Mechanical Circulatory Support in Advanced Heart Failure: Single-Center Experience

Background

Currently, ventricular assist device (VAD) or total artificial heart (TAH) mechanical support provides an effective treatment of unstable patients with advanced heart failure. We report our single-center experience with mechanical circulatory support therapy.

Methods

From March 2002 to December 2012, 107 adult patients (mean age, 56.8 ± 9.9 y; range, 31–76 y) were primarly supported on temporary or long-term VAD or TAH support as treatment for refractory heart failure at our institution. Temporary extracorporeal radial VAD support (group A) was established in 49 patients (45.7%), and long-term paracorporeal and intracorporeal VAD or TAH (group B) in 58 patients (54.2%). Left ventricular (LVAD) support was established in 55 patients (51.4%; n = 33, Heartmate II; n = 6, Heartmate I XVE; n = 4, Heartware HVAD; and n = 12, Centrimag) and biventricular (BVAD/TAH) support (group B) in 28 patients (26.1%; n = 10, Thoratec paracorporeal; n = 2, Heartware HVAD, n = 1, Thoratec implantable; n = 1, Syncardia TAH; and n = 14, Centrimag). The temporary Centrimag was the only device adopted as isolated right ventricular (RVAD) support, and it was inserted in 24 patients (22.4%).

Results

In group A, overall mean support time was 10.2 ± 6.6 days (range, 3–43 d). In group B, LVAD mean support time was 357 ± 352.3 days (range, 1–902 d) and BVAD/TAH support time was 98 ± 82.6 days (range, 8–832 d). In group A, the overall success rate was 55.1% (27 patients). In group B, LVAD overall success rate was 74.4% (32 patients) and BVAD/TAH success rate was 50% (7 patients). Overall heart transplantation rate for both groups was 27.1% (n = 2, group A; n = 27, group B). Overall 1-year and 5-year survivals after heart transplantation were 72.4% (n = 21) and 58.6% (n = 17), respectively.

Conclusions

Mechanical circulatory support is an effective strategy even in cases of end-stage heart failure according to our experience. Further improvement of VAD and TAH technologies may support their adoption as an encouraging alternative to heart transplantation in the near future.     

Control strategy for biventricular assistance with mixed-flow pumps

A left ventricular assist device (LVAD) is an effective method to rescue severe heart failure. Although some require a biventricular assist, the control method for the biventricular assist device (BVAD) with a rotary pump is rarely shown. The objective of this study was to investigate the strategy for controlling BVAD with rotary pumps by in vivo studies. Using 5 piglets, we set a BVAD through a left thoracotomy and made global ischemia for 30 min by clamping the base of the ascending aorta. After unclamping, the analysis of pumping performance acted for 6 h reperfusion. We set the target flow of the LVAD and set the right ventricular assist device (RVAD) speed limit as less than when the atrial collapse occurs. To detect the ventricular collapse without any specific sensor, we calculated the index of current amplitude from motor current waveform and simultaneous mean current value. In all cases, over 6 h of observation was performed, and the RVAD was weaned almost automatically.     

左心室及双心室辅助装置对缺血心肌的影响

目的 比较左心室辅助装置（LVAD）和双心室辅助装置（BVAD）对缺血心肌再灌注后心脏血流动力学、心肌能量代谢物质和心肌超微结构中线粒体形态的影响。方法 将16只绵羊随机分为LVAD组和BVAD组,每组8只,常温阻断升主动脉25分钟,造成双心室缺血损伤的动物模型。结扎右颈内动脉远端,在心脏复跳后应用转子泵分别行LVAD（左心室－右颈内动脉径路）和BVAD（左心室－右颈内动脉和右心室－肺动脉径路）辅助循环120分钟,测定血流动力学,心肌三磷酸腺苷、磷酸肌酸、观察心肌超微结构变化。结果 施行BVAD或LVAD辅助循环的同时增加容量负荷能够显著改善心脏血流动力学,但LVAD组右心房压显著高于BVAD组（P＜0．05）;BVAD组右心室心肌三磷酸腺苷、磷酸肌酸含量和心肌线粒体比表面值均高于LVAD组（P＜0．05）。结论 BVAD与LVAD更有助于促进双心室缺血损伤心肌的功能恢复。     

In Vitro and In Vivo Characterization of Three Different Modes of Pump Operation When Using a Left Ventricular Assist Device as a Right Ventricular Assist Device

