Early planned institution of biventricular mechanical circulatory support results in improved outcomes compared with delayed conversion of a left ventricular assist device to a biventricular assist device

The Society of Thoracic Surgeons Intermacs 2024 Annual Report: Focus on Outcomes in Younger Patients

The 15th Annual Report from The Society of Thoracic Surgeons Interagency Registry for Mechanically Assisted Circulatory Support includes 29,634 continuous-flow left ventricular assist devices from the 10-year period between 2014 and 2024. The outcomes reported here demonstrate continued improved survival in the current era of fully magnetically levitated devices, with a significantly higher 1-year (85.7% vs 78.4%) and 5-year (59.7% vs 43.7%) survival than those receiving non-magnetically levitated devices. Magnetically levitated device recipients are experiencing a lower incidence of adverse events, including freedom from gastrointestinal bleeding (72.6%), device malfunction (82.9%), and stroke (86.7%) at 5 years. Additionally, a focus on a subgroup of patients younger than 50 years of age has demonstrated both superior outcomes in survival (91.6% survival at 1 year and 72.6% survival at 5 years) and decreased incidence of adverse events compared with older recipients. This younger cohort also demonstrated more tolerance to the characteristics of sex, race, ethnicity, and psychosocial indicators that are associated with worse outcomes after heart transplantation. Based upon these data, a potential net prolongation of life may be realized by considering prolonged left ventricular assist device support prior to heart transplantation in this population. These analyses provide preliminary data that could positively influence adoption of left ventricular assist device technology in groups previously not seen as candidates for this therapy, while providing a more responsible donor allocation strategy for advanced heart failure patients.

Crossing Boundaries: Utilizing Left-sided Impella for Right Ventricular Mechanical Support and Intraoperative Transesophageal Echocardiogram Considerations

OBJECTIVE

Right ventricular failure is a leading cause of mortality among patients with various etiologies of cardiogenic shock. This case series outlines an innovative approach to directly unloading the right ventricle with the Impella LD or 5.5 without crossing the tricuspid valve in cases requiring tricuspid valve repair or replacement.

DESIGN

Retrospective single-center review.

SETTING

Single tertiary care university hospital.

PARTICIPANTS

Patients who underwent Impella LD or 5.5 insertions for right ventricular support.

INTERVENTIONS

Impella LD or 5.5 inserted directly into the right ventricle via the pulmonary artery.

MEASUREMENTS AND MAIN RESULTS

Patients' baseline, intraoperative, and immediate postoperative clinical and echocardiographic data were obtained. Of the five consecutive patients with severe preoperative right ventricular failure who underwent surgical tricuspid valve procedures and Impella placement, three of the patients underwent concomitant left heart procedures. The Impella was preemptively inserted before separation from cardiopulmonary bypass in all patients. Four patients were extubated within the first 24 hours and ambulated with the Impella by postoperative day (POD) 3. By POD 10, four patients had sufficient right ventricular recovery to allow for Impella LD explant. One patient died due to septic shock with the right ventricular assist device still in place. One patient was transitioned to comfort measures 29 days after explant of the Impella device.

CONCLUSIONS

Left-sided Impella can be used to support the right ventricle in patients who have undergone surgical tricuspid valve procedures. It provides direct right ventricular unloading, does not cross a newly replaced or repaired tricuspid valve, and allows early ambulation.

Evaluation and Management of Kidney Dysfunction in Advanced Heart Failure: A Scientific Statement From the American Heart Association

Early identification of kidney dysfunction in patients with advanced heart failure is crucial for timely interventions. In addition to elevations in serum creatinine, kidney dysfunction encompasses inadequate maintenance of sodium and volume homeostasis, retention of uremic solutes, and disrupted endocrine functions. Hemodynamic derangements and maladaptive neurohormonal upregulations contribute to fluctuations in kidney indices and electrolytes that may recover with guideline-directed medical therapy. Quantifying the extent of underlying irreversible intrinsic kidney disease is crucial in predicting whether optimization of congestion and guideline-directed medical therapy can stabilize kidney function. This scientific statement focuses on clinical management of patients experiencing kidney dysfunction through the trajectory of advanced heart failure, with specific focus on (1) the conceptual framework for appropriate evaluation of kidney dysfunction within the context of clinical trajectories in advanced heart failure, including in the consideration of advanced heart failure therapies; (2) preoperative, perioperative, and postoperative approaches to evaluation and management of kidney disease for advanced surgical therapies (durable left ventricular assist device/heart transplantation) and kidney replacement therapies; and (3) the key concepts in palliative care and decision-making processes unique to individuals with concomitant advanced heart failure and kidney disease.

Management of Post-cardiotomy Shock

Patients undergoing cardiac surgery experience significant physiologic derangements that place them at risk for multiple shock phenotypes. Any combination of cardiogenic, obstructive, hemorrhagic, or vasoplegic shock occurs commonly in post-cardiotomy patients. The approach to the diagnosis and management of these shock states has many facets that are distinct compared to non-surgical cardiac intensive care unit patients. Additionally, the approach to and associated outcomes of cardiac arrest in the post-cardiotomy population are uniquely characterized by emergent bedside resternotomy if the circulation is not immediately restored. This review focuses on the unique aspects of the diagnosis and management of post-cardiotomy shock.

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.

Preoperative passive venous pressure-driven cardiac function determines left ventricular assist device outcomes

BACKGROUND

Right heart output in heart failure can be compensated through increasing systemic venous pressure. We determined whether the magnitude of this "passive cardiac output" can predict LVAD outcomes.

METHODS

This was a retrospective review of 383 patients who received a continuous-flow LVAD at the University of Michigan between 2012 and 2021. Pre-LVAD cardiac output driven by venous pressure was determined by dividing right atrial pressure by mean pulmonary artery pressure, multiplied by total cardiac output. Normalization to body surface area led to the passive cardiac index (PasCI). The Youden J statistic was used to identify the PasCI threshold, which predicted LVAD death by 2 years.

RESULTS

Increased preoperative PasCI was associated with reduced survival (hazard ratio [HR], 2.27; P < .01), and increased risk of right ventricular failure (RVF) (HR, 3.46; P = .04). Youden analysis showed that a preoperative PasCI ≥0.5 (n = 226) predicted LVAD death (P = .10). Patients with PasCI ≥0.5 had poorer survival (P = .02), with a trend toward more heart failure readmission days (mean, 45.09 ± 67.64 vs 35.13 ± 45.02 days; P = .084) and increased gastrointestinal bleeding (29.2% vs 20.4%; P = .052). Additionally, of the 97 patients who experienced readmissions for heart failure, those with pre-LVAD implantation PasCI ≥0.5 were more likely to have more than 1 readmission (P = .05).

CONCLUSIONS

Although right heart output can be augmented by raising venous pressure, this negatively impacts end-organ function and increases heart failure readmission days. Patients with a pre-LVAD PasCI ≥0.5 have worse post-LVAD survival and increased RVF. Using the PasCI metric in isolation or incorporated into a predictive model may improve the management of LVAD candidates with RV dysfunction.

Special Considerations for Advanced Heart Failure Surgeries: Durable Left Ventricular Devices and Heart Transplantation

Heart transplantation and durable left ventricular assist devices (LVADs) represent two definitive therapies for end-stage heart failure in the modern era. Despite technological advances, both treatment modalities continue to experience unique risks that impact surgical and perioperative decision-making. Here, we review special populations and factors that impact risk in LVAD and heart transplant surgery and examine critical decisions in the management of these patients. As both heart transplantation and the use of durable LVADs as destination therapy continue to increase, these considerations will be of increasing relevance in managing advanced heart failure and improving outcomes.

Machine Learning Multicenter Risk Model to Predict Right Ventricular Failure After Mechanical Circulatory Support: The STOP-RVF Score

Importance

The existing models predicting right ventricular failure (RVF) after durable left ventricular assist device (LVAD) support might be limited, partly due to lack of external validation, marginal predictive power, and absence of intraoperative characteristics.

Objective

To derive and validate a risk model to predict RVF after LVAD implantation.

