Poster No. 122 Predicting the rate of progressive dilation by wall shear stress in bicuspidaortic valve patients

Background

Despite the high prevalence of ascending aorta (AAo) dilation in bicuspid aortic valve (BAV) patients there is limited evidence of dilation aetiology. Several cross-sectional studies pointed to a role for wall shear stress (WSS), but this hypothesis has not been tested. Recently, a technique for 3D-maps of aortic growth from two contrast-enhanced computed tomography angiograms (CTA) was presented and validated. We aim to test if local WSS predicts local dilation rates in BAV patients.

Materials and methods

Forty BAV patients free from aortic valve disease and previous relevant interventions underwent a baseline 4D flow CMR followed by two CTA. WSS, and its axial and circumferential components, and growth rate (GR) were computed at 64 standardized regions in the ascending aortic (AAo). A two-tailed p-value < 0.05 was considered statistically significant.

Results and conclusions

Patients were relatively young (51 ± 13 yeas) and follow-up duration was 44.8 ± 2.6 months. Growth rate was heterogeneous in the AAo, with fastest progression located in the outer mid AAo region and in the inner region of the proximal-mid AAo. WSS magnitude and WSS axial component were maximum in the right region of the mid AAo while circumferential WSS was highest in the outer region of the mid AAo, the region experiencing fastest growth. Significant associations between GR and circumferential WSS were located in the regions with fastest progressive dilation, while WSS magnitude and its axial component resulted in limited predictive capacity. In conclusion, circumferential WSS is related to fast progressive dilation in BAV patients.

Funding

PI17/00381,SEC/FEC-INV-CLI20/015,LCF/BQ/PR22/11920008,RTC2019-007280-1.

Mapping of thoracic aorta growth rate on serial self-navigated 3D whole-heart magnetic resonance angiographies by image registration

Introduction

Accurate and reproducible assessment of aortic diameters and their growth rate is of key importance for the management of patients with thoracic aortic aneurysms [1,2]. It has been recently shown that image registration permits the assessment of progressive aortic dilation on ECG-gated contrast-enhanced CT angiography, outperforming manual quantification and allowing for 3D aortic size and growth mapping [3]. However, exposure to radiation makes it convenient to limit the use of CT for serial follow-up, especially in young patients. Self-navigated 3D whole-heart CMR acquisitions provides excellent image quality overcoming these limitations [4].

Purpose

To evaluate the accuracy and reproducibility of registration-based assessment of aortic dilation using self-navigated 3D whole-heart CMR acquisitions.

Methods

Fifteen patients with two self-navigated 3D whole-heart CMR images obtained at least 1 year apart were included. Aortic root and thoracic aorta diameters were measured by 2 independent observers both manually (multiplanar reconstruction) and with the registration-based technique. To perform registration-based assessment, the aorta was semi-automatically segmented and typical anatomical landmarks were placed by each observer at baseline [3]. Geometrical mapping between baseline and follow-up acquisitions was obtained using deformable image registration, and applied to the baseline aortic surface points to obtain their location at follow-up. Finally, aortic diameters and their growth rate were automatically measured and used to calculated 3D aortic dilation maps. Agreement between techniques and their inter-observer reproducibility were calculated.

Results

Patients age was 27.2±14.5 years and 40% were male. Mean follow-up duration was 2.7±1.6 years. Compared to manual assessment, the registration-based technique presented low bias and excellent agreement for aortic diameters (Table 1), and low bias and moderate agreement for growth rates both in the aortic root and the thoracic aorta (Table, Fig. 1A). The techniques presented similar inter-observer reproducibility in the assessment of aortic diameters (Table 1), while the registration-based method demonstrated much higher inter-observer reproducibility in the assessment of growth rates in the aortic root and the thoracic aorta (Table 1, Fig. 1A and B). Three-dimensional mapping of thoracic aortic diameters and growth was highly reproducible (mean regional ICC=0.90 for diameters; 0.82 for growth rate).

Conclusion

The assessment of the dilation rate of the thoracic aorta via registration of serial self-navigated 3D whole-heart CMR acquisitions is accurate and reproducible in the aortic root and the thoracic aorta. Thus, it allows to assess local aortic growth without the drawbacks of CT.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III and Ministerio de Ciencia e Innovaciόn (Spain)

Circumferential wall shear stress predicts co-localized progressive dilation in bicuspid aortic valve patients

Background

Bicuspid aortic valve (BAV), a congenital heart defect, is associated with ascending aorta (AAo) dilation. Whether the high prevalence of dilation in BAV patients is related to alteration of aortic blood flow and thus in wall shear stress (WSS) [1,2], which have been associated with aortic wall degeneration [3], or intrinsic abnormalities of the aortic wall, such as altered aortic stiffness [4], has not been established. Recently, a technique for the semi-automatic quantification of progressive aortic dilation maps via image registration has been introduced [5].

Purpose

To test whether ascending aorta WSS predicts co-localized progressive dilation in BAV patients.

Methods

Forty BAV patients free from moderate and severe aortic valve regurgitation (regurgitant fraction <16%) and stenosis (maximum velocity at the aortic valve <3m/s), with no previous aortic or aortic valve surgery or replacement and included in a double-blind clinical trial (BICATOR, NCT02679261) were enrolled. All patients underwent a baseline 4D flow CMR study to assess aortic hemodynamics, followed by two contrast-enhanced computed tomography angiographies to quantify progressive dilation. WSS was computed at 64 pre-specified standardized ascending aortic regions, automatically obtained dividing the ascending aorta into 8 equidistant longitudinal sections which were further divided along the circumference into 8 equal regions (I = inner, L = left, O = outer and R = right) [2]. WSS was also projected into axial and circumferential directions, as previously described [1,2]. Progressive dilation was assessed in terms of growth rate (GR), i.e. increase in diameter divided by follow-up duration [mm/year], following a previously described methodology [5], at the same 64 pre-specified ascending aortic locations. A two-tailed p-value <0.05 was considered statistically significant.

