Predicting the Risk of Right Ventricular Failure in Patients Undergoing Left Ventricular Assist Device Implantation

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.

Improving the Prediction of 1-Year Right Ventricular Failure After Left Ventricular Assist Device Implantation

Previous predictive models for postimplant right heart failure (RHF) following left ventricular assist device (LVAD) implantation have demonstrated limited performance on validation datasets and are susceptible to overfitting. Thus, the objective of this study was to develop an improved predictive model with reduced overfitting and improved accuracy in predicting RHF in LVAD recipients. The study involved 11,967 patients who underwent continuous-flow LVAD implantation between 2008 and 2016, with an RHF incidence of 9% at 1 year. Using an eXtreme Gradient Boosting (XGBoost) algorithm, the training data were used to predict RHF at 1 year postimplantation, resulting in promising area under the curve (AUC)-receiver operating characteristic (ROC) of 0.8 and AUC-precision recall curve (PRC) of 0.24. The calibration plot showed that the predicted risk closely corresponded with the actual observed risk. However, the model based on data collected 48 hours before LVAD implantation exhibited high sensitivity but low precision, making it an excellent screening tool but not a diagnostic tool.

In search of similarity in adverse events journeys of patients with left ventricular assist devices

OBJECTIVE

The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Event data set contains an expansive collection of longitudinal evidence of the course of adverse events (AEs) of >15,000 patients who have received a left ventricular assist device (LVAD). Buried in the huge Event data set is knowledge that can provide a deeper understanding of the patterns of the "AE journey" of patients with LVAD. Thus, the goal of this study was to examine the Event data set from a comprehensive perspective to identify unique relationships and patterns of AEs, alert potential challenges, and suggest future research directions.

METHODS

A sequential pattern mining algorithm called SPADE (ie, Sequential PAttern Discovery using Equivalence classes) was applied to 86,912 recorded AEs of 15,820 patients with a continuous-flow LVAD between 2008 and 2016, extracted from the publicly accessible INTERMACS registry. The patterns of AE journey were investigated by posing 5 descriptive research questions about most common types of AE, concomitant AEs, AE sequences, AE subsequences, and interesting relations between AEs.

RESULTS

The analysis revealed several characteristics of patterns of the AE journey of patients who received an LVAD that accounts for the types and temporal ordering of successive AEs, combinations of AEs, and their timing after surgery.

CONCLUSIONS

The high diversity and sparsity of the types and timing of AE occurrences make the AE journeys of patients dissimilar from each other, impeding the discovery of highly-patterned AE journeys among the patients. This study suggests 2 salient directions for future studies to tackle this issue using cluster analysis to cluster patients into more similar groups and translate these results into a practical clinical tool to forecast the next AE based on the history of previous AEs.

An Analysis of 186 Transplants for Pediatric or Congenital Heart Disease: Impact of Pretransplant VAD

BACKGROUND

We reviewed our management strategy and outcome data for all 181 patients with pediatric or congenital heart disease who received 186 heart transplants from January 1, 2011, to March 1, 2022, and evaluated the impact of pretransplant ventricular assist device (VAD).

METHODS

Continuous variables are presented as mean (SD); median [interquartile range] (range). Categorical variables are presented as number (percentage). Univariable associations with long-term mortality were assessed with Cox proportional hazards models. Impact of pretransplant VAD on survival was estimated with multivariable models.

RESULTS

Pretransplant VAD was present in 53 of 186 transplants (28.5%). Patients with VAD were younger (years): 4.8 (5.6); 1 [0.5-8] (0.1-18) vs 12.1 (12.7); 10 [0.7-17] (0.1-58); P = .0001. Patients with VAD had a higher number of prior cardiac operations: 3.0 (2.3); 2 [1-4] (1-12) vs 1.8 (1.9); 2 [0-3] (0-8); P = .0003. Patients with VAD were also more likely to receive an ABO-incompatible transplant: 10 of 53 (18.9%) vs 9 of 133 (6.8%); P = .028. Univariable associations with long-term mortality included: In multivariable analysis, pretransplant VAD did not impact survival while controlling for each one of the factors shown in univariable analysis to be associated with long-term mortality. Kaplan-Meier 5-year survival (95% CI) was 85.8% (80.0%-92.1%) for all patients, 84.3% (77.2%-92.0%) without pretransplant VAD, and 91.1% (83.1%-99.9%) with pretransplant VAD.

CONCLUSIONS

Our single-institution analysis of 181 patients receiving 186 heart transplants for pediatric or congenital heart disease over 11.25 years reveals similar survival in patients with (n = 51) and without (n = 130) pretransplant VAD. The presence of a pretransplant VAD is not a risk factor for mortality after transplantation for pediatric or congenital heart disease.

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.

Right Ventricle-Pulmonary Artery Coupling in Patients Undergoing Cardiac Interventions

PURPOSE OF REVIEW

This review aims to summarize the fundamentals of RV-PA coupling, its non-invasive means of measurement, and contemporary understanding of RV-PA coupling in cardiac surgery, cardiac interventions, and congenital heart disease.

