Evolution of Late Right Heart Failure With Left Ventricular Assist Devices and Association With Outcomes

Right Ventricular Assist Device Placement During Left Ventricular Assist Device Implantation Is Associated With Improved Survival

Right ventricular failure (RVF) is a significant cause of mortality in patients undergoing left ventricular assist device (LVAD) implantation. Although right ventricular assist devices (RVADs) can treat RVF in the perioperative LVAD period, liberal employment before RVF is not well established. We therefore compared the survival outcomes between proactive RVAD placement at the time of LVAD implantation with a bailout strategy in patients with RVF. Retrospectively, 75 adult patients who underwent durable LVAD implantation at our institution and had an RVAD placed proactively before LVAD implantation or as a bailout strategy postoperatively due to hemodynamically unstable RVF were evaluated. Patients treated with a proactive RVAD strategy had lower Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) and a higher proportion of these required temporary mechanical circulatory support (MCS) preoperatively. Preoperative hemodynamic profiling showed a low pulmonary artery pulsatility index (PAPi) score of 1.8 ± 1.4 and 1.6 ± 0.94 ( p = 0.42) in the bailout RVAD and proactive RVAD groups, respectively. Survival at 3, 6, and 12 months post-LVAD implantation was statistically significantly higher in patients who received a proactive RVAD. Thus, proactive RVAD implantation is associated with short- and medium-term survival benefits compared to a bailout strategy in RVF patients undergoing LVAD placement.

Right heart failure with left ventricular assist devices: Preoperative, perioperative and postoperative management strategies. A clinical consensus statement of the Heart Failure Association (HFA) of the ESC

Right heart failure (RHF) following implantation of a left ventricular assist device (LVAD) is a common and potentially serious condition with a wide spectrum of clinical presentations with an unfavourable effect on patient outcomes. Clinical scores that predict the occurrence of right ventricular (RV) failure have included multiple clinical, biochemical, imaging and haemodynamic parameters. However, unless the right ventricle is overtly dysfunctional with end-organ involvement, prediction of RHF post-LVAD implantation is, in most cases, difficult and inaccurate. For these reasons optimization of RV function in every patient is a reasonable practice aiming at preparing the right ventricle for a new and challenging haemodynamic environment after LVAD implantation. To this end, the institution of diuretics, inotropes and even temporary mechanical circulatory support may improve RV function, thereby preparing it for a better adaptation post-LVAD implantation. Furthermore, meticulous management of patients during the perioperative and immediate postoperative period should facilitate identification of RV failure refractory to medication. When RHF occurs late during chronic LVAD support, this is associated with worse long-term outcomes. Careful monitoring of RV function and characterization of the origination deficit should therefore continue throughout the patient's entire follow-up. Despite the useful information provided by the echocardiogram with respect to RV function, right heart catheterization frequently offers additional support for the assessment and optimization of RV function in LVAD-supported patients. In any patient candidate for LVAD therapy, evaluation and treatment of RV function and failure should be assessed in a multidimensional and multidisciplinary manner.

Surgical Treatment of Tricuspid Valve Regurgitation in Patients Undergoing Left Ventricular Assist Device Implantation: Interim analysis of the TVVAD trial

OBJECTIVES

Right heart failure remains a serious complication of left ventricular assist device therapy. Many patients presenting for left ventricular assist device implantation have significant tricuspid regurgitation. It remains unknown whether concurrent tricuspid valve surgery reduces postoperative right heart failure. The primary aim was to identify whether concurrent tricuspid valve surgery reduced the incidence of moderate or severe right heart failure within the first 6 months after left ventricular assist device implantation.

METHODS

Patients with moderate or severe tricuspid regurgitation on preoperative echocardiography were randomized to left ventricular assist device implantation alone (no tricuspid valve surgery) or with concurrent tricuspid valve surgery. Randomization was stratified by preoperative right ventricular dysfunction. The primary end point was the frequency of moderate or severe right heart failure within 6 months after surgery.

RESULTS

This report describes a planned interim analysis of the first 60 randomized patients. The tricuspid valve surgery group (n = 32) had mild or no tricuspid regurgitation more frequently on follow-up echocardiography studies compared with the no tricuspid valve surgery group (n = 28). However, at 6 months, the incidence of moderate and severe right heart failure was similar in each group (tricuspid valve surgery: 46.9% vs no tricuspid valve surgery: 50%, P = .81). There was no significant difference in postoperative mortality or requirement for right ventricular assist device between the groups. There were also no significant differences in secondary end points of functional status and adverse events.

CONCLUSIONS

The presence of significant tricuspid regurgitation before left ventricular assist device is associated with a high incidence of right heart failure within the first 6 months after surgery. Tricuspid valve surgery was successful in reducing postimplant tricuspid regurgitation compared with no tricuspid valve surgery but was not associated with a lower incidence of right heart failure.

Association between pulmonary artery pulsatility and mortality after implantation of left ventricular assist device

AIMS

Right ventricular failure after left ventricular assist device (LVAD) implantation is a major concern that remains challenging to predict. We sought to investigate the relationship between preoperative pulmonary artery pulsatility index (PAPi) and mortality after LVAD implantation.

