P1447 Ascending aorta longitudinal strain in bicuspid aortic valve patients: a comparison with healthy volunteers and patients with degenerative aortic aneurysm

Funding Acknowledgements

Spanish Ministry of Economy and Competitiveness RTC-2016-5152-1, ISCIII PI17/00381, La Marató de TV3 (20151330), Eur FP7/People 267128 and CIBERCV

Background

Histological findings of fibrillin-1 deficiency in bicuspid aortic valve (BAV) ascending aorta (AAo), as observed in Marfan (MFS), supported the existence of intrinsic aortic wall abnormalities, but recent studies reported the absence of an intrinsic impairment in stiffness. A recent study in MFS showed that AAo longitudinal strain was reduced in MFS and predicted dilation and aortic events. This parameter has not been studied in BAV.

Purpose

We investigated whether ascending aorta longitudinal strain is intrinsically altered in BAV with respect to tricuspid aortic valve (TAV) individuals.

Methods

80 BAV, 31 healthy volunteers (HV) and 29 TAV with AAo aneurysm, all without moderate valvular disease, were consecutively included. AAo dilation was defined as a z-score > 2. The 1.5T CMR protocol included a set of 2D cine CMR stacks covering the proximal aorta in saggital, coronal and axial views. AAo longitudinal strain was computed by an in-house Matlab code performing a feature tracking of the aortic valve in each of the cine images.

Results

Twenty (25%) of BAV had AAo dilation. AAo longitudinal strain was lower in non-dilated BAV compared to HV, but the difference was not significant in multivariate analysis adjusted for AAo diameter and systolic blood pressure. Similarly, the difference between dilated BAV and dilated TAV found in univariate analysis was not confirmed by multivariate analysis. On the other hand, both dilated BAV and TAV showed decreased AAo longitudinal strain compared to HV, which were confirmed in multivariate analyses.

Conclusions

AAo longitudinal strain, a marker of aortic stiffness with predictive value in MFS, is not altered in BAV patients compared to TAV matched for dilation prevalence. Reduced AAo longitudinal strain was independently associated with dilation in both BAV and TAV.

Table 1 HV vs. NON-DILATED BAV DILATED BAV vs DILATED TAV HV vs. DILATED BAV HV vs. DILATED TAV HV NON-DILATED BAV Univariate /multivariate p-value DILATED TAV DILATED BAV Univariate /multivariate p-value Univariate/ Multivariate p-value Univariate p-value N 31 20 29 60 Age [years 35 ± 8 49 ± 16 <0.001/ NS 66 ± 13 49 ± 14 <0.001 / <0.001 <0.001 / 0.052 <0.001 / NS Sex [% male] 42 35 0.629 24 42 0.097 / NS 0.969 0.149 BSA [m2] 1.83 ± 0.17 1.81 ± 0.14 0.702 1.95 ± 0.24 1.82 ± 0.22 0.015 / <0.001 0.881 0.030 / NS SBP [mmHg] 119 ± 11 132 ± 16 0.002 / 0.029 133 ± 17 138 ± 19 0.304 <0.001 / NS <0.001 / NS DBP [mmHg] 69 ± 11 73 ± 6 0.099 / NS 77 ± 9 79 ± 11 0.455 <0.001 / 0.016 0.004 / 0.023 Ascending aorta diameter [mm] 26 ± 4 33 ± 3 <0.001 / 0.006 46 ± 7 43 ± 6 0.032 / NS <0.001 / 0.001 <0.001 /0.007 AAo long strain [%] 10.5 ± 3.6 8.4 ± 4.1 0.067/ NS 5.9 ± 2.7 7.7 ± 3.6 0.023 / NS 0.001 / 0.002 <0.001 / 0.023 Demographics and uni- and multivariate analyses of AAo longitudinal strain

P4131Abnormal flow pattern in the main pulmonary artery of Marfan patients is related to local dilation

Introduction

Marfan syndrome (MFS) is a hereditary connective tissue disorder caused by mutation in the FBN1 gene. Main pulmonary artery (MPA) dilation is very prevalent in MFS patients. Indeed, the old Ghent nosology considered main pulmonary artery (MPA) dilation as diagnostic criterion of MFS patients. Although clinical complications related to pulmonary dilation in MFS are rare, this may potentially lead to MPA dissection or be a marker of vascular disease in MFS. Studies regarding potential causes of MPA dilation in MFS patients are very scarce.

Purpose

Through 4D flow CMR, we aimed to assess whether flow abnormalities exist in the MPA of MFS patients and their relation to local diameter.

Methods

Fifty-five consecutive Marfan syndrome adults (MFS) and 22 healthy volunteers (HV) were prospectively enrolled. All subjects underwent non-contrast-enhanced 4D flow-MRI, obtaining 4D flow field and a 3D angiography. The MPA was segmented from the 3D angiography, and the segmentation was used to mask 4D velocity data. Four, equidistant analysis planes were placed in the MPA between the pulmonary valve and the pulmonary artery bifurcation. Common descriptors of large arteries hemodynamics were computed at each plane: maximum velocity, systolic flow reversal ratio (a descriptor of the amount of systolic backward flow) and circumferentially-averaged axial and circumferential wall shear stress (WSS). Pulmonary artery diameters were measured on axial images. MPA dilation was defined as a diameter larger than 27 mm in women and 29 mm in men. Systolic (SBP) and diastolic (DBP) systemic blood pressure were measured at the brachial artery with a calibrated cuff immediately after the scan.