RECENT FINDINGS

The need for more accessible clinical means of evaluation of RV-PA coupling has driven researchers to investigate surrogates using cardiac MRI, echocardiography, and right-sided pressure measurements in patients undergoing cardiac surgery/interventions, as well as patients with congenital heart disease. Recent research has aimed to validate these alternative means against the gold standard, as well as establish cut-off values predictive of morbidity and/or mortality. This emerging evidence lays the groundwork for identifying appropriate RV-PA coupling surrogates and integrating them into perioperative clinical practice.

Artificial Intelligence Approaches for Predicting the Risks of Durable Mechanical Circulatory Support Therapy and Cardiac Transplantation

Background: The use of AI-driven technologies in probing big data to generate better risk prediction models has been an ongoing and expanding area of investigation. The AI-driven models may perform better as compared to linear models; however, more investigations are needed in this area to refine their predictability and applicability to the field of durable MCS and cardiac transplantation. Methods: A literature review was carried out using Google Scholar/PubMed from 2000 to 2023. Results: This review defines the knowledge gaps and describes different AI-driven approaches that may be used to further our understanding. Conclusions: The limitations of current models are due to missing data, data imbalances, and the uneven distribution of variables in the datasets from which the models are derived. There is an urgent need for predictive models that can integrate a large number of clinical variables from multicenter data to account for the variability in patient characteristics that influence patient selection, outcomes, and survival for both durable MCS and HT; this may be fulfilled by AI-driven risk prediction models.

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.

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.

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 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.

A single-institutional experience with 36 children less than 5 kilograms supported with the Berlin Heart: Comparison of congenital versus acquired heart disease

OBJECTIVES

We reviewed outcomes in all 36 consecutive children <5 kg supported with the Berlin Heart pulsatile ventricular assist device at the University of Florida, comparing those with acquired heart disease (n = 8) to those with congenital heart disease (CHD) (n = 28).

METHODS

The primary outcome was mortality. The Kaplan-Meier method and log-rank tests were used to assess group differences in long-term survival after ventricular assist device insertion. T-tests using estimated survival proportions were used to compare groups at specific time points.

RESULTS

Of 82 patients supported with the Berlin Heart at our institution, 49 (49/82 = 59.76%) weighed <10 kg and 36 (36/82 = 43.90%) weighed <5 kg. Of 36 patients <5 kg, 26 (26/36 = 72.22%) were successfully bridged to transplantation. (The duration of support with ventricular assist device for these 36 patients <5 kg was [days]: median = 109, range = 4-305.) Eight out of 36 patients <5 kg had acquired heart disease, and all eight [8/8 = 100%] were successfully bridged to transplantation. (The duration of support with ventricular assist device for these 8 patients <5 kg with acquired heart disease was [days]: median = 50, range = 9-130.) Twenty-eight of 36 patients <5 kg had congenital heart disease. Eighteen of these 28 [64.3%] were successfully bridged to transplantation. (The duration of support with ventricular assist device for these 28 patients <5 kg with congenital heart disease was [days]: median = 136, range = 4-305.) For all 36 patients who weighed <5 kg: 1-year survival estimate after ventricular assist device insertion = 62.7% (95% confidence interval = 48.5-81.2%) and 5-year survival estimate after ventricular assist device insertion = 58.5% (95% confidence interval = 43.8-78.3%). One-year survival after ventricular assist device insertion = 87.5% (95% confidence interval = 67.3-99.9%) in acquired heart disease and 55.6% (95% confidence interval = 39.5-78.2%) in CHD, P = 0.036. Five-year survival after ventricular assist device insertion = 87.5% (95% confidence interval = 67.3-99.9%) in acquired heart disease and 48.6% (95% confidence interval = 31.6-74.8%) in CHD, P = 0.014.

CONCLUSION

Pulsatile ventricular assist device facilitates bridge to transplantation in neonates and infants weighing <5 kg; however, survival after ventricular assist device insertion in these small patients is less in those with CHD in comparison to those with acquired heart disease.

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.

The Roles of Venopulmonary Arterial Extracorporeal Membrane Oxygenation

OBJECTIVES

Concise definitive review of the use of venopulmonary arterial extracorporeal membrane oxygenation (V-PA ECMO) support in patients with cardiopulmonary failure.

DATA SOURCES

Original investigations identified through a PubMed search with search terms "percutaneous right ventricular assist device," "oxy-RVAD," "V-PA ECMO," and "veno-pulmonary arterial ECMO" were reviewed and evaluated for relevance.

STUDY SELECTION

Studies that included more than three patients supported with V-PA ECMO were included.

DATA EXTRACTION

Clinically relevant data from included studies, including patient-important outcomes, were summarized and discussed.

