early graft function and can reduce long term graft survival. Hydrogen has antioxidant and anti‐inflammatory properties that can reduce the effects of ischemic injury. The aim of this study was to examine the effects of hydrogen gas administered during reperfusion in a preclinical model of kidney ischemia reperfusion injury. Porcine kidneys underwent 15 min of warm ischemia followed by 22 h of cold ischemia. They were then reperfused for 6 h with whole autologous blood on an ex vivo reperfusion circuit. Paired kidneys were randomized to control (n = 6) (25% oxygen, 5% carbon dioxide, 70% nitrogen) or hydrogen (n = 6) (2% hydrogen, 25% oxygen, 5% carbon dioxide, 68% nitrogen) groups. Tissue, urine, and blood samples were collected at baseline and hourly throughout the reperfusion period. Baseline measurements were similar across groups. Following perfusion, there was no significant difference between control and hydrogen groups in urine output (693 mL vs. 608 mL, P = 0.86), renal blood flow (105.9 vs. 108 mL/min/100g, P = 0.89), acid‐base homeostasis, or creatinine clearance. There was a significant increase in cytokine levels from baseline to 6 h in both groups (IL‐1β P = 0.002; IL‐6 P = 0.004; IL‐8 P = 0.002). However, there were no significant differences in levels of inflammatory cytokines (IL1β, IL‐6, and IL‐8) between the groups. The administration of hydrogen gas did not improve renal function, reduce oxidative damage, or inflammation during the reperfusion of ischemically damaged kidneys.     

Impact of Residual Mitral Regurgitation on Right Ventricular Systolic Function After Left Ventricular Assist Device Implantation

Significant mitral regurgitation (MR) is thought to decrease after left ventricular assist device (LVAD) implantation, and therefore repair of mitral valve is not indicated in current practice. However, residual moderate and severe MR leads to pulmonary artery pressure increase, thereby resulting in right ventricular (RV) dysfunction during follow‐up. We examined the impact of residual MR on systolic function of the right ventricle by echocardiography after LVAD implantation. This study included 90 patients (mean age: 51.7 ± 10.9 years, 14.4% female) who underwent LVAD implantation (HeartMate II = 21, HeartWare = 69) in a single center between December 2010 and June 2014. Echocardiograms obtained at 3–6 months and over after implantation were analyzed retrospectively. RV systolic function was graded as normal, mild, moderate, and severely depressed. MR (≥moderate) was observed in 43 and 44% of patients at early and late period, respectively. Systolic function of the RV was severely depressed in 16 and 9% of all patients. Initial analysis (mean duration of support 174.3 ± 42.5 days) showed a statistically significant correlation between less MR and improved systolic function of RV (P = 0.01). Secondary echocardiographic analysis (following a mean duration of support of 435.1 ± 203 days) was also statistically significant for MR degree and RV systolic dysfunction (P = 0.008). Residual MR after LVAD implantation may cause deterioration of RV systolic function and cause right‐sided heart failure symptoms. Repair of severe MR, in selected patients such as those with severe pulmonary hypertension and depressed RV, may be considered to improve the patient's clinical course during pump support.     

Formation of Blood Foam in the Air Trap During Hemodialysis Due to Insufficient Automatic Priming of Dialyzers