Dual rotary left ventricular assist devices (LVADs) have been used clinically to support patients with biventricular failure. However, due to the lower vascular resistance in the pulmonary circulation compared with its systemic counterpart, excessively high pulmonary flow rates are expected if the right ventricular assist device (RVAD) is operated at its design LVAD speed. Three possible approaches are available to match the LVAD to the pulmonary circulation: operating the RVAD at a lower speed than the LVAD (mode 1), operating both pumps at their design speeds (mode 2) while relying on the cardiovascular system to adapt, and operating both pumps at their design speeds while restricting the diameter of the RVAD outflow graft (mode 3). In this study, each mode was characterized using in vitro and in vivo models of biventricular heart failure supported with two VentrAssist LVADs. The effect of each mode on arterial and atrial pressures and flow rates for low, medium, and high vascular resistances and three different contractility levels were evaluated. The amount of speed/diameter adjustment required to accommodate elevated pulmonary vascular resistance (PVR) during support with mode 3 was then investigated. Mode 1 required relatively low systemic vascular resistance to achieve arterial pressures less than 100 mm Hg in vitro, resulting in flow rates greater than 6 L/min. Mode 2 resulted in left atrial pressures above 25 mm Hg, unless left heart contractility was near‐normal. In vitro, mode 3 resulted in expected arterial pressures and flow rates with an RVAD outflow diameter of 6.5 mm. In contrast, all modes were achievable in vivo, primarily due to higher RVAD outflow graft resistance (more than 500 dyn·s/cm⁵), caused by longer cannula. Flow rates could be maintained during instances of elevated PVR by increasing the RVAD speed or expanding the outflow graft diameter using an externally applied variable graft occlusion device. In conclusion, suitable hemodynamics could be produced by either restricting or not restricting the right outflow graft diameter; however, the latter required an operation of the RVAD at lower than design speed. Adjustments in outflow restriction and/or RVAD speed are recommended to accommodate varying PVR.     

Experimental study of optimal driving mode in biventricular assist device

It has been known that the ventricular assist device (VAD) is effective in profound ventricular failure refractory to conventional drugs and the intra-aortic balloon pumping. The patients with biventricular failure required biventricular mechanical support for survival. Until recently, biventricular assist device (BVAD) were applied in a few instances unfortunately. In this experimental study biventricular failure was induced by pulmonary artery banding and ligation of left anterior descending coronary artery in 20 pigs, and the BVAD was operated and the optimal driving mode was examined on the flow ratio of the right and left pumps. Group I animals were treated with BVAD, in the condition pump flow ratio right ventricular assist device (RVAD): left ventricular assist device (LVAD) = 1: less than 0.5 (4 pigs), group II were RVAD:LVAD = 1:0.5 less than or equal to less than 1 (8 pigs), and group III were RVAD:LVAD = 1:1 less than or equal to (8 pigs). CVP and RVEDP were decreased by operating the BVAD in all groups. In the group I, the flow of LVAD was less than a half of that of RVAD and the condition of excess left ventricular preload was elicited, and left ventricular failure was accelerated and it was difficult to maintain the systemic circulation. In contrast, in group II and III, the left ventricular preload was decreased, and left ventricular failure improved, and it was maintain the systemic circulation. PCWP/CVP was calculated as a method to determine clinically the right and left pump flow.(ABSTRACT TRUNCATED AT 250 WORDS)     

Complication Profile of the Berlin Heart EXCOR Biventricular Support in Children

In chronic cardiomyopathy, mechanical circulatory support (MCS) plays an increasingly important role for children as the shortage of suitable donor hearts increases waiting time on the transplant list. We report our experience with the paracorporal Berlin Heart EXCOR System (Berlin Heart AG, Berlin, Germany) used as a biventricuclar assist device (BVAD). Nine patients with a BVAD EXCOR system were treated between 2006 and 2012; out of these patients, four were less than 18 years old (6, 14, 14, and 17 years old). Their diagnoses were postcardotomy failure (n = 1), dilatative cardiomyopathy (n = 2), and terminal heart failure (n = 1). Overall survival, waiting time for heart transplantation (HTx) and complication profile for the BVAD were analyzed retrospectively. Thirty days' mortality was 25% (n = 1). One child died after 84 days on support due to cerebral bleeding. Mean support time was 218.75 days (4, 84, 262, and 525 days). Pump chamber exchange was necessary three times due to pump chamber thrombosis (n = 2) and partial pump chamber membrane rupture (n = 1). Complications included: sepsis (n = 1), drive line infection requiring intravenous antibiotics (n = 2), and recurrent epistaxis (n = 3). Two children were successfully transplanted after 262/525 days on BVAD; they are currently at home (follow‐up: 1.9 and 2.3 years). The EXCOR is a life‐saving MCS system suitable for long‐term paracorporeal biventricular assistance.     