METHODS AND RESULTS

A retrospective analysis of the ASSIST-ICD multicentre registry allowed the assessment of PAPi before LVAD according to the formula [(systolic pulmonary artery pressure - diastolic pulmonary artery pressure)/central venous pressure]. The primary endpoint was survival at 3 months, according to the threshold value of PAPi determined by the receiver operating characteristic (ROC) curve. A multivariate analysis including demographic, echographic, haemodynamic, and biological variables was performed to identify predictive factors for 2 year mortality. One hundred seventeen patients were included from 2007 to 2021. The mean age was 58.45 years (±13.16), with 15.4% of women (sex ratio 5.5). A total of 53.4% were implanted as bridge to transplant and 43.1% as destination therapy. Post-operative right ventricular failure was observed in 57 patients (48.7%), with no significant difference between survivors and non-survivors at 1 month (odds ratio 1.59, P = 0.30). The median PAPi for the whole study population was 2.83 [interquartile range 1.63-4.69]. The threshold value of PAPi determined by the ROC curve was 2.84. Patients with PAPi ≥ 2.84 had a higher survival rate at 3 months [PAPi < 2.84: 58.1% [46.3-72.8%] vs. PAPi ≥ 2.84: 89.1% [81.1-97.7%], hazard ratio (HR) 0.08 [0.02-0.28], P < 0.01], with no significant difference after 3 months (HR 0.67 [0.17-2.67], P = 0.57). Other predictors of 2 year mortality were systemic hypertension (HR 4.22 [1.49-11.97], P < 0.01) and diabetes mellitus (HR 4.90 [1.83-13.14], P < 0.01). LVAD implantation as bridge to transplant (HR 0.18 [0.04-0.74], P = 0.02) and heart transplantation (HR 0.02 [0.00-0.18], P < 0.01) were associated with a higher survival rate at 2 years.

CONCLUSIONS

Preoperative PAPi < 2.84 was associated with a higher risk of early mortality after LVAD implantation without impacting 2 year outcomes among survivors.

Changing Strategy Between Bridge to Transplant and Destination LVAD Therapy After the First 3 Months: Analysis of the STS-INTERMACS Database

BACKGROUND

Left ventricular assist devices (LVADs) have been implanted as bridge to transplantation (BTT), bridge to candidacy (BTC) or destination therapy (DT) on the basis of relative and absolute contraindications to transplantation. Multiple factors may lead to changes in the strategy of support after LVAD implantation.

METHODS

Based on INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) 2012-2020 data, 11,262 patients survived to 3 months on continuous-flow LVADs with intent of BTT or DT. Preimplant characteristics and early events post-LVAD were analyzed in relation to changes in BTT or DT strategy during the next 12 months.

RESULTS

Among 3216 BTT patients at 3 months, later transplant delisting or death without transplant occurred in 536 (16.7%) and was more common with age, profiles 1-2, renal dysfunction, and independently for prior cardiac surgery (HR 1.25, 95% CI 1.04-1.51; P = 0.02). Post-LVAD events of infections, gastrointestinal bleeding, stroke, and right heart failure as defined by inotropic therapy, predicted delisting and death, as did in-hospital location at 3 months (HR 1.67, 95% CI 1.20-2.33; P = 0.0024). Of 8046 patients surviving to 3 months with the intent of destination therapy, 750 (9.3%) subsequently underwent listing or transplantation, often with initial histories of acute HF (HR 1.70, 95% CI 1.27-2.27; P = 0.0012) or malnutrition-cachexia (1.73, 95% CI 1.14-2.63; P = 0.0099). Multiple gastrointestinal bleeding events (≥ 4) with LVAD increased transition from BTT to DT (HR 4.22, 95% CI 1.46-12.275; P = 0.0078) but also from DT to BTT (HR 5.17, 95% CI 1.92-13.9; P = 0.0011).

CONCLUSIONS

Implant strategies change over time in relation to preimplant characteristics and adverse events post implant. Preimplant recognition of factors predicting later change in implant strategy will refine initial triage, whereas further reduction of post-LVAD complications will expand options, including eventual consideration of heart transplantation.

Occult right ventricular dysfunction and right ventricular-vascular uncoupling in left ventricular assist device recipients

BACKGROUND

Detecting right heart failure post left ventricular assist device (LVAD) is challenging. Sensitive pressure-volume loop assessments of right ventricle (RV) contractility may improve our appreciation of post-LVAD RV dysfunction.

METHODS

Thirteen LVAD patients and 20 reference (non-LVAD) subjects underwent comparison of echocardiographic, right heart cath hemodynamic, and pressure-volume loop-derived assessments of RV contractility using end-systolic elastance (Ees), RV afterload by effective arterial elastance (Ea), and RV-pulmonary arterial coupling (ratio of Ees/Ea).

RESULTS

LVAD patients had lower RV Ees (0.20 ± 0.08 vs 0.30 ± 0.15 mm Hg/ml, p = 0.01) and lower RV Ees/Ea (0.37 ± 0.14 vs 1.20 ± 0.54, p < 0.001) versus reference subjects. Low RV Ees correlated with reduced RV septal strain, an indicator of septal contractility, in both the entire cohort (r = 0.68, p = 0.004) as well as the LVAD cohort itself (r = 0.78, p = 0.02). LVAD recipients with low RV Ees/Ea (below the median value) demonstrated more clinical heart failure (71% vs 17%, p = 0.048), driven by an inability to augment RV Ees (0.22 ± 0.11 vs 0.19 ± 0.02 mm Hg/ml, p = 0.95) to accommodate higher RV Ea (0.82 ± 0.38 vs 0.39 ± 0.08 mm Hg/ml, p = 0.002). Pulmonary artery pulsatility index (PAPi) best identified low baseline RV Ees/Ea (≤0.35) in LVAD patients ((area under the curve) AUC = 0.80); during the ramp study, change in PAPi also correlated with change in RV Ees/Ea (r = 0.58, p = 0.04).

CONCLUSIONS

LVAD patients demonstrate occult intrinsic RV dysfunction. In the setting of excess RV afterload, LVAD patients lack the RV contractile reserve to maintain ventriculo-vascular coupling. Depression in RV contractility may be related to LVAD left ventricular unloading, which reduces septal contractility.

Kidney Function Trajectories and Right Heart Failure Following LVAD Implantation

BACKGROUND

Preoperative kidney dysfunction is a risk factor for right heart failure (RHF) after implantation of a left ventricular assist device (LVAD). However, characteristic kidney function trajectories before and after post-LVAD RHF are uncertain, so we investigated this.

