Does Size Matter for Female Continuous-flow LVAD Recipients? A Translational Approach to a Decade Long Question

Sex Disparities in Left Ventricular Assist Device Implantation: Delayed Presentation and Worse Right Heart Failure

We explored whether women undergo continuous-flow left ventricular assist device (CF-LVAD) implantation in later stages of heart failure (HF) than men, evidenced by worse preoperative right HF (RHF). We also compared two propensity models with and without preoperative RHF to assess its effect on outcomes. INTERMACS was queried from July 2008 to December 2017. Propensity model 1 matched men and women on age ≥50 years, HF etiology, body surface area, INTERMACS class, comorbidities, device strategy, temporary mechanical circulatory support, and device type. Model 2 included these variables plus LV end-diastolic diameter, right atrial pressure/pulmonary capillary wedge pressure, pulmonary artery pulsatility index, and right ventricular ejection fraction. The primary outcome was all-cause mortality. Secondary outcomes comprise RHF, rehospitalization, renal dysfunction, stroke, and device malfunction. In model 1, characteristics were comparable between 3,195 women and 3,195 men, except women more often had preoperative RHF and postoperative right VAD support and had worse 1 year and overall survival. In model 2, after propensity matching for additional risk factors for preoperative RHF, 1,119 women and 1,119 men had comparable post-LVAD implant RVAD use and survival. These findings suggest that women present more often with biventricular failure and after implantation have higher RHF and mortality rates.

The Future of Durable Mechanical Circulatory Support: Emerging Technological Innovations and Considerations to Enable Evolution of the Field

The field of durable mechanical circulatory support (MCS) has undergone an incredible evolution over the past few decades, resulting in significant improvements in longevity and quality of life for patients with advanced heart failure. Despite these successes, substantial opportunities for further improvements remain, including in pump design and ancillary technology, perioperative and postoperative management, and the overall patient experience. Ideally, durable MCS devices would be fully implantable, automatically controlled, and minimize the need for anticoagulation. Reliable and long-term total artificial hearts for biventricular support would be available; and surgical, perioperative, and postoperative management would be informed by the individual patient phenotype along with computational simulations. In this review, we summarize emerging technological innovations in these areas, focusing primarily on innovations in late preclinical or early clinical phases of study. We highlight important considerations that the MCS community of clinicians, engineers, industry partners, and venture capital investors should consider to sustain the evolution of the field.

Hemodynamic Evaluation of Asynchronous Speed Modulation of a Continuous-Flow Left Ventricular Assist Device in an Acute-Myocardial Injury Sheep Model

Asynchronous rotational-speed modulation of a continuous-flow left ventricular assist device (LVAD) can increase pulsatility; however, the feasibility of hemodynamic modification by asynchronous modulation of an LVAD has not been sufficiently verified. We evaluated the acute effect of an asynchronous-modulation mode under LVAD support and the accumulated effect of 6 consecutive hours of driving by the asynchronous-modulation mode on hemodynamics, including both ventricles, in a coronary microembolization-induced acute-myocardial injury sheep model. We evaluated 5-min LVAD-support hemodynamics, including biventricular parameters, by switching modes from constant-speed to asynchronous-modulation in the same animals ("acute-effect evaluation under LVAD support"). To determine the accumulated effect of a certain driving period, we evaluated hemodynamics including biventricular parameters after weaning from 6-hour (6 h) LVAD support by constant-speed or asynchronous-modulation mode ("6h-effect evaluation"). The acute-effect evaluation under LVAD support revealed that, compared to the constant-speed mode, the asynchronous-modulation mode increased vascular pulsatility but did not have significantly different effects on hemodynamics, including both ventricles. The 6 h-effect evaluation revealed that the hemodynamics did not differ significantly between the two groups except for some biventricular parameters which did not indicate negative effects of the asynchronous-modulation mode on both ventricles. The asynchronous-modulation mode could be feasible to increase vascular pulsatility without causing negative effects on hemodynamics including both ventricles. Compared to the constant-speed mode, the asynchronous-modulation mode increased pulsatility during LVAD support without negative effects on hemodynamics including both ventricles in the acute phase. Six hours of LVAD support with the asynchronous-modulation mode exerted no negative effects on hemodynamics, including both ventricles, after weaning from the LVAD.

