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.