Fluid-structure interaction simulations outperform computational fluid dynamics in the description of thoracic aorta haemodynamics and in the differentiation of progressive dilation in Marfan syndrome patients.

Abnormal fluid dynamics at the ascending aorta may be at the origin of aortic aneurysms. This study was aimed at comparing the performance of computational fluid dynamics (CFD) and fluid-structure interaction (FSI) simulations against four-dimensional (4D) flow magnetic resonance imaging (MRI) data; and to assess the capacity of advanced fluid dynamics markers to stratify aneurysm progression risk. Eight Marfan syndrome (MFS) patients, four with stable and four with dilating aneurysms of the proximal aorta, and four healthy controls were studied. FSI and CFD simulations were performed with MRI-derived geometry, inlet velocity field and Young's modulus. Flow displacement, jet angle and maximum velocity evaluated from FSI and CFD simulations were compared to 4D flow MRI data. A dimensionless parameter, the shear stress ratio (SSR), was evaluated from FSI and CFD simulations and assessed as potential correlate of aneurysm progression. FSI simulations successfully matched MRI data regarding descending to ascending aorta flow rates (R 2 = 0.92) and pulse wave velocity (R 2 = 0.99). Compared to CFD, FSI simulations showed significantly lower percentage errors in ascending and descending aorta in flow displacement (-46% ascending, -41% descending), jet angle (-28% ascending, -50% descending) and maximum velocity (-37% ascending, -34% descending) with respect to 4D flow MRI. FSI- but not CFD-derived SSR differentiated between stable and dilating MFS patients. Fluid dynamic simulations of the thoracic aorta require fluid-solid interaction to properly reproduce complex haemodynamics. FSI- but not CFD-derived SSR could help stratifying MFS patients.

Decreased rotational flow and circumferential wall shear stress as early markers of descending aorta dilation in Marfan syndrome: a 4D flow CMR study.

BACKGROUND: Diseases of the descending aorta have emerged as a clinical issue in Marfan syndrome following improvements in proximal aorta surgical treatment and the consequent increase in life expectancy. Although a role for hemodynamic alterations in the etiology of descending aorta disease in Marfan patients has been suggested, whether flow characteristics may be useful as early markers remains to be determined. METHODS: Seventy-five Marfan patients and 48 healthy subjects were prospectively enrolled. In- and through-plane vortexes were computed by 4D flow cardiovascular magnetic resonance (CMR) in the thoracic aorta through the quantification of in-plane rotational flow and systolic flow reversal ratio, respectively. Regional pulse wave velocity and axial and circumferential wall shear stress maps were also computed. RESULTS: In-plane rotational flow and circumferential wall shear stress were reduced in Marfan patients in the distal ascending aorta and in proximal descending aorta, even in the 20 patients free of aortic dilation. Multivariate analysis showed reduced in-plane rotational flow to be independently related to descending aorta pulse wave velocity. Conversely, systolic flow reversal ratio and axial wall shear stress were altered in unselected Marfan patients but not in the subgroup without dilation. In multivariate regression analysis proximal descending aorta axial (p = 0.014) and circumferential (p = 0.034) wall shear stress were independently related to local diameter. CONCLUSIONS: Reduced rotational flow is present in the aorta of Marfan patients even in the absence of dilation, is related to aortic stiffness and drives abnormal circumferential wall shear stress. Axial and circumferential wall shear stress are independently related to proximal descending aorta dilation beyond clinical factors. In-plane rotational flow and circumferential wall shear stress may be considered as an early marker of descending aorta dilation in Marfan patients.

Association between Marfan syndrome and oral health status: A systematic review and meta-analysis.

BACKGROUND: The purpose was to identify and assess the existing scientific evidence from epidemiologic, non-experimental, observational studies of associations between Marfan's syndrome and oral diseases. MATERIAL AND METHODS: Electronic literature searches in MEDLINE (OVID), The Cochrane Library, Scopus and the Web of Science were conducted to identify all relevant articles. Eligibility was based on inclusion criteria, and quality assessments were conducted. The outcome variables were probing depth, gingival margin, clinical attachment level, bleeding on probing, gingival status, periodontal status, tooth mobility, furcation involvement and decayed, missing and filled teeth index. After extracting data, meta-analyses were carried out. RESULTS: Out of 527 potentially eligible papers, 3 cross-sectional studies were included. No statistically significant differences were found in the number of sites with bleeding on probing (OR: 1.26; 95% CI: 0.47 to 3.42; P = 0.65; I2: 0%), probing depth (MD: -0.14 mm; 95% CI: -0.24 to 0.53; P = 0.46; I2: 93%), periodontal status (WMD: 0.68 points; 95% CI: -0.48 to 1.83; P = 0.25; I2: 98%) nor number of decayed, missing and filled teeth index score (MD: 1.08 points.; 95% CI: -1.27 to 3.42; P = 0.37; I2: 0%). CONCLUSIONS: Patients diagnosed with Marfan's syndrome do not seem to have worsened oral health status. Due to the high number of patients with Marfan's syndrome that have prosthetic heart valves, an adequate dental monitoring as well as a strict maintenance therapy program should be implemented.