Circulatory response to volume expansion and transjugular intrahepatic portosystemic shunt in refractory ascites: Relationship with diastolic dysfunc…

2015

Abstract Background Cirrhotic cardiomyopathy may lead to heart failure in stressful circumstances, such as after transjugular intrahepatic portosystemic shunt (TIPS) placement. Aim To examine whether acute volume expansion predicts haemodynamic changes after TIPS and elicits signs of impending heart failure. Methods We prospectively evaluated refractory ascites patients (group A) and compensated cirrhotics (group B), who underwent echocardiography, NT-proBNP measurement, and heart catheterization before and after volume load; group A repeated measurements after TIPS. Results 15 patients in group A (80% male; 54 ± 12.4 years) and 8 in group B (100% male; 56 ± 6.2 years) were enrolled. Echoca…

Three-dimensional parametric modeling of bicuspid aortopathy and comparison with computational flow predictions

2017

Bicuspid aortic valve (BAV)-associated ascending aneurysmal aortopathy (namely "bicuspid aortopathy") is a heterogeneous disease making surgeon predictions particularly challenging. Computational flow analysis can be used to evaluate the BAV-related hemodynamic disturbances, which likely lead to aneurysm enlargement and progression. However, the anatomic reconstruction process is time consuming so that predicting hemodynamic and structural evolution by computational modeling is unfeasible in routine clinical practice. The aim of the study was to design and develop a parametric program for three-dimensional (3D) representations of aneurysmal aorta and different BAV phenotypes starting from s…

Modelling cardiac mechanics of left ventricular noncompaction

2020

Left ventricular noncompaction (LVNC) can be defined as a cardiomyopathy characterised by a pattern of prominent trabecular structure and deep intertrabecular recesses, that is thought to be caused by an arrest of normal endomyocardial morphogenesis. Using patient-specific computational modelling, we assessed the cardiac mechanics of five patients with LVNC and compared myocardial stress and pump performance to those of healthy controls. Findings shown that patients with LVNC have impaired left ventricular (LV) function, making it possible that the lack of fibre shortening of noncompacted layer can determine poor heart function. Pronounced end-systolic wall stress on left ventricular wall o…

Evaluation of ventricular wall stress and cardiac function in patients with dilated cardiomyopathy

2015

Dilated cardiomyopathy is a heart disease characterized by both left ventricular dilatation and left ventricular systolic dysfunction, leading to cardiac remodeling and ultimately heart failure. We aimed to investigate the effect of dilated cardiomyopathy on the pump performance and myocardial wall mechanics using patient-specific finite element analysis. Results evinced pronounced end-systolic wall stress on left ventricular wall of patients with dilated cardiomyopathy as compared to that of normal hearts. In dilated cardiomyopathy, both end-diastolic and end-systolic pressure–volume relationships of left ventricle and right ventricle were shifted to the right compared to controls, sugges…

Cardiac sarcoidosis: Matching speckle tracking echocardiography to macroscopic Ventricular pathology (a case report)

2016

Patients with bicuspid aortic valve are likely to receive an aortic valve prosthesis during prophylactic resection of their ascending aortic aneurysm.

2015

This study aims to evaluate whether thepresence or discovery of a BAV under ATAA repair would impactthe decision-making of the surgical procedure choice.

Biomechanical implications of excessive endograft protrusion into the aortic arch after thoracic endovascular repair

2015

Endografts placed in the aorta for thoracic endovascular aortic repair (TEVAR) may determine malappositioning to the lesser curvature of the aortic wall, thus resulting in a devastating complication known as endograft collapse. This premature device failure commonly occurs in young individuals after TEVAR for traumatic aortic injuries as a result of applications outside the physical conditions for which the endograft was designed. In this study, an experimentally-calibrated fluid-structure interaction (FSI) model was developed to assess the hemodynamic and stress/strain distributions acting on the excessive protrusion extension (PE) of endografts deployed in four young patients underwent TE…

An In Vitro Phantom Study on the Role of the Bird-Beak Configuration in Endograft Infolding in the Aortic Arch.

2015

Purpose: To assess endograft infolding for excessive bird-beak configurations in the aortic arch in relation to hemodynamic variables by quantifying device displacement and rotation of oversized stent-grafts deployed in a phantom model. Methods: A patient-specific, compliant, phantom pulsatile flow model was reconstructed from a patient who presented with collapse of a Gore TAG thoracic endoprosthesis. Device infolding was measured under different flow and pressure conditions for 3 protrusion extensions (13, 19, and 24 mm) of the bird-beak configuration resulting from 2 TAG endografts with oversizing of 11% and 45%, respectively. Results: The bird-beak configuration with the greatest protr…

Difference in hemodynamic and wall stress of ascending thoracic aortic aneurysms with bicuspid and tricuspid aortic valve.

