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

Current issues of destination therapy in Japan: to achieve 5-year or even longer survival

In April 2021, destination therapy (DT) was finally approved in Japan. Since DT does not aim at heart transplantation (HT), our goal is to have a patient safely remain on an implantable ventricular assist device (VAD) for the rest of his/her life. To achieve this goal, similarly to bridge-to-transplant (BTT) patients, the authors believe the following six aspects are even more crucial in DT patients: (1) to appropriately assess risks before implantation, (2) to carefully determine the ability to manage the device by multidisciplinary discussions, (3) to prevent complications by improving the quality of care, (4) to expand the number of facilities that can take care of DT patients by improving collaboration among the facilities, (5) to reduce the burden of caregivers by utilizing social resources, and (6) to establish a home palliative care system based on advance care planning. In addition, for elderly DT patients to live happy and long lives, it is essential to help them to find a purpose of life and to keep activities of daily living, such as employment, schooling, and participation in social activities, just like the general elderly population. Our goals are not only to do our best for the patients just in front of us, but also to establish a system to follow up our DT cohort, same as BTT one, by all-Japan manner. In the present review, we discuss the current state of DT in Japan and what we need to focus on to maintain or improve its long-term performance.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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.

Cellular and Molecular Mechanisms Activated by a Left Ventricular Assist Device

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

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

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