Sex disparities in left ventricular assist device implantation outcomes: A systematic review and meta-analysis of over 50 000 patients

BACKGROUND

Left ventricular assist devices (LVAD) represent an important therapeutic option for patients progressing to end-stage heart failure. Women have been historically underrepresented in LVAD studies, and have been reported to have worse outcomes despite technological optimisation. We aimed to systematically explore the evidence on sex disparities in the use and outcomes of LVAD implantation.

METHODS

A systematic database search with meta-analysis was conducted of comparative original articles of men versus women undergoing LVAD implantation, in EMBASE, MEDLINE, Cochrane database and Google Scholar, from inception to July 2022. Primary outcomes were stroke (haemorrhagic and ischaemic) and early/overall mortality. Secondary outcomes were LVAD thrombosis, right VAD implantation, major bleeding, kidney dysfunction, and device/driveline infection.

RESULTS

Our search yielded 137 relevant studies, including 22 meeting the inclusion criteria with a total of 53 227 patients (24.2% women). Overall mortality was higher in women (odds ratio [OR] 1.35, 95% confidence interval [CI] 1.05-1.62, p = 0.02), as was overall stroke (OR 1.32, 95%CI 1.06-1.66, p = 0.01), including ischemic (OR 1.80, 95%CI 1.22-2.64, p = 0.003) and haemorrhagic (OR 1.72, 95%CI 1.09-2.70, p = 0.02). Women had more frequent right VAD implantation (OR 2.11, 95%CI 1.24-3.57, p = 0.006) and major bleeding (OR 1.40, 95%CI 1.06-1.85, p = 0.02). Kidney dysfunction, LVAD thrombosis, and device/driveline infections were comparable between sexes.

CONCLUSIONS

Our analysis suggests that women face a greater risk of adverse events and mortality post-LVAD implantation. Although the mechanisms remain unclear, the difference in outcomes is thought to be multifactorial. Further research, that includes comprehensive pre-operative characteristics and post-operative outcomes, is encouraged.

Sex‐related differences in left ventricular assist device utilization and outcomes: results from the PCHF‐VAD registry

AIMS

Data on sex and left ventricular assist device (LVAD) utilization and outcomes have been conflicting and mostly confined to US studies incorporating older devices. This study aimed to investigate sex-related differences in LVAD utilization and outcomes in a contemporary European LVAD cohort.

METHODS AND RESULTS

This analysis is part of the multicentre PCHF-VAD registry studying continuous-flow LVAD patients. The primary outcome was all-cause mortality. Secondary outcomes included ventricular arrhythmias, right ventricular failure, bleeding, thromboembolism, and the haemocompatibility score. Multivariable Cox regression models were used to assess associations between sex and outcomes. Overall, 457 men (81%) and 105 women (19%) were analysed. At LVAD implant, women were more often in Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile 1 or 2 (55% vs. 41%, P = 0.009) and more often required temporary mechanical circulatory support (39% vs. 23%, P = 0.001). Mean age was comparable (52.1 vs. 53.4 years, P = 0.33), and median follow-up duration was 344 [range 147-823] days for women and 435 [range 190-816] days for men (P = 0.40). No significant sex-related differences were found in all-cause mortality (hazard ratio [HR] 0.79 for female vs. male sex, 95% confidence interval [CI] [0.50-1.27]). Female LVAD patients had a lower risk of ventricular arrhythmias (HR 0.56, 95% CI [0.33-0.95]) but more often experienced right ventricular failure. No significant sex-related differences were found in other outcomes.

CONCLUSIONS

In this contemporary European cohort of LVAD patients, far fewer women than men underwent LVAD implantation despite similar clinical outcomes. This is important as the proportion of female LVAD patients (19%) was lower than the proportion of females with advanced HF as reported in previous studies, suggesting underutilization. Also, female patients were remarkably more often in INTERMACS profile 1 or 2, suggesting later referral for LVAD therapy. Additional research in female patients is warranted.

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.