2012

The aortic dissection (AoD) of an ascending thoracic aortic aneurysm (ATAA) initiates when the hemodynamic loads exerted on the aneurysmal wall overcome the adhesive forces holding the elastic layers together. Parallel coupled, two-way fluid–structure interaction (FSI) analyses were performed on patient-specific ATAAs obtained from patients with either bicuspid aortic valve (BAV) or tricuspid aortic valve (TAV) to evaluate hemodynamic predictors and wall stresses imparting aneurysm enlargement and AoD. Results showed a left-handed circumferential flow with slower-moving helical pattern in the aneurysm's center for BAV ATAAs whereas a slight deviation of the blood flow toward the anterolater…

Constitutive modeling of ascending thoracic aortic aneurysms using microstructural parameters.

2016

Ascending thoracic aortic aneurysm (ATAA) has been associated with diminished biomechanical strength and disruption in the collagen fiber microarchitecture. Additionally, the congenital bicuspid aortic valve (BAV) leads to a distinct extracellular matrix structure that may be related to ATAA development at an earlier age than degenerative aneurysms arising in patients with the morphological normal tricuspid aortic valve (TAV). The purpose of this study was to model the fiber-reinforced mechanical response of ATAA specimens from patients with either BAV or TAV. This was achieved by combining image-analysis derived parameters of collagen fiber dispersion and alignment with tensile testing dat…

Long-Term Structural and Functional Myocardial Adaptations in Healthy Living Kidney Donors: A Pilot Study

2015

Background and Aims Compensatory renal hypertrophy following unilateral nephrectomy (UNX) occurs in the remaining kidney. However, the long-Term cardiac adaptive process to UNX remains poorly defined in humans. Our goal was to characterize myocardial structure and function in living kidney donors (LKDs), approximately 12 years after UNX. Methods and Results Cardiac function and structure in 15 Italian LKDs, at least 5 years after UNX (median time from donation = 8.4 years) was investigated and compared to those of age and sex matched U.S. citizens healthy controls (n = 15). Standard and speckle tracking echocardiography (STE) was performed in both LKDs and controls. Plasma angiotensin II, a…

In Silico Shear and Intramural Stresses are Linked to Aortic Valve Morphology in Dilated Ascending Aorta

2017

Objective/Background: The development of ascending aortic dilatation in patients with bicuspid aortic valve (BAV) is highly variable, and this makes surgical decision strategies particularly challenging. The purpose of this study was to identify new predictors, other than the well established aortic size, that may help to stratify the risk of aortic dilatation in BAV patients.Methods: Using fluid-structure interaction analysis, both haemodynamic and structural parameters exerted on the ascending aortic wall of patients with either BAV ( n = 21) or tricuspid aortic valve (TAV; n = 13) with comparable age and aortic diameter (42.7 +/- 5.3 mm for BAV and 45.4 +/- 10.0 mm for TAV) were compared…

Mechanics of pericardial effusion: A simulation study

2015

Pericardial effusion is a pathological accumulation of fluid within pericardial cavity, which may compress heart chambers with hemodynamic impairment. We sought to determine the mechanics underlying the physiology of the hemodynamic impairment due to pericardial effusion using patient-specific computational modeling. Computational models of left ventricle and right ventricle were based on magnetic resonance images obtained from patients with pericardial effusion and controls. Myocardial material parameters were adjusted, so that volumes of ventricular chambers and pericardial effusion agreed with magnetic resonance imaging data. End-diastolic and end-systolic pressure–volume relationships …

Three-dimensional parametric modeling of bicuspid aortopathy and comparison with computational flow predictions

2016

Bicuspid aortic valve (BAV)-associated ascending aneurysmal aortopathy (namely “bicuspid aortopathy”) is a heterogeneous disease making surgeon predictions particularly challenging. Computational flow analysis can be used to evaluate the BAV-related hemodynamic disturbances, which likely lead to aneurysm enlargement and progression. However, the anatomic reconstruction process is time consuming so that predicting hemodynamic and structural evolution by computational modeling is unfeasible in routine clinical practice. The aim of the study was to design and develop a parametric program for three-dimensional (3D) representations of aneurysmal aorta and different BAV phenotypes starting fr…