DATA SYNTHESIS

We identified four groups of patients where V-PA ECMO has been studied: acute respiratory distress syndrome, right ventricular dysfunction after left ventricular assist device placement, bridge to lung transplantation, and pulmonary embolism. Most identified works are small, single center, and retrospective in nature, precluding definitive conclusions regarding the efficacy of V-PA ECMO. There have been no clinical trials evaluating the efficacy of V-PA ECMO for any indication.

CONCLUSIONS

V-PA ECMO is a promising form of extracorporeal support for patients with right ventricular dysfunction. Future work should focus on identifying the optimal timing and populations for the use of V-PA ECMO.

Postoperative care of 14 patients with left ventricular assist devices: a case series

A left ventricular assist device is a mechanical device that is surgically implanted in the heart to partially or completely replace the function of the heart. Left ventricular assist devices are of vital importance in the treatment of patients with heart failure. There are different recommendations for the postoperative care of patients undergoing left ventricular assist device implantation in different countries, and no uniform standard has been developed. The first implantation of a left ventricular assist device in Eastern China was performed in February 2021; since that date, 14 patients underwent implantation until February 2023. This report describes the postoperative care of these 14 patients with end-stage heart failure who underwent left ventricular assist device placement, all of whom were discharged with a good prognosis.

Contemporary Evidence and Practice on Right Heart Catheterization in Patients with Acute or Chronic Heart Failure

Heart failure (HF) has a global prevalence of 1-2%, and the incidence around the world is growing. The prevalence increases with age, from around 1% for those aged <55 years to >10% for those aged 70 years or over. Based on studies in hospitalized patients, about 50% of patients have heart failure with reduced ejection fraction (HFrEF), and 50% have heart failure with preserved ejection fraction (HFpEF). HF is associated with high morbidity and mortality, and HF-related hospitalizations are common, costly, and impact both quality of life and prognosis. More than 5-10% of patients deteriorate into advanced HF (AdHF) with worse outcomes, up to cardiogenic shock (CS) condition. Right heart catheterization (RHC) is essential to assess hemodynamics in the diagnosis and care of patients with HF. The aim of this article is to review the evidence on RHC in various clinical scenarios of patients with HF.

Total artificial heart implantation as a bridge to transplantation in the United States

OBJECTIVES

Although the SynCardia total artificial heart (SynCardia Systems, LLC) was approved for use as a bridge to transplantation in 2004 in the United States, most centers do not adopt the total artificial heart as a standard bridging strategy for patients with biventricular failure. This study was designed to characterize the current use and outcomes of patients placed on total artificial heart support.

METHODS

The United Network of Organ Sharing Standard Transplant Research File was queried to identify total artificial heart implantation in the United States between 2005 and 2018. Multivariable Cox regression models were used for risk prediction.

RESULTS

A total of 471 patients (mean age, 49 years; standard deviation, 13 years; 88% were male) underwent total artificial heart implantation. Of 161 transplant centers, 11 centers had cumulative volume of 10 or more implants. The 6-month cumulative incidence of mortality on the total artificial heart was 24.6%. The 6-month cumulative incidence of transplant was 49.0%. The 1-year mortality post-transplantation was 20.0%. Cumulative center volume less than 10 implants was predictive of both mortality on the total artificial heart (hazard ratio, 2.2, 95% confidence interval, 1.5-3.1, P < .001) and post-transplant mortality after a total artificial heart bridge (hazard ratio, 1.5, 95% confidence interval, 1.0-2.2, P = .039).

CONCLUSIONS

Total artificial heart use is low, but the total artificial heart can be an option for biventricular bridge to transplant with acceptable bridge to transplant and post-transplant survival, especially in higher-volume centers. The observation of inferior outcomes in lower-volume centers raises questions as to whether targeted training, center certifications, and minimum volume requirements could improve outcomes for patients requiring the total artificial heart.

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights From 2023

This special article is the 16th in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr. Kaplan, and the editorial board for the opportunity to continue this series, namely the research highlights of the past year in the specialty of cardiothoracic and vascular anesthesiology. The major themes selected for 2023 are outlined in this introduction, and each highlight is reviewed in detail in the main article. The literature highlights in the specialty for 2023 begin with an update on perioperative rehabilitation in cardiothoracic surgery, with a focus on novel methods to best assess patients in the preoperative and postoperative periods, and the impact of rehabilitation on outcomes. The second major theme is focused on cardiac surgery, with the authors discussing new insights into inhaled pulmonary vasodilators, coronary revascularization surgery, and discussion of causes of coronary graft failure after surgery. The third theme is focused on cardiothoracic transplantation, with discussions focusing on bridge-to-transplantation strategies. The fourth theme is focused on mechanical circulatory support, with discussions focusing on both temporary and durable support. The fifth and final theme is an update on medical cardiology, with a focus on outcomes of invasive approaches to heart disease. The themes selected for this article are only a few of the diverse advances in the specialty during 2023. These highlights will inform the reader of key updates on various topics, leading to improved perioperative outcomes for patients with cardiothoracic and vascular disease.

