Dor procedure for dyskinetic anteroapical myocardial infarction fails to improve contractility in the border zone

Abstract

Background Endoventricular patch plasty (Dor) is used to reduce left ventricular (LV) volume after myocardial infarction (MI) and subsequent LV remodeling. Methods and Results End-diastolic and end-systolic pressure volume and Starling relationships were measured and magnetic resonance (MRI) images with non-invasive tags used to calculate 3D myocardial strain in six sheep 2 weeks before, and 2 and 6 weeks after the Dor procedure. These experimental results were previously reported. The imaging data from one sheep was incomplete. Animal specific finite element (FE) models were created from the remaining five animals using MRI images and LV pressure obtained at early diastolic filling. FE models were optimized using 3D strain and used to determine systolic material properties, Tmax,skinned-fiber, and diastolic and systolic stress in remote myocardium and borderzone (BZ). Six weeks after Dor procedure, end-diastolic and end-systolic stress in the BZ were substantially reduced. However, although there was a slight increase in Tmax,skinned-fiber in the BZ near the MI at 6 weeks, the change was not significant. Conclusions The Dor procedure decreases end-diastolic and end-systolic stress but fails to improve contractility in the infarct BZ. Future work should focus on measures that will enhance BZ function alone or in combination with surgical remodeling.

A Novel Method for Quantifying Smooth Regional Variations in Myocardial Contractility Within an Infarcted Human Left Ventricle Based on Delay-Enhanced Magnetic Resonance Imaging

“…With confidence in our method, we applied it to the longitudinal study of the effect of LV aneurysm repair using an undersized patch (Dor procedure) on regional contractilities [26]. We found that the Dor procedure decreases end-diastolic and end-systolic stress but fails to improve BZ contractility.…”

“…Perhaps the inability of the Dor procedure to improve BZ contractility is the primary reason for the neutral STICH trial outcome. In fact, Sun et al [26] concluded that the future work are inverted compared to those in the viability map, so that the regions are consistent: healthy regions (high contractility) appear in blue, while the infarcted region (low contractility) appears in red. Note that because the core infarct area is rather small, the region with zero contractility (red) is small as well.…”

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

“…The amount of stress reduction necessary to halt or reverse nonischemic infarct extension in the BZ is unknown. In animal models, Guccione and colleagues (35) have demonstrated that reduced wall stress does not result in improved BZ contractile function because the inherent contractile function of the myocytes in this region is irreversibly impaired (35). Based on the STICH Trial, it appears that reduced wall stress does not result in improved symptoms nor increases longevity for that patient cohort.…”

Infarct Size Determines Myocardial Uptake of CD34 + Cells in the Peri-Infarct Zone

“…33 Thus, infarct border zone is a key target for therapies aimed at inhibiting adverse LV remodeling. Indeed, both experimental and clinical evidence suggests that failure to inhibit apoptosis 34 and to stimulate the dedifferentiated surviving cells in the peri-infarct viable myocardium may be associated with adverse LV remodeling occurring despite surgical resection of the infarct scar. 34 Further work is required to assess the impact of CD34 + cell uptake in the peri-infarct zone on the prevention of postinfarct LV remodeling and the role of cell-engineering strategies in boosting this effect.…”