Design, Setting, and Participants

This was a hybrid prospective-retrospective multicenter cohort study conducted from April 2008 to July 2019 of patients with advanced heart failure (HF) requiring continuous-flow LVAD. The derivation cohort included patients enrolled at 5 institutions. The external validation cohort included patients enrolled at a sixth institution within the same period. Study data were analyzed October 2022 to August 2023.

Exposures

Study participants underwent chronic continuous-flow LVAD support.

Main Outcome and Measures

The primary outcome was RVF incidence, defined as the need for RV assist device or intravenous inotropes for greater than 14 days. Bootstrap imputation and adaptive least absolute shrinkage and selection operator variable selection techniques were used to derive a predictive model. An RVF risk calculator (STOP-RVF) was then developed and subsequently externally validated, which can provide personalized quantification of the risk for LVAD candidates. Its predictive accuracy was compared with previously published RVF scores.

Results

The derivation cohort included 798 patients (mean [SE] age, 56.1 [13.2] years; 668 male [83.7%]). The external validation cohort included 327 patients. RVF developed in 193 of 798 patients (24.2%) in the derivation cohort and 107 of 327 patients (32.7%) in the validation cohort. Preimplant variables associated with postoperative RVF included nonischemic cardiomyopathy, intra-aortic balloon pump, microaxial percutaneous left ventricular assist device/venoarterial extracorporeal membrane oxygenation, LVAD configuration, Interagency Registry for Mechanically Assisted Circulatory Support profiles 1 to 2, right atrial/pulmonary capillary wedge pressure ratio, use of angiotensin-converting enzyme inhibitors, platelet count, and serum sodium, albumin, and creatinine levels. Inclusion of intraoperative characteristics did not improve model performance. The calculator achieved a C statistic of 0.75 (95% CI, 0.71-0.79) in the derivation cohort and 0.73 (95% CI, 0.67-0.80) in the validation cohort. Cumulative survival was higher in patients composing the low-risk group (estimated <20% RVF risk) compared with those in the higher-risk groups. The STOP-RVF risk calculator exhibited a significantly better performance than commonly used risk scores proposed by Kormos et al (C statistic, 0.58; 95% CI, 0.53-0.63) and Drakos et al (C statistic, 0.62; 95% CI, 0.57-0.67).

Conclusions and Relevance

Implementing routine clinical data, this multicenter cohort study derived and validated the STOP-RVF calculator as a personalized risk assessment tool for the prediction of RVF and RVF-associated all-cause mortality.

Durability of Tricuspid Valve Repair in Patients Undergoing Left Ventricular Assist Device Implantation

Objectives: Benefits of tricuspid valve repair (TVR) in left ventricular assist device (LVAD) patients have been questioned. High TVR failure rates have been reported. Remaining or recurring TR was found to be a risk factor for right heart failure (RHF). Therefore, we assessed our experience. Methods: Since 12/2010, 195 patients have undergone LVAD implantation in our center. Almost half (n = 94, 48%) received concomitant TVR (LVAD+TVR). These patients were included in our analysis. Echocardiographic and clinical data were assessed. Median follow-up was 2.8 years (7 days-0.6 years). Results were correlated with clinical outcomes. Results: LVAD+TVR patients were 59.8 ± 11.4 years old (89.4% male) and 37.3% were INTERMACS level 1 and 2. Preoperative TR was moderate in 28 and severe in 66 patients. RV function was severely impaired in 61 patients reflected by TAPSE-values of 11.2 ± 2.9 mm (vs. 15.7 ± 3.8 mm in n = 33; p < 0.001). Risk for RHF according to EUROMACS-RHF risk score was high (>4 points) in 60 patients, intermediate (>2-4 points) in 19 and low (0-2 points) in 15. RHF occurred in four patients (4.3%). Mean duration of echocardiographic follow-up was 2.8 ± 2.3 years. None of the patients presented with severe and only five (5.3%) with moderate TR. The vast majority (n = 63) had mild TR, and 26 patients had no/trace TR. Survival at 1, 3 and 5 years was 77.4%, 68.1% and 55.6%, 30-day mortality was 11.7% (n = 11). Heart transplantation was performed in 12 patients (12.8%). Conclusions: Contrary to expectations, concomitant TVR during LVAD implantation may result in excellent repair durability, which appears to be associated with low risk for RHF.

Dynamic load modulation predicts right heart tolerance of left ventricular cardiovascular assist in a porcine model of cardiogenic shock

Ventricular assist devices (VADs) offer mechanical support for patients with cardiogenic shock by unloading the impaired ventricle and increasing cardiac outflow and subsequent tissue perfusion. Their ability to adjust ventricular assistance allows for rapid and safe dynamic changes in cardiac load, which can be used with direct measures of chamber pressures to quantify cardiac pathophysiologic state, predict response to interventions, and unmask vulnerabilities such as limitations of left-sided support efficacy due to intolerance of the right heart. We defined hemodynamic metrics in five pigs with dynamic peripheral transvalvular VAD (pVAD) support to the left ventricle. Metrics were obtained across a spectrum of disease states, including left ventricular ischemia induced by titrated microembolization of a coronary artery and right ventricular strain induced by titrated microembolization of the pulmonary arteries. A sweep of different pVAD speeds confirmed mechanisms of right heart decompensation after left-sided support and revealed intolerance. In contrast to the systemic circulation, pulmonary vascular compliance dominated in the right heart and defined the ability of the right heart to adapt to left-sided pVAD unloading. We developed a clinically accessible metric to measure pulmonary vascular compliance at different pVAD speeds that could predict right heart efficiency and tolerance to left-sided pVAD support. Findings in swine were validated with retrospective hemodynamic data from eight patients on pVAD support. This methodology and metric could be used to track right heart tolerance, predict decompensation before right heart failure, and guide titration of device speed and the need for biventricular support.

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.

ProtekDuo percutaneous ventricular support system-physiology and clinical applications

The ProtekDuo (LivaNova, London, UK) cannula is a dual-lumen device, typically inserted into the right internal jugular (IJ) vein through a percutaneous approach, with fluoroscopy or ultrasound guidance. When connected to a pump, such as the TandemHeart (LivaNova, London, UK) or CentriMag (Abbott, Pleasanton, CA, USA), it can function as a right ventricular (RV) mechanical circulatory support (MCS). When an oxygenator is also added [veno-pulmonary (V-P)], it can provide extracorporeal membrane oxygenation (ECMO) support. This review aims to provide a comprehensive overview of the device's physiology and clinical applications. In the setting of RV failure (RVF), the ProtekDuo cannula, with its outflow in the main pulmonary artery (PA), can bypass the failing RV, improving pulmonary flow, left atrial (LA) filling pressures, and left ventricular (LV) preload. This can also reduce ventricular interdependence and leftward shift of the interventricular septum that occurs in RVF. In this review, the key sections expand on the use of the ProtekDuo cannula in the management of critically ill patients, specifically, the use of ProtekDuo for RV myocardial infarction (MI) RVF, LV assist device (LVAD) implantation-associated RVF, RVF post-heart transplantation, temporary biventricular MCS as bridge to recovery (ECpella 2.0 or PROpella), biventricular support as bridge to recovery or decision, isolated LV failure, post lung transplantation (LT) care, and other miscellaneous clinical scenarios. ProtekDuo is an important tool in the armory of RVF management. The ProtekDuo system is expected to gain more popularity given its clear advantages such as groin-free approach allowing for mobility, easy percutaneous deployment, compatibility with various pumps and oxygenators, and the versatility to be integrated in numerous configurations. In an era of expanding MCS options, further research is needed to better understand the optimal tool for specific patient subsets.