Results

Demographic and clinical characteristics of the patients are shown in Table 1. WSS and growth rate maps are shown in Figure 1. Follow-up duration was 44.8±2.6 months. Growth rate (Figure 1A) was heterogeneously distributed, being highest (up to 0.26 mm/year) in the outer region of the mid AAo and in the inner region of the proximal-mid AAo. Circumferential WSS showed highest values in the outer region of the mid AAo (Figure 1C) while WSS (magnitude) and its axial component (Figure 1B and D) presented maximum values in the right region of the mid AAo. Maps of statistically significant association between GR and WSS values showed circumferential WSS to be correlated with GR in regions where progressive dilation was fastest, while WSS magnitude and its axial component resulted in limited associations with GR maps.

Conclusions

Circumferential wall shear stress predicts location-matched progressive dilation in bicuspid aortic valve patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study has received funding from the Instituto de Salud Carlos III (PI17/00381). Guala A. has received funding from Spanish Ministry of Science, Innovation and Universities (IJC2018-037349-I). Table 1. DemographicsFigure 1. GR and WSS maps and correlations

Do morphological, haemodynamic and biomechanical parameters relate to aortic growth rate in chronic type B aortic dissection? A 4D flow CMR study

Background

Aortic dissection (AD) is the most devastating complication of thoracic aortic disease (1). In the chronic phase, yearly clinical and imaging follow-up of the maximum aortic diameter is recommended, since indication for thoracic endovascular aortic repair or surgery is suggested by guidelines in case of thoracic aortic enlargement or false lumen (FL) aneurysms (2). Most of the reported parameters related adverse events in chronic AD are focused on morphological variables (3) and not on the haemodynamics and biomechanics of the FL.

Purpose

To evaluate the relationship between aortic growth rate and anatomical variables, flow patterns and aortic stiffness in patients with chronic type B AD.

Methods

Forty-one patients with chronic type B aortic dissection, no connective tissue disorders and with an imaging follow-up including two computed tomography angiograms (CTA) acquired at least 3 years apart underwent contrast-enhanced 4D-flow CMR and MR angiography (MRA). The FL volume was segmented from MRA, and velocity data inside the 3D volume of the FL was extracted from 4D-flow CMR and used for parameter quantification. Retrograde systolic and diastolic flow, wall shear stress (WSS) and in-plane rotational flow (IRF) were calculated at 8 equidistant planes in the distal descending aorta (DAo), from the pulmonary bifurcation to the diaphragmatic level, and averaged values were used [4]. Aortic stiffness in the FL was assessed in terms of pulse wave velocity (PWV), which was calculated from the third supraortic trunk to the diaphragmatic level on 4D-flow CMR [5]. The percentage of thrombus in the FL was calculated as the ratio of thrombus and FL volumes on MRA. Dominant entry tear area was quantified on the baseline CTA (Figure 1). Aortic growth rate (GR) was defined as the difference between final and baseline aortic diameters as measured on CTA divided by follow-up duration.

Results

Anatomical, haemodynamic and biomechanical parameters are shown in Table. Twenty-five patients have repaired type A AD with residual entry tear and 16 have type B AD. Mean follow-up duration was of 4.9±2.7 years. In bivariate analysis, WSS, IRF and PWV were positively related to GR, whereas dominant entry tear area and percentage of thrombus in the FL showed a positive tendency with GR (Table) (Figure). In multivariate analysis IRF, PWV, dominant entry tear area and thrombus in the FL were positively and independently associated with GR (Table). Retrograde systolic and diastolic flow were not related to GR while WSS tended to statistical significance.

Conclusions

In-plane rotational flow, regional aortic stiffness, dominant entry tear area and percentage of thrombus in the false lumen are positively and independently related to aortic growth rate in patients with chronic type B aortic dissection. Further prospective studies are needed to confirm if the assessment of these parameters may help to identify patients at higher risk of adverse clinical events.

Funding Acknowledgement

Type of funding sources: None. Table 1Figure 1

Accurate and reproducible aortic growth rate mapping via registration of serial contrast-enhanced computed tomography angiograms

Introduction

Accurate assessment of aortic diameters and growth rates is key for clinical management of patients with aortic aneurysms [1]. Manual assessment on multiplanar reformatted views of computed tomography angiograms (CTA) is recommended [1], although its reproducibility in the assessment of growth rates has not been reported [2]. Image registration has been proposed to provide 3D maps of aortic diameters and growth [3], but its accuracy and reproducibility have not been established.

Purpose

To quantify accuracy and inter-observer reproducibility of aortic root and thoracic aorta diameters and growth rate by registration of serial CTAs compared to current standard.

Methods

Forty non-operated patients with ≥2 contrast-enhanced ECG-gated CTA acquired at least 6 months apart were included. Aortic diameters and growth rates were measured in the aortic root and thoracic aorta by two independent observers, both with the current standard and with the registration-based technique. To perform registration-based assessment, each observer semi-automatically segmented the aorta at baseline and located typical anatomical landmarks (Fig. 1A). Then, deformable image registration was used to map baseline and follow-up CT scans and deformation was applied to the baseline aortic surface points to obtain their location at follow-up (Fig. 1B). Finally, aortic root diameters and growth rate and 3D maps of thoracic aortic diameters and growth rate were automatically obtained (Fig. 1C). Agreement between techniques and their inter-observer reproducibility were calculated.

Results

Follow-up duration was 3.3±1.5 years (range 0.52–6.2). Compared with manual assessment, registration-based aortic diameters presented low bias and excellent agreement in the aortic root (0.42 mm, ICC=0.99) and the thoracic aorta (0.55 mm, ICC=0.99), and similar inter-observer reproducibility (ICC=0.99 for both). Compared with manual assessment, registration-based growth rates presented low bias and good agreement in the aortic root (0.12 mm/y, ICC=0.84) and the thoracic aorta (0.03 mm/y, ICC=0.77) (Fig. 2A), and much higher inter-observer reproducibility (ICC=0.96 vs 0.68 in the aortic root, ICC=0.96 vs 0.80 in the thoracic aorta) (Fig. 2B and C). Registration-based aortic growth rates reproducibility at 6 months follow-up was comparable to that obtained by manual assessment at 2.7 years (LoA = [−0.01, 0.33] and LoA = [−0.13, 0.21], respectively). Aortic diameters and growth rate 3D maps were highly reproducible (ICC>0.9) in the whole thoracic aorta.