Left Ventricular Assist Device Emergencies: Diagnosis and Management

Durable left ventricular assist devices (LVADs) are a virtually limitless advanced therapy option for an increasingly growing population of patients with end-stage advanced heart failure. As of 2019, 30% to 40% of all patients diagnosed with heart failure were categorized as New York Heart Association class III or IV. In 2018 more than 3.2 million office visits and 1.4 million emergency department visits carried a primary diagnosis of heart failure. Given the rapid growth of the LVAD population, facility in the diagnosis and management of common perioperative and outpatient LVAD emergencies has become of paramount importance in a variety of clinical settings.

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.

Pressure-Volume Loops for Reviewing Right Ventricular Physiology and Failure in the Context of Left Ventricular Assist Device Implantation

Right ventricular (RV) function is complex as a number of determinants beyond preload, inotropy and afterload play a fundamental role. In particular, arterial elastance (Ea), ventriculo-arterial coupling (VAC), and (systolic) ventricular interdependence play a vital role for the right ventricle. Understanding and actively visualizing these interactions in the failing RV as well as in the altered hemodynamic and morphological situation of left ventricular assist device (LVAD) implantation may aid clinicians in their understanding of RV dysfunction and failure. While, admittedly, hard data is scarce and invasive pressure-volume loop measurements will not become routine in cardiac surgery, we hope that clinicians will benefit from the comprehensive, simulation-based review of RV pathology. In particular, the aim of this article is to first, address and clarify the pathophysiologic hemodynamic factors that lead to RV dysfunction and then, second, expand upon this basis examining the changes occurring by LVAD implantation. This is illustrated using Harvi software which shows elastance, ventricular arterial coupling, and ventricular interdependence by simultaneously showing pressure volume loops of the right and left ventricle.

An in silico study of the effects of left ventricular assist device on right ventricular function and inter-ventricular interaction

BACKGROUND

Left ventricular assist device (LVAD) is associated with a high incidence of right ventricular (RV) failure, which is hypothesized to be caused by the occurring inter-ventricular interactions when the LV is unloaded. Factors contributing to these interactions are unknown.

METHODS

We used computer modeling to investigate the impact of the HeartMate 3 LVAD on RV functions. The model was first calibrated against pressure-volume (PV) loops associated with a heart failure (HF) patient and validated against measurements of inter-ventricular interactions in animal experiments. The model was then applied to investigate the effects of LVAD on (1) RV chamber contractility indexed byV 60 derived from its end-systolic PV relationship, and (2) RV diastolic function indexed byV 20 derived from its end-diastolic PV relationship. We also investigated how septal wall thickness and regional contractility affect the impact of LVAD on RV function.

RESULTS

The impact of LVAD on RV chamber contractility is small at a pump speed lower than 4k rpm. At a higher pump speed between 4k and 9k rpm, however, RV chamber contractility is reduced (by ~3% at 6k rpm and ~10% at 9k rpm). The reduction of RV chamber contractility is greater with a thinner septal wall or with a lower myocardial contractility at the LV free wall, septum, or RV free wall.

CONCLUSION

RV chamber contractility is reduced at a pump speed higher than 4k rpm, and this reduction is greater with a thinner septal wall or lower regional myocardial contractility. Findings here may have clinical implications in identifying LVAD patients who may suffer from RV failure.

Outcomes of Children Supported With Pulsatile Paracorporeal Ventricular Assist Device: Congenital Versus Acquired Heart Disease

BACKGROUND

We reviewed the outcomes of 82 consecutive pediatric patients (less than 18 years of age) supported with the Berlin Heart ventricular assist device (VAD), comparing those with congenital heart disease (CHD; n  =  44) with those with acquired heart disease (AHD; n  =  37).

METHODS

The primary outcome was mortality after VAD insertion. Kaplan-Meier methods and log-rank tests were used to assess group differences in long-term survival.

RESULTS

Forty-four CHD patients were supported (age: median  =  65 days, range  =  4 days-13.3 years; weight [kg]: median  =  4, range  =  2.4-42.3). Ten biventricular CHD patients were supported with eight biventricular assist devices (BiVADs), one left ventricular assist device (LVAD) only, and one LVAD converted to BiVAD, while 34 univentricular CHD patients were supported with single ventricle-ventricular assist devices (sVADs). In CHD patients, duration of VAD support was [days]: median  =  134, range  =  4-554. Of 44 CHD patients, 28 underwent heart transplantation, 15 died on VAD, and one was still on VAD. Thirty-seven AHD patients were supported (age: median  =  1.9 years, range  =  27 days-17.7 years; weight [kg]: median  =  11, range  =  3.1-112), including 34 BiVAD and 3 LVAD. In AHD patients, duration of VAD support was [days]: median  =  97, range  =  4-315. Of 37 AHD patients, 28 underwent transplantation, three died on VAD, five weaned off VAD (one of whom underwent heart transplantation 334 days after weaning), and one was still on VAD. One-year survival after VAD insertion was 59.9% (95% CI  =  46.7%-76.7%) in CHD and 88.6% (95% CI  =  78.8%-99.8%) in AHD, P  =  .0004. Five-year survival after VAD insertion was 55.4% (95% CI  =  40.8%-75.2%) in CHD and 85.3% (95% CI  =  74.0%-98.2%) in AHD, P  =  .002.