METHODS AND RESULTS

We identified individuals who received primary continuous-flow LVAD implantation from July 1, 2014 to December 31, 2017 in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) data set. Incident RHF was ascertained using the INTERMACS definition at 1 and 3 months and classified as transient or persistent. Kidney function trajectories before and after RHF onset, and relationships of baseline kidney function with RHF risk at the different time points, were assessed. We identified 8076 LVAD recipients who met inclusion criteria. Incident RHF was present at 1 month in 26.4%. There were 4850 individuals with follow-up at 3 months, with incident RHF in 4.2%. Kidney function trajectories differed from pre-LVAD implantation to 1-month follow-up by RHF category, with those developing persistent RHF having no improvement in baseline kidney function. For trajectories before the 3-month RHF ascertainment time, the shape was similar for those with and without RHF, with lower estimated glomerular filtration rate levels among those who developed RHF. Baseline estimated glomerular filtration rate levels below the normal range were associated with higher risk of RHF at 1 and 3 months.

CONCLUSIONS

In LVAD recipients, preimplantation kidney function and subsequent kidney function trajectories differed substantially by RHF at 1 and 3 months postimplantation, even after adjustment for several confounders. This may demonstrate bidirectional associations between kidney function and right ventricular function in LVAD recipients.

Right heart failure after durable left ventricular assist device implantation

INTRODUCTION

Right heart failure (RHF) is a well-known complication after left ventricular assist device (LVAD) implantation and portends increased morbidity and mortality. Understanding the mechanisms and predictors of RHF in this clinical setting may offer ideas for early identification and aggressive management to minimize poor outcomes. A variety of medical therapies and mechanical circulatory support options are currently available for the management of post-LVAD RHF.

AREAS COVERED

We reviewed the existing definitions of RHF including its potential mechanisms in the context of durable LVAD implantation and currently available medical and device therapies. We performed a literature search using PubMed (from 2010 to 2023).

EXPERT OPINION

RHF remains a common complication after LVAD implantation. However, existing knowledge gaps limit clinicians' ability to adequately address its consequences. Early identification and management are crucial to reducing the risk of poor outcomes, but existing risk stratification tools perform poorly and have limited clinical applicability. This is an area ripe for investigation with the potential for major improvements in identification and targeted therapy in an effort to improve outcomes.

Encouraging Regular Aortic Valve Opening for EVAHEART 2 LVAD Support Using Virtual Patient Hemodynamic Speed Modulation Analysis

This study focuses on investigating the EVAHEART 2 left ventricular assist device (LVAD) toward designing optimal pump speed modulation (PSM) algorithms for encouraging aortic valve (AV) flow. A custom-designed virtual patient hemodynamic model incorporating the EVAHEART 2 pressure-flow curves, cardiac chambers, and the systemic and pulmonary circulations was developed and used in this study. Several PSM waveforms were tested to evaluate their influence on the mean arterial pressure (MAP), cardiac output (CO), and AV flow for representative heart failure patients. Baseline speeds were varied from 1,600 to 2,000 rpm. For each baseline speed, the following parameters were analyzed: 1) PSM ratio (reduced speed/baseline speed), 2) PSM duration (3-7 seconds), 3) native ventricle contractility, and 4) patient MAP of 70 and 80 mm Hg. More than 2,000 rpm virtual patient scenarios were explored. A lower baseline speed (1,600 and 1,700 rpm) produced more opportunities for AV opening and more AV flow. Higher baseline speeds (1,800 and 2,000 rpm) had lower or nonexistent AV flow. When analyzing PSM ratios, a larger reduction in speed (25%) over a longer PSM (5+ seconds) duration produced the most AV flow. Lower patient MAP and increased native ventricle contractility also contributed to improving AV opening frequency and flow. This study of the EVAHEART 2 LVAD is the first to focus on leveraging PSM to enhance pulsatility and encourage AV flow. Increased AV opening frequency can benefit aortic root hemodynamics, thereby improving patient outcomes.

Right Heart Reserve Function Assessed With Fluid Loading Predicts Late Right Heart Failure After Left Ventricular Assist Device Implantation

BACKGROUND

A left ventricular assist device (LVAD) is an effective therapeutic option for advanced heart failure. Late right heart failure (LRHF) is a complication after LVAD implantation that is associated with increasing morbidity and mortality; however, the assessment of right heart function, including right heart reserve function after LVAD implantation, has not been established. We focused on a fluid-loading test with right heart catheterization to evaluate right heart preload reserve function and investigate its impact on LRHF.

METHODS

Patients aged > 18 years who received a continuous-flow LVAD between November 2007 and December 2022 at our institution, and underwent right heart catheterization with saline loading (10 mL/kg for 15 minutes) 1 month after LVAD implantation, were included.

RESULTS

Overall, 31 cases of LRHF or death (right heart failure [RHF] group) occurred in 149 patients. In the RHF vs the non-RHF groups, the pulmonary artery pulsatility index (PAPi) at rest (1.8 ± 0.89 vs 2.5 ± 1.4, P = 0.02) and the right ventricular stroke work index (RVSWi) change ratio with saline loading (0.96 ± 0.32 vs 1.1 ± 0.20, P = 0.03) were significantly different. The PAPi at rest and the RVSWi change ratio with saline loading were identified as postoperative risks for LRHF and death. The cohort was divided into 3 groups based on whether the PAPi at rest and the RVSWi change ratio were low. The event-free curve differed significantly among the 3 groups (P < 0.001).

CONCLUSIONS

Hemodynamic assessment with saline loading can evaluate the right ventricular preload reserve function of patients with an LVAD. A low RVSWi change with saline loading was a risk factor for LRHF following LVAD implantation.