We were encouraged to investigate the reasons for large amounts of foam observed in bloodlines during hemodialysis (HD). Foam was visible in the venous air trap within the Artis Gambro dialysis device. Estimates of the extent of foam were graded (0—no foam, 10—extensive foam) by two persons that were blind to the type of dialyzer used. Thirty‐seven patients were involved in the dialysis procedures. Consecutive dialyses were graded using dialyzers from Fresenius Medical Care (CorDiax dialyzers that were used for high flux HD—FX80 and FX100, and for hemodiafiltration—FX1000). The extracorporeal circuit was primed automatically by dialysate using Gambro Artis software 8.15 006 (Gambro, Dasco, Medolla Italy, Baxter, Chicago, IL, USA). The priming volume recommended by the manufacturer was 1100 mL, whereas our center uses 1500 mL. Extensive amounts of blood foam were visual in the air traps. Although the manufacturer recommended extension of priming volume up to 3000 mL, this did not eliminate the foam. Microbubble measurement during HD revealed the air to derive from the dialyzers. When changing to PF210H dialyzers (Baxter) and using a priming volume of 1500 mL, the foam was significantly less (P < 0.01). The extent of foam correlated with the size of the FX‐dialyzer surface (P = 0.002). The auto‐priming program was updated to version 8.21 by the manufacturer and the extent of foam in the air trap using FX dialyzers was now reduced and there was no longer a difference between FX and PF dialyzers, although less foam was still visible in the venous air trap during several dialyses. In conclusion, this study urgently calls attention to blood foam development in the venous air trap when using Artis devices and priming software 8.15 in combination with Fresenius dialyzers. Updated auto‐priming software (version 8.21) of Artis should be requested to reduce the extent of foam for the Fresenius dialyzers. Other interactions may also be present. We recommend further studies to clarify these problems. Meanwhile caution is warranted for the combined use of dialysis devices and dialyzers with incompatible automatic priming.     

Does an Open Recirculation Line Affect the Flow Rate and Pressure in a Neonatal Extracorporeal Life Support Circuit With a Centrifugal or Roller Pump?

The objective of this study is to evaluate the impact of an open or closed recirculation line on flow rate, circuit pressure, and hemodynamic energy transmission in simulated neonatal extracorporeal life support (ECLS) systems. The two neonatal ECLS circuits consisted of a Maquet HL20 roller pump (RP group) or a RotaFlow centrifugal pump (CP group), Quadrox‐iD Pediatric oxygenator, and Biomedicus arterial and venous cannulae (8 Fr and 10 Fr) primed with lactated Ringer's solution and packed red blood cells (hematocrit 35%). Trials were conducted at flow rates ranging from 200 to 600 mL/min (200 mL/min increments) with a closed or open recirculation line at 36°C. Real‐time pressure and flow data were recorded using a custom‐based data acquisition system. In the RP group, the preoxygenator flow did not change when the recirculation line was open while the prearterial cannula flow decreased by 15.7–20.0% (P < 0.01). Circuit pressure, total circuit pressure drop, and hemodynamic energy delivered to patients also decreased (P < 0.01). In the CP group, the prearterial cannula flow did not change while preoxygenator flow increased by 13.6–18.8% (P < 0.01). Circuit pressure drop and hemodynamic energy transmission remained the same. The results showed that the shunt of an open recirculation line could decrease perfusion flow in patients in the ECLS circuit using a roller pump, but did not change perfusion flow in the circuit using a centrifugal pump. An additional flow sensor is needed to monitor perfusion flow in patients if any shunts exist in the ECLS circuit.     

Development of a Tissue‐Engineered Artificial Ligament: Reconstruction of Injured Rabbit Medial Collateral Ligament With Elastin‐Collagen and Ligament Cell Composite Artificial Ligament