The outcomes of a standardized protocol for extracorporeal mechanical circulatory support selection-left ventricular challenge protocol

There are no criteria for surgical mechanical circulatory system (MCS) selection for acute heart failure. Since 2021, we have utilized cardiopulmonary bypass system to assess patients' heart and lung condition to inform surgical MCS selection. we aimed to retrospectively analyze the outcomes of treatments administered using our protocol. We analyzed the data of 19 patients who underwent surgical MCS implantation. We compared patients' characteristics across the biventricular-assist device (BiVAD), central Y-Y extracorporeal membrane oxygenation (ECMO), central ECMO, and left VAD (LVAD) systems. Patients' diagnoses included fulminant myocarditis (47.4%), dilated cardiomyopathy (21.1%), acute myocardial infarction (15.8%), infarction from aortic dissection (5.3%), doxorubicin-related cardiomyopathy (5.3%), and tachycardia-induced myocarditis (5.3%). Eight patients (42.1%) underwent LVAD implantation, 1 (5.2%) underwent central ECMO, 4 (21.1%) underwent BiVAD implantation, and 6 (31.6%) underwent central Y-Y ECMO. 48 h after surgery, both the pulmonary arterial and right atrial pressures were effectively controlled, with median values being 19.0 mmHg and 9.0 mmHg, respectively. No patients transitioned from LVAD to BiVAD in the delayed period. Cerebrovascular events occurred in 21.1%. Successful weaning was achieved in 11 patients (57.9%), and 5 patients (26.3%) were converted to durable LVAD. Two-year cumulative survival was 84.2%. Our protocol showed good results for device selection in patients with heart failure, and device selection according to this protocol enabled good control of the pulmonary and systemic circulations.

How do mechanical circulatory support patients die? Autopsy findings for left-ventricular assist device/total artificial heart nonsurvivors

BACKGROUND

Although life saving for end-stage heart failure patients, permanent mechanical circulatory support (MCS) is often the proximate cause of death in those that do not survive to transplant. Autopsy remains the gold standard for diagnosing causes of death and a vital tool for better understanding underlying pathology of nonsurvivors. The aim of this study was to determine the frequency and outcomes of autopsy investigations and compare these with premortem clinical assessment.

METHODS

The autopsy findings and medical records of all patients who underwent left ventricular assist device (LVAD) or total artificial heart (TAH) insertion between June 1994 and April 2022 as a bridge to transplant, but subsequently died pre-heart transplantation were reviewed.

RESULTS

A total of 203 patients had a LVAD or TAH implanted during the study period. Seventy-eight patients (M=59, F=19) died prior to transplantation (age 55 [14] years, INTERMACS=2). Autopsies were conducted in 26 of 78 patients (33%). Three were limited studies. The leading contributor to cause of death was respiratory (14/26), either nosocomial infection or associated with multiorgan failure. Intracranial hemorrhage was the second most common cause of death (8/26). There was a major discrepancy rate of 17% and a minor discrepancy rate of 43%. Autopsy study added a total of 14 additional contributors of death beyond clinical assessment alone (Graphical Abstract).

CONCLUSIONS

Over an observational period of 26years, the frequency of autopsy was low. To improve LVAD/TAH patient survival to transplant, better understanding as to cause of death is required. Patients with MCS have complex physiology and are at high risk of infection and bleeding complications.

Perioperative Right Ventricular Dysfunction and Abnormalities of the Tricuspid Valve Apparatus in Patients Undergoing Cardiac Surgery

Right ventricular (RV) dysfunction frequently occurs after cardiac surgery and is linked to adverse postoperative outcomes, including mortality, reintubation, stroke, and prolonged ICU stays. While various criteria using echocardiography and hemodynamic parameters have been proposed, a consensus remains elusive. Distinctive RV anatomical features include its thin wall, which presents a triangular shape in a lateral view and a crescent shape in a cross-sectional view. Principal causes of RV dysfunction after cardiac surgery encompass ischemic reperfusion injury, prolonged ischemic time, choice of cardioplegia and its administration, cardiopulmonary bypass weaning characteristics, and preoperative risk factors. Post-left ventricular assist device (LVAD) implantation RV dysfunction is common but often transient, with a favorable prognosis upon resolution. There is an ongoing debate regarding the benefits of concomitant surgical repair of the RV in the presence of regurgitation. According to the literature, the gold standard techniques for assessing RV function are cardiac magnetic resonance imaging and hemodynamic assessment using thermodilution. Echocardiography is widely favored for perioperative RV function evaluation due to its accessibility, reproducibility, non-invasiveness, and cost-effectiveness. Although other techniques exist for RV function assessment, they are less common in clinical practice. Clinical management strategies focus on early detection and include intravenous drugs (inotropes and vasodilators), inhalation drugs (pulmonary vasodilators), ventilator strategies, volume management, and mechanical support. Bridging research gaps in this field is crucial to improving clinical outcomes associated with RV dysfunction in the near future.

Successful echocardiography-guided medical management of severe early post-implant right ventricular failure in a patient with left ventricular assist device support: a case report

BACKGROUND

Post-implant right heart failure (RHF) has been recognized as a crucial prognostic factor in patients receiving left ventricular assist devices (LVADs), and its management has long attracted attention from cardiologists and surgeons.

CASE PRESENTATION

This report described an 18-year-old female with acutely deteriorating heart failure due to dilated cardiomyopathy who underwent paracorporeal pulsatile-flow LVAD and developed early post-implant RHF. At postoperative day (POD) six, she was almost asymptomatic at rest on 2.5 mg/kg/min of dobutamine; however, the echocardiogram, performed as part of the daily postoperative care, revealed a severely enlarged right ventricle with a decompressed left ventricle, implying the development of post-implant RHF. Bolus infusion of saline and reduction of pump flow (6.0 L/min to 3.0 L/min) led to normalization of both ventricular shapes in 30 s, suggesting that RHF could be managed without surgical interventions. Milrinone was started on POD six, followed by sildenafil administration on POD seven. Fluid balance was strictly adjusted under the close observation of daily echocardiograms. Milrinone and dobutamine were discontinued on PODs 18 and 21, respectively. The patient was listed for a heart transplant on POD 40. Despite reduced right ventricular function (right ventricular stroke work index of 182.34 mmHg*ml/m- 2, body surface area 1.5 m2), she was successfully converted to implantable LVAD on POD 44 with no recurrence of post-implant RHF thereafter for four years.

CONCLUSIONS

In post-implant RHF management, early detection, together with proper and prompt medical management, is crucial to avoiding any surgical intervention. Close observation of daily echocardiograms might be helpful in detecting subclinical RHF and is useful for post-implant medical management.

A novel intrapericardial pulsatile device for individualized, biventricular circulatory support without direct blood contact

OBJECTIVE

Due to severely limited donor heart availability, durable mechanical circulatory support remains the only treatment option for many patients with end-stage heart failure. However, treatment complexity persists due to its univentricular support modality and continuous contact with blood. We investigated the function and safety of reBEAT (AdjuCor GmbH), a novel, minimal invasive mechanical circulatory support device that completely avoids blood contact and provides pulsatile, biventricular support.

METHODS

For each animal tested, an accurately sized cardiac implant was manufactured from computed tomography scan analyses. The implant consists of a cardiac sleeve with three inflatable cushions, 6 epicardial electrodes and driveline connecting to an electro-pneumatic, extracorporeal portable driver. Continuous epicardial electrocardiogram signal analysis allows for systolic and diastolic synchronization of biventricular mechanical support. In 7 pigs (weight, 50-80 kg), data were analyzed acutely (under beta-blockade, n = 5) and in a 30-day long-term survival model (n = 2). Acquisition of intracardiac pressures and aortic and pulmonary flow data were used to determine left ventricle and right ventricle stroke work and stroke volume, respectively.

RESULTS

Each implant was successfully positioned around the ventricles. Automatic algorithm electrocardiogram signal annotations resulted in precise, real-time mechanical support synchronization with each cardiac cycle. Consequently, progressive improvements in cardiac hemodynamic parameters in acute animals were achieved. Long-term survival demonstrated safe device integration, and clear and stable electrocardiogram signal detection over time.

CONCLUSIONS

The present study demonstrates biventricular cardiac support with reBEAT. Various demonstrated features are essential for realistic translation into the clinical setting, including safe implantation, anatomical fit, safe device-tissue integration, and real-time electrocardiogram synchronized mechanical support, result in effective device function and long-term safety.