Development of totally implantable pulsatile biventricular assist device

Approximately 10% to 15% of all patients implanted with left ventricular assist devices (LVADs) have required right heart support with another device. The necessity of aggressive biventricular support has already been proposed. Therefore, the totally implantable biventricular assist device (BVAD) was developed. The width of the BVAD main body was 87 mm, the thickness 67 mm, and the height 106 mm, while the weight was 785 g. The automatic control algorithm was developed to prevent lung edema and atrial rupture.     

Mechanical Circulatory Support for Severe Heart Failure After Operation

To evaluate the clinical results of circulatory support for severe heart failure after operation, we examined 62 patients (39 males and 23 females) who underwent circulatory support for postoperative heart failure from 1984 to 1996. Their ages ranged from 22 to 78 (mean 52) years. In 62 patients, 35 had valvular, 25 had ischemic, and 2 had congenital heart disease. Postoperation, 29 patients underwent venoarterial bypass (VAB), 20 had biventricular bypass (BVB), and 8 had left ventricular bypass (LVB). The remaining 5 patients received a pulsatile left ventricular assist device (LVAD). The weaning and discharge rates of the patients by type of support were 51.7% and 31.0% with VAB, 75.0% and 55.0% with BVB, 87.5% and 37.5% with LVB, and 60.0% and 40.0% with LVAD, respectively. The complete results of this series (64.5% weaning rate and 40.3% discharge rate) were acceptable.     

Assessment of right pump outflow banding and speed changes on pulmonary hemodynamics during biventricular support with two rotary left ventricular assist devices

The absence of an effective, easily implantable right ventricular assist device (RVAD) significantly diminishes long‐term treatment options for patients with biventricular heart failure. The implantation of a second rotary left ventricular assist device (LVAD) for right heart support is therefore being considered; however, this approach exhibits technical challenges when adapting current devices to produce the lower pressures required of the pulmonary circulation. Hemodynamic adaptation may be achieved by either reducing the rotational speed of the right pump impeller or reducing the diameter of the right outflow cannula by the placement of a restricting band; however, the optimal value and influence of changes to each parameter are not well understood. Hemodynamics were therefore investigated using different banding diameters of the right outflow cannula (3–6.5 mm) and pump speeds (500–4500 rpm), using two identical rotary blood pumps coupled to a pulsatile mock circulation loop. Reducing the speed of the right pump from 4900 rpm (for left ventricle support) to 3500 rpm, or banding the Ø10 mm (area 78.5 mm²) right outflow graft to Ø5.4 mm (22.9 mm²) produced suitable hemodynamics. Pulmonary pressures were most sensitive to banding diameters, especially when RVAD flow exceeded LVAD flow. This occurred between Ø5.3 and Ø6.5 mm (22.05–38.5 mm²) and speeds between 3200 and 4400 rpm, with the flow imbalance potentially leading to pulmonary congestion. Total flow was not affected by banding diameters and speeds below this range, and only increased slightly at higher values. Both right outflow banding or right pump speed reduction were found to be effective techniques to allow a rotary LVAD to be used directly for right heart support. However, the observed sensitivity to diameter and speed indicate that challenges may be presented when setting appropriate values for each patient, and control over these parameters is desirable.     

A novel,highly discriminatory risk model predicting acute severe right ventricular failure in patients undergoing continuous‐flow left ventricular assist device implant