Hemodynamic Optimization by Invasive Ramp Test in Patients Supported With HeartMate 3 Left Ventricular Assist Device

In patients supported by the HeartMate 3 left ventricular assist device (HM3 LVAD), pump speed adjustments may improve hemodynamics. We investigated the hemodynamic implications of speed adjustments in HM3 recipients undergoing hemodynamic ramp tests. Clinically stable HM3 recipients who underwent routine invasive hemodynamic ramp tests between 2015 and 2022 at our center were included. Filling pressure optimization, defined as central venous pressure (CVP) <12 mm Hg and pulmonary capillary wedge pressure (PCWP) <18 mm Hg, was assessed at baseline and final pump speeds. Patients with optimized pressures were compared to nonoptimized patients. Overall 60 HM3 recipients with a median age of 62 years (56, 71) and time from LVAD implantation of 187 days (124, 476) were included. Optimized filling pressures were found in 35 patients (58%) at baseline speed. Speed was adjusted in 84% of the nonoptimized patients. Consequently, 39 patients (65%) had optimized pressures at final speed. There were no significant differences in hemodynamic findings between baseline and final speeds (p > 0.05 for all). Six and 12 month readmission-free rates were higher in optimized compared with nonoptimized patients (p = 0.03 for both), predominantly due to lower cardiac readmission-free rates (p = 0.052). In stable outpatients supported with HM3 who underwent routine ramp tests, optimized hemodynamics were achieved in only 2 of 3 of the patients. Patients with optimized pressures had lower all-cause readmission rates, primarily driven by fewer cardiac-related hospitalizations.

The Role of Artificial Intelligence and Machine Learning in the Prediction of Right Heart Failure after Left Ventricular Assist Device Implantation: A Comprehensive Review

One of the most challenging and prevalent side effects of LVAD implantation is that of right heart failure (RHF) that may develop afterwards. The purpose of this study is to review and highlight recent advances in the uses of AI in evaluating RHF after LVAD implantation. The available literature was scanned using certain key words (artificial intelligence, machine learning, left ventricular assist device, prediction of right heart failure after LVAD) was scanned within Pubmed, Web of Science, and Google Scholar databases. Conventional risk scoring systems were also summarized, with their pros and cons being included in the results section of this study in order to provide a useful contrast with AI-based models. There are certain interesting and innovative ML approaches towards RHF prediction among the studies reviewed as well as more straightforward approaches that identified certain important predictive clinical parameters. Despite their accomplishments, the resulting AUC scores were far from ideal for these methods to be considered fully sufficient. The reasons for this include the low number of studies, standardized data availability, and lack of prospective studies. Another topic briefly discussed in this study is that relating to the ethical and legal considerations of using AI-based systems in healthcare. In the end, we believe that it would be beneficial for clinicians to not ignore these developments despite the current research indicating more time is needed for AI-based prediction models to achieve a better performance.

Right Ventricular Contractility and Pulmonary Arterial Coupling After Less Invasive Left Ventricular Assist Device Implantation

Right ventricular failure contributes significantly to morbidity and mortality after left ventricular assist device implantation. Recent data suggest a less invasive strategy (LIS) via thoracotomy may be associated with less right ventricular failure than conventional median sternotomy (CMS). However, the impact of these approaches on load-independent right ventricular (RV) contractility and RV-pulmonary arterial (RV-PA) coupling remains uncertain. We hypothesized that the LIS approach would be associated with preserved RV contractility and improved RV-PA coupling compared with CMS. We performed a retrospective study of patients who underwent durable, centrifugal left ventricular assist device implantation and had paired hemodynamic assessments before and after implantation. RV contractility (end-systolic elastance [Ees]), RV afterload (pulmonary effective arterial elastance [Ea]), and RV-PA coupling (Ees/Ea) were determined using digitized RV pressure waveforms. Forty-two CMS and 21 LIS patients were identified. Preimplant measures of Ees, Ea, and Ees/Ea were similar between groups. After implantation, Ees declined significantly in the CMS group (0.60-0.40, p  = 0.008) but not in the LIS group (0.67-0.58, p  = 0.28). Coupling (Ees/Ea) was unchanged in CMS group (0.54-0.59, p  = 0.80) but improved significantly in the LIS group (0.58-0.71, p  = 0.008). LIS implantation techniques may better preserve RV contractility and improve RV-PA coupling compared with CMS.

Soluble Suppression of Tumorigenicity-2 Predicts Mortality and Right Heart Failure in Patients With a Left Ventricular Assist Device

BACKGROUND

Soluble suppression of tumorigenicity-2 (sST2) predicts mortality in patients with heart failure. The predictive value of sST2 in patients with a left ventricular assist device remains unknown. Therefore, we studied the relationship between sST2 and outcome after left ventricular assist device implantation.

METHODS AND RESULTS

sST2 levels of patients with a left ventricular assist device implanted between January 2015 and December 2022 were included in this observational study. The median follow-up was 25 months, during which 1573 postoperative sST2 levels were measured in 199 patients, with a median of 29 ng/mL. Survival of patients with normal and elevated preoperative levels was compared using Kaplan-Meier analysis, which did not differ significantly (P=0.22) between both groups. The relationship between postoperative sST2, survival, and right heart failure was evaluated using a joint model, which showed a significant relationship between the absolute sST2 level and mortality, with a hazard ratio (HR) of 1.20 (95% CI, 1.10-1.130; P<0.01) and an HR of 1.22 (95% CI, 1.07-1.39; P=0.01) for right heart failure, both per 10-unit sST2 increase. The sST2 instantaneous change was not predictive for survival or right heart failure (P=0.99 and P=0.94, respectively). Multivariate joint model analysis showed a significant relationship between sST2 with mortality adjusted for NT-proBNP (N-terminal pro-B-type natriuretic peptide), with an HR of 1.19 (95% CI, 1.00-1.42; P=0.05), whereas the HR of right heart failure was not significant (1.22 [95% CI, 0.94-1.59]; P=0.14), both per 10-unit sST2 increase.

CONCLUSIONS

Time-dependent postoperative sST2 predicts all-cause mortality after left ventricular assist device implantation after adjustment for NT-proBNP. Future research is warranted into possible target interventions and the optimal monitoring frequency.