Prospective Phenotyping of Right Ventricle Function Following Intra-Aortic Balloon Pump Counterpulsation in Left Ventricular Assist Device Candidates: Outcomes and Predictors of Response

Intra-aortic balloon pump (IABP) may be applied to optimize advanced heart failure (AHF) patients and improve right ventricular (RV) function before left ventricular assist device (LVAD) implantation. We aimed to evaluate the outcome of this intervention and define RV response predictors. Decompensated AHF patients, not eligible for LVAD because of poor RV function, who required IABP for stabilization were enrolled. Echocardiography and invasive hemodynamics were serially applied to determine fulfillment of prespecified "LVAD eligibility RV function" criteria (right atrium pressure [RA] <12 mm Hg, pulmonary artery pulsatility index [PAPi] >2.00, RA/pulmonary capillary wedge pressure [PCWP] <0.67, RV strain <-14.0%). Right ventricular-free wall tissue was harvested to assess interstitial fibrosis. Eighteen patients (12 male), aged 38 ± 14 years were supported with IABP for 55 ± 51 (3-180) days. In 11 (61.1%), RV improved and fulfilled the prespecified criteria, while seven (38.9%) showed no substantial improvement. Histopathology revealed an inverse correlation between RV interstitial fibrosis and functional benefit following IABP: interstitial fibrosis correlated with post-IABP RA ( r = 0.63, p = 0.037), RA/PCWP ( r = 0.87, p = 0.001), PAPi ( r = -0.83, p = 0.003). Conclusively, IABP improves RV function in certain AHF patients facilitating successful LVAD implantation. Right ventricular interstitial fibrosis quantification may be applied to predict response and guide preoperative patient selection and optimization. http://links.lww.com/ASAIO/A995.

Blood flow kinetic energy is a novel marker for right ventricular global systolic function in patients with left ventricular assist device therapy

Objectives

Right ventricular (RV) failure remains a major concern in heart failure (HF) patients undergoing left ventricular assist device (LVAD) implantation. We aimed to measure the kinetic energy of blood in the RV outflow tract (KE-RVOT) - a new marker of RV global systolic function. We also aimed to assess the relationship of KE-RVOT to other echocardiographic parameters in all subjects and assess the relationship of KE-RVOT to hemodynamic parameters of RV performance in HF patients.

Methods

Fifty-one subjects were prospectively enrolled into 4 groups (healthy controls, NYHA Class II, NYHA Class IV, LVAD patients) as follows: 11 healthy controls, 32 HF patients (8 NYHA Class II and 24 Class IV), and 8 patients with preexisting LVADs. The 24 Class IV HF patients included 21 pre-LVAD and 3 pre-transplant patients. Echocardiographic parameters of RV function (TAPSE, St', Et', IVA, MPI) and RV outflow color-Doppler images were recorded in all patients. Invasive hemodynamic parameters of RV function were collected in all Class IV HF patients. KE-RVOT was derived from color-Doppler imaging using a vector flow mapping proprietary software. Kruskal-Wallis test was performed for comparison of KE-RVOT in each group. Correlation between KE-RVOT and echocardiographic/hemodynamic parameters was assessed by linear regression analysis. Receiver operating characteristic curves for the ability of KE-RVOT to predict early phase RV failure were generated.

Results

KE-RVOT (median ± IQR) was higher in healthy controls (55.10 [39.70 to 76.43] mW/m) than in the Class II HF group (22.23 [15.41 to 35.58] mW/m, p < 0.005). KE-RVOT was further reduced in the Class IV HF group (9.02 [5.33 to 11.94] mW/m, p < 0.05). KE-RVOT was lower in the LVAD group (25.03 [9.88 to 38.98] mW/m) than the healthy controls group (p < 0.005). KE-RVOT had significant correlation with all echocardiographic parameters and no correlation with invasive hemodynamic parameters. RV failure occurred in 12 patients who underwent LVAD implantation in the Class IV HF group (1 patient was not eligible due to death immediately after the LVAD implantation). KE-RVOT cut-off value for prediction of RV failure was 9.15 mW/m (sensitivity: 0.67, specificity: 0.75, AUC: 0.66).

Conclusions

KE-RVOT, a novel noninvasive measure of RV function, strongly correlates with well-established echocardiographic markers of RV performance. KE-RVOT is the energy generated by RV wall contraction. Therefore, KE-RVOT may reflect global RV function. The utility of KE-RVOT in prediction of RV failure post LVAD implantation requires further study.

Efficacy of levosimendan infusion in patients undergoing a left ventricular assist device implant in a propensity score matched analysis of the EUROMACS registry-the Euro LEVO-LVAD study

OBJECTIVES

Early right-sided heart failure (RHF) was seen in 22% of recipients of a left ventricular assist device (LVAD) in the European Registry for Patients with Mechanical Circulatory Support (EUROMACS). However, the optimal treatment of post-LVAD RHF is not well known. Levosimendan has proven to be effective in patients with cardiogenic shock and in those with end-stage heart failure. We sought to evaluate the efficacy of levosimendan on post-LVAD RHF and 30-day and 1-year mortality.

METHODS

The EUROMACS Registry was used to identify adults with mainstream continuous-flow LVAD implants who were treated with preoperative levosimendan compared to a propensity matched control cohort.

RESULTS

In total, 3661 patients received mainstream LVAD, of which 399 (11%) were treated with levosimendan pre-LVAD. Patients given levosimendan had a higher EUROMACS RHF score [4 (2- 5.5) vs 2 (2- 4); P < 0.001], received more right ventricular assist devices (RVAD) [32 (8%) vs 178 (5.5%); P = 0.038] and stayed longer in the intensive care unit post-LVAD implant [19 (8-35) vs 11(5-25); P < 0.001]. Yet, there was no significant difference in the rate of RHF, 30-day, or 1-year mortality. Also, in the matched cohort (357 patients taking levosimendan compared to an average of 622 controls across 20 imputations), we found no evidence for a difference in postoperative severe RHF, RVAD implant rate, length of stay in the intensive care unit or 30-day and 1-year mortality.

CONCLUSIONS

In this analysis of the EUROMACS registry, we found no evidence for an association between levosimendan and early RHF or death, albeit patients taking levosimendan had much higher risk profiles. For a definitive conclusion, a multicentre, randomized study is warranted.

Safety and efficacy of ProtekDuo right ventricular assist device: A systemic review

BACKGROUND

Right ventricular failure is associated with increased morbidity and mortality. The ProtekDuo (Livanova, Uk) is a dual-lumen cannula that allows for percutaneous right ventricular support and may be connected to a centrifugal blood pump such as the TandemHeart or LifeSparc (Livanova, UK). This systematic review aims to evaluate the safety and efficacy of ProtekDuo right ventricular support and evaluate potential clinical variables that can influence outcomes.

METHODS

PubMed, MEDLINE, SCOPUS, EMBASE, and the Cochrane Library were systematically searched. Studies meeting inclusion criteria, where ProtekDuo was used as the right ventricular assist device with reported numerical death counts for mortality as outcome measures. The primary endpoints were in-hospital 30-day and 1-year mortality rates. Secondary endpoints included ICU length of stay, conversion rates to surgical RVADs, ProtekDuo wean rates, duration of use of ProtekDuo, and adverse event rates.

RESULTS

Of 49 studies reviewed, 7 met inclusion criteria with study periods between October 2014 and November 2019. ProtekDuo was utilized due to RV failure post-LVAD insertion in 64.8% (68/105) of patients. In-hospital mortality, 30-day mortality, and 1-year mortality ranged between 9%-46%, 15%-40%, and 19%-40%, respectively. Weaning from ProtekDuo and conversion to surgical RVAD ranged between 24%-91% and 11%-35%, respectively. The ICU stay average ranged from 15.8 to 36 days and ProtekDuo mean support duration ranged from 10.5 to 58 days.

CONCLUSION

The ProtekDuo cannula is increasingly utilized as a right ventricular support device. Despite the sparse retrospective data available with variable patient characteristics and study design, percutaneous RV mechanical support via ProtekDuo cannula is a safe and feasible option.