Ligament reconstruction using a tissue‐engineered artificial ligament (TEAL) requires regeneration of the ligament‐bone junction such that fixation devices such as screws and end buttons do not have to be used. The objective of this study was to develop a TEAL consisting of elastin‐coated polydioxanone (PDS) sutures covered with elastin and collagen fibers preseeded with ligament cells. In a pilot study, a ring‐type PDS suture with a 2.5 mm (width) bone insertion was constructed with/without elastin coating (Ela‐coat and Non‐coat) and implanted into two bone tunnels, diameter 2.4 mm, in the rabbit tibia (6 cases each) to access the effect of elastin on the bond strength. PDS specimens taken together with the tibia at 6 weeks after implantation indicated growth of bone‐like hard tissues around bone tunnels accompanied with narrowing of the tunnels in the Ela‐coat group and not in the Non‐coat group. The drawout load of the Ela‐coat group was significantly higher (28.0 ± 15.1 N, n = 4) than that of the Non‐coat group (7.6 ± 4.6 N, n = 5). These data can improve the mechanical bulk property of TEAL through extracellular matrix formation. To achieve this TEAL model, 4.5 × 10⁶ ligament cells were seeded on elastin and collagen fibers (2.5 cm × 2.5 cm × 80 µm) prior to coil formation around the elastin‐coated PDS core sutures having ball‐shape ends with a diameter of 2.5 mm. Cell‐seeded and cell‐free TEALs were implanted across the femur and the tibia through bone tunnels with a diameter of 2.4 mm (6 cases each). There was no incidence of TEAL being pulled in 6 weeks. Regardless of the remarkable degradation of PDS observed in the cell‐seeded group, both the elastic modulus and breaking load of the cell‐seeded group (n = 3) were comparable to those of the sham‐operation group (n = 8) (elastic modulus: 15.4 ± 1.3 MPa and 18.5 ± 5.7 MPa; breaking load: 73.0 ± 23.4 N and 104.8 ± 21.8 N, respectively) and higher than those of the cell‐free group (n = 5) (elastic modulus: 5.7 ± 3.6 MPa; breaking load: 48.1 ± 11.3 N) accompanied with narrowed bone tunnels and cartilage matrix formation. These data suggest that elastin increased the bond strength of TEAL and bone. Furthermore, our newly developed TEAL from elastin, collagen, and ligament cells maintained the strength of the TEAL even if PDS was degraded.     

Transplantation of Cold Stored Porcine Kidneys After Controlled Oxygenated Rewarming

The concept of “controlled oxygenated rewarming” (COR) using ex vivo machine perfusion after cold storage was evaluated as tool to improve renal graft function after transplantation. Renal function after 20 min warm ischemia and 21 h cold storage was studied in an auto‐transplant model in pigs (25–30 kg, n = 6 per group). In the study group, preimplant ex vivo machine perfusion for 90 min was added after cold storage, including gentle warming up of the graft to 20°C (COR). Kidneys that were only cold stored for 21 h served as controls. In vivo follow up was one week; the remaining native kidney was removed during transplantation. COR significantly improved cortical microcirculation upon early reperfusion and reduced free radical mediated injury and cellular apoptosis. Post‐transplant kidney function (peak levels in serum) was also largely and significantly improved in comparison to the control group. A weak inverse correlation was found between renal flow during COR and later peak creatinine after transplantation (r² = 0.5), better values were seen for oxygen consumption, measured during machine perfusion at 20°C (r² = 0.81). Gentle graft rewarming prior to transplantation by COR improves post‐transplant graft outcome and may also be a valuable adjunct in pretransplant graft assessment.     

Successful Bridge‐to‐Transplant of Functionally Univentricular Patients With a Modified Continuous‐Flow Ventricular Assist Device

A continuous flow extracorporeal ventricular assist device (VAD) was modified to support functionally univentricular infants and children awaiting heart transplantation. A centrifugal VAD, designed to flow from 1.5 to 8 L/min, was used as a bridge‐to‐transplant in four patients with functionally univentricular circulation. A variable restrictive recirculation shunt permitted lower flow ranges in small patients. In hypoxic patients, an oxygenator was incorporated into the circuit. From 2012 to 2015, the modified VAD was placed in four patients with Glenn physiology. Age ranged from 0.97 to 6.98 years (median = 2.2 yrs). Body surface area ranged from 0.41 to 0.84 m² (median = 0.54 m²). One patient was on extracorporeal membrane oxygenation prior to VAD. A recirculation shunt was used in three patients. Three patients required temporary use of an oxygenator for 4, 10, and 27 days. Median time on the VAD was 32.3 days (range = 23–43 days). A decrease in the cavopulmonary pressure was noted in all patients, as was a fall in the B‐type natriuretic peptide. Three patients survived transplant and were discharged at 28–82 days post‐transplantation. One patient died after 35 days of support. Two patients experienced major bleeding events. Two patients experienced cerebrovascular accidents, one major and one minor. The centrifugal VAD successfully supported palliated functionally univentricular patients awaiting heart transplantation. The modified recirculation shunt facilitated the successful support of patients in whom optimal flows were substantially lower than that recommended by the manufacturer. The continuous‐flow VAD effectively decompressed the cavopulmonary system. The design allowed placement of an in‐line oxygenator in hypoxic patients. Further investigation is required to decrease the thromboembolic events, and associated morbidity, in patients supported with this device.     