Conclusions

Progressive aortic dilation assessment via registration of CTAs is accurate and more reproducible than the current standard even over follow-ups as short as 6 months, and further provides robust 3D mapping of aortic diameters and growth rates. Its application may provide new insights in aneurysms pathophysiology and improve the clinical management of these patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study has received funding from the Instituto de Salud Carlos III (PI17/00381). Guala A. has received funding from Spanish Ministry of Science, Innovation and Universities (IJC2018-037349-I). Figure 1. Methodology.Figure 2. Growth rate comparison.

Bicuspid aortic valve fusion length correlates with maximum aortic diameter and heamodynamic abnormalities: a 4D flow CMR study

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Guala A. received funding from the Spanish Ministry of Science, Innovation and Universities.

Background

Bicuspid aortic valve (BAV), a congenital heart defect, is associated with ascending aorta dilation, possibly via alteration of aortic blood flow [1]. In BAV abnormal flow condition have been associated with aortic extracellular matrix dysregulation and elastic fiber degeneration [2]. Current morphological classification of BAV patients with aortic valve with a single fusion between two adjacent leaflets does not allow for risk stratification.

Purpose

This research work tested whether the extent of fusion between leaflets is related to AAo diameter and flow alterations.

Methods

Ninety BAV patients free from moderate and severe aortic valve disease and with no previous aortic or aortic valve surgery or replacement were prospectively enrolled. A comprehensive magnetic resonance protocol comprised a stack of double-oblique 2D balanced steady-state free-precession (bSSFP) cine CMR of the aortic valve, which was used to measure the length of the fusion between leaflets, a cine CMR at the level of the pulmonary bifurcation to assess aortic diameter and 4D flow MRI sequence to assess flow characteristics and regional stiffness [3]. Jet angle and flow radial displacement, quantifying the extent of flow eccentricity, and systolic flow reversal ratio (SFRR), assessing the relative amount of backward flow during systole, were computed at 8 equidistant planes in the ascending aorta and 4 equidistant planes in the aortic arch [4]. A two-tailed p-value < 0.05 was considered statistically significant.

Results

The length of leaflet fusion varied widely (median 7.7 mm, inter-quartile range [5.5; 10.2]), Table 1). In bivariate analysis, fusion length was also associated to ascending aortic diameter (R = 0.391, p < 0.001), age (R = 0.313, p = 0.005) and body surface area (R = 0.396, p < 0.001). It was also positively related to flow abnormalities: like displacement in the proximal and distal ascending aorta, jet angle in the mid ascending aorta, and SFRR in the ascending aorta and the aortic arch (see Figure 1). The association between fusion length and ascending aorta diameter persisted in multivariate analysis after correction for age (p = 0.006).

Conclusions

Bicuspid aortic valve fusion extent varies greatly and it is associated with aortic diameter, possibly through flow alterations. Prospective longitudinal studies are needed to establish whether fusion length may allow for risk stratification in bicuspid aortic valve patients.

Aortic rotational flow patterns and stiffness by 4D flow CMR in patients with Loeys-Dietz syndrome compared to healthy volunteers and patients with Marfan syndrome

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): La Marató de TV3, Instituto de Salud Carlos III through the project and Spanish Ministry of Science, Innovation and Universities.

BACKGROUND

Loeys-Dietz (LDS) and Marfan (MFS) syndromes are rare genetic connective tissue disorders associated with progressive aortic dilation, however, aortic dissections have been observed at lower aortic root diameters in LDS than in MFS. Recent CMR studies in MFS patients reported increased aortic stiffness (1–3) and altered rotational flow (4), but research on aortic flow dynamics and biomechanics in LDS is lacking.

PURPOSE

The aim of this study was to assess rotational aortic flow and aortic stiffness in LDS compared to healthy volunteers (HV) and MFS patients, using 4Dflow CMR.

METHODS

Twenty-one LDS and 44 MFS patients, without previous aortic dissection or surgery, and 43 HV underwent a non-contrast-enhanced 4D flow CMR. Aortic stiffness was quantified at the AAo and DAo using pulse wave velocity (PWV). In-plane rotational flow (IRF), systolic flow reversal ratio (SFRR) (5) and local aortic diameters were obtained at 20 equidistant planes from the ascending (AAo) to the proximal descending aorta (DAo).

RESULTS

LDS patients had lower IRF at the distal AAo and proximal DAo compared to HV (p = 0.053 and 0.004, respectively), once adjusted for age, stroke volume and local aortic diameter; but no differences were found with respect to MFS (Figure). Although SFRR at the proximal DAo was increased in LDS patients compared to both HV (p = 0.037) and MFS populations (p = 0.015), once adjusted for age and aortic diameter, the difference in magnitude was small (Figure). On the other hand, AAo and DAo PWV revealed stiffer aortas in LDS patients compared to HV but no differences versus MFS patients (Table).

CONCLUSIONS

Patients with Loeys-Dietz syndrome showed decreased in-plane rotational flow and abnormally-high regional aortic stiffness compared to healthy controls, and similar hemodynamics and aortic stiffness with respect to patients with Marfan syndrome.

Aortic flow dynamics and stiffness in Loeys-Dietz syndrome patients: a comparison with healthy volunteers and Marfan syndrome patients

AIMS

To assess aortic flow and stiffness in patients with Loeys-Dietz syndrome (LDS) by 4D flow and cine cardiovascular magnetic resonance (CMR) and compare the results with those of healthy volunteers (HV) and Marfan syndrome (MFS) patients.

