Key questions about aortic insufficiency in patients with durable left ventricular assist devices

Aortic insufficiency in the patient on contemporary durable left ventricular assist device support: A state-of-the-art review on preoperative and postoperative assessment and management

The development of aortic insufficiency (AI) during HeartMate 3 durable left ventricular assist device (dLVAD) support can lead to ineffective pump output and recurrent heart failure symptoms. Progression of AI often comingles with the occurrence of other hemodynamic-related events encountered during LVAD support, including right heart failure, arrhythmias, and cardiorenal syndrome. While data on AI burdens and clinical impact are still insufficient in patients on HeartMate 3 support, moderate or worse AI occurs in approximately 8% of patients by 1 year and studies suggest AI continues to progress over time and is associated with increased frequency of right heart failure. The first line intervention for AI management is prevention, undertaking surgical intervention on the insufficient valve at the time of dLVAD implant and avoiding excessive device flows and hypertension during long-term support. Device speed augmentation may then be undertaken to try and overcome the insufficient lesion, but the progression of AI should be anticipated over the long term. Surgical or transcatheter aortic valve interventions may be considered in dLVAD patients with significant persistent AI despite medical management, but neither intervention is without risk. It is imperative that future studies of dLVAD support capture AI in clinical end-points using uniform assessment and grading of AI severity by individuals trained in AI assessment during dLVAD support.

Enhancing the implantation of mechanical circulatory support devices using computational simulations

Introduction: Patients with end-stage heart failure (HF) may need mechanical circulatory support such as a left ventricular assist device (LVAD). However, there are a range of complications associated with LVAD including aortic regurgitation (AR) and thrombus formation. This study assesses whether the risk of developing aortic conditions can be minimised by optimising LVAD implantation technique. Methods: In this work, we evaluate the aortic flow patterns produced under different geometrical parameters for the anastomosis of the outflow graft (OG) to the aorta using computational fluid dynamics (CFD). A three-dimensional aortic model is created and the HeartMate III OG positioning is simulated by modifying (i) the distance from the anatomic ventriculo-arterial junction (AVJ) to the OG, (ii) the cardinal position around the aorta, and (iii) the angle between the aorta and the OG. The continuous LVAD flow and the remnant native cardiac cycle are used as inlet boundaries and the three-element Windkessel model is applied at the pressure outlets. Results: The analysis quantifies the impact of OG positioning on different haemodynamic parameters, including velocity, wall shear stress (WSS), pressure, vorticity and turbulent kinetic energy (TKE). We find that WSS on the aortic root (AoR) is around two times lower when the OG is attached to the coronal side of the aorta using an angle of 45° ± 10° at a distance of 55 mm. Discussion: The results show that the OG placement may significantly influence the haemodynamic patterns, demonstrating the potential application of CFD for optimising OG positioning to minimise the risk of cardiovascular complications after LVAD implantation.

Transcatheter aortic valve replacement in the management of aortic insufficiency secondary to left ventricular assist device implantation: a case report

Background

Left ventricular assist device (LVAD) is considered either a destination therapy for patients with end-stage heart failure or heart transplantation bridging. LVAD implantation often causes aortic insufficiency (AI), which requires aortic valve repair. However, severe acute AI does not respond well to medication, and re-operation means higher risk to the patients; the most effective therapeutic strategies for LVAD-induced AI still need further exploration. In this report, we present the first described case of new-onset, severe LVAD-induced AI in China with a patient who underwent transcatheter aortic valve replacement (TAVR) and achieved significant improvement in functional capacity and symptoms with lower operation risk.

Case Description

A 55-year-old male patient was diagnosed with dilated cardiomyopathy for 14 years. The effect of the medication gradually deteriorated, LVAD (HeartCon®) was implanted one year earlier. The patient complained of intermittent chest tightness for one week, which had been aggravated for two days before hospitalization. Echocardiographic findings revealed new-onset, severe LVAD-induced AI. TAVR was performed with a self-expandable stent-valve (TAV30, Vitaflow Liberty). Within minutes, the patient recovered with rapid disappearance of chest tightness and stable vital signs. Before discharge, the position of the artificial valve was fixed without incomplete closure nor thrombus attachment, yielding a left ventricular ejection fraction (LVEF) of 35%. The patient was hospitalized for 38 days, and followed up with outpatient treatment, the condition was stable until 19 June 2023.

Conclusions

TAVR could be an effective, safe, and less invasive means of restoring ejection fraction for patients with a LVAD who develop severe AI.

Aortic valve disorders and left ventricular assist devices

Aortic valve disorders are important considerations in advanced heart failure patients being evaluated for left ventricular assist devices (LVAD) and those on LVAD support. Aortic insufficiency (AI) can be present prior to LVAD implantation or develop de novo during LVAD support. It is usually a progressive disorder and can lead to impaired LVAD effectiveness and heart failure symptoms. Severe AI is associated with worsening hemodynamics, increased hospitalizations, and decreased survival in LVAD patients. Diagnosis is made with echocardiographic, device assessment, and/or catheterization studies. Standard echocardiographic criteria for AI are insufficient for accurate diagnosis of AI severity. Management of pre-existing AI includes aortic repair or replacement at the time of LVAD implant. Management of de novo AI on LVAD support is challenging with increased risks of repeat surgical intervention, and percutaneous techniques including transcatheter aortic valve replacement are assuming greater importance. In this manuscript, we provide a comprehensive approach to contemporary diagnosis and management of aortic valve disorders in the setting of LVAD therapy.