Changes in Total Cardiac Output and Oxygen Extraction During Exercise in Patients Supported With an HVAD Left Ventricular Assist Device

Following implantation of a left ventricular assist device (LVAD), acceptable functional performance is now being achieved; however, peak VO₂ and peak work load (watts) remain considerably limited. Maximum physical capacity is essentially dependent on generated cardiac output (CO) and arteriovenous oxygen difference (avDO₂). We investigated the changes in CO and avDO₂ during exercise in LVAD patients with an HVAD pump (HeartWare Inc., Framingham, MA, USA). Approximately 6 weeks after implantation, 20 patients (100% male, 60.8 ± 7.3 years old, BMI 25.7 ± 3.3) underwent a six‐minute walk test (6MWT), a cardiopulmonary exercise test (CPET), and noninvasive hemodynamic measurement. The mean six‐minute walking distance (6MWD) was 403 m (68% of predicted), and mean peak VO₂ was 10.9 mL/kg/min (39% of predicted). Mean total CO improved from 3.8 L at rest to 7.0 L at maximum exercise. The mean avDO₂ increased from 7.4 mL/dL (44% of oxygen content) at rest to 13.2 mL/dL (75% of oxygen content) at maximum exercise. There was a significant increase in both total CO (P < 0.01) and avDO₂ (P < 0.05) between rest and sub‐maximum exercise. As exercise levels increased, however, no further significant changes were achieved. Long‐term studies, especially in combination with exercise programs, would be desirable in order to observe the development of these parameters.     

Hybrid Continuous‐Flow Total Artificial Heart

Clinical studies using total artificial hearts (TAHs) have demonstrated that pediatric and adult patients derive quality‐of‐life benefits from this form of therapy. Two clinically‐approved TAHs and other pumps under development, however, have design challenges and limitations, including thromboembolic events, neurologic impairment, infection risk due to large size and percutaneous drivelines, and lack of ambulation, to name a few. To address these limitations, we are developing a hybrid‐design, continuous‐flow, implantable or extracorporeal, magnetically‐levitated TAH for pediatric and adult patients with heart failure. This TAH has only two moving parts: an axial impeller for the pulmonary circulation and a centrifugal impeller for the systemic circulation. This device will utilize the latest generation of magnetic bearing technology. Initial geometries were established using pump design equations, and computational modeling provided insight into pump performance. The designs were the basis for prototype manufacturing and hydraulic testing. The study results demonstrate that the TAH is capable of delivering target blood flow rates of 1–6.5 L/min with pressure rises of 1–92 mm Hg for the pulmonary circulation and 24–150 mm Hg for the systemic circulation at 1500–10 000 rpm. This initial design of the TAH was successful and serves as the foundation to continue its development as a novel, more compact, nonthrombogenic, and effective therapeutic alternative for infants, children, adolescents, and adults with heart failure.     

Managing Traps and Pitfalls During Initial Steps of an ECMO Retrieval Program Using a Miniaturized Portable System: What Have We Learned From the First Two Years?