METHODS AND RESULTS

Twenty-one LDS and 44 MFS patients with no previous aortic dissection or surgery and 35 HV underwent non-contrast-enhanced 4D flow CMR. In-plane rotational flow (IRF), systolic flow reversal ratio (SFRR), and aortic diameters were obtained at 20 planes from the ascending (AAo) to the proximal descending aorta (DAo). IRF and SFRR were also quantified for aortic regions (proximal and distal AAo, arch and proximal DAo). Peak-systolic wall shear stress (WSS) maps were also estimated. Aortic stiffness was quantified using pulse wave velocity (PWV) and proximal AAo longitudinal strain. Compared to HV, LDS patients had lower rotational flow at the distal AAo (P = 0.002), arch (P = 0.002), and proximal DAo (P < 0.001) even after adjustment for age, stroke volume, and local diameter. LDS patients had higher SFRR in the proximal DAo compared to both HV (P = 0.024) and MFS patients (P = 0.015), even after adjustment for age and local diameter. Axial and circumferential WSS in LDS patients were lower than in HV. AAo circumferential WSS was lower in LDS compared to MFS patients. AAo and DAo PWV and proximal AAo longitudinal strain revealed stiffer aortas in LDS patients compared to HV (P = 0.007, 0.005, and 0.029, respectively) but no differences vs. MFS patients.

CONCLUSION

Greater aortic stiffness as well as impaired IRF and WSS were present in LDS patients compared to HV. Conversely, similar aortic stiffness and overlapping aortic flow features were found in Loeys-Dietz and Marfan patients.

Aortic root longitudinal strain by speckle-tracking echocardiography predicts progressive aortic root dilation in Marfan syndrome patients

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Science, Innovation and Universities; Instituto de Salud Carlos III

Introduction

In Marfan syndrome (MFS) patients reduced longitudinal strain of the ascending aorta (AAo) as measured by applying feature-tracking on cine cardiac magnetic resonance (CMR) images predicts aortic root dilation and aortic events during the follow-up. Speckle-tracking is well established for cardiac deformation assessment but proximal aorta applications are challenging due to limited wall thickness and substantial cardiac motion. Moreover, echocardiography is widely used in the clinical assessment aortic diseases.

Purpose

We aimed to test a speckle-tracking tool for root longitudinal strain analysis in terms of comparison with CMR-derived AAo longitudinal strain and reproducibility and as predictor of dilation in MFS patients.

Methods

Thirty-five MFS patients diagnosed by original GHENT criteria, with maximum aortic root diameter of 45 mm and free from previous aortic dissection or cardiac/aortic surgery and non-severe aortic regurgitation were consecutive enrolled and followed-up. CMR and echocardiography were performed less than 2 months apart. Baseline and final aortic root diameter were measured on CMR images. To quantify aortic root cyclic elongation by echocardiography, two regions of interests were manually created covering both walls in a parasternal long-axis view and tracked along the cardiac cycle (Figure 1). Longitudinal strain was computed as the average of maximum increase in relative distance of several sub-regions covering both walls. CMR-derived AAo longitudinal strain was available in 29 patients. Intra-observer reproducibility was tested in 15 patients via intraclass correlation coefficient (ICC) for single-rater absolute agreement.

Results

Aortic root longitudinal strain by echocardiography was mildly related to CMR-derived AAo longitudinal strain (R = 0.27) and was larger compared to CMR-derived values (16.2 ± 6.0 vs 11.3 ± 4.3). Reproducibility was high, with ICC of 0.811, R = 0.802, p &lt; 0.001. After a mean follow up of 76 ± 13 months, aortic root diameter grew in 20 patients with a rate of 0.29± 0.24 mm/year. Overall mean growth-rate was 0.87 ± 0.33 mm/year. In multivariable analysis corrected for age and baseline aortic root diameter, baseline longitudinal strain by echocardiography was independently and inversely related to progressive dilation (p = 0.033).

Conclusions

The measurement of aortic root longitudinal strain by speckle-tracking echocardiography is feasible. Aortic root longitudinal strain is an independent predictor of progressive dilation in MFS patients. This may permit the improvement of risk-stratification in aortic diseases in large scale studies.

Abstract Figure 1

Leaflets fusion length in bicuspid aortic valve is related to ascending and aortic root dilation and ascending aorta wall shear stress

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Spanish Ministry of Science, Innovation and Universities, Instituto de Salud Carlos III

Background

Bicuspid aortic valve (BAV) is the most common congenital heart defect, consisting in the fusion of two aortic valve leaflets. Altered flow patterns have been related to aortic wall degeneration in BAV patients and may be responsible for the high prevalence of aortic disease in these patients. A number of studies on excised BAV or using advanced imaging modalities reported a wide variability of fusion extent between leaflet, but no previous study assessed whether leaflet fusion length may be used to stratify BAV patients.

Purpose

We aimed to test whether leaflet fusion extent can be quantified by cardiac magnetic resonance imaging (CMR) and whether it is related to aortic dilation and flow abnormalities in non-dysfunctional BAV.

Methods

One hundred and twenty BAV adults with no previous aortic or aortic valve surgery or significant valvular disease were consecutively enrolled. Patients with two sinuses of Valsalva (true BAV) or fusion of the left and non-coronary cusps, both being rare forms of BAV, were excluded. Twenty-eight healthy volunteers were also included for comparison. A 4D flow CMR sequence was acquired and circumferential wall shear stress and pulse wave velocity were assessed in the ascending aorta. A stack of double-oblique cine images of the aortic valve were used to quantify the length of the fusion between leaflets.

Results

The length of the fusion between leaflets was effectively measured in 112/120 patients (93%). Reproducibility was good (ICC = 0.826). Fusion length varied greatly (range 2.3 – 15.4 mm, 7.8 ± 3.2 mm, tertiles cut-off points were 6 and 9.3 mm). After correction for age, BSA, stroke volume and BAV fusion morphotype, fusion length was independently associated with diameter at the sinus of Valsalva (p = 0.002). Moreover, once corrected for age, stroke volume and ascending aorta pulse wave velocity, fusion length was positively related to ascending aorta diameter (p = 0.028). The comparison of maps of circumferential peak-systolic WSS in healthy volunteers (left) and BAV patients pertaining to the three leaflet fusion length tertiles is shown in Figure 1. Circumferential WSS progressively increase with larger fusion length. This trend was statistically significant (p &lt; 0.05) in the right and outer regions of the proximal and mid ascending aorta.

