Right ventricular failure after left ventricular assist device implantation: the need for an implantable right ventricular assist device

Right ventricular failure after implantation of a left ventricular assist device is an unremitting problem. Consideration of portal circulation is important for reversing liver dysfunction and preventing multiple organ failure after left ventricular assist device implantation. To achieve these objectives, it is imperative to maintain the central venous pressure as low as possible. A more positive application of right ventricular assistance is recommended. Implantable pulsatile left ventricular assist devices cannot be used as a right ventricular assist device because of their structure and device size. To improve future prospects, it is necessary to develop an implantable right ventricular assist device based on a rotary blood pump.     

6 months of "temporary" support by Levitronix left ventricular assist device

An otherwise healthy 47-year-old man presented to the emergency department in cardiogenic shock after suffering a massive myocardial infarction due to left main occlusion. He was initially supported by extracorporeal membrane oxygenation and subsequently was converted to paracorporeal support with a Levitronix left ventricular assist device. He experienced multiple postoperative complications including renal failure, respiratory failure, retroperitoneal hematoma requiring suspension of anticoagulation, and fungal bloodstream infection precluding transition to an implantable device. He was reconditioned and successfully underwent orthotopic heart transplant 183 days after presentation. A discussion of the relevant issues is included.     

Long‐term support by left ventricular assist device for arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heart muscle disorder characterized by right ventricular enlargement, right heart failure (HF), and ventricular arrhythmias which lead to sudden death especially in young adults. Current recommendations for management of patients with ARVC are antiarrhythmic medications, catheter ablation, and implantable cardioverter defibrillator therapy to prevent sudden cardiac death. However, despite these treatments, few patients suffer from recurrent ventricular arrhythmias or HF unresponsive to conventional management. Heart transplantation (HTx) is a preferred treatment for these cases, but because of a persistent donor heart shortage in Japan, ventricular assist device (VAD) support has become an important option for a management of the end‐stage ARVC. Previous articles reported 4 cases of a successful management by left ventricular assist device (LVAD), but the longest interval of LVAD support was only 333 days. We present 3 cases of ARVC patients who were successfully managed by LVAD implantation for more than a year. These 3 cases are unconventional examples of ARVC patients, considering the nature of the disease. The novelty of these cases should be taken in the context of the extremely long waiting period for HTx in Japan.     

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.     

Prediction of right ventricular failure after left ventricular assist device implantation in patients with heart failure: a meta-analysis comparing echocardiographic parameters

 Open in a separate windowOBJECTIVESBetween 10% and 40% of patients who receive a left ventricular assistance device (LVAD) suffer from right ventricular failure (RVF) shortly after the device is implanted. Patients with post-LVAD RVF tend to have poor outcomes. Only a few predictive factors concerning the right ventricle (RV) have been investigated. Our goal was to search for non-invasive variables that correlate with RV function, focusing on echocardiographic parameters of the RV. METHODSWe selected 3 parameters: tricuspid annular plane systolic excursion, right ventricular fractional area change and right ventricular global longitudinal strain. We searched the literature and pooled relevant studies in a meta-analysis. Finally, we performed a statistical analysis to confirm whether each parameter was a reliable predictor of RVF after LVAD implantation.RESULTSWe retained 19 articles involving a total of 1561 patients. We found a pooled standardized mean deviation of −0.13 cm for the tricuspid annular plane systolic excursion, with the lower and upper tails of −0.21 and −0.04 cm, respectively. Concerning the right ventricular fractional area change, the averaged standardized mean deviation was equal to −2.61%, with the lower and upper extremities of −4.12% and −1.09%, respectively. Finally, regarding the global longitudinal strain, the standardized mean deviation was equal to −2.06% with an uncertainty value between −3.23% and −0.88%.CONCLUSIONSThe tricuspid annular plane systolic excursion could be a reliable parameter in RVF prediction. The right ventricular fractional area change and global longitudinal strain are likely to be stronger predictors of RVF after LVAD implantation. Prospective studies should be carried out to confirm this observation.     

Design and initial testing of a mock human circulatory loop for left ventricular assist device performance testing

A mock circulatory loop, which simulates the human circulatory system, is needed to bench test the various versions of continuous flow (CF) left ventricular assist devices (LVADs). This article describes the design and initial testing of such a loop. The loop consists of: (1) pulsatile left and right cardiac simulators; (2) air/water tanks to model the venous and arterial compliances; (3) tygon tubes to model the venous, arterial, and other system flow resistances; and (4) a tuning clamp to model the variation in system resistance characteristics under different cardiac pressure/flow conditions. Several loop measurements were carried out without an LVAD to verify the cardiovascular modeling of a healthy person in sleep, rest, and physical activity, and in different pathological states, and compared to the data found in the literature to validate the loop performance prior to LVAD testing.     

