Exploration of Intracardiac Geometry and Hemodynamics During HeartMate 3 Therapy: A Novel Approach Using Photon-Counting CT and Computational Fluid Dynamics

1. BACKGROUND

In recent years, the use of the mechanical circulatory support device, HeartMate 3 (HM3) (Abbott Laboratories, Lake Forest, IL), has garnered significant attention in the realm of circulatory support for advanced heart failure. The tangible advantages of the HM3, including enhanced hemocompatibility leading to reduced thromboembolic events and improved survival rates compared to its predecessors. The transition towards HM3 is particularly noteworthy as the system is not only likely to serve as a bridge to heart transplantation or decision-making but is increasingly being discussed as an effective destination therapy. Despite these advancements, there remains an imperative for meticulous hemodynamic monitoring throughout any mechanical circulatory support treatment. Traditionally, echocardiography has been predominantly employed as the hemodynamic imaging modality. However, echocardiographic evaluations of these patients present notable challenges, especially concerning shadows from the pump's metal, making it difficult to fully comprehend cardiac function and hemodynamics during the treatment.

Over the past decade, computed tomography (CT) has seen rapid advancements, with modern equipment now facilitating high-resolution anatomical imaging of the heart throughout the cardiac cycle (4D CT). Until recently, however, CT also posed a challenge for the examination of patients with mechanical circulatory support devices due to significant metal artifacts. The newly introduced photon-counting computed tomography (PC-CT), however, now enables scans that yield higher resolution images with reduced metal artifacts. From time-resolved CT, functional information can subsequently be derived and extracted. Techniques for automatic tracking of cardiac wall motion throughout the cardiac cycle, along with the utilization of computational dynamics to numerically solve fluid mechanical equations have previously been shown, which have proven to enable simulations of intracardiac hemodynamic maps.

The increasing indications for treatment with mechanical circulatory support underscore the current demand for continuously improved care quality and clinical understanding of this therapeutic option. Although the treatment enhances both prognosis and quality of life, serious and fatal complications remain recurrent. To the knowledge of the investigators, there has yet been no conducted research addressing the potential application of the novel PC-CT in patients with mechanical circulatory support devices, and certainly none that have established numerical frameworks on this data in an attempt to compute, visualize, and exploratively understand intracardiac hemodynamics during the treatment.

1.2 OBJECTIVES