Various risk models with differing discriminatory power and predictive accuracy have been used to predict right ventricular failure (RVF) after left ventricular assist device (LVAD) placement. There remains an unmet need for a contemporary risk score for continuous flow (CF)‐LVADs. We sought to independently validate and compare existing risk models in a large cohort of patients and develop a simple, yet highly predictive risk score for acute, severe RVF. Data from the Mechanical Circulatory Support Research Network (MCSRN) registry, consisting of patients who underwent CF‐LVAD implantation, were randomly divided into equal‐sized derivation and validation samples. RVF scores were calculated for the entire sample, and the need for a right ventricular assist device (RVAD) was the primary endpoint. Candidate predictors from the derivation sample were subjected to backward stepwise logistic regression until the model with lowest Akaike information criterion value was identified. A risk score was developed based on the identified variables and their respective regression coefficients. Between May 2004 and September 2014, 734 patients underwent implantation of CF‐LVADs [HeartMate II LVAD, 76% (n = 560), HeartWare HVAD, 24% (n = 174)]. A RVAD was required in 4.5% (n = 33) of the patients [Derivation cohort, n = 15 (4.3%); Validation cohort, n = 18 (5.2%); P = 0.68)]. 19.5% of the patients (n = 143) were female, median age at implant was 59 years (IQR, 49.4–65.3), and median INTERMACS profile was 3 (IQR, 2–3). RVAD was required in 4.5% (n = 33) of the patients. Correlates of acute, severe RVF in the final model included heart rate, albumin, BUN, WBC, cardiac index, and TR severity. Areas under the curves (AUC) for most commonly used risk predictors ranged from 0.61 to 0.78. The AUC for the new model was 0.89 in the derivation and 0.92 in the validation cohort. Proposed risk model provides very high discriminatory power predicting acute severe right ventricular failure and can be reliably applied to patients undergoing placement of contemporary continuous flow left ventricular assist devices.     

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.     

Pulmonary Valve Opening With Two Rotary Left Ventricular Assist Devices for Biventricular Support

Right ventricular failure is a common complication associated with rotary left ventricular assist device (LVAD) support. Currently, there is no clinically approved long‐term rotary right ventricular assist device (RVAD). Instead, clinicians have implanted a second rotary LVAD as RVAD in biventricular support. To prevent pulmonary hypertension, the RVAD must be operated by either reducing pump speed or banding the outflow graft. These modes differ in hydraulic performance, which may affect the pulmonary valve opening (PVO) and subsequently cause fusion, valvular insufficiency, and thrombus formation. This study aimed to compare PVO with the RVAD operated at reduced speed or with a banded outflow graft. Baseline conditions of systemic normal, hypo, and hypertension with severe biventricular failure were simulated in a mock circulation loop. Biventricular support was provided with two rotary VentrAssist LVADs with cardiac output restored to 5 L/min in banded outflow and reduced speed conditions, and systemic and pulmonary vascular resistances (PVR) were manipulated to determine the range of conditions that allowed PVO without causing left ventricular suction. Finally, RVAD sine wave speed modulation (±550 rpm) strategies (co‐ and counter‐pulsation) were implemented to observe the effect on PVO. For each condition, outflow banding had higher PVR (97 ± 20 dyne/s/cm⁵ higher) for when the pulmonary valve closed compared to reduced speed. In addition, counter‐pulsation demonstrated greater PVO than co‐pulsation and constant speed. For the purpose of reducing the risks of pulmonary valve insufficiency, fusion, and thrombotic event, this study recommends a RVAD with a steeper H‐Q gradient by banding and further exploration of RVAD speed modulation.     

Current Strategy for Severe Heart Failure with Mechanical Circulatory Support

Abstract: In the last 10 years, 37 patients received assisted circulation or a ventricular assist device after open-heart operations at the Heart Institute of Japan. After cardiovascular surgery, 12 patients underwent venoarte-rial bypass (VAB), 13 had biventricular bypass (BVB), 8 had left ventricular bypass (LVB), and the remaining 4 received a left ventricular assist device (LVAD). Weaning and discharge rates of the patients by type of circulatory supports were 41.7 and 25.0% with VAB, 69.3 and 46.2% with BVB, 87.5 and 37.5% with LVB, 75.0 and 50.0% with LVAD, and 44.4 and 11.1% with PCPS, respectively. Concerning complications of postcardiotomy circulatory support, hemorrhage and ventricular arrhythmia postcardiotomy circulatory support, hemorrhage, and ventricular arrhythmia (immature weaning) decreased with low-heparinized isolated left ventricular supports (i.e., LVB, LVAD). However, profound biventricular failure, infection, and multiple organ failure remain as possible complications with any type of assisted circulation. These results suggest that early application of circulatory support and appropriate selection of the mode of support and devices used are important for successful circulatory support.     