Results

Compared with HV, MFS patients presented similar age, BSA, SBP and maximum blood velocity, but had larger MPA diameter (27.8 vs 25.1 mm, p<0.001) and higher DBP (75.5 vs 66.8 mmHg, p=0.003). According to the used threshold, 45% (27) of MFS patients had MPA dilation. Compared with HV, Marfan patients presented an increased systolic flow reversal ratio in the proximal part of the MPA (Figure 1). In MFS patients axial WSS was reduced in central sections of the MPA, while the circumferential component was not difference with respect to HV. All these flow abnormalities were also present in the subset of 28 MFS patients without pulmonary artery dilation. In multivariable analysis, MPA diameter was independently related to age (B=0.056; p=0.032), sex (B=−2.3; p=0.02) and axial (B=6.4; p=0.039) and circumferential (B=33.9; p<0.001) WSS.

Figure 1

Conclusions

Dilation of the main pulmonary artery is prevalent in Marfan syndrome patients. Abnormal increase in systolic vortexes and reduction in axial WSS were present in dilated and non-dilated MPA in MFS patients. Axial and circumferential WSS were independently related to MPA diameter. The eventual predictive role of abnormal pulmonary flow pattern in pulmonary artery dilation in MFS patients remain to be established

Acknowledgement/Funding

Instituto de Salud Carlos III (PI14/0106), La Maratό de TV3 (20151330), CIBERCV and FP7/People (267128)

The mitogenome of a 35,000-year-old Homo sapiens from Europe supports a Palaeolithic back-migration to Africa

After the dispersal of modern humans (Homo sapiens) Out of Africa, hominins with a similar morphology to that of present-day humans initiated the gradual demographic expansion into Eurasia. The mitogenome (33-fold coverage) of the Peştera Muierii 1 individual (PM1) from Romania (35 ky cal BP) we present in this article corresponds fully to Homo sapiens, whilst exhibiting a mosaic of morphological features related to both modern humans and Neandertals. We have identified the PM1 mitogenome as a basal haplogroup U6*, not previously found in any ancient or present-day humans. The derived U6 haplotypes are predominantly found in present-day North-Western African populations. Concomitantly, those found in Europe have been attributed to recent gene-flow from North Africa. The presence of the basal haplogroup U6* in South East Europe (Romania) at 35 ky BP confirms a Eurasian origin of the U6 mitochondrial lineage. Consequently, we propose that the PM1 lineage is an offshoot to South East Europe that can be traced to the Early Upper Paleolithic back migration from Western Asia to North Africa, during which the U6 lineage diversified, until the emergence of the present-day U6 African lineages.

Temporal mitochondrial DNA variation in the Basque Country: influence of post-neolithic events

The Basque population has been considered an outlier in a large number of genetic studies, due to its hypothesized antiquity and greater genetic isolation. The present paper deals with an analysis of the mtDNA variability of the historical population of Aldaieta (VI-VII c. AD; Basque Country) which, together with genetic data existing for other prehistoric populations of the Basque Country (4,500-5,000 YBP), permits an appraisal of the hypotheses proposed for the origin of the genetic differentiation of the Basque population. Given that this is an aDNA study, application has been made both of standard precautions, to avoid contamination, and of authentication criteria (analysis of duplicates, replication in an independent laboratory, quantification of target DNA, sequencing and cloning of PCR products). The variability of the mtDNA haplogroups of the historical population of Aldaieta falls within the range of the present-day populations of Europe's Atlantic fringe, whereas the prehistoric populations of the Basque Country display clear differentiation in relation to all others. Consequently, we suggest that between 5,000-1,500 YBP approximately, there may have been gene flow amongst the western European populations that homogenised mtDNA lineages.

An mtDNA analysis in ancient Basque populations: implications for haplogroup V as a marker for a major paleolithic expansion from southwestern europe

mtDNA sequence variation was studied in 121 dental samples from four Basque prehistoric sites, by high-resolution RFLP analysis. The results of this study are corroborated by (1) parallel analysis of 92 bone samples, (2) the use of controls during extraction and amplification, and (3) typing by both positive and negative restriction of the linked sites that characterize each haplogroup. The absence of haplogroup V in the prehistoric samples analyzed conflicts with the hypothesis proposed by Torroni et al., in which haplogroup V is considered as an mtDNA marker for a major Paleolithic population expansion from southwestern Europe, occurring approximately 10,000-15,000 years before the present (YBP). Our samples from the Basque Country provide a valuable tool for checking the previous hypothesis, which is based on genetic data from present-day populations. In light of the available data, the most realistic scenario to explain the origin and distribution of haplogroup V suggests that the mutation defining that haplogroup (4577 NlaIII) appeared at a time when the effective population size was small enough to allow genetic drift to act-and that such drift is responsible for the heterogeneity observed in Basques, with regard to the frequency of haplogroup V (0%-20%). This is compatible with the attributed date for the origin of that mutation (10,000-15, 000 YBP), because during the postglacial period (the Mesolithic, approximately 11,000 YBP) there was a major demographic change in the Basque Country, which minimized the effect of genetic drift. This interpretation does not rely on migratory movements to explain the distribution of haplogroup V in present-day Indo-European populations.

Data on six short-tandem repeat polymorphisms in an autochthonous Basque population

Population data studies for six short-tandem repeat loci (HUMCSF1P0, HUMTPOX, HUMTH01, HUMHPRTB, HUMFES/FPS, and HUMvWF) were carried out on a sample of 326 autochthonous Basques. Comparing with other European samples, we found the highest frequencies known so far for allele 11 of the HUMCSF1P0 locus (0.380), allele 10 of the HUMFES/FPS locus (0.384), and allele 17 of the HUMvWF locus (0.329). On the other hand, we found the lowest frequencies recorded in Europe for allele 12 of the HUMCSF1P0 locus (0.291), allele 7 of the HUMTH01 locus (0.128), and allele 11 of the HUMFES/FPS system (0.317). These results support the hypothesis that the Basque population is a remnant of early European settlers.