A novel metrics to predict right heart failure after left ventricular assist device implantation

BACKGROUND

Right Heart Failure (RHF) is a severe complication that can occur after left ventricular assist device (LVAD) implantation, increasing early and late mortality. Although numerous RHF predictive scores have been developed, limited data exist on the external validation of these models. We therefore aimed at comparing existent risk score models and identifying predictors of severe RHF at our center.

METHODS

In this retrospective, single-center analysis, clinical, biological and functional data were collected in patients implanted with a LVAD between 2011 and 2020. Early severe RHF was defined as the use of inotropes for ≥ 14 days, nitric oxide use for ≥ 48 h or unplanned right-sided circulatory support. Risk models were evaluated for the primary outcome of RHF or RVAD implantation by means of logistic regression and receiver operating characteristic curves.

RESULTS

Among 92 patients implanted, 24 (26%) developed early severe RHF. The EUROMACS-RHF risk score performed the best in predicting RHF (C = 0.82-95% CI: 0.68-0.90), compared with the other scores (Michigan, CRITT). In addition, we developed a new model, based on four variables selected for the best reduced logistic model: the INTERMACS level, the number of inotropes used, the ratio of right atrial/pulmonary capillary wedge pressure and the ratio of right ventricle/left ventricle diameters by echocardiography. This model demonstrated significant discrimination of RHF (C = 0.9-95% CI: 0.76-0.96).

CONCLUSION

Amongst available risk scores, EUROMACS-RHF performs best to predict the occurrence of RHF after LVAD implantation. Our model's performance compares well to the EUROMACS-RHF score, adding a more objective parameter to RV function evaluation.

Concomitant tricuspid valve repair in left ventricular assist device implantation may increase the risk for temporary right ventricular support but does not impact overall outcomes

OBJECTIVES

Tricuspid valve repair in left ventricular assist device implantation continues to pose a challenge and may impact the occurrence of early and late right heart failure. We investigated the effects of concomitant tricuspid repair on clinical outcomes.

METHODS

A retrospective, multicentre study enrolled adult patients who received continuous-flow left ventricular assist devices between 2005 and 2017 and compared those who received concomitant tricuspid valve repair to those who did not. Primary outcomes were early right heart failure necessitating temporary ventricular assist devices and right heart failure-related rehospitalizations requiring inotropic or diuretic treatment.

RESULTS

Out of 526 patients who underwent left ventricular assist device implantation, 110 (21%) received a concomitant tricuspid valve repair. Those patients were sicker, and most had moderate or severe tricuspid regurgitation. A significantly higher incidence of temporary right ventricular assist devices was observed in the group with concomitant tricupid valve repair (18% vs. 11%, P = 0.049), with a significantly elevated risk for temporary right heart assist device (sHR 1.68, 95% CI 1.04-2.72; P = 0.037). After adjusting for confounders, no significant differences were found in the incidence of and risk for most clinical outcomes, including right heart failure-related rehospitalizations (P = 0.891) and death (P = 0.563).

CONCLUSIONS

Concomitant tricuspid valve repair, when deemed necessary in left ventricular assist device implantation, may increase the risk of early right heart failure requiring a temporary right ventricular assist device but does not impact the incidence or risk of death or rehospitalizations due to late right heart failure.

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.

Update on the Practical Role of Echocardiography in Selection, Implantation, and Management of Patients Requiring Left Ventricular Assist Device Therapy

PURPOSE OF REVIEW

Echocardiography is a valuable tool for management of patients with a left ventricular assist device (LVAD). We present an updated review on the practical applications of the role of echocardiography for pre- and postoperative evaluation of patients selected.

RECENT FINDINGS

The LVAD is a temporary or permanent option for patients with advanced heart failure who are unresponsive to other therapy. Use of the device has its own risks, and implantation remains a complex procedure. Transthoracic and transesophageal echocardiography are useful tools for patient evaluation and monitoring both peri- and postoperatively, as we previously presented. Assessment of left and right ventricular function, complications such as thrombus formation or intracardiac shunting, and valvular disease are all important in this assessment. This also aids in predicting postoperative complications. Placement of the device is confirmed intraoperatively, and subsequent ramp studies are used to determine optimal device settings. Right ventricular (RV) failure is the most common postoperative complication and preoperative evaluation of its function is crucial. Studies suggest that tricuspid annular plane systolic excursion, RV fractional area change, and RV global longitudinal strain are strong predictors of RV failure; LV ejection fraction, size, and end-diastolic diameter are also important markers. Aortic regurgitation and mitral stenosis must always be corrected prior to LVAD placement. However, direct visualization before and after implantation, especially to rule out potential contraindications such as thrombi, cannot be overemphasized. Ramp studies remain an integral part of device optimization and may result in greater myocardial recovery than previously realized.

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.

Biventricular Compared to Left Ventricular Impella and Norepinephrine Support in a Porcine Model of Severe Cardiogenic Shock

Contemporary management of cardiogenic shock (CS) with vasopressors is associated with increased cardiac workload and despite the use of unloading devices such as the Impella pump, concomitant vasopressors are often necessary. Therefore, we compared if cardiac workload could be reduced and end-organ perfusion preserved with biventricular support (Bipella) compared to ImpellaCP and norepinephrine in pigs with left ventricular (LV) CS caused by left main coronary microembolization. Cardiac workload was calculated from heart rate × ventricular pressure-volume area obtained from conductance catheters placed in the LV and right ventricle (RV), whereas organ perfusion was measured from venous oxygen saturation in the pulmonary artery (SvO 2 ) and the kidney- and the cerebral vein. A cross-over design was used to access the difference after 30 minutes of ImpellaCP and norepinephrine 0.1 µg/kg/min versus Bipella for 60 minutes. Bipella treatment reduced LV workload ( p = 0.0078) without significant difference in RV workload from ImpellaCP and norepinephrine, however a decrease in SvO 2 (49[44-58] vs . 66[63-73]%, p = 0.01) and cerebral venous oxygen saturations (62[48-66] vs . 71[63-77]%, p = 0.016) was observed during Bipella compared to ImpellaCP and norepinephrine. We conclude that Bipella reduced LV workload but did not preserve end-organ perfusion compared to ImpellaCP and norepinephrine in short-term LV CS.

Incremental Value of Global Longitudinal Strain to Michigan Risk Score and Pulmonary Artery Pulsatility Index in Predicting Right Ventricular Failure Following Left Ventricular Assist Devices

BACKGROUND

The incremental utility of right ventricular (RV) strain on predicting right ventricular failure (RVF) following left ventricular assist device (LVAD) implantation, beyond clinical and haemodynamic indices, is not clear.

METHODS

Two hundred and forty-six (246) patients undergoing LVAD implantation, who had transthoracic echocardiograms pre and post LVAD, pulmonary artery pulsatility index (PAPI) measurements and Michigan risk score, were included. We analysed RV global longitudinal strain (GLS) using speckle tracking echocardiography. RVF following LVAD implantation was defined as the need for medical support for >14 days, or unplanned RV assist device insertion after LVAD implantation.

RESULTS

Mean preoperative RV-GLS was -7.8±2.8%. Among all, 27% developed postoperative RVF. A classification and regression tree analysis identified preoperative Michigan risk score, PAPI and RV-GLS as important parameters in predicting postoperative RVF. Eighty per cent (80%) of patients with PAPI <2.1 developed postoperative RVF, while only 4% of patients with PAPI >6.8 developed RVF. For patients with a PAPI of 2.1-3.2, having baseline Michigan risk score >2 points conferred an 81% probability of subsequent RVF. For patients with a PAPI of 3.3-6.8, having baseline RV-GLS of -4.9% or better conferred an 86% probability of no subsequent RVF. The sensitivity and specificity of this algorithm for predicting postoperative RVF were 67% and 93%, respectively, with an area under the curve of 0.87.

CONCLUSION

RV-GLS has an incremental role in predicting the development of RVF post-LVAD implantation, even after controlling for clinical and haemodynamic parameters.