Value of Invasive Hemodynamic Assessments in Patients Supported by Continuous-Flow Left Ventricular Assist Devices

Left ventricular assist devices (LVADs) are increasingly used in patients with end-stage heart failure (HF). There is a significant risk of HF admissions and hemocompatibility-related adverse events that can be minimized by optimizing the LVAD support. Invasive hemodynamic assessment, which is currently underutilized, allows personalization of care for patients with LVAD, and may decrease the need for recurrent hospitalizations. It also aids in triaging patients with persistent low-flow alarms, evaluating reversal of pulmonary vasculature remodeling, and assessing right ventricular function. In addition, it can assist in determining the precipitant for residual HF symptoms and physical limitation during exercise and is the cornerstone of the assessment of myocardial recovery. This review provides a comprehensive approach to the use of invasive hemodynamic assessments in patients supported with LVADs.

Predicting Survival of End-Stage Heart Failure Patients Receiving HeartMate-3: Comparing Machine Learning Methods

HeartMate 3 is the only durable left ventricular assist devices (LVAD) currently implanted in the United States. The purpose of this study was to develop a predictive model for 1 year mortality of HeartMate 3 implanted patients, comparing standard statistical techniques and machine learning algorithms. Adult patients registered in the Society of Thoracic Surgeons, Interagency Registry for Mechanically Assisted Circulatory Support (STS-INTERMACS) database, who received primary implant with a HeartMate 3 between January 1, 2017, and December 31, 2019, were included. Epidemiological, clinical, hemodynamic, and echocardiographic characteristics were analyzed. Standard logistic regression and machine learning (elastic net and neural network) were used to predict 1 year survival. A total of 3,853 patients were included. Of these, 493 (12.8%) died within 1 year after implantation. Standard logistic regression identified age, Model End Stage Liver Disease (MELD)-XI score, right arterial (RA) pressure, INTERMACS profile, heart rate, and etiology of heart failure (HF), as important predictor factors for 1 year mortality with an area under the curve (AUC): 0.72 (0.66-0.77). This predictive model was noninferior to the ones developed using the elastic net or neural network. Standard statistical techniques were noninferior to neural networks and elastic net in predicting 1 year survival after HeartMate 3 implantation. The benefit of using machine-learning algorithms in the prediction of outcomes may depend on the type of dataset used for analysis.

Postoperative Pulmonary Artery Pulsatility Index Improves Prediction of Right Ventricular Failure After Left Ventricular Assist Device Implantation

OBJECTIVES

This study evaluated whether the postoperative pulmonary artery pulsatility index (PAPi) is associated with postoperative right ventricular dysfunction after durable left ventricular assist device (LVAD) implantation.

DESIGN

Single-center retrospective observational cohort study.

SETTING

The University of Kansas Medical Center, a tertiary-care academic medical center.

PARTICIPANTS

Sixty-seven adult patients who underwent durable LVAD implantation between 2017 and 2019.

INTERVENTIONS

All patients underwent open cardiac surgery with cardiopulmonary bypass under general anesthesia with pulmonary artery catheter insertion.

MEASUREMENTS AND MAIN RESULTS

Clinical and hemodynamic data were collected before and after surgery. The Michigan right ventricular failure risk score and the European Registry for Patients with Mechanical Circulatory Support score were calculated for each patient. The primary outcome was right ventricular failure, defined as a composite of right ventricular mechanical circulatory support, inhaled pulmonary vasodilator therapy for 48 hours or greater, or inotrope use for 14 days or greater or at discharge. Thirty percent of this cohort (n = 20) met the primary outcome. Preoperative transpulmonary gradient (odds ratio [OR] 1.15, 95% CI 1.02-1.28), cardiac index (OR 0.83, 95% CI 0.71-0.98), and postoperative PAPi (OR 0.85, 95% CI 0.75-0.97) were the only hemodynamic variables associated with the primary outcome. The addition of postoperative PAPi was associated with improvement in the predictive model performance of the Michigan score (area under the receiver operating characteristic curve 0.73 v 0.56, p = 0.03). An optimal cutoff point for postoperative PAPi of 1.56 was found.

CONCLUSIONS

The inclusion of postoperative PAPi offers more robust predictive power for right ventricular failure in patients undergoing durable LVAD implantation, compared with the use of existing risk scores alone.

Cellular and Molecular Mechanisms Activated by a Left Ventricular Assist Device

Left ventricular assist devices (LVADs) represent the final treatment for patients with end-stage heart failure (HF) not eligible for transplantation. Although LVAD design has been further improved in the last decade, their use is associated with different complications. Specifically, inflammation, fibrosis, bleeding events, right ventricular failure, and aortic valve regurgitation may occur. In addition, reverse remodeling is associated with substantial cellular and molecular changes of the failing myocardium during LVAD support with positive effects on patients' health. All these processes also lead to the identification of biomarkers identifying LVAD patients as having an augmented risk of developing associated adverse events, thus highlighting the possibility of identifying new therapeutic targets. Additionally, it has been reported that LVAD complications could cause or exacerbate a state of malnutrition, suggesting that, with an adjustment in nutrition, the general health of these patients could be improved.

Catheter Ablation for Tachyarrhythmias in Left Ventricular Assist Device Recipients: Clinical Significance and Technical Tips

The demand for durable left ventricular assist devices (LVADs) has been increasing worldwide in tandem with the rising population of advanced heart failure patients. Especially in cases of destination therapy, instead of bridges to transplantation, LVADs require a lifelong commitment. With the increase in follow-up periods after implantation and given the lack of donor hearts, the need for managing concomitant tachyarrhythmias has arisen. Atrial and ventricular arrhythmias are documented in approximately 20% to 50% of LVAD recipients during long-term device support, according to previous registries. Atrial arrhythmias, primarily atrial fibrillation, generally exhibit good hemodynamic tolerance; therefore, catheter ablation cannot be easily recommended due to the risk of a residual iatrogenic atrial septal defect that may lead to a right-to-left shunt under durable LVAD supports. The clinical impacts of ventricular arrhythmias, mainly ventricular tachycardia, may vary depending on the time periods following the index implantation. Early occurrence after the operation affects the hospitalization period and mortality; however, the late onset of ventricular tachycardia causes varying prognostic impacts on a case-by-case basis. In cases of hemodynamic instability, catheter ablation utilizing a trans-septal approach is necessary to stabilize hemodynamics. Nonetheless, in some cases originating from the intramural region or the epicardium, procedural failure may occur with the endocardial ablation. Specialized complications associated with the state of LVAD support should be carefully considered when conducting procedures. In LVAD patients, electrophysiologists, circulatory support specialists, and surgeons should collaborate as an integrated team to address the multifaceted issues related to arrhythmia management.