The aim of this study was to provide early and mid‐term results of the newly established extracorporeal membrane oxygenation (ECMO) retrieval service in a tertiary cardiothoracic center using the miniaturized portable Cardiohelp System (Maquet, Rastatt, Germany). A particular attention was paid to organizational and logistic specifics as well as challenges and pitfalls associated with initial phase of the program. From January 2015 until January 2017 a heterogenic group of 28 consecutive patients underwent ECMO implantation in distant hospitals for acute cardiac, pulmonary or combined failure as a bridge‐to‐decision and were subsequently transported to our institution. Each cannulation was performed bedside on intensive care units (ICU) using the Seldinger's technique. Early outcomes and mid‐term overall survival with up to two‐year follow‐up along with the impact of ongoing cardiopulmonary resuscitation (CPR) on outcome were presented. Also, changes in hemodynamics and tissue perfusion factors 24 h after ECMO implantation were evaluated. ECMO implantations were performed in 15 distant departments with the median distance of 23(10;40) (maximum 60) km. A total of 15 patients (54%) were cannulated under CPR with the median duration of 30(20;110) (maximum 180) min. After 24 h of support there were significant improvements in SvO₂ (P = 0.021), mean arterial pressure (P = 0.027), FiO₂ (P = 0.001), lactate (P = 0.001), and pH (P < 0.001). The mean ECMO support duration was 96 ± 100 (maximum 384) hours, whereas 11 patients (40%) were weaned off support and discharged from hospital. Overall cumulative survival in patients without the need for CPR was 61.5% at one week and 38.5% at 1 month, 6 month, and 1 year, whereas patients requiring CPR survived in 40% at one week, and 33.3% at 1 month, 6 month, and 1 year (Log‐Rank (Mantel‐Cox) P = 0.374, Breslow (Generalized Wilcoxon) P = 0.162). Our initial experience shows that launching new ECMO retrieval programs in centers with sufficient ICU capacities and local ECMO experience can be feasible and associated with acceptable “real world” results despite the initial learning curve. Rapid logistical organization and team flexibility are the key points to ensure comparable survival of patients requiring prolonged CPR.     

Central Extracorporeal Life Support With Left Ventricular Decompression to Berlin Heart Excor: A Reliable “Bridge to Bridge” Strategy in Crash and Burn Patients

The aim of this study was to compare patients with severe biventricular heart failure who underwent Berlin Heart Excor implantation with (cardiogenic shock [CS] status) or without the need for preoperative extracorporeal life support (ECLS) as a bridge to long‐term device. A total of 40 consecutive patients with severe biventricular heart failure underwent Berlin Heart Excor implantation with (CS status, n = 20, 50%) or without (control, n = 20, 50%) the need for preoperative ECLS as a bridge to long‐term device from March 2007 to May 2015 at our institution. Demographics and preoperative baseline characteristics as well as early and long‐term outcomes including mortality and complication rates were retrospectively compared between the two groups. There were no statistically significant differences in terms of demographics and most preoperative clinical characteristics. The mean age in the ECLS (CS group) and control group was 43.5 ± 19.4 and 41.3 ± 16.4 (P = 0.705), whereas 20 and 25% of patients were females (P = 1.000). However, patients from the ECLS group had preoperatively higher lactate (P = 0.037), aspartate aminotransferase (P < 0.001), and alanine aminotransferase (P < 0.001) levels, all of them significantly decreased after surgery (P  = 0.004, P = 0.017, and P = 0.001, respectively) and did not show any statistical differences to the corresponding values from the control group (P = 0.597, P = 0.491, and P = 0.339, respectively). Postoperatively, patients from the control and ECLS groups had statistically similar incidences of liver failure (30 vs. 35%, P = 0.736), renal failure (45 vs. 70%, P = 0.110), need for reopening (35 vs. 60%, P = 0.113), major cerebrovascular events (35 vs. 30%, P = 0.736), sepsis (10 vs. 25%, P = 0.407), wound infection (20 vs. 30%, P = 0.716), abdominal ischemia requiring surgery (28.6 vs. 36.8%, P = 0.719), and acute respiratory distress syndrome (25 vs. 35.3%, P = 1.000). The proportion of patients who were bridged to transplantation was statistically similar between the ECLS and the control groups (40 vs. 52.6%, P = 0.429). Furthermore, there were no statistically significant differences in terms of early (Breslow [generalized Wilcoxon] P = 0.907) and long‐term (log‐rank [Mantel–Cox] P = 0.787) overall cumulative survival accounting for 30‐day survival of 75 versus 75%, 6‐month survival of 60 versus 55%, 1‐year survival of 54 versus 40%, and 7‐year survial of 47 versus 40% in the control and ECLS groups, respectively. ECLS in critical CS as a bridge to implantation of the Berlin Heart Excor ventricular assist device is safe and is associated with improvement in end‐organ function leading to similar excellent early and long‐term survival and incidences of major complications as in patients without the need for preoperative ECLS support.     