Conclusions

Bicuspid aortic leaflet fusion length varies considerably and it is independently associated with ascending aorta and aortic root dilation, possibly through flow alterations.

Abstract Figure 1

Regional curvature in thoracic aortic aneurysms of different aetiologies and its relationship with established risk factors

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Science, Innovation and Universities ; Instituto de Salud Carlos III

Introduction

The aorta is a 3D hollow, curvilinear elastic structure whose diseases have life-threatening consequences. Despite much effort has been paid to study aortic diameter, diameter is a poor predictor of events. Conversely, much less is known about aortic curvature, its distribution in the thoracic aorta and the potential impact of risk factors in aneurysms associated with different conditions. Currently, 4D flow magnetic resonance imaging (4D flow CMR) allows to obtain 3D geometry, 4D flow data and regional aortic stiffness.

Purpose

We aim to study regional aortic curvature in thoracic aorta aneurysms of different aetiologies and define its relationship with established risk factors.

Methods

One-hundred twenty patients (40 for each group, selected out of prospective cohorts of 156 bicuspid aortic valve – BAV-, 77 Marfan –MFS- and 67 patients with a degenerative aneurysm – TAVdeg-) were matched for age, sex and BSA via propensity score with 40 healthy volunteers (HV). The thoracic aorta was semi-automatically segmented from angiograms and the centreline was computed. Local curvature was assessed at 20 planes covering the thoracic aorta from the sinotubular junction to the proximal descending aorta (DAo) at the level of the pulmonary artery bifurcation. Local curvature was normalized by subject mean thoracic aorta curvature. Length was measured as centreline length. Aortic stiffness was measured in the DAo by pulse wave velocity (PWV). Aneurysm was defined by z-score ≥ 2 using diameters measured by double-oblique cine CMR.

Results

Matching was successful in all groups with the exception of a residual age difference between HV and TAVdeg. Curvature in HV showed a fairly smooth transition between the straighter ascending aorta (AAo) and DAo to a more curved aortic arch, with a peak in the mid aortic arch (Figure 1A).  Conversely, all patients’ groups presented a peak in curvature in the proximal DAo and a decreased local curvature in the aortic arch and mid DAo close to the level of the pulmonary artery. BAV and TAVdeg patients showed also increased curvature in the mid AAo, were dilation is prevalent. Conversely, in the same area MFS showed a reduced curvature and limited prevalence of aneurysm. In the overall population, age, AAo and root diameters, mean blood pressure, DAo PWV and aortic length, all established risk factors for aortic events, were inversely related to curvature in the distal AAo and aortic arch (Figure 1B).

Conclusions

Aneurysms related to different aetiologies show similar abnormalities in aortic curvature, with limited curvature in the aortic arch and a peak soon after the third supra-aortic vessel. Age, aortic diameter, length, stiffness and blood pressure, all known risk factors, are all related to reduced curvature in the distal ascending aorta and aortic arch.

Abstract Figure.

Semi-automatic quantification of aortic root progressive dilation by automatic co-registration of computed tomography angiograms: a preliminary comparison with manual assessment in Marfan patients

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Spanish Ministry of Science, Innovation and Universities Instituto de Salud Carlos III

Background. Dilation of the aortic root is a key feature of Marfan syndrome and it is related to the occurrence of aortic events and death. On top of maximum diameter, rapid annual growth rate is suggested by guidelines for indication of aortic root replacement. Current gold-standard for aortic root diameter assessment is manual quantification on multiplanar reformatted 3D computed tomography (CT) or magnetic resonance angiogram. However, inter- and intra-observer reproducibility are limited and different measurement methods, i.e. cusp-to-cusp and cusp-to-commissure, may be used in different clinical centres, leading to difficulties in the clinical assessment of progressive dilation.

Purpose. We aimed to test whether aortic root growth rate during follow-up can be reliably quantified by semi-automatic co-registration of two CT angiograms.

Methods. Seven Marfan syndrome patients, free from previous aortic surgery, with a total of 11 pairs of CT were identified. Manual assessment of six aortic root diameters (right-non coronary -RN- , right-left -RL- and left-non coronary -LN- cusp-to-cusp and R, L and N cusp-to-commissure) was obtained from all CTs by an experienced researcher blind to semi-automatic results. The thoracic aorta and the outflow tract were semi-automatically segmented in the baseline CT and commissure and cusps were manually located. A 10 mm-thick region of interest containing the aortic wall was automatically generated from segmentation boundary. Co-registration was obtained with three, fully-automatic steps. Firstly, baseline and follow-up CT scans were aligned by means of a rigid registration. Then, scans were co-registered with multi-resolution affine followed by b-spline non-rigid registrations based on mutual information metric. The transformation pertaining to the location of baseline commissure and cusps points was used to locate the same points in the follow-up scan (Fig. 1 top).

Results. Follow-up duration was 35 ± 22 (range 12-70.3) months. Automatic quantification of diameter growth during the follow-up was obtained in 62 out of 66 (94%) diameter comparisons. High Pearson correlation coefficients (R) and ICC were found between manual and semi-automatic assessment of growth rate, both for cusp-to-cusp and cusp-to-commissure diameters: R = 0.727 and ICC = 0.678 for RN; R = 0.822 and ICC = 0.602 for RL; R = 0.648 and ICC = 0.668 for LN; R = 0.726 and ICC = 0.711 for R; R = 0.911 and ICC = 0.895 for L and R = 0.553 and ICC = 0.482 for N. Scatter and Bland-Altman plots for all growth rates (Fig. 1) confirmed very good correlation (R = 0.810) but a slight tendency (R=-0.270) for underestimation at high growth rate.  No correlation was found between follow-up duration and difference between techniques (R = 0.06).

Conclusions. Semi-automatic quantification of aortic root growth rate by co-registration of pairs of CT angiograms is feasible for follow-up as short as one year. Larger studies are needed to confirm these preliminary data.