Prognostic value of TAPSE/PASP ratio in right ventricular failure after left ventricular assist device implantation: Experience from a tertiary center

Background

In this study, we aimed to investigate the prognostic value of the tricuspid annular plane systolic excursion (TAPSE)/ pulmonary arterial systolic pressure (PASP) ratio in right ventricular failure patients undergoing left ventricular assist device implantation.

Methods

Between February 2013 and February 2020, a total of 75 heart failure patients (65 males, 10 females; median age: 54 years; range, 21 to 66 years) were retrospectively analyzed. The prognostic value of TAPSE/PASP ratio was assessed using the multivariate Cox regression models and confirmed using the Kaplan-Meier analyses.

Results

Forty-one (55.4%) patients had an ischemic heart failure etiology. The indication for assist device implantation was bridge to transplant in 64 (85.3%) patients. The overall survival rates at one, three, and five years following left ventricular assist device implantation were 82.7%, 68%, and 49.3%, respectively. Right ventricular failure was observed in 24 (32%) patients during follow-up. In the multivariate analysis, TAPSE/PASP was found to be independently associated with postoperative right ventricular failure (HR: 1.63; 95% CI: 1.49-2.23). A TAPSE/PASP of 0.34 mm/mmHg was found to be the most accurate predictor value, with lower ratios correlating with right ventricular failure. The Kaplan-Meier analysis showed a better overall survival using a TAPSE/PASP ≥ of 0.34 mm/mmHg (p<0.001).

Conclusion

A lower TAPSE/PASP ratio, particularly lower values than 0.34 mm/mmHg, strongly predicts right ventricular failure after left ventricular assist device implantation in patients with advanced heart failure.

Echocardiography in Cardiac Assist Devices

In patients with medically refractory heart failure or cardiogenic shock, both temporary and durable mechanical circulatory support devices can be used to support cardiac circulation. Both transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) are widely available, relatively noninvasive, and avoid radiation exposure. Thus, echocardiography is an invaluable tool that provides vital information aiding in preprocedure evaluation, placement, management, and weaning of cardiac assist devices. The purpose of this article is to review the utility of both TTE and TEE in managing patients with cardiac assist devices.

Role of Echocardiography in the Management of Patients with Advanced (Stage D) Heart Failure Related to Nonischemic Cardiomyopathy

Echocardiography (ECHO) is indispensable for evaluation of patients with terminal chronic heart failure (HF) who require transplantation or mechanical circulatory support by a left- or biventricular assist device (LVAD or BiVAD, respectively). In LVAD candidates, ECHO represents the first-line investigation necessary for a timely discovery of heart-related risk factors for potentially life-threatening post-operative adverse events, including identification of patients who necessitate a biventricular support. ECHO is also required for intra-operative guiding of VAD implantation and finding of the most appropriate setting of the device for an optimal ventricular unloading, postoperative surveillance of the VAD support, and monitoring of the RV changes in LVAD recipients. Thanks to the ECHO, which has decisively contributed to the proof that prolonged VAD support can facilitate cardiac reverse remodeling and functional improvement to levels which allow successful weaning of carefully selected patients from LVAD or BiVAD, the previous opinion that chronic non-ischemic cardiomyopathy (NICMP) is irreversible could be refuted. In patients with normalized and stable right heart catheter-derived hemodynamic parameters obtained at short-term interruptions of VAD support, ECHO has proved able to predict post-weaning long-term freedom from HF recurrence in patients with pre-implant terminal chronic NICMP. The purpose of this article is to offer an actualized theoretical and practical support for clinicians engaged in this particularly challenging and topical issue especially due to the new practical aspects which have emerged in conjunction with the growing use of long-term ventricular assist devices as bridge-to-transplantation or as destination therapy, as well as the increasing evidence that, in some patients, such VAD can become a bridge-to-recovery, allowing the removal of the device after a longer support time.

Predicting, Recognizing, and Treating Right Heart Failure in Patients Undergoing Durable LVAD Therapy

Despite advancing technology, right heart failure after left ventricular assist device implantation remains a significant source of morbidity and mortality. With the UNOS allocation policy change, a larger proportion of patients proceeding to LVAD are destination therapy and consist of an overall sicker population. Thus, a comprehensive understanding of right heart failure is critical for ensuring the ongoing success of durable LVADs. The purpose of this review is to describe the effect of LVAD implantation on right heart function, review the diagnostic and predictive criteria related to right heart failure, and discuss the current evidence for management and treatment of post-LVAD right heart failure.

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.

A standardized definition for right ventricular failure in cardiac surgery patients

Right ventricular failure (RVF) is a significant cause of mortality and morbidity after cardiac surgery. Despite its prognostic importance, RVF remains under investigated and without a universally accepted definition in the perioperative setting. We foresee that the provision of a standardized perioperative definition for RVF based on practical and objective criteria will help to improve quality of care through early detection and facilitate the generalization of RVF research to advance this field. This article provides an overview of RVF aetiology, pathophysiology, current diagnostic modalities, as well as a summary of existing RVF definitions. This is followed by our proposal for a standardized definition of perioperative RVF, one that captures RV structural and functional abnormalities through a multimodal approach based on anatomical, echocardiographic, and haemodynamic criteria that are readily available in the perioperative setting (Central Image).

Right and left ventricular assist devices are an option for bridge to heart transplant

Background

Patients with a left ventricular assist device with right ventricular failure are prioritized on the heart transplant waitlist; however, their post-transplant survival is less well characterized. We aimed to determine whether pretransplant right ventricular failure affects postoperative survival in patients with a left ventricular assist device as a bridge to transplant.

Methods

We performed a retrospective review of the 2005-2018 Organ Procurement and Transplantation Network/United Network for Organ Sharing registry for candidates aged 18 years or more waitlisted for first-time isolated heart transplantation after left ventricular assist device implantation. Candidates were stratified on the basis of having right ventricular failure, defined as the need for right ventricular assist device or intravenous inotropes. Baseline demographic and clinical characteristics were compared among the 3 groups, and post-transplant survival was assessed.

Results

Our cohort included 5605 candidates who met inclusion criteria, including 450 patients with right ventricular failure, 344 patients with a left ventricular assist device and intravenous inotropes as a bridge to transplant, 106 patients with a left ventricular assist device and right ventricular assist device, and 5155 patients with a left ventricular assist device as a bridge to transplant without the need for right side support. Compared with patients without right ventricular failure, patients with a left ventricular assist device as a bridge to transplant with right ventricular failure were younger (median age 51 years, 55 vs 56 years, P < .001) and waited less time for organs (median 51 days, 93.5 vs 125 days, P < .001). These patients also had longer post-transplant length of stay (median 18 days, 20 vs 16 days, P < .001). Right ventricular failure was not associated with decreased post-transplant long-term survival on unadjusted Kaplan–Meier analysis (P = .18). Neither preoperative right ventricular assist device nor intravenous inotropes independently predicted worse survival on multivariate Cox proportional hazards analysis. However, pretransplant liver dysfunction (total bilirubin >2) was an independent predictor of worse survival (hazard ratio, 1.74; 95% confidence interval, 1.39-2.17; P < .001), specifically in the left ventricular assist device group and not in the left ventricular assist device + right ventricular assist device/intravenous inotropes group.

Conclusions

Patients with biventricular failure are prioritized on the waiting list, because their critical pretransplant condition has limited impact on their post-transplant survival (short-term effect only); thus, surgeons should be confident to perform transplantation in these severely ill patients. Because liver dysfunction (a surrogate marker of right ventricular failure) was found to affect long-term survival in patients with a left ventricular assist device, surgeons should be encouraged to perform transplantation in these severely ill patients after a recipient's optimization by inotropes or a right ventricular assist device because even when the bilirubin level is elevated in these patients (treated with right ventricular assist device/inotropes), their long-term survival is not affected. Future studies should assess recipients' optimization before organ acceptance to improve long-term survival.

