Inflow-to-Outflow Stent Frame Expansion, Ellipticity, and Decoupling in Evolut TAVR: Implications for Mid-term Hemodynamic Performance.

Background: The native aortic annulus for self-expanding transcatheter aortic valve replacement (TAVR) has variable ellipticity. A noncircular and underexpanded transcatheter aortic valve (TAV) may impact hemodynamic performance. This study aimed to quantify Evolut TAV (Medtronic) frame ellipticity and expansion 30 days post-TAVR and evaluate their impact on 1-year hypoattenuating leaflet thickening and 4-year hemodynamics.

Hydrodynamic Assessment of Explanted Degenerated Transcatheter Aortic Valves: Novel Insights Into Noncalcific and Calcific Mechanisms.

Background: The etiology of transcatheter aortic valve (TAV) degeneration is poorly understood, particularly noncalcific mechanisms.

Objectives: The authors sought to investigate noncalcific and calcific mechanisms of TAV degeneration and evaluate their impact on leaflet function by bench testing, imaging, and histology.

Methods: TAV explants were obtained from the EXPLANT THV registry and clinical institutions.

Feasibility of Coronary Access Following Redo-TAVR for Evolut Failure: A Computed Tomography Simulation Study.

Background: Coronary accessibility following redo-transcatheter aortic valve replacement (redo-TAVR) is increasingly important, particularly in younger low-risk patients. This study aimed to predict coronary accessibility after simulated Sapien-3 balloon-expandable valve implantation within an Evolut supra-annular, self-expanding valve using pre-TAVR computed tomography (CT) imaging.

Methods: A total of 219 pre-TAVR CT scans from the Evolut Low-Risk CT substudy were analyzed.

Feasibility of redo-TAVI in self-expanding Evolut valves: a CT analysis from the Evolut Low Risk Trial substudy.

Background: Transcatheter aortic valve implantation in an existing transcatheter valve (redo-TAVI) pins the index valve leaflets in the open position (neoskirt), which can cause coronary flow compromise and limit access. Whether anatomy may preclude redo-TAVI in self-expanding Evolut valves is unknown.

Aims: We aimed to evaluate the anatomical feasibility of redo-TAVI by simulating implantation of a balloon-expandable SAPIEN 3 (S3) within an Evolut or an Evolut within an Evolut.

Impact of generator replacement on the risk of Fidelis lead fracture.

Background: A dilemma arises about the merits of conservative management vs lead replacement and/or extraction when patients with a Medtronic Sprint Fidelis lead undergo generator replacement. Conflicting reports suggest that the fracture rate may increase after generator change.

Objective: The purpose of this study was to investigate the effect of generator replacement on Fidelis lead performance.

MRI Reconstructions of Human Phrenic Nerve Anatomy and Computational Modeling of Cryoballoon Ablative Therapy.

The primary goal of this computational modeling study was to better quantify the relative distance of the phrenic nerves to areas where cryoballoon ablations may be applied within the left atria. Phrenic nerve injury can be a significant complication of applied ablative therapies for treatment of drug refractory atrial fibrillation. To date, published reports suggest that such injuries may occur more frequently in cryoballoon ablations than in radiofrequency therapies.

Left phrenic nerve anatomy relative to the coronary venous system: Implications for phrenic nerve stimulation during cardiac resynchronization therapy.

The objective of this study was to quantitatively characterize anatomy of the human phrenic nerve in relation to the coronary venous system, to reduce undesired phrenic nerve stimulation during left-sided lead implantations. We obtained CT scans while injecting contrast into coronary veins of 15 perfusion-fixed human heart-lung blocs. A radiopaque wire was glued to the phrenic nerve under CT, then we created three-dimensional models of anatomy and measured anatomical parameters.

The relative anatomy of the coronary arterial and venous systems: implications for coronary interventions.

An anatomical understanding of human coronary arterial and venous systems is necessary for device development and therapy applications that utilize these vessels. We investigated the unique use of contrast-CT scans from perfusion-fixed human hearts for three-dimensional visualization and analysis of anatomical features of the coronary systems. The coronary arterial and venous systems of eleven perfusion-fixed human hearts were modeled using contrast-CT and Mimics software.

The prevalence of coronary sinus and left circumflex artery overlap in relation to the mitral valve.

Objectives: Characterize where the circumflex artery crosses between the coronary sinus and mitral valve in order to minimize the occurrence of coronary compression during percutaneous indirect mitral valve interventions.

Background: Treatment of mitral valve regurgitation using an indirect percutaneous approach via access through the coronary sinus remains under active research and development. Characterization of anatomical locations where the circumflex artery crosses between the coronary sinus and mitral valve is important for mitigation of serious ischemic complications.

The benefits of the Atlas of Human Cardiac Anatomy website for the design of cardiac devices.

This paper describes how the Atlas of Human Cardiac Anatomy website can be used to improve cardiac device design throughout the process of development. The Atlas is a free-access website featuring novel images of both functional and fixed human cardiac anatomy from over 250 human heart specimens. This website provides numerous educational tutorials on anatomy, physiology and various imaging modalities.

A detailed assessment of the human coronary venous system using contrast computed tomography of perfusion-fixed specimens.

Background: Access to the coronary venous system is required for the delivery of several cardiac therapies including cardiac resynchronization therapy, coronary sinus ablation, and coronary drug delivery. Therefore, characterization of the coronary venous anatomy will provide insights to gain improved access to these vessels and subsequently improved therapies. For example, cardiac resynchronization therapy has a 30% nonresponder rate, partially due to suboptimal lead placement within the coronary veins.

Anatomical reconstructions of the human cardiac venous system using contrast-computed tomography of perfusion-fixed specimens.

A detailed understanding of the complexity and relative variability within the human cardiac venous system is crucial for the development of cardiac devices that require access to these vessels. For example, cardiac venous anatomy is known to be one of the key limitations for the proper delivery of cardiac resynchronization therapy (CRT)(1) Therefore, the development of a database of anatomical parameters for human cardiac venous systems can aid in the design of CRT delivery devices to overcome such a limitation. In this research project, the anatomical parameters were obtained from 3D reconstructions of the venous system using contrast-computed tomography (CT) imaging and modeling software (Materialise, Leuven, Belgium).

Human coronary venous anatomy: implications for interventions.

The coronary venous system is a highly variable network of veins that drain the deoxygenated blood from the myocardium. The system is made up of the greater cardiac system, which carries the majority of the deoxygenated blood to the right atrium, and the smaller cardiac system, which drains the blood directly into the heart chambers. The coronary veins are currently being used for several biomedical applications, including but not limited to cardiac resynchronization therapy, ablation therapy, defibrillation, perfusion therapy, and annuloplasty.