Abstract Figure. CT measurements. Automatic vs manual.

Relationship between aortic distensibility and aortic regurgitation depending on aortic valve anatomy. A CMR study

Background

Aortic regurgitation (AR) can be evaluated by cardiac magnetic resonance (CMR).The most commonly used method to quantify AR is direct measurement using phase contrast (PC) imaging, at the aortic root (as close as possible to the aortic valve), for the calculation of regurgitant fraction (RF). Aortic distensibility (AD) may affect aortic valve dynamics and, as a result, aortic regurgitation grade. However, the impact of aortic distensibility in this evaluation remains unknown.

Purpose

The aim of the study was to evaluate the relationship between AD and AR in patients with different aortic valve anatomy.

Methods

213 patients with different AR severity grades and aortic valve anatomy (tricuspid (TAV) and bicuspid valve (BAV) patients) were enrolled (32.2% female, 74% BAV, 55.5±15.4 years), excluding connective tissue disease. All patients underwent a CMR study with PC sequences for the evaluation of regurgitant fraction at the aortic valve level. AR was considered as mild (&lt;15%), moderate (15–30%) or severe (&gt;30%) depending on RF value. Furthermore we used cine-sequences to estimate aortic diameters and distensibilities, using Art Fun software. Distensibility was calculated as (change in aortic area between systole and diastole/diastolic area)/brachial pulse pressure.

Results

159 (73.7%) AR were mild, 30 (14.1%) moderate and 24 (11.3%) severe. RF significantly correlated with aortic root diameter (r=0.337, p&lt;0.001) and did not correlate with AD at the level of proximal descending aorta (r=0.121 and p=0.107). Furthermore descendig aorta distensibility correlated with age (r=−0.631, p&lt;0.001) and aortic root diameter (r=−0.224, p=0.002). Dividing population in two different groups, depending on aortic valve anatomy, in TAV patients RF continued to not correlate with AD (r=0.159, p=0.369). In contrast, RF in BAV patients was positively correlated with AD (r=0.223, p=0.007) even after adjustment for aortic diameter and age in a multiple regression model (p&lt;0.001, R2=0.478).

Conclusions

In our study, aortic regurgitation is positively related to descending aorta distensibility in BAV patients, regardless of age and aortic root diameter. Thus, AD may play a role in the evaluation of AR in case of bicuspid valves. In contrast, in TAV patients, distensibility does not seem to influence the assessment of AR severity.

Descending aorta distensibility

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Research grant provided by the Cardiopath PhD program

Aortic stiffness and hemodynamics in Loeys-Dietz syndrome by 4Dflow CMR: a comparison with healthy volunteers and patients with Marfan syndrome

Background

Connective tissue disorders, such as Loeys-Dietz (LDS) and Marfan (MFS) syndromes, are rare genetic diseases associated with progressive aortic dilation. Aortic dissections have been observed at lower aortic root diameters in LDS than in MFS, and research on aortic flow dynamics and biomechanics in LDS is lacking.

Purpose

To evaluate rotational aortic flow and aortic stiffness in LDS compared to healthy volunteers (HV) and MFS patients, using 4Dflow CMR.

Methods

Twenty-one LDS and 44 MFS patients, without previous aortic dissection or surgery, and 44 HV underwent a non-contrast-enhanced 4D flow CMR. In-plane rotational flow (IRF), systolic flow reversal ratio (SFRR) and local aortic diameters were obtained at 20 equidistant planes from the ascending (AAo) to the proximal descending aorta (DAo). Aortic stiffness was quantified at the AAo and DAo using pulse wave velocity (PWV).

Results

LDS patients had lower IRF at the distal AAo and proximal DAo compared to HV (p=0.053 and 0.004, respectively), once adjusted for age, stroke volume and local aortic diameter; but no differences were found with respect to MFS (Figure). Although SFRR at the proximal DAo was increased in LDS patients compared to both HV (p=0.037) and MFS populations (p=0.015), once adjusted for age and aortic diameter, the difference in magnitude was small (Figure). On the other hand, AAo and DAo PWV revealed stiffer aortas in LDS patients compared to HV but no differences versus MFS patients (Table).

Conclusions

LDS patients showed decreased in-plane rotational flow and abnormally-high regional aortic stiffness compared to healthy controls, and similar hemodynamics and aortic stiffness with respect to MFS patients

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Instituto de Salud Carlos III, La Maratό TV3

The role of descending aorta diastolic reverse flow in the quantification of aortic regurgitation by CMR

Background

EACVI recommends the use of an “integrative approach”, using several parameters, in aortic regurgitation (AR) quantification. This approach is easily achieved by echocardiography although cardiovascular magnetic resonance (CMR) remains the gold standard for the quantification of regurgitant fraction (RF).

Purpose

The aim of the study was to analyze the accuracy of descending aorta (DA) diastolic reverse flow in the assessment of chronic AR severity by CMR to identify an additional parameter.

Methods

188 patients (34% female, 54.6±15.6 years) with different severity grades of chronic AR were enrolled. All patients underwent a CMR study. Aortic regurgitation was considered as absent (≤1%), mild (≤15%), moderate (≤15%) or severe (≥30%) depending on RF value at valve level. Furthermore, cine-sequences were used to estimate aortic diameters and distensibilities using Art Fun software. Velocity-time integral (VTI) of reverse flow in DA was calculated from maximum velocity curves by an in-house MatLab code.

Results

AR was absent in 21 (12%) patients, mild in 114 (62.9%), moderate in 23 (12.7%) and severe in 21 (11.6%).DA VTI reverse flow was significantly higher as was the RF at valve level (r=0.805, p&lt;0.001) (IMG, Table). It also positively correlated withaortic root diameter (r=0.347, p&lt;0.001) and DA distensibility (r=0.279, p&lt;0.001). It did not correlate with age (r=−0.91, p=0.22). In a statistically significant multiple regression model (p&lt;0.001, R2 = 0.697), although VTI reverse flow in DA correlated strongly with RF at valve level (p&lt;0.001; beta = 0.733), it was also influenced by DA distensibility (p&lt;0.001; beta = 0.197) and aortic root diameter (p&lt;0.001; beta= 0.140).

