Impact of surgical ventricular restoration on ventricular shape, wall stress, and function in heart failure patients

Abstract

Surgical ventricular restoration (SVR) was designed to treat patients with aneurysms or large akinetic walls and dilated ventricles. Yet, crucial aspects essential to the efficacy of this procedure like optimal shape and size of the left ventricle (LV) are still debatable. The objective of this study is to quantify the efficacy of SVR based on LV regional shape in terms of curvedness, wall stress, and ventricular systolic function. A total of 40 patients underwent magnetic resonance imaging (MRI) before and after SVR. Both short-axis and long-axis MRI were used to reconstruct end-diastolic and end-systolic three-dimensional LV geometry. The regional shape in terms of surface curvedness, wall thickness, and wall stress indexes were determined for the entire LV. The infarct, border, and remote zones were defined in terms of end-diastolic wall thickness. The LV global systolic function in terms of global ejection fraction, the ratio between stroke work (SW) and end-diastolic volume (SW/EDV), the maximal rate of change of pressure-normalized stress (dσ*/dt(max)), and the regional function in terms of surface area change were examined. The LV end-diastolic and end-systolic volumes were significantly reduced, and global systolic function was improved in ejection fraction, SW/EDV, and dσ*/dt(max). In addition, the end-diastolic and end-systolic stresses in all zones were reduced. Although there was a slight increase in regional curvedness and surface area change in each zone, the change was not significant. Also, while SVR reduced LV wall stress with increased global LV systolic function, regional LV shape and function did not significantly improve.

Right ventricular regional wall curvedness and area strain in patients with repaired tetralogy of Fallot

“…The methods of MRI data processing for LV have been developed and used in previous studies (35,44,47,48). Briefly, the MRI data were processed using a semi-automatic technique provided in the CMRtools suite (Cardiovascular Solutions).…”

“…An in-house software was used to reconstruct the RV endocardial meshes at ED and ES as well as to calculate the surface shape descriptors, expressed in terms of local normal curvature and curvedness (35,44,47,48). To evaluate the shape at a particular point on the mesh, a local surface geometry was fitted to the region and the normal curvature was then calculated as (6,12):…”

“…If significant PR is found, cardiac MRI is performed to quantify PR severity and RV function (20). Many studies have shown that MRI is the best and most comprehensive approach to quantify the three dimensional (3-D) ventricular geometry and function (4,25,(47)(48), compared with echocardiography (16,41), ventriculography (14,46), angiography (33), and indicator-dilution methods (10). In patients with demonstrable severe PR and borderline RV function, serial MRI assessment becomes mandatory for timing of pulmonary valve replacement (PVR; Ref.…”

Image-Based Left Ventricular Shape Analysis for Sudden Cardiac Death Risk Stratification

“…25,28 Note that increases in wall stress are believed to be the principal change that occurs during LV remodeling, 4 and our RWT metric accounts for both radius of curvature and WT, the two geometric parameters that contribute to wall stress. 29 Hence, of the three shape metrics we considered in this study, RWT produced the maximum number of significant differences between patients with and without events.…”

“…Also, only end-diastolic images are used in this study. Our framework can be extended to utilize the end systolic phase, where the effects of LV remodeling are more pronounced, 7,29 and to analyze change in shape metrics over the cardiac cycle.…”