Preclinical Models for Translational Investigations of Left Ventricular Assist Device‐Associated von Willebrand Factor Degradation

Evidence suggests a major role for von Willebrand factor (vWF) in left ventricular assist device (LVAD)‐associated bleeding. However, the mechanisms of vWF degradation during LVAD support are not well understood. We developed: (i) a simple and inexpensive vortexer model; and (ii) a translational LVAD mock circulatory loop to perform preclinical investigations of LVAD‐associated vWF degradation. Whole blood was obtained from LVAD patients (n = 8) and normal humans (n = 15). Experimental groups included: (i) blood from continuous‐flow LVAD patients (baseline vs. post‐LVAD, n = 8); (ii) blood from normal humans (baseline vs. 4 h in vitro laboratory vortexer, ～ 2400 rpm, shear stress ～175 dyne/cm², n = 8); and (iii) blood from normal humans (baseline vs. 12 h HeartMate II mock circulatory loop, 10 000 rpm, n = 7). vWF multimers and degradation fragments were characterized with electrophoresis and immunoblotting. Blood from LVAD patients, blood exposed to in vitro supraphysiologic shear stress, and blood circulated through an LVAD mock circulatory loop demonstrated a similar profile of decreased large vWF multimers and increased vWF degradation fragments. A laboratory vortexer and an LVAD mock circulatory loop reproduced the pathologic degradation of vWF that occurs during LVAD support. Both models are appropriate for preclinical studies of LVAD‐associated vWF degradation.     

Cardiac Index Declines During Long‐Term Left Ventricular Device Support

To investigate longitudinal trends in valvular and ventricular function with long‐term left ventricular assist device (LVAD) therapy, we analyzed hemodynamic and echocardiographic data of patients with at least 2 years of continuous LVAD support. All 130 patients who underwent HeartMate II implantation at our institution between 2005 and 2012 were reviewed. Twenty patients had hemodynamic and echocardiographic evaluations in both the early (0–6 months) and late (2–3 years) postoperative period. Patients on inotropic therapy or temporary mechanical support were excluded. The average times of early and late hemodynamic evaluations were 59 ± 41 days and 889 ± 160 days, respectively. Cardiac index (CI) declined by an average of 0.4 L/min/m² (P = 0.04) with concomitant increase in pulmonary capillary wedge pressure (PCWP; P = 0.02). The right atrial pressure to PCWP (RAP:PCWP) ratio decreased during LVAD support suggesting improvement in right ventricular function. While there was an increase in degree of aortic insufficiency (AI) at the late follow‐up period (P = 0.008), dichotomization by median decline in CI (?0.4 L/min/m²) indicated no difference in prevalence of AI among the groups. CI declined in patients with HeartMate II after 2 years of continuous support. An increase in preload and afterload was observed in those with the greatest decline in CI.     

A modified implantation technique for temporary right ventricular assist device: Enabling ambulation and less invasive decannulation

This report describes our unique temporary right ventricular assist device (RVAD) implantation technique, which enables early mobilization even during biventricular support and subsequent less invasive RVAD removal without needing resternotomy upon recovery.     

Exercise Performance of Chronic Heart Failure Patients in the Early Period of Support by an Axial‐Flow Left Ventricular Assist Device as Destination Therapy

Axial‐flow left ventricular assist devices (LVADs) are increasingly used as destination therapy in end‐stage chronic heart failure (CHF), as they improve survival and quality of life. Their effect on exercise tolerance in the early phase after implantation is still unclear. The aim of this study was to evaluate the effect of LVADs on the exercise capacity of a group of CHF patients within 2 months after initiation of circulatory support. Cardiopulmonary exercise test data were collected for 26 consecutive LVAD‐implanted CHF patients within 2 months of initiation of assistance; the reference group consisted of 30 CHF patients not supported by LVAD who were evaluated after an episode of acute heart failure. Both LVAD and reference groups showed poor physical performance; LVAD patients achieved lower workload (LVAD: 36.3 ± 9.0 W, reference: 56.6 ± 18.2 W, P < 0.001) but reached a similar peak oxygen uptake (peak VO₂; LVAD: 12.5 ± 3.0 mL/kg/min, reference: 13.6 ± 2.9 mL/kg/min, P = ns) and similar percentages of predicted peak VO₂ (LVAD: 48.8 ± 13.9%, reference: 54.2 ± 15.3%, P = ns). While the values of the O₂ uptake efficiency slope were 12% poorer in LVAD patients than in reference patients (1124.2 ± 226.3 vs. 1280.2 ± 391.1; P = ns), the kinetics of VO₂ recovery after exercise were slightly better in LVAD patients (LVAD: 212.5 ± 62.5, reference: 261.1 ± 80.2 sec, P < 0.05). In the first 2 months after initiation of circulatory support, axial‐flow LVAD patients are able to sustain a low‐intensity workload; though some cardiopulmonary exercise test parameters suggest persistence of a marked physical deconditioning, their cardiorespiratory performance is similar to that of less compromised CHF patients, possibly due to positive hemodynamic effects beginning to be produced by the assist device.     