Conclusions

VTI reverse flow in DA correlates strongly with the degree of AR and may be useful in the assessment of its severity. Neverthless, owing to the influence of other factors (aortic distensibility and aortic root diameter), it cannot be used as a single parameter in the quantification of AR severity by CMR.

Scatter Plot graphs

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): research grant provided by the Cardiopath PhD program

Screening of Embolic Sources by Point-of-Care Ultrasound in the Acute Phase of Ischemic Stroke

Our objective was to evaluate hand-held echocardiography as point of care ultrasound scanning (POCUS) to detect sources of embolism in the acute phase of stroke. Prospective, unicentric observational cohort study of non-lacunar ischemic stroke patients evaluated by V Scan device. The main sources of embolism (MSEs) were classified into embolic valvulopathies and severe ventricular dysfunction. We looked for atrial fibrillation (AF) predictors in strokes of undetermined etiology. MSEs were detected in 19.23% (25/130). Large vessel occlusion (LVO) (odds ratio [OR]: 4.24, 95% confidence interval [CI]: 1.01-17.85) and chronic heart failure (OR: 13.25, 95% CI: 3.54-49.50) were independent predictors of MSEs. LVO (OR: 6.54, 95% CI: 1.62-26.27) and left atrial area >20 cm² (OR: 7.01, 95% CI: 1.75-28.09) independently predicted AF. Patients with LVO and chronic heart disease may benefit from hand-held echocardiography as part of POCUS in the acute phase of ischemic stroke. Left atrial area measured was an independent predictor of AF in strokes of undetermined etiology.

P372 Aortic stiffness in Loeys-Dietz syndrome: a comparison with Marfan syndrome patients and healthy volunteers

Funding Acknowledgements

ISCIII PI14/0106 and PI17/00381, La Marató de TV3 (20151330), Eur FP7/People 267128 and CIBERCV

BACKGROUND

Genetic syndromic aortic diseases are rare, with Marfan syndrome (MFS) being the most common. However, less is known of Loeys-Dietz syndrome (LDS) which has much lower prevalence and presumed worse prognosis. Increased aortic stiffness in MFS has been previously described but no studies have evaluated aortic biomechanics in LDS. Pulse wave velocity (PWV) is the gold standard measure for arterial stiffness and can be quantified by 4D flow MRI. We aim to evaluate regional aortic PWV by 4D flow MRI in LDS compared to MFS and healthy volunteers.

METHODS

Sixteen LDS patients with a pathogenic mutation, 76 MFS and 49 healthy volunteers were prospectively and consecutively included. No patient had previous aortic dissection or surgery. All underwent a 4D flow MRI study in a 1.5 T clinical scanner. Ascending (AAo) and descending (DAo) aorta PWV were computed using wavelet analysis of the systolic upslope for transit time calculation (Figure). Statistical comparison was made with non-parametric analysis to account for the non-normality of data and multivariate analysis was evaluated separately for AAo and DAo PWV.

RESULTS

Ascending and descending aortic PWV revealed stiffer aortas in LDS patients than in healthy volunteers, even after adjustment for diameter of sinus of Valsalva (SoV) and sex. Conversely, no differences in aortic stiffness were found between LDS and MFS patients (Table).

CONCLUSIONS

Abnormally high regional aortic stiffness was observed in LDS patients when compared with controls. The severity of increased regional aortic stiffness was found similar to the one affecting MFS patients.

Table Controls (N = 49) LDS (N = 16) MFS (N = 76) LDS vs. HV LDS vs. MFN Parameter Unadjusted p-value Adjusted p-value Unadjusted p-value Adjusted p-value Age [years] 39 ± 12 39 ± 16 36 ± 12 0.903 0.599 Men 32 (65%) 6 (37%) 34 (45%) 0.079 0.782 Weight [kg] 72 ± 11 69 ± 13 74 ± 16 0.288 0.194 Height [cm] 172 ± 8 172 ±12 181 ± 11 0.834 0.008 Systolic BP [mmHg] 126 ± 18 125 ± 14 127 ± 17 0.957 0.523 Diastolic BP [mmHg] 70 ± 11 77 ± 6 75 ± 12 0.011 0.318 SoV diameter [mm] 30.6 ± 3.9 35.4 ± 4.6 38.1 ± 5.9 0.001 0.060 AAo diameter [mm] 27.7 ± 3.8 29,0 ± 5.0 29.7 ± 5.4 0.458 0.579 DAo diameter [mm] 20.0 ± 2.0 21.3 ± 3.6 22.9 ± 3.8 0.546 0.124 AAo PWV [m/s] 5.2 ± 1.9 7.6 ± 2.4 7.3 ± 2.8 0.001 0.050* 0.534 NS DAo PWV [m/s] 7.1 ± 2.2 9.4 ± 2.6 10.7 ± 4.6 0.003 0.025** 0.493 NS

Abstract P372 Figure

P1600 Aortic dilatation in patients with chronic descending aorta dissection is related to maximum false-lumen systolic flow deceleration rate as evaluated by 4D-flow MRI

Background

Due to improved surgical strategies a growing number of patients survive acute aortic dissection. Patent false lumen (FL) is common in chronic dissection and it has been associated with poor prognosis, which is mainly driven by FL expansion. Several variables indirectly related to flow characteristics have been associated with progressive aortic dilation. We aimed to evaluate whether the maximum systolic flow deceleration rate (MSDR) in the FL, quantified by 4D-flow MR, is related to FL dilation in chronic type B aortic dissection.

Methods

Twenty-nine patients with a patent FL after aortic dissection and a prior follow-up of at least 3 years underwent contrast-enhanced 4D-flow MR. Marfan patients were excluded. Time-resolved FL flow acceleration was calculated in a 5 cm-long volume of the descending aorta around the level of the pulmonary bifurcation. MSDR was determined as the maximum minus the minimum acceleration in systole over the corresponding time interval (Figure 1a). Aortic growth rate (GR) was measured as the difference between final and initial maximum FL diameters obtained by angio-CT divided by follow-up duration. Population was divided into tertiles based on GR.