CONCLUSIONS

Pulsatile VAD facilitates bridge-to-transplantation in neonates, infants, and children with CHD; however, survival after VAD insertion is worse in patients with CHD than in patients with AHD.

When all Else Fails, Try This: The HeartMate III Left Ventricle Assist Device

Heart failure (HF) is a progressive disease. It is estimated that more than 250,000 patients suffer from advanced HF with reduced ejection fraction refractory to medical therapy. With limited donor pool for heart transplant, continue flow left ventricle assist device (LVAD) is a lifesaving treatment option for patients with advanced HF. This review will provide an update on indications, contraindications, and associated adverse events for LVAD support with a summary of the current outcomes data.

Timing and Outcomes of Concurrent and Sequential Biventricular Assist Device Implantation: A Society of Thoracic Surgeons Intermacs Analysis

BACKGROUND

Biventricular heart failure remains a clinically challenging condition to manage. Available literature describing the use of durable biventricular assist device (BiVAD) support has numerous limitations hindering the development of useful treatment algorithms. Analysis of BiVAD use within a large multicenter data set is needed to clarify outcomes associated with this therapy.

METHODS

The Society of Thoracic Surgeons Intermacs database was queried to identify adults aged ≥18 years who received durable circulatory support from January 1, 2010, to December 31, 2220. The data set was divided into the following cohorts: (1) left ventricular assist device (LVAD) only (n = 27,325), (2) LVAD and concurrent right ventricular assist device (RVAD) (n = 1090), and (3) LVAD and sequential RVAD (n = 556). Propensity score matching was used to compare 1-year mortality and adverse events between concurrent (n = 565) and sequential BiVADs (n = 565).

RESULTS

Overall survival within 1 year was significantly worse for the BiVAD cohort compared with the LVAD-only cohort (12-month survival: 50.8% vs 82.6%; log-rank P < .001). In a propensity-matched cohort, patients implanted with a BiVAD concurrently had an improved survival compared with those implanted an LVAD and an RVAD sequentially (12-month survival: 55.8% vs 41.8%; log-rank P < .001). Early (<3 months) adverse event rates were higher among patients receiving sequential BiVADs for bleeding, infection, neurologic dysfunction, and renal dysfunction (P < .01).

CONCLUSIONS

After matching for patient and disease characteristics, patients with sequential BiVAD implantation have worse outcomes than patients with concurrent BiVAD implantation.

Proportion of right ventricular failure and echocardiographic predictors in continuous-flow left ventricular assist device: a systematic review and meta-analysis

Background

Right ventricular failure (RVF) in patients with a continuous-flow left ventricle assist device (CF-LVAD) is associated with higher incidence of mortality. This systematic review aims to assess the overall proportion of RVF and the pre-operative echocardiographic parameters which are best correlating to RVF.

Methods

A systematic research was conducted between 2008 and 2019 on MEDLINE, EMBASE, PUBMED, UPTODATE, OVID, COCHRANE LIBRARY, and Google Scholar electronic databases by performing a PRISMA flowchart. All observational studies regarding echocardiographic predictors of RVF in patients undergoing CF-LVAD implantation were included.

Results

A total number of 19 observational human studies published between 2008 and 2019 were included. We identified 524 RVF patients out of a pooled final population of 1741 patients. The RVF overall proportion was 28.25% with 95% confidence interval (CI) 0.24-0.34. The highest variability of perioperative echocardiographic parameters between the RVF and no right ventricular failure (NO-RVF) groups has been found with tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), and right ventricular global longitudinal strain (RVGLS). Their standardized mean deviation (SMD) was - 0.33 (95% CI - 0.54 to - 0.11; p value 0.003), - 0.34 (95% CI - 0.53 to - 0.15; p value 0.0001), and 0.52 (95% CI 0.79 to 0.25; p value 0.0001), respectively.

Conclusions

The echocardiographic predictors of RVF after CF-LVAD placement are still uncertain. However, there seems to be a trend of statistical correlation between TAPSE, FAC, and RVGLS with RVF event after CF-LVAD placement.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-022-01447-7.

How to select a patient for LVAD

Left ventricular assist device (LVAD) implantation leads to improvement in symptoms and survival in patients with advanced heart failure. An important factor in improving outcomes post-LVAD implantation is optimal preoperative patient selection and optimization. In this review, we highlight the latest on the evaluation of patients with advanced heart failure for LVAD candidacy, including discussion of patient selection, implantation timing, laboratory and other testing considerations, and the importance of psychosocial evaluation. Such thorough evaluation by multidisciplinary team can serve to improve the outcomes of a complex group of patients with advanced heart failure being evaluated for LVAD.

