title: Analysis of patient-specific surgical ventricular restoration: importance of an ellipsoidal left ventricular geometry for diastolic and systolic function.
abstract: Surgical ventricular restoration (SVR) is a procedure designed to treat heart failure by surgically excluding infarcted tissues from the dilated failing left ventricle. To elucidate and predict the effects of geometrical changes from SVR on cardiac function, we created patient-specific mathematical (finite-element) left ventricular models before and after surgery using untagged magnetic resonance images. Our results predict that the postsurgical improvement in systolic function was compromised by a decrease in diastolic distensibility in patients. These two conflicting effects typically manifested as a more depressed Starling relationship (stroke volume vs. end-diastolic pressure) after surgery. By simulating a restoration of the left ventricle back to its measured baseline sphericity, we show that both diastolic and systolic function improved. This result confirms that the increase in left ventricular sphericity commonly observed after SVR (endoventricular circular patch plasty) has a negative impact and contributes partly to the depressed Starling relationship. On the other hand, peak myofiber stress was reduced substantially (by 50%) after SVR, and the resultant left ventricular myofiber stress distribution became more uniform. This significant reduction in myofiber stress after SVR may help reduce adverse remodeling of the left ventricle. These results are consistent with the speculation proposed in the Surgical Treatment for Ischemic Heart Failure trial (20) for the neutral outcome, that "the lack of benefit seen with surgical ventricular reconstruction is that benefits anticipated from surgical reduction of left ventricular volume (reduced wall stress and improvement in systolic function) are counter-balanced by a reduction in diastolic distensibility."
authors: Department of Surgery, University of California, San Francisco, California, USA.
authors: Lik Chuan
authors: LC
authors: Lee
authors: Jonathan F
authors: JF
authors: Wenk
authors: Liang
authors: L
authors: Zhong
authors: Doron
authors: D
authors: Klepach
authors: Zhihong
authors: Z
authors: Zhang
authors: Liang
authors: L
authors: Ge
authors: Mark B
authors: MB
authors: Ratcliffe
authors: Tarek I
authors: TI
authors: Zohdi
authors: Edward
authors: E
authors: Hsu
authors: Jose L
authors: JL
authors: Navia
authors: Ghassan S
authors: GS
authors: Kassab
authors: Julius M
authors: JM
authors: Guccione
mesh_terms: D000465:Algorithms; D001794:Blood Pressure / Q000502:physiology; D001026:Coronary Artery Bypass; D003971:Diastole / Q000502:physiology; D020342:Finite Element Analysis; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D013599:Systole / Q000502:physiology; D013903:Thoracic Surgery; D016277:Ventricular Function, Left / Q000502:physiology
keywords: coronary artery bypass grafting; finite-element modeling; myocardial infarction; surgical ventricular restoration
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