Image-Based Computational Hemodynamics Analysis of Systolic Obstruction in Hypertrophic Cardiomyopathy.

Ivan Fumagalli,Roberto Scrofani,Piermario Vitullo,Antonio F Corno,Christian Vergara,Alfio Quarteroni,Marco Fedele,Sonia Ippolito

doi:10.3389/fphys.2021.787082

Ivan Fumagalli, Roberto Scrofani + Show 6 more

Open Access

https://doi.org/10.3389/fphys.2021.787082

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Abstract

Hypertrophic Cardiomyopathy (HCM) is a pathological condition characterized by an abnormal thickening of the myocardium. When affecting the medio-basal portion of the septum, it is named Hypertrophic Obstructive Cardiomyopathy (HOCM) because it induces a flow obstruction in the left ventricular outflow tract. In any type of HCM, the myocardial function can become compromised, possibly resulting in cardiac death. In this study, we investigated with computational analysis the hemodynamics of patients with different types of HCM. The aim was quantifying the effects of this pathology on the intraventricular blood flow and pressure gradients, and providing information potentially useful to guide the indication and the modality of the surgical treatment (septal myectomy). We employed an image-based computational approach, integrating fluid dynamics simulations with geometric and functional data, reconstructed from standard cardiac cine-MRI acquisitions. We showed that with our approach we can better understand the patho-physiological behavior of intraventricular blood flow dynamics due to the abnormal morphological and functional aspect of the left ventricle. The main results of our investigation are: (a) a detailed patient-specific analysis of the blood velocity, pressure and stress distribution associated to HCM; (b) a computation-based classification of patients affected by HCM that can complement the current clinical guidelines for the diagnosis and treatment of HOCM.

Highlights

IntroductionHypertrophic Cardiomyopathy (HCM) is a typically congenital cardiac disorder characterized by an abnormal thickening of the myocardium (wall thickness exceeding 15 mm, in adult patients) without additional causes inducing secondary hypertrophy (Elliott et al, 2014)
Hypertrophic Cardiomyopathy (HCM) is a typically congenital cardiac disorder characterized by an abnormal thickening of the myocardium without additional causes inducing secondary hypertrophy (Elliott et al, 2014)
Since we focused our study on the systolic phase, and we want to analyze the effects of only the HCM-associated ventricular shape and motion on the blood flow, we prescribed a physiological pressure waveform, derived from Wiggers diagrams (Wiggers, 1923), as outflow condition at the distal section out of the ascending aorta

Summary

Introduction

Hypertrophic Cardiomyopathy (HCM) is a typically congenital cardiac disorder characterized by an abnormal thickening of the myocardium (wall thickness exceeding 15 mm, in adult patients) without additional causes inducing secondary hypertrophy (Elliott et al, 2014). When the thickening affects the medio-basal region of the interventricular septum, this condition may cause a flow obstruction in the Left Ventricular Outflow Tract (LVOT), and it is named Hypertrophic Obstructive Cardiomyopathy (HOCM). People with mild forms of HOCM often remain oligosymptomatic or even asymptomatic for many years Otherwise, they may develop dyspnea, angina pectoris, or stressinduced syncope, with an increased risk of sudden cardiac death, in young people and athletes, more exposed to physical efforts that require a sudden increase of the cardiac output. The LVOT obstruction is dynamical, and largely influenced by changes in left ventricular pressure overload and contractility, with subsequently increased systolic pressure in the Left Ventricle (LV) and possible secondary Mitral Valve Regurgitation (MVR), myocardial ischemia, and reduction in cardiac output. A Systolic Anterior Motion (SAM) of the mitral valve can occur, further worsening the LVOT obstruction (Jiang et al, 1987; Geske et al, 2012; Ibrahim et al, 2012; Sherrid et al, 2016; Akiyama et al, 2017)

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