Right Ventricular Sarcomere Contractile Depression and the Role of Thick Filament Activation in Human Heart Failure With Pulmonary Hypertension

BACKGROUND

Right ventricular (RV) contractile dysfunction commonly occurs and worsens outcomes in patients with heart failure with reduced ejection fraction and pulmonary hypertension (HFrEF-PH). However, such dysfunction often goes undetected by standard clinical RV indices, raising concerns that they may not reflect aspects of underlying myocyte dysfunction. We thus sought to characterize RV myocyte contractile depression in HFrEF-PH, identify those components reflected by clinical RV indices, and uncover underlying biophysical mechanisms.

METHODS

Resting, calcium-, and load-dependent mechanics were prospectively studied in permeabilized RV cardiomyocytes isolated from explanted hearts from 23 patients with HFrEF-PH undergoing cardiac transplantation and 9 organ donor controls.

RESULTS

Unsupervised machine learning using myocyte mechanical data with the highest variance yielded 2 HFrEF-PH subgroups that in turn mapped to patients with decompensated or compensated clinical RV function. This correspondence was driven by reduced calcium-activated isometric tension in decompensated clinical RV function, whereas surprisingly, many other major myocyte contractile measures including peak power and myocyte active stiffness were similarly depressed in both groups. Similar results were obtained when subgroups were first defined by clinical indices, and then myocyte mechanical properties in each group compared. To test the role of thick filament defects, myofibrillar structure was assessed by x-ray diffraction of muscle fibers. This revealed more myosin heads associated with the thick filament backbone in decompensated clinical RV function, but not compensated clinical RV function, as compared with controls. This corresponded to reduced myosin ATP turnover in decompensated clinical RV function myocytes, indicating less myosin in a crossbridge-ready disordered-relaxed (DRX) state. Altering DRX proportion (%DRX) affected peak calcium-activated tension in the patient groups differently, depending on their basal %DRX, highlighting potential roles for precision-guided therapeutics. Last, increasing myocyte preload (sarcomere length) increased %DRX 1.5-fold in controls but only 1.2-fold in both HFrEF-PH groups, revealing a novel mechanism for reduced myocyte active stiffness and by extension Frank-Starling reserve in human heart failure.

CONCLUSIONS

Although there are many RV myocyte contractile deficits in HFrEF-PH, commonly used clinical indices only detect reduced isometric calcium-stimulated force, which is related to deficits in basal and recruitable %DRX myosin. Our results support use of therapies to increase %DRX and enhance length-dependent recruitment of DRX myosin heads in such patients.

Rescuing the right ventricle: A conceptual framework to target new interventions for patients receiving a durable left ventricular assist device

Despite significant advances in durable LVAD technology, right heart failure remains a morbid and fatal condition that is difficult to predict, prevent, and successfully treat.

Interventricular-Septal Output While Supported on Left Ventricular Assist Device Therapy

The effects of left ventricular unloading on septal function in patients with left ventricular assist devices (LVADs) have not been well characterized in vivo. The purpose of this study was to evaluate the relationship between markers of septal function with echocardiography in relationship to RV dysfunction and late RV failure after LVAD implantation. A retrospective study was conducted of patients supported on centrifugal-flow LVADs implanted over a 10-year period. Echocardiographic data were collected pre-operatively and up to 2 years after implantation. Interventricular septum (IVS) measurements were taken at end-systole and end-diastole. Interventricular-septal output (ISO) was calculated using the formula: (IVSs-IVSd)×heart rate. A total of 110 patients were included. An immediate and sustained reduction in both lateral annulus systolic velocity (RVS') and TAPSE were observed after implant ( p < 0.0001). However, ISO gradually decreased over time ( p < 0.0001). While ISO was not predictive of late RV failure, a decrease in ISO by 25% or greater from pre-implant to hospital discharge was associated with late RV failure (OR 4.8; 95% CI, 1.4-16.5; p = 0.012) even after adjusting for relevant clinical variables ( p ≤ 0.01 for each model). RV function is known to be influenced by mechanical ventricular interdependence and we demonstrate that measurement of ISO may be a useful marker in assessing RV dysfunction and predicting RV failure in patients following LVAD implantation.

Left Ventricular Assist Device as a Destination Therapy: Current Situation and the Importance of Patient Selection

Advanced heart failure is a growing problem for which the best treatment is cardiac transplantation. However, the shortage of donors' hearts made left ventricular assist devices as destination therapy (DT-LVAD) a highly recommended alternative: they improved mid-term prognosis as well as patients' quality of life. Current intracorporeal pumps with a centrifugal continuous flow evolved in the last few years. Since 2003, when first LVAD was approved for long-term support, smaller device sizes with better survival and hemocompatibility profile were reached. The most important difficulty lies in the moment of the implant. Recent indications range from INTERMACS class 2 to 4, with close monitoring in intermediate cases. Moreover, a large multiparametric study is needed for considering the candidacy: basal situation, with a special interest in frailty, comorbidities, including renal and hepatic dysfunction, and medical background, considering every prior cardiac condition, must be evaluated. In addition, some clinical risk scores can be helpful to measure the possibility of right heart failure or morbi-mortality. With this review, we sought to summarize all the device improvements, with their updated clinical results, as well as to focus on all the patient selection criteria.