Results

Demographic and clinical variables were similar among GR tertiles (Table). MSDR was lower in patients with a GR &lt;1mm/year (group 1) compared to both the other two patient groups (p = 0.009 and 0.003 for groups 2 and 3, respectively) (Figure 1c). MSDR showed a marked positive linear correlation with GR (R = 0.481, p = 0.008) (Figure 1b).

Conclusions

The MSDR in the FL of chronic type B aortic dissection is linearly related to FL growth rate and discriminated between tertiles of aortic dilation. Prospective longitudinal studies are need to unveil possible prognostic value of this parameter.

Table Group 1 (n = 9) Group 2 (n = 10) Group 3 (n = 10) p-value Age (years) 63.44 ±13.54 62.50 ± 13.60 64.56 ± 6.67 0.902 BSA (m2) 2.00 ± 0.18 1.77 ± 0.20 1.94 ± 0.12 0.213 Men 6 (86%) 4 (57%) 4 (100%) 0.210 Hypertension 4 (66%) 5 (71%) 4 (100%) 0.438 Atheroclerosis 1 (17%) 1 (14%) 0 (0%) 0.699 Initial Diameter (mm) 45.00 ± 7.69 36.00 ± 4.20 37.00 ± 6.48 0.078 Final Diameter (mm) 49.50 ± 6.74 44.86 ± 5.70 59.25 ± 9.84 0.049 Follow-up (year) 11.83 ± 8.79 7.82 ± 3.34 8.08 ± 4.05 0.921 GR (mm/year) 0.27 ± 0.29 1.18 ± 0.26 2.64 ± 0.97 &lt;0.001 MSDR (cm/s3) 1212.18 ± 467.61 2410.54 ± 1034.30 2558.16 ± 1098.06 0.005

Abstract P1600 Figure 1

P1601 Relationship between aortic distensibility and aortic regurgitation assessed by CMR in bicuspid valve patients

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

The severity of aortic regurgitation can be evaluated with cardiac magnetic resonance (CMR) through calculation of regurgitant fraction (RF) in phase contrast sequences acquired at the aortic root (as close as possible to the aortic valve). However, the impact of aortic distensibility in this evaluation remains unkown.

PURPOSE

The aim of the study was to evaluate the relation between aortic distensibility and RF valve in bicuspid aortic valve patients.

METHODS

We enrolled bicuspid aortic valve patients without significant aortic stenosis (maximum velocity &lt;2.5 m/s) and connective tissue disease. All patients underwent a CMR study with phase contrast sequences for evaluation of regurgitant fraction at the level of the aortic valve. Aortic regurgitation was considered as mild, moderate or severe depending on RF value (mild &lt;15%; moderate 15-30%; severe &gt;30%). Furthermore we used cine-sequences of aortic root, ascending and proximal descending aorta to estimate aortic diameters and distensibilities, using Art Fun software. Distensibility was calculated as (change in aortic area between systole and diastole/diastolic area)/brachial pulse pressure.

RESULTS

A total of 98 bicuspid aortic valve patients were included (30% female, 49.7 ± 14.5 years). 75 (76,5%) AR was mild, 17 (17,4%) moderate and 6 (6,1%) severe. RF valvewas significantly correlated with aortic root diameter (r= 0.430 y p &lt; 0.001 )and aortic distensibility at the level of the ascending (r = 0.273 p =0.016) and descending aorta (r = 0.502 and p&lt; 0.001). Aortic distensibility was positively correlated with RFvalve even after adjustment for aortic diameter ( p = 0.002 and p &lt;0.001 respectively) . (Table) (IMG)

CONCLUSIONS

In our study, aortic regurgitation in bicuspid valve patients, evaluated by CMR using RF valve, is related to aortic distensibility. Thus, aortic distensibility should be included in the evaluation of aortic regurgitation by CMR as additional parameter. However, longitudinal studies are needed to evaluate the impact of including aortic distensibility in the evaluation of AR severity by CMR.

AR SEVERITY MILD MODERATE SEVERE Descending aorta distensibility(mean ± std. deviation) 2693,68 ± 997,5 3285,8 ±1952,7 5042,99 ±2873,44 Correlation between AR severity (by RFvalve) and descending aorta distensibility

Abstract P1601 Figure.

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 &gt; 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 &lt;0.001/ NS 66 ± 13 49 ± 14 &lt;0.001 / &lt;0.001 &lt;0.001 / 0.052 &lt;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 / &lt;0.001 0.881 0.030 / NS SBP [mmHg] 119 ± 11 132 ± 16 0.002 / 0.029 133 ± 17 138 ± 19 0.304 &lt;0.001 / NS &lt;0.001 / NS DBP [mmHg] 69 ± 11 73 ± 6 0.099 / NS 77 ± 9 79 ± 11 0.455 &lt;0.001 / 0.016 0.004 / 0.023 Ascending aorta diameter [mm] 26 ± 4 33 ± 3 &lt;0.001 / 0.006 46 ± 7 43 ± 6 0.032 / NS &lt;0.001 / 0.001 &lt;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 &lt;0.001 / 0.023 Demographics and uni- and multivariate analyses of AAo longitudinal strain

P1827Maximum systolic flow deceleration rate in the false lumen by 4D-flow MRI is associated with aortic dilatation in patients with chronic descending aorta dissection

Introduction

Patent false lumen (FL) in aortic dissection has been associated with poor prognosis mainly due to aortic expansion. Although morphologic variables have been related to aortic dilatation as expression of high pressure in the FL, they do not reflect flow characteristics. We propose the maximum systolic flow deceleration rate (MSDR) in the FL, quantified by 4Dflow, assuming that flow should be strongly decelerated during systole under high pressure.

Methods

Twenty-nine patients with a patent FL after aortic dissection (no Marfan syndrome) and with a follow-up of at least 3 years underwent a contrast-enhanced 4D-flow MR. FL acceleration was calculated during the cardiac cycle in a sub-volume of the descending aorta