Bridging patients in cardiogenic shock with a paracorporeal pulsatile biventricular assist device to heart transplantation-a single-centre experience

OBJECTIVES

We evaluated the outcome of patients in cardiogenic shock receiving a paracorporeal pulsatile biventricular assist device as a bridge to transplantation.

METHODS

We performed a retrospective single-centre analysis of all patients who received a Berlin Heart Excor® at our institution between 2004 and 2019.

RESULTS

A total of 97 patients (90 adults, 7 paediatric) were analysed. Eighty-four patients were in Interagency Registry for Mechanically Assisted Circulatory Support level 1 (80 adults, 4 paediatric). Diagnoses were dilated cardiomyopathy (n = 41), ischaemic cardiomyopathy (n = 17) or myocardial infarction (n = 4), myocarditis (n = 15), restrictive cardiomyopathy (n = 2), graft failure after heart transplant (n = 7), postcardiotomy heart failure (n = 5), postpartum cardiomyopathy (n = 3), congenital heart disease (n = 1), valvular cardiomyopathy (n = 1) and toxic cardiomyopathy (n = 1). All patients were in biventricular heart failure and had secondary organ dysfunction. The mean duration of support was 63 days (0-487 days). There was a significant decrease in creatinine values after assist device implantation (from 1.83 ± 0.79 to 1.12 ± 0.67 mg/dl, P = 0.001) as well as a decrease in bilirubin values (from 3.94 ± 4.58 to 2.65 ± 3.61 mg/dl, P = 0.084). Cerebral stroke occurred in 16 patients, bleeding in 15 and infection in 13 patients. Forty-eight patients died on support, while 49 patients could be successfully bridged to transplantation. Thirty-day survival and 1-year survival were 70.1% and 41.2%, respectively.

CONCLUSIONS

A pulsatile biventricular assist device is a reasonable therapeutic option in cardiogenic shock, when immediate high cardiac output is necessary to rescue the already impaired kidney and liver function of the patient.

Continuous-flow left ventricular assist device: Current knowledge, complications, and future directions

Long-term continuous-flow left ventricular assist devices have become a real alternative to heart transplantation in patients with advanced heart failure, achieving a promising 2-year event-free survival rate with new-generation devices. Currently, this technology has spread throughout the world, and any cardiologist or cardiac surgeon should be familiar with its fundamentals and its possible complications as well as the advances made in recent years. The aim of this review is to describe current knowledge, management of complications, and future directions of this novel heart-failure therapy.

Invasive Haemodynamic Assessment Before and After Left Ventricular Assist Device Implantation: A Guide to Current Practice

Mechanical circulatory support for the management of advanced heart failure is a rapidly evolving field. The number of durable long-term left ventricular assist device (LVAD) implantations increases each year, either as a bridge to heart transplantation or as a stand-alone ‘destination therapy’ to improve quantity and quality of life for people with end-stage heart failure. Advances in cardiac imaging and non-invasive assessment of cardiac function have resulted in a diminished role for right heart catheterisation (RHC) in general cardiology practice; however, it remains an essential tool in the evaluation of potential LVAD recipients, and in their long-term management. In this review, the authors discuss practical aspects of performing RHC and potential complications. They describe the haemodynamic markers associated with a poor prognosis in patients with left ventricular systolic dysfunction and evaluate the measures of right ventricular (RV) function that predict risk of RV failure following LVAD implantation. They also discuss the value of RHC in the perioperative period; when monitoring for longer term complications; and in the assessment of potential left ventricular recovery.

Strategies for Mechanical Right Ventricular Support during Left Ventricular Assist Device Implant

BACKGROUND

Refractory right ventricular failure at the time of left ventricular assist device implantation requires treatment with supplemental mechanical circulatory support. However, the optimal strategy for support remains unknown.

METHODS

All patients undergoing first time durable left ventricular assist device implantation with a contemporary device were selected from the national Society of Thoracic Surgeons Database (2011-2019). Patients requiring right ventricular assist device (RVAD) or venoarterial extracorporeal membrane oxygenation (VA-ECMO) were included in the analysis. Patients were stratified by RVAD or VA-ECMO and by timing of placement (intraoperative vs. postoperative).

RESULTS

18,423 left ventricular assist device implants were identified, of which 940 (5.1%) required RVAD (n=750) or VA-ECMO (n=190) support. Patients receiving an RVAD more frequently had preoperative inotrope requirement (76% vs. 62%, p<0.01) and severe tricuspid regurgitation (20% vs. 13%, p<0.01). RVAD patients experienced lower rates of postoperative renal failure (40% vs. 51%, p=0.02) and limb ischemia (4% vs. 13%, p<0.01), as well as significantly less operative mortality (41% vs. 54%, p<0.01). After risk-adjustment with propensity score analysis, support with VA-ECMO was associated with a higher risk of mortality (Risk Ratio 1.46 [1.21-1.77], p<0.01) compared to patients receiving an RVAD. Importantly, institution of right ventricular support postoperatively was associated with higher mortality (1.43, p<0.01) compared to intraoperative initiation.

CONCLUSIONS

Patients with severe right ventricular failure in the setting of durable left ventricular assist device implantation may benefit from the use of RVAD over VA-ECMO. Regardless of the type of support, initiation at the index operation was associated with improved outcomes.

Use of extracorporeal membrane oxygenation for heart graft dysfunction in adults: incidence, risk factors and outcomes in a multicentric study

Background:

The decision about whether to use venoarterial extracorporeal membrane oxygenation (VA-ECMO) in patients with cardiac graft dysfunction (GD) is usually made on a case-by-case basis and is guided by the team’s experience. We aimed to determine the incidence of VA-ECMO use after heart transplantation (HT), to assess early- and long-term outcomes and to assess risk factors for the need for VA-ECMO and early mortality in these patients.

Methods:

We included adults who underwent heart transplantation at 3 cardiac centres who met the most recent International Society for Heart and Lung Transplantation definition of graft dysfunction (GD) over a 10-year period. Pre-transplant, intraoperative and posttransplant characteristics of the heart recipients as well as donor characteristics were analyzed and compared among recipients with GD treated with and without VA-ECMO.

Results:

There were 135 patients with GD in this study, of whom 66 were treated with VA-ECMO and 69 were not. The mean follow-up averaged 81.2 months (standard deviation 36 mo, range 0–184 mo); follow-up was complete in 100% of patients. The overall incidence of GD (30%) and of VA-ECMO use increased over the study period. We did not identify any predictive pre-transplantation factors for VA-ECMO use, but patients who required VA-ECMO had higher serum lactate levels and higher inotropes doses after HT. The overall survival rates were 83% and 42% at 1 year and 78% and 40% at 5 years among patients who received only medical treatment and those who received VA-ECMO, respectively. Delayed initiation of VA-ECMO and postoperative bleeding were strongly associated with increased in-hospital mortality.

Conclusion:

The incidence of GD increased over the study period, and the need for VA-ECMO among patients with GD remains difficult to predict. In-hospital mortality decreased over time but remained high among patients who required VA-ECMO, especially among patients with delayed initiation of VA-ECMO.

A multi-institutional retrospective analysis on impact of RV acute mechanical support timing after LVAD implantation on 1-year mortality and predictors of RV acute mechanical support weaning

BACKGROUND

There is little insight into which patients can be weaned off right ventricular (RV) acute mechanical circulatory support (AMCS) after left ventricular assist device (LVAD) implantation. We hypothesize that concomitant RV AMCS insertion instead of postoperative implantation will improve 1-year survival and increase the likelihood of RV AMCS weaning.

METHODS

A multicenter retrospective database of 826 consecutive patients who received a HeartMate II or HVAD between January 2007 and December 2016 was analyzed. We identified 91 patients who had early RV AMCS on index admission. Cox proportional-hazards model was constructed to identify predictors of 1-year mortality post-RV AMCS implantation and competing risk modeling identified RV AMCS weaning predictors.