Heart Transplantation in Patients Less Than 18 Years of Age: Comparison of 2 Eras Over 36 Years and 323 Transplants at a Single Institution

BACKGROUND

We reviewed our management strategy and outcome data for all 311 patients less than 18 years of age who underwent 323 heart transplants at our institution (1986 to 2022) in order to assess changes in patterns of practice and outcomes over time and to compare two consecutive eras: era 1 (154 heart transplants [1986 to 2010]) and era 2 (169 heart transplants [2011 to 2022]).

STUDY DESIGN

Descriptive comparisons between the two eras were performed at the level of the heart transplant for all 323 transplants. Kaplan-Meier survival analyses were performed at the level of the patient for all 311 patients, and log-rank tests were used to compare groups.

RESULTS

Transplants in era 2 were younger (6.6 ± 6.5 years vs 8.7 ± 6.1 years, p = 0.003). More transplants in era 2 were in infants (37.9% vs 17.5%, p < 0.0001), had congenital heart disease (53.8% vs 39.0%, p < 0.010), had high panel reactive antibody (32.1% vs 11.9%, p < 0.0001), were ABO-incompatible (11.2% vs 0.6%, p < 0.0001), had prior sternotomy (69.2% vs 39.0%, p < 0.0001), had prior Norwood (17.8% vs 0%, p < 0.0001), had prior Fontan (13.6% vs 0%, p < 0.0001), and were in patients supported with a ventricular assist device at the time of heart transplant (33.7% vs 9.1%, p < 0.0001). Survival at 1, 3, 5, and 10 years after transplant was as follows: era 1 = 82.4% (76.5 to 88.8), 76.9% (70.4 to 84.0), 70.7% (63.7 to 78.5), and 58.8% (51.3 to 67.4), respectively; era 2 = 90.3% (85.7 to 95.1), 85.4% (79.7 to 91.5), 83.0% (76.7 to 89.8), and 66.0% (49.0 to 88.8), respectively. Overall Kaplan-Meier survival in era 2 was better (log-rank p = 0.03).

CONCLUSIONS

Patients undergoing cardiac transplantation in the most recent era are higher risk but have better survival.

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.

A Single-Institutional Experience with 36 Children Smaller Than 5 Kilograms Supported with the Berlin Heart Ventricular Assist Device (VAD) over 12 Years: Comparison of Patients with Biventricular versus Functionally Univentricular Circulation

OBJECTIVES

We reviewed outcomes in all 36 consecutive children <5 kg supported with the Berlin Heart pulsatile ventricular assist device (VAD) at the University of Florida, comparing those with univentricular circulation (n  =  23) to those with biventricular circulation (n  =  13).

METHODS

The primary outcome was mortality. Kaplan-Meier methods and log-rank tests were used to assess group differences in long-term survival after VAD insertion. T-tests using estimated survival proportions and standard errors were used to compare groups at specific time points.

RESULTS

Of all 82 patients ever supported with Berlin Heart at our institution, 49 (49/82  =  59.76%) weighed <10 kg and 36 (36/82  =  43.90%) weighed <5 kg. Of these 36 patients who weighed <5 kg, 26 (26/36  =  72.22%) were successfully bridged to transplantation. Of these 36 patients who weighed <5 kg, 13 (13/36  =  36.1%) had biventricular circulation and were supported with 12 biventricular assist devices (BiVADs) and 1 left ventricular assist device (LVAD) (Age [days]: median  =  67, range  =  17-212; Weight [kilograms]: median  =  4.1, range  =  3.1-4.9), while 23 (23/36  =  63.9%) had univentricular circulation and were supported with 23 single ventricle-ventricular assist devices (sVADs) (Age [days]: median  =  25, range  =  4-215; Weight [kilograms]: median  =  3.4, range  =  2.4-4.9). Of 13 biventricular patients who weighed <5 kg, 12 (12/23  =  92.3%) were successfully bridged to cardiac transplantation. Of 23 functionally univentricular patients who weighed <5 kg, 14 (14/23  =  60.87%) were successfully bridged to cardiac transplantation. For all 36 patients who weighed <5 kg: 1-year survival estimate after VAD insertion  =  62.7% (95% confidence interval [CI]  =  48.5%-81.2%) and 5-year survival estimate after VAD insertion  =  58.5% (95% CI  =  43.8%-78.3%). One-year survival after VAD insertion: 84.6% (95% CI  =  67.1%-99.9%) in biventricular patients and 49.7% (95% CI  =  32.3%-76.4%) in univentricular patients, P  =  0.018. Three-year survival after VAD insertion: 84.6% (95% CI  =  67.1%-99.9%) in biventricular patients and 41.4% (95% CI  =  23.6%-72.5%) in univentricular patients, P  =  0.005.