Kidney health and function with left ventricular assist devices

PURPOSE OF REVIEW

Mechanical circulatory support (MCS) is a group of evolving therapies used for indications ranging from temporary support during a cardiac procedure to permanent treatment of advanced heart failure. MCS is primarily used to support left ventricle function, in which case the devices are termed left ventricular assist devices (LVADs). Kidney dysfunction is common in patients requiring these devices, yet the impact of MCS itself on kidney health in many settings remains uncertain.

RECENT FINDINGS

Kidney dysfunction can manifest in many different forms in patients requiring MCS. It can be because of preexisting systemic disorders, acute illness, procedural complications, device complications, and long-term LVAD support. After durable LVAD implantation, most persons have improvement in kidney function; however, individuals can have markedly different kidney outcomes, and novel phenotypes of kidney outcomes have been identified.

SUMMARY

MCS is a rapidly evolving field. Kidney health and function before, during, and after MCS is relevant to outcomes from an epidemiologic perspective, yet the pathophysiology underlying this is uncertain. Improved understanding of the relationship between MCS use and kidney health is important to improving patient outcomes.

Late Right Heart Failure After Left Ventricular Assist Device Implantation: Contemporary Insights and Future Perspectives

Late right heart failure (RHF) is increasingly recognized in patients with long-term left ventricular assist device (LVAD) support and is associated with decreased survival and increased incidence of adverse events such as gastrointestinal bleeding and stroke. Progression of right ventricular (RV) dysfunction to clinical syndrome of late RHF in patients supported with LVAD is dependent on the severity of pre-existing RV dysfunction, persistent or worsening left- or right-sided valvular heart disease, pulmonary hypertension, inadequate or excessive left ventricular unloading, and/or progression of the underlying cardiac disease. RHF likely represents a continuum of risk with early presentation and progression to late RHF. However, de novo RHF develops in a subset of patients leading to increased diuretic requirement, arrhythmias, renal and hepatic dysfunction, and heart failure hospitalizations. The distinction between isolated late RHF and RHF due to left-sided contributions is lacking in registry studies and should be the focus of future registry data collection. Potential management strategies include optimization of RV preload and afterload, neurohormonal blockade, LVAD speed optimization, and treatment of concomitant valvular disease. In this review, the authors discuss definition, pathophysiology, prevention, and management of late RHF.

Characteristics and Predictors of Late Right Heart Failure After Left Ventricular Assist Device Implantation

Late right heart failure (LRHF) following left ventricular assist device (LVAD) implantation remains poorly characterized and challenging to predict. We performed a multicenter retrospective study of LRHF in 237 consecutive adult LVAD patients, in which LRHF was defined according to the 2020 Mechanical Circulatory Support Academic Research Consortium guidelines. Clinical and hemodynamic variables were assessed pre- and post-implant. Competing-risk regression and Kaplan-Meier survival analysis were used to assess outcomes. LRHF prediction was assessed using multivariable logistic and Cox proportional hazards regression. Among 237 LVAD patients, 45 (19%) developed LRHF at a median of 133 days post-LVAD. LRHF patients had more frequent heart failure hospitalizations ( p < 0.001) alongside other complications. LRHF patients did not experience reduced bridge-to-transplant rates but did suffer increased mortality (hazard ratio 1.95, 95% confidence interval [CI] 1.11-3.42; p = 0.02). Hemodynamically, LRHF patients demonstrated higher right atrial pressure, mean pulmonary arterial pressure, and pulmonary vascular resistance (PVR), but no difference in pulmonary arterial wedge pressure. History of early right heart failure, blood urea nitrogen (BUN) > 35 mg/dl at 1 month post-LVAD, and diuretic requirements at 1 month post-LVAD were each significant, independent predictors of LRHF in multivariable analysis. An LRHF prediction risk score incorporating these variables predicted LRHF with excellent discrimination (log-rank p < 0.0001). Overall, LRHF post-LVAD is more common than generally appreciated, with significant morbidity and mortality. Elevated PVR and precapillary pulmonary pressures may play a role. A risk score using early right heart failure, elevated BUN, and diuretic requirements 1 month post implant predicted the development of LRHF.

HFSA Expert Consensus Statement on the Medical Management of Patients on Durable Mechanical Circulatory Support

The medical management of patients supported with durable continuous flow left ventricular assist device (LVAD) support encompasses pharmacologic therapies administered in the preoperative, intraoperative, postoperative and chronic LVAD support stages. As patients live longer on LVAD support, the risks of LVAD-related complications and progression of cardiovascular and other diseases increase. Using existing data from cohort studies, registries, randomized trials and expert opinion, this Heart Failure Society of America Consensus Document on the Medical Management of Patients on Durable Mechanical Circulatory Support offers best practices on the management of patients on durable MCS, focusing on pharmacological therapies administered to patients on continuous flow LVADs. While quality data in the LVAD population are few, the utilization of guideline directed heart failure medical therapies (GDMT) and the importance of blood pressure management, right ventricular preload and afterload optimization, and antiplatelet and anticoagulation regimens are discussed. Recommended pharmacologic regimens used to mitigate or treat common complications encountered during LVAD support, including arrhythmias, vasoplegia, mucocutaneous bleeding, and infectious complications are addressed. Finally, this document touches on important potential pharmacological interactions from anti-depressants, herbal and nutritional supplements of relevance to providers of patients on LVAD support.