Transesophageal echocardiographic evaluation in mechanically assisted circulation

Transesophageal echocardiography (TEE) has assumed an increasing importance in cardiothoracic surgery, but its use in patients with mechanically assisted circulation is unclear. We performed TEE in 11 patients: total artificial heart (TAH) 2, right ventricular assist device (RVAD) 2, left ventricular assist device (LVAD) 6, biventricular assist device (BVAD) 1. TEE was helpful in three areas. (1) selection of the assist device (AD): evaluation of left and right ventricular function allows differentiation of left, right or biventricular failure. (2) management of patient and optimization of pump performance: in all patients, correct cannula position and pump flow could be identified. Right ventricular failure in the presence of LVAD was found to cause hemodynamic instability in 4 patients. In 1 patient with repeated RV dilation and hypotension despite RVAD, TEE allowed optimal pump settings to be determined. (3) weaning from AD: Recovery of ventricular function can be assessed prior to weaning and repeatedly monitored during weaning. TEE in TAH is limited to problems such as identification of atrial thrombus or inflow valve dysfunction. We conclude that TEE is useful in the setting of mechanically assisted circulation for AD selection, improvement of patient management, optimization of pump performance and during weaning from AD.     

HeartWare Ventricular Assist Device Implantation for Pediatric Heart Failure—A Single Center Approach

While pediatric HeartWare HVAD application has increased, determining candidacy and timing for initiation of pediatric VAD support has remained a challenge. We present our experience with a systematic approach to HVAD implantation as a bridge to pediatric heart transplantation. We performed a retrospective, single center review of pediatric patients (n = 11) who underwent HVAD implantation between September 2014 and January 2018. Primary endpoints evaluated were survival to heart transplantation, need for right ventricular assist device (RVAD) at any point, ongoing HVAD support, or death. Median patient age was 11 years (range: 3–16). Median BSA was 1.25 m² (range: 0.56–2.1). Heart failure etiologies requiring support were dilated cardiomyopathy (n = 8), myocarditis (n = 1), congenital mitral valve disease (n = 1), and single ventricle heart failure (n = 1). Median time from cardiac ICU admission for heart failure to HVAD placement was 15 days (range 3–55), based on standardized VAD implantation criteria involving imaging assessment and noncardiac organ evaluation. The majority of patients (91%) were INTERMACS Level 2 at time of implant. Three patients (27%) had CentriMag RVAD placement at time of HVAD implantation. Two of these three patients had successful RVAD explanation within 2 weeks. Median length of HVAD support was 60 days (range 6–405 days). Among the 11 patients, survival during HVAD therapy to date is 91% (10/11) with 9 (82%) bridged to heart transplantation and one (9%) continuing to receive support. Posttransplant survival has been 100%, with median follow‐up of 573 days (range 152–1126). A systematic approach to HVAD implantation can provide excellent results in pediatric heart failure management for a variety of etiologies and broad BSA range.     

Extracorporeal Life Support Bridge to Ventricular Assist Device: The Double Bridge Strategy

In patients requiring left ventricular assist device (LVAD) support, it can be difficult to ascertain suitability for long‐term mechanical support with LVAD and eventual transplantation. LVAD implantation in a shocked patient is associated with increased morbidity and mortality. Interest is growing in the utilization of extracorporeal life support (ECLS) as a bridge‐to‐bridge support for these critically unwell patients. Here, we reviewed our experience with ECLS double bridging. We hypothesized that ECLS double bridging would stabilize end‐organ dysfunction and reduce ventricular assist device (VAD) implant perioperative mortality. We conducted a retrospective review of prospectively collected data for 58 consecutive patients implanted with a continuous‐flow LVAD between January 2010 and December 2013 at The Alfred Hospital, Melbourne, Victoria, Australia. Twenty‐three patients required ECLS support pre‐LVAD while 35 patients underwent LVAD implantation without an ECLS bridge. Preoperative morbidity in the ECLS bridge group was reflected by increased postoperative intensive care duration, blood loss, blood product use, and postoperative renal failure, but without negative impact upon survival when compared with the no ECLS group. ECLS stabilization improved end‐organ function pre‐VAD implant with significant improvements in hepatic and renal dysfunction. This series demonstrates that the use of ECLS bridge to VAD stabilizes end‐organ dysfunction and reduces VAD implant perioperative mortality from that traditionally reported in these “crash and burn” patients.