RESULTS

There were 91 of 826 patients (11%) who required RV AMCS after CF-LVAD implantation with 51 (56%) receiving a concomitant RV AMCS and 40 (44%) implanted with a postoperative RV AMCS during their ICU stay; 48 (53%) patients were weaned from RV AMCS support. Concomitant RV AMCS with CF-LVAD insertion was associated with lower mortality (HR 0.45 [95% CI 0.26-0.80], p = 0.01) in multivariable model (which included age, BMI, angiotensin-converting enzyme inhibitor use, and heart transplantation as a time-varying covariate). In the multivariate competing risk analysis, a TPG < 12 (SHR 2.19 [95% CI 1.02-4.70], p = 0.04) and concomitant RV AMCS insertion (SHR 3.35 [95% CI 1.73-6.48], p < 0.001) were associated with a successful wean.

CONCLUSIONS

In patients with RVF after LVAD implantation, concomitant RV AMCS insertion at the time of LVAD was associated with improved 1-year survival and increased chances of RV support weaning compared to postoperative insertion.

Contemporary Mechanical Circulatory Support with Continuous Flow Biventricular Assist Devices: A Systematic Review

As the incidence of heart failure increases, so too has that of biventricular failure. While transplantation remains the gold standard therapy for end-stage heart failure, the limited organ supply has increased the need for durable mechanical circulatory support. We therefore sought to conduct a systematic review of continuous flow ventricular assist devices in a biventricular configuration (CF-BiVAD). An electronic search of PubMed and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases was performed using the keyword "BIVAD". Studies were reviewed to identify discrete variables, including implant indication, INTERMACs profile, timing of implant, mean age and BMI, and the anticoagulation/antiplatelet regimens employed post implant. Outcomes of interest included mortality and the incidence of thrombus, bleeding, infection, stroke and renal failure. A total of 25 studies met inclusion criteria. No single variable was consistently reported, with only four studies reporting all five adverse effects. INTERMACs profile at implant and anticoagulation/antiplatelet regimen were reported in less than 50% of studies. Of those reporting mortality, there was a wide range of follow-up, from less than six months to >10 years, and the survival rate was similarly widely variable. Additionally, more than 50% of studies failed to isolate CF-BiVAD from alternative means of biventricular support, such as temporary support platforms, TAH, and pulsatile VADs. Therefore high-quality quantitative analysis is not possible. In summary, CF-BiVAD literature has a very heterogenous reporting of data. Standard reporting criteria may allow for future analyses to determine which patient characteristics portend a favorable outcome with CF-BiVAD implantation.

Treatment of Advanced Heart Failure-Focus on Transplantation and Durable Mechanical Circulatory Support: What Does the Future Hold?

Heart transplantation (HTx) is the treatment of choice in patients with late-stage advanced heart failure (Advanced HF). Survival rates 1, 5, and 10 years after transplantation are 87%, 77%, and 57%, respectively, and the average life expectancy is 9.16 years. However, because of the donor organ shortage, waiting times often exceed life expectancy, resulting in a waiting list mortality of around 20%. This review aims to provide an overview of current standard, recent advances, and future developments in the treatment of Advanced HF with a focus on long-term mechanical circulatory support and HTx.

Pre-operative atrial fibrillation and early right ventricular failure after left ventricular assist device implantation: a systematic review and meta-analysis

BACKGROUND

Right ventricular failure (RVF) remains a major cause of morbidity and mortality after left ventricular assist device (LVAD). Atrial fibrillation (AF) is known for its deleterious effects on cardiac function and hemodynamics. The association of pre-operative AF with the risk of early post-LVAD RVF has not been well described.

METHOD

A comprehensive literature search was performed through April, 9 2021. Cohort studies comparing the risk of post-operative RVF and/or need for right ventricular assist device (RVAD) after LVAD in patients with or without AF were included. Pooled odds ratio (OR) with 95% confidence intervals (CI) and I² statistic were calculated using the random-effects model.

RESULTS

Six studies were included in the analysis. Post-operative RVF was reported in 5 studies (1,841 patients) and RVAD use was reported in 4 studies (1,355 patients). There is a non-significant trend toward a higher risk of post-operative RVF in the AF group (pooled OR=1.25, 95%CI=0.99-1.58). No significant association between AF and RVAD use is noted (pooled OR=1.17, 95%CI=0.82-1.66).

CONCLUSIONS

Pre-operative AF is not significantly associated with higher risks of post-operative RVF and RVAD use after LVAD implantation, although the trend toward higher post-operative RVF is observed in patients with pre-operative AF. Additional research using a larger study population is warranted to better understand the association of pre-operative AF and the development of post-LVAD RVF.

Predicting post-operative right ventricular failure using video-based deep learning

Despite progressive improvements over the decades, the rich temporally resolved data in an echocardiogram remain underutilized. Human assessments reduce the complex patterns of cardiac wall motion, to a small list of measurements of heart function. All modern echocardiography artificial intelligence (AI) systems are similarly limited by design - automating measurements of the same reductionist metrics rather than utilizing the embedded wealth of data. This underutilization is most evident where clinical decision making is guided by subjective assessments of disease acuity. Predicting the likelihood of developing post-operative right ventricular failure (RV failure) in the setting of mechanical circulatory support is one such example. Here we describe a video AI system trained to predict post-operative RV failure using the full spatiotemporal density of information in pre-operative echocardiography. We achieve an AUC of 0.729, and show that this ML system significantly outperforms a team of human experts at the same task on independent evaluation.

External assessment of the EUROMACS right-sided heart failure risk score

The EUROMACS Right-Sided Heart Failure Risk Score was developed to predict right ventricular failure (RVF) after left ventricular assist device (LVAD) placement. The predictive ability of the EUROMACS score has not been tested in other cohorts. We performed a single center analysis of a continuous-flow (CF) LVAD cohort (n = 254) where we calculated EUROMACS risk scores and assessed for right ventricular heart failure after LVAD implantation. Thirty-nine percent of patients (100/254) had post-operative RVF, of which 9% (23/254) required prolonged inotropic support and 5% (12/254) required RVAD placement. For patients who developed RVF after LVAD implantation, there was a 45% increase in the hazards of death on LVAD support (HR 1.45, 95% CI 0.98–2.2, p = 0.066). Two variables in the EUROMACS score (Hemoglobin and Right Atrial Pressure to Pulmonary Capillary Wedge Pressure ratio) were not predictive of RVF in our cohort. Overall, the EUROMACS score had poor external discrimination in our cohort with area under the curve of 58% (95% CI 52–66%). Further work is necessary to enhance our ability to predict RVF after LVAD implantation.

Percutaneous venopulmonary artery extracorporeal membrane oxygenation for right heart failure after left ventricular assist device insertion

OBJECTIVES

Right ventricular failure after left ventricular assist device (LVAD) insertion is associated with significant mortality and morbidity. Mechanical support options include right ventricular assist devices, venoarterial extracorporeal membrane oxygenation (ECMO) and venopulmonary artery ECMO, the latter often involving central cannulation. We sought to evaluate the feasibility and early outcomes of a truly percutaneous venopulmonary artery (pVPA) ECMO strategy, with the potential advantage of bedside removal once weaned.

METHODS

Data from a single tertiary centre were reviewed retrospectively from January 2014 to January 2019. During this time, 54 patients underwent LVAD insertion, with 19 requiring mechanical support for right ventricular failure. Among them, 10 patients received pVPA ECMO. Implantation of the pVPA ECMO was performed under transoesophageal echocardiography and fluoroscopy guidance, with an inflow cannula placed in the right atrium via the right femoral vein and an outflow cannula placed in the left pulmonary artery (PA) via the right internal jugular vein.

RESULTS

Cannula insertion was 100% successful with no need for repositioning. Eight patients (80%) were able to be successfully weaned (at the bedside); 6 were discharged from the hospital and there were no cases of early sepsis, mediastinitis or thromboembolism. At follow-up, 5 patients had received transplants (50%), with 1 on LVAD support as destination therapy (10%). Survival was 60 ± 15% and 50 ± 16% at 6 and 12 months, respectively.

CONCLUSIONS

pVPA ECMO is 100% technically feasible and is an efficient method for temporary right ventricular support after LVAD insertion with the advantage of simple bedside removal and avoidance of a PA graft remnant in the chest cavity.