Ventricular arrhythmias following continuous-flow left ventricular assist device implantation: A systematic review

Ventricular arrhythmias (VA) are not uncommon after continuous-flow left ventricular assist device (CF-LVAD) implantation. In this systematic review, we sought to identify the patterns of VA that occurred following CF-LVAD implantation and evaluate their outcomes. An electronic search was performed to identify all articles reporting the development of VA following CF-LVAD implantation. VA was defined as any episode of ventricular fibrillation (VF) or sustained (>30 seconds) ventricular tachycardia (VT). Eleven studies were pooled for the analysis that included 393 CF-LVAD patients with VA. The mean patient age was 57 years [95%CI: 54; 61] and 82% [95%CI: 73; 88] were male. Overall, 37% [95%CI: 19; 60] of patients experienced a new onset VA after CF-LVAD implantation, while 60% [95%CI: 51; 69] of patients had a prior history of VA. Overall, 88% of patients [95%CI: 78; 94] were supported on HeartMate II CF-LVAD, 6% [95%CI: 3; 14] on HeartWare HVAD, and 6% [95%CI: 2; 13] on other CF-LVADs. VA was symptomatic in 47% [95%CI: 28; 68] of patients and in 50% [95%CI: 37; 52], early VA (<30 days from CF-LVAD) was observed. The 30-day mortality rate was 7% [95%CI: 5; 11]. Mean follow-up was 22.9 months [95%CI: 4.8; 40.8], during which 27% [95%CI: 17; 39] of patients underwent heart transplantation. In conclusion, approximately a third of patients had new VA following CF-LVAD placement. VA in CF-LVAD patients is often symptomatic, necessitates treatment, and carries a worse prognosis.     

The influence of preoperative dialysis on survival after continuous-flow left ventricular assist device implantation

 Open in a separate windowOBJECTIVESDialysis is considered a contraindication to continuous-flow left ventricular assist device (CF-LVAD) implantation. We evaluated clinical outcomes and survival in carefully selected, low-risk patients with renal failure who required dialysis before CF-LVAD implantation.METHODSWe extracted medical record data of patients who underwent CF-LVAD placement at our centre between 1 January 2006 and 31 August 2017, with 2 clinical scenarios: those who required long-term (>14 days) dialysis and those who required short-term (≤14 days) dialysis immediately before implantation. Demographic, clinical and intraoperative characteristics and survival outcomes were assessed.RESULTSOf 621 patients who underwent CF-LVAD implantation during the study period, 31 underwent dialysis beforehand. Of these, 17 required long-term dialysis (13 haemodialysis, 4 peritoneal dialysis), and 14 underwent short-term haemodialysis. Compared with the long-term dialysis patients, the short-term dialysis patients were more likely to be Interagency Registry for Mechanically Assisted Circulatory Support profile 1–2 (92.9% vs 70.6%; P < 0.001), to have needed preoperative mechanical circulatory support (78.6% vs 70.6%; P < 0.01) and to have higher in-hospital mortality (85.7% vs 29.4%; P = 0.01). Patients stable on long-term dialysis had acceptable overall survival and markedly better 6-month and 1-year survival than those with short-term dialysis before implantation (64.7% vs 14.3% and 58.8% vs 7.1%, respectively; P < 0.001).CONCLUSIONSCarefully selected patients who are stable on long-term dialysis have acceptable survival rates after CF-LVAD implantation. Patients with acute renal failure had much poorer outcomes than those with chronic end-stage renal disease.     

Sternectomy for Candida albicans sternal osteomyelitis after left ventricular assist device implantation

Fungal osteomyelitis is an uncommon complication after cardiac surgery and associated with high mortality. A case of Candida albicans and Staphylococcus epidermidis osteomyelitis with device infection after implantation of a left ventricular assist device in a 60-year-old male patient is presented here. After clinical identification and confirmation with microbiological examinations and fluorodeoxyglucose positron emission tomography (FDG-PET) scan, debridement was performed. Surgical specimens grew C. albicans and S. epidermidis. Fluconazole, daptomycin, and negative pressure wound therapy were initiated, but failed to achieve healing. Total sternectomy and pectoralis flap reconstruction were performed. There was no recurrent infection for C. albicans on a prolonged antifungal regime. The combination of antifungal therapy and aggressive surgical debridement may be useful to control fungal osteomyelitis.     

Cadaver fitting study of the DexAide right ventricular assist device

The DexAide right ventricular assist device (RVAD) has been developed to provide an implantable RVAD option to surgeons. The aim of this study was to determine the optimal cannula design and optimal implantation location of the DexAide RVAD in preparation for its clinical use. Separately, a HeartMate XVE left ventricular assist device (LVAD) and CorAide LVAD models were implanted into the preperitoneal and right thoracic space, and the anatomical fit of the DexAide RVAD was evaluated in five preserved human cadavers. The DexAide RVAD inflow cannula was inserted through the diaphragmatic surface of the right ventricle and the outflow was directed to the pulmonary artery. Right thoracic implantation of the DexAide RVAD provided an excellent fit with either the HeartMate or CorAide LVAD in all cadavers. The results of this study will guide improvements in the designs of cannulae and implantation of the DexAide RVAD in future clinical applications.     