Biventricular assist devices and total artificial heart: Strategies and outcomes

In contrast to the advanced development of the left ventricular assist device (LVAD) therapy for advanced heart failure, the mechanical circulatory support (MCS) with biventricular assist device (BVAD) and total artificial heart (TAH) options remain challenging. The treatment strategy of BVAD and TAH therapy largely depends on the support duration. For example, an extracorporeal centrifugal pump, typically referred to as a temporary surgical extracorporeal right ventricular assist device, is implanted for the short term with acute right ventricular failure following LVAD implantation. Meanwhile, off-label use of a durable implantable LVAD is a strategy for long-term right ventricular support. Hence, this review focuses on the current treatment strategies and clinical outcomes based on each ventricle support duration. In addition, the issue of heart failure post-heart transplantation (post-HT) is explored. We will discuss MCS therapy options for post-HT recipients.

Left Ventricular Assist Devices: A Primer For the General Cardiologist

Durable implantable left ventricular assist devices (LVADs) have been shown to improve survival and quality of life for patients with stage D heart failure. Even though LVADs remain underused overall, the number of patients with heart failure supported with LVADs is steadily increasing. Therefore, general cardiologists will increasingly encounter these patients. In this review, we provide an overview of the field of durable LVADs. We discuss which patients should be referred for consideration of advanced heart failure therapies. We summarize the basic principles of LVAD care, including medical and surgical considerations. We also discuss the common complications associated with LVAD therapy, including bleeding, infections, thrombotic issues, and neurologic events. Our goal is to provide a primer for the general cardiologist in the recognition of patients who could benefit from LVADs and in the principles of managing patients with LVAD. Our hope is to "demystify" LVADs for the general cardiologist.

Planned Combo Strategy for LVAD Implantation in ECMO Patients: A Proof of Concept to Face Right Ventricular Failure

We propose a patient-tailored strategy that considers the risk for postoperative right heart failure, utilizing the percutaneous ProtekDuo cannula (Livanova, London, UK) in an innovative way to perform cardiopulmonary bypass during LVAD implantation in ECMO patients. Our novel protocol is based on the early intra-operative use of the ProtekDuo cannula, adopting the distal lumen as the pulmonary vent and the proximal lumen as the venous inflow cannula during cardiopulmonary bypass. This configuration is rapidly switched to the standard fashion to provide planned postoperative temporary right ventricular support, in selected patients at high risk of right ventricular failure. From September 2020 to June 2022, six patients were supported with the ProtekDuo cannula during and after an intracorporeal LVAD implantation (five of which were minimally invasive): four HeartMate III (Abbott, U.S.A.) and two HVAD (Medtronic Inc, MN). In all cases, the ProtekDuo cannula was correctly positioned and removed without complications after a median period of 8 days. Non-fatal bleeding (bronchial hemorrhage) occurred in one patient (17%) during biventricular support. Thirty-day mortality was 0%. From this preliminary work, our novel strategy demonstrated to be a feasible solution for planned minimally invasive right ventricular support in ECMO patients scheduled for a durable LVAD implantation.

Prediction, prevention, and management of right ventricular failure after left ventricular assist device implantation: A comprehensive review

Left ventricular assist devices (LVADs) are increasingly common across the heart failure population. Right ventricular failure (RVF) is a feared complication that can occur in the early post-operative phase or during the outpatient follow-up. Multiple tools are available to the clinician to carefully estimate the individual risk of developing RVF after LVAD implantation. This review will provide a comprehensive overview of available tools for RVF prognostication, including patient-specific and right ventricle (RV)-specific echocardiographic and hemodynamic parameters, to provide guidance in patient selection during LVAD candidacy. We also offer a multidisciplinary approach to the management of early RVF, including indications and management of right ventricular assist devices in this setting to provide tools that help managing the failing RV.

Right heart failure after left ventricular assist device: From mechanisms to treatments

Left ventricular assist device (LVAD) therapy is a lifesaving option for patients with medical therapy-refractory advanced heart failure. Depending on the definition, 5-44% of people supported with an LVAD develop right heart failure (RHF), which is associated with worse outcomes. The mechanisms related to RHF include patient, surgical, and hemodynamic factors. Despite significant progress in understanding the roles of these factors and improvements in surgical techniques and LVAD technology, this complication is still a substantial cause of morbidity and mortality among LVAD patients. Additionally, specific medical therapies for this complication still are lacking, leaving cardiac transplantation or supportive management as the only options for LVAD patients who develop RHF. While significant effort has been made to create algorithms aimed at stratifying risk for RHF in patients undergoing LVAD implantation, the predictive value of these algorithms has been limited, especially when attempts at external validation have been undertaken. Perhaps one of the reasons for poor performance in external validation is related to differing definitions of RHF in external cohorts. Additionally, most research in this field has focused on RHF occurring in the early phase (i.e., ≤1 month) post LVAD implantation. However, there is emerging recognition of late-onset RHF (i.e., > 1 month post-surgery) as a significant cause of morbidity and mortality. Late-onset RHF, which likely has a unique physiology and pathogenic mechanisms, remains poorly characterized. In this review of the literature, we will describe the unique right ventricular physiology and changes elicited by LVADs that might cause both early- and late-onset RHF. Finally, we will analyze the currently available treatments for RHF, including mechanical circulatory support options and medical therapies.