CONCLUSION

Pulsatile VAD facilitates bridge to transplantation in neonates and infants weighing <5 kg; however, survival after VAD insertion in these small patients is less in those with univentricular circulation in comparison to those with biventricular circulation.

Experience With SynCardia Total Artificial Heart as a Bridge to Transplantation in 100 Patients

BACKGROUND

The SynCardia temporary total artificial heart (TAH-t) is an effective bridge to transplantation for patients with severe biventricular failure. However, granular single-center data from high-volume centers are lacking. We report our experience with the first 100 TAH-t recipients.

METHODS

A prospective institutional database was used to identify 100 patients who underwent 101 TAH-t implantations between 2012 and 2022. Patients were stratified and compared according to Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile 1 vs 2 or greater. Median follow-up on device support was 94 days (interquartile range, 33-276), and median follow-up after transplantation was 4.6 years (interquartile range, 2.1-6.0).

RESULTS

Overall, 61 patients (61%) were successfully bridged to transplantation and 39 (39%) died on TAH-t support. Successful bridge rates between INTERMACS profile 1 and INTERMACS profile 2 or greater patients were similar (55.6% [95% CI, 40.4%-68.3%] vs 67.4% [95% CI, 50.5%-79.6%], respectively; P = .50). The most common adverse events (rates per 100 patient-months) on TAH-t support included infection (15.8), ischemic stroke (4.6), reoperation for mediastinal bleeding (3.5), and gastrointestinal bleeding requiring intervention (4.3). The most common cause of death on TAH-t support was multisystem organ failure (n = 20, 52.6%). Thirty-day survival after transplantation was 96.7%; survival at 6 months, 1 year, and 5 years after transplantation was 95.1% (95% CI, 85.4%-98.4%), 86.6% (95% CI, 74.9%-93.0%), and 77.5% (95% CI, 64.2%-86.3%), respectively.

CONCLUSIONS

Acceptable outcomes can be achieved in the highest acuity patients using the TAH-t as a bridge to heart transplantation.

Supporting the "forgotten" ventricle: The evolution of percutaneous RVADs

Right heart failure (RHF) can occur as the result of an acute or chronic disease process and is a challenging clinical condition for surgeons and interventionalists to treat. RHF occurs in approximately 0.1% of patients after cardiac surgery, in 2-3% of patients following heart transplantation, and in up to 42% of patients after LVAD implantation. Regardless of the cause, RHF portends high morbidity and mortality and is associated with longer hospital stays and higher healthcare costs. The mainstays of traditional therapy for severe RHF have included pharmacological support, such as inotropes and vasopressors, and surgical right ventricular (RV) assist devices. However, in recent years catheter-based mechanical circulatory support (MCS) strategies have offered novel solutions for addressing RHF without the morbidity of open surgery. This manuscript will review the pathophysiology of RHF, including the molecular underpinnings, gross structural mechanisms, and hemodynamic consequences. The evolution of techniques for supporting the right ventricle will be explored, with a focus on various institutional experiences with percutaneous ventricular assist devices.

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.

Hemodynamic reserve predicts early right heart failure after LVAD implantation

BACKGROUND

Early right heart failure (RHF) remains a major source of morbidity and mortality after left ventricular assist device (LVAD) implantation, yet efforts to predict early RHF have proven only modestly successful. Pharmacologic unloading of the left ventricle may be a risk stratification approach allowing for assessment of right ventricular and hemodynamic reserve.

METHODS

We performed a multicenter, retrospective analysis of patients who had undergone continuous-flow LVAD implantation from October 2011 to April 2020. Only those who underwent vasodilator testing with nitroprusside during their preimplant right heart catheterization were included (n = 70). Multivariable logistic regression was used to determine independent predictors of early RHF as defined by Mechanical Circulatory Support-Academic Research Consortium.

RESULTS

Twenty-seven patients experienced post-LVAD early RHF (39%). Baseline clinical characteristics were similar between patients with and without RHF. Patients without RHF, however, achieved higher peak stroke volume index (SVI) (30.1 ± 8.8 vs 21.7 ± 7.4 mL/m2; p < 0.001; AUC: 0.78; optimal cut-point: 22.1 mL/m2) during nitroprusside administration. Multivariable analysis revealed that peak SVI was significantly associated with early RHF, demonstrating a 16% increase in risk of early RHF per 1 ml/m2 decrease in SVI. A follow up cohort of 10 consecutive patients from July 2020 to October 2021 resulted in all patients being categorized appropriately in regards to early RHF versus no RHF according to peak SVI.

CONCLUSION

Peak SVI with nitroprusside administration was independently associated with post-LVAD early RHF while resting hemodynamics were not. Vasodilator testing may prove to be a strong risk stratification tool when assessing LVAD candidacy though additional prospective validation is needed.

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.