An advanced physiological controller design for a left ventricular assist device to prevent left ventricular collapse

A continuous flow left ventricle assist device (LVAD), which is mainly composed of a continuous flow blood pump and a physiological controller, has only one control input, the rotational speed of the pump, but at least three performance criteria to meet. The challenge for the physiological controller of a long-term continuous flow LVAD is the adaptability to different cardiovascular loading situations and the ability to handle systemic and parametric uncertainties with only one control input. The physiological LVAD controller presented in this article exhibits good performance in terms of the three performance criteria in different physiological loading conditions, such as disturbance, resting, and moderate exercise, for a patient with congestive heart failure. The collapse of the left ventricle, which is an inherent problem for a continuous flow LVAD, has been prevented because of the control algorithm design.     

Clinical characteristics and outcomes of patients requiring prolonged inotropes after left ventricular assist device implantation

Limited data exist regarding patients with continuous-flow left ventricular assist device (LVAD) support who require long-term inotropes. Our primary objective was to evaluate the clinical characteristics and all-cause mortality of LVAD recipients with prolonged inotrope use (PIU). Secondary endpoints were to compare predictors of PIU, mortality, risk of late re-initiation of inotropes, time to gastrointestinal bleed (GIB), infection, and arrhythmias. Retrospective cohort study was conducted on adult patients with primary continuous-flow LVADs implanted from January 2008 to February 2017 and the patients were followed up through February 2018. We defined PIU as ≥14 days of inotrope support. Kaplan–Meier method, competing risk models and Cox proportional hazard models were used. Final analytic sample was 203 patients, 58% required PIU, and 10% were discharged on inotropes. There was no difference in preimplant characteristics. One-year survival rate was 87% if no PIU required, 74% if PIU required, and 72% if discharged on inotropes. PIU was associated with longer length of stay and higher incidence of GIB. We found no association between PIU and late re-initiation of inotropes, infection or arrhythmias. Adjusted hazard risk of death was increased in patients with PIU (HR = 1.66, P = .046), older age (HR = 1.28, P = .031), and higher creatinine levels (HR = 1.60, P = .007). Prolonged inotrope use is frequently encountered following LVAD implantation and is associated with adverse prognosis but remains a therapeutic option. Inability to wean inotropes prior to hospital discharge is a marker of patients at particularly higher risk of mortality following LVAD implantation.     

气动泵的不同流量对急性左心衰竭辅助作用的实验研究

目的 用血液动力学、心肌超微结构及神经体液指标评价左室辅助装置（ＬＶＡＤ）的有效性。方法 ,对２０条急笥左心衰犬进行高,中、低流量的１８０ｍｉｎ左室辅助,观察其对上述指标的影响。结果 ＬＶＡＤ可使急性左心衰犬各项血流动力学指标迅速趋于稳定,血浆肾素,血管紧张素Ⅱ,内皮素下降,一氧化氮升高,与心力衰竭时差异有显著意义;使心肌细胞水肿和线粒体肿胀减轻。结论 不同辅助流量对急性左心衰时支持均有效,但以中     

Right ventricular failure after implantation of continuous flow left ventricular assist device: analysis of predictors and outcomes

Postoperative right ventricular failure is a serious complication for up to 50% of patients following LVAD insertion. Predicting RV failure is an important factor for patients as planned BiVAD support has been shown to correlate with better outcomes compared to delayed BiVAD to LVAD conversion. This retrospective study examined prospectively collected data for 101 patients implanted with an LVAD between 2003 and 2013, aiming to establish preoperative predictive factors for RVF post‐LVAD insertion, analyze outcomes, and validate existing RVF scoring systems. In our cohort, 63 patients (62.4%) developed RV failure and consequently demonstrated consistently poorer survival throughout the follow‐up period (log‐rank p = 0.01). Multivariable logistic regression identified two significant variables: cardiac index <2.2 preoperatively despite inotropic support (OR 4.6 [95%CI 1.8–11.8]; p = 0.001) and preoperative tricuspid regurgitation (OR 8.1 [95%CI 1.9–34]; p = 0.004). Patients who developed RV failure had more complicated postoperative courses including longer ICU stay (p < 0.001), higher incidence of transfusions (p = 0.03) and re‐intubation (p = 0.001), longer ventilation duration (p < 0.001), and higher incidence of returning to theater (p = 0.0008). This study found that previous validation models had only moderate correlation with our population emphasizing the need for prospective validation of these scores in the current era of continuous flow devices.