Mechanical circulatory support devices and treatment strategies for right heart failure

The importance of right heart failure (RHF) treatment is magnified over the years due to the increased risk of mortality. Additionally, the multifactorial origin and pathophysiological mechanisms of RHF render this clinical condition and the choices for appropriate therapeutic target strategies remain to be complex. The recent change in the United Network for Organ Sharing (UNOS) allocation criteria of heart transplant may have impacted for the number of left ventricular assist devices (LVADs), but LVADs still have been widely used to treat advanced heart failure, and 4.1 to 7.4% of LVAD patients require a right ventricular assist device (RVAD). In addition, patients admitted with primary left ventricular failure often need right ventricular support. Thus, there is unmet need for temporary or long-term support RVAD implantation exists. In RHF treatment with mechanical circulatory support (MCS) devices, the timing of the intervention and prediction of duration of the support play a major role in successful treatment and outcomes. In this review, we attempt to describe the prevalence and pathophysiological mechanisms of RHF origin, and provide an overview of existing treatment options, strategy and device choices for MCS treatment for RHF.

Novel Approaches to Imaging the Pulmonary Vasculature and Right Heart

There is an increased appreciation for the importance of the right heart and pulmonary circulation in several disease states across the spectrum of pulmonary hypertension and left heart failure. However, assessment of the structure and function of the right heart and pulmonary circulation can be challenging, due to the complex geometry of the right ventricle, comorbid pulmonary airways and parenchymal disease, and the overlap of hemodynamic abnormalities with left heart failure. Several new and evolving imaging modalities interrogate the right heart and pulmonary circulation with greater diagnostic precision. Echocardiographic approaches such as speckle-tracking and 3-dimensional imaging provide detailed assessments of regional systolic and diastolic function and volumetric assessments. Magnetic resonance approaches can provide high-resolution views of cardiac structure/function, tissue characterization, and perfusion through the pulmonary vasculature. Molecular imaging with positron emission tomography allows an assessment of specific pathobiologically relevant targets in the right heart and pulmonary circulation. Machine learning analysis of high-resolution computed tomographic lung scans permits quantitative morphometry of the lung circulation without intravenous contrast. Inhaled magnetic resonance imaging probes, such as hyperpolarized 129Xe magnetic resonance imaging, report on pulmonary gas exchange and pulmonary capillary hemodynamics. These approaches provide important information on right ventricular structure and function along with perfusion through the pulmonary circulation. At this time, the majority of these developing technologies have yet to be clinically validated, with few studies demonstrating the utility of these imaging biomarkers for diagnosis or monitoring disease. These technologies hold promise for earlier diagnosis and noninvasive monitoring of right heart failure and pulmonary hypertension that will aid in preclinical studies, enhance patient selection and provide surrogate end points in clinical trials, and ultimately improve bedside care.

The “Right” Definition for Post–Left Ventricular Assist Device Right Heart Failure: The More We Learn, the Less We Know

Right heart failure is a major cause of morbidity and mortality following left ventricular assist device implantation. Over the past few decades, the definition proposed by the Interagency Registry of Mechanical Circulatory Support and Society of Thoracic Surgeons has continually evolved to better identify this complex pathology. We propose that the latest definition proposed by the Mechanical Circulatory Support Academic Research Consortium in 2020 will increase our recognition and understanding of this complex disease phenomenon.

Ventricular and Atrial Pressure—Volume Loops: Analysis of the Effects Induced by Right Centrifugal Pump Assistance

The main indications for right ventricular assist device (RVAD) support are right heart failure after implantation of a left ventricular assist device (LVAD) or early graft failure following heart transplantation. We sought to study the effects induced by different RVAD connections when right ventricular elastance (EesRIGHT) was modified using numerical simulations based on atrial and ventricular pressure–volume analysis. We considered the effects induced by continuous-flow RVAD support on left/right ventricular/atrial loops when EesRIGHT changed from 0.3 to 0.8 mmHg/mL during in-series or parallel pump connection. Pump rotational speed was also addressed. Parallel RVAD support at 4000 rpm with EesRIGHT = 0.3 mmHg/mL generated percentage changes up to 60% for left ventricular pressure–volume area and external work; up to 20% for left ventricular ESV and up to 25% for left ventricular EDV; up to 50% change in left atrial pressure-volume area (PVLAL-A) and only a 3% change in right atrial pressure–volume area (PVLAR-A). Percentage variation was lower when EesRIGHT = 0.8 mmHg/mL. Early recognition of right ventricular failure followed by aggressive treatment is desirable, so as to achieve a more favourable outcome. RVAD support remains an option for advanced right ventricular failure, although the onset of major adverse events may preclude its use.

When Nothing Goes Right: Risk Factors and Biomarkers of Right Heart Failure after Left Ventricular Assist Device Implantation

Right heart failure (RHF) is a severe complication after left ventricular assist device (LVAD) implantation. The aim of this study was to analyze the incidence, risk factors, and biomarkers for late RHF including the possible superiority of the device and implantation method. This retrospective, single-center study included patients who underwent LVAD implantation between 2014 and 2018. Primary outcome was freedom from RHF over one-year after LVAD implantation; secondary outcomes included pre- and postoperative risk factors and biomarkers for RHF. Of the 145 consecutive patients (HeartMate 3/HVAD: n = 70/75; female: 13.8%), thirty-one patients (21.4%) suffered RHF after a mean LVAD support of median (IQR) 105 (118) days. LVAD implantation method (less invasive: 46.7% vs. 35.1%, p = 0.29) did not differ significantly in patients with or without RHF, whereas the incidence of RHF was lower in HeartMate 3 vs. HVAD patients (12.9% vs. 29.3%, p = 0.016). Multivariate Cox proportional hazard analysis identified HVAD (HR 4.61, 95% CI 1.12–18.98; p = 0.03), early post-op heart rate (HR 0.96, 95% CI 0.93–0.99; p = 0.02), and central venous pressure (CVP) (HR 1.21, 95% CI 1.05–1.39; p = 0.01) as independent risk factors for RHF, but no association of RHF with increased all-cause mortality (HR 1.00, 95% CI 0.99–1.01; p = 0.50) was found. To conclude, HVAD use, lower heart rate, and higher CVP early post-op were independent risk factors for RHF following LVAD implantation.