In Vitro Evaluation of an Alternative Neonatal Extracorporeal Life Support Circuit on Hemodynamic Performance and Bubble Trap

The objective of this study was to evaluate an alternative neonatal extracorporeal life support (ECLS) circuit with a RotaFlow centrifugal pump and Better‐Bladder (BB) for hemodynamic performance and gaseous microemboli (GME) capture in a simulated neonatal ECLS system. The circuit consisted of a Maquet RotaFlow centrifugal pump, a Quadrox‐iD Pediatric diffusion membrane oxygenator, 8 Fr arterial cannula, and 10 Fr venous cannula. A “Y” connector was inserted into the venous line to allow for comparison between BB and no BB. The circuit and pseudopatient were primed with lactated Ringer's solution and packed human red blood cells (hematocrit 35%). All hemodynamic trials were conducted at flow rates ranging from 100 to 600 mL/min at 36°C. Real‐time pressure and flow data were recorded using a data acquisition system. For GME testing, 0.5 cc of air was injected via syringe into the venous line. GME were detected and characterized with or without the BB using the Emboli Detection and Classification Quantifier (EDAC) System. Trials were conducted at flow rates ranging from 200 to 500 mL/min. The hemodynamic energy data showed that up to 75.2% of the total hemodynamic energy was lost from the circuit. The greatest pressure drops occurred across the arterial cannula and increased with increasing flow rate from 10.1 mm Hg at 100 mL/min to 114.3 mm Hg at 600 mL/min. The EDAC results showed that the BB trapped a significant amount of the GME in the circuit. When the bladder was removed, GME passed through the pump head and the oxygenator to the arterial line. This study showed that a RotaFlow centrifugal pump combined with a BB can help to significantly decrease the number of GME in a neonatal ECLS circuit. Even with this optimized alternative circuit, a large percentage of the total hemodynamic energy was lost. The arterial cannula was the main source of resistance in the circuit.     

Survival Results After Implantation of Intrapericardial Third‐Generation Centrifugal Assist Device: An INTERMACS‐Matched Comparison Analysis

Reports on third‐generation centrifugal intrapericardial pumps (HeartWare International, Inc., Framingham, MA, USA) have shown better survival results than the previous‐generation devices. However, outcomes depending on the preoperative level of stability can substantially differ, resulting in a limited analysis of potentialities and drawbacks of a given device. In the present study we sought to compare in our single‐center experience the survival results of this third‐generation device with previous left ventricular systems taking into account the different preoperative Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) levels. Between February 1993 and March 2012, 287 patients underwent assist device implantation in our university hospital (INTERMACS Level 1‐2 = 158 patients; INTERMACS Level 3‐4‐5 = 129 patients). Assist devices implanted were: Group A (HVAD HeartWare, n = 52), group B (previous continuous‐flow ventricular assist device [VAD], InCor [Berlin Heart, Berlin, Germany], n = 37; VentrAssist [VentraCor, Inc., Chatswood, NSW, Australia], n = 7; DeBakey [MicroMed Cardiovascular, Inc., Houston, TX, USA], n = 32), and group C (pulsatile systems, n = 159). After cumulative support duration of 54 436 days and a mean follow‐up of 6.21 ± 7.46 months (range 0–45.21 months), log‐rank analysis revealed a survival for group A of 82.0%, 70.4%, and 70.4%; for group B of 84.0%, 48.2%, 33.7%; and for group C of 71.6%, 46.1%, 33.8%, at 1, 12, and 24 months respectively, with a significantly (P = 0.013) better outcome for group A. When stratifying the survival on the basis of INTERMACS level, no significant survival improvement was observed among all patients who underwent VAD implantation in INTERMACS 1‐2 (P = 0.47). However, among patients who underwent elective VAD implantation (INTERMACS 3‐4‐5), group A had a significantly better outcome (P = 0.005) compared with the other INTERMACS‐matched groups (B,C) with a survival rate of 88.8% in group A versus 34.2% in group B and 45.6% in group C at 24 months, respectively. Elective HVAD system implantation shows improved survival benefit over the other INTERMACS‐matched devices. Moreover, preoperative unstable hemodynamics resulted in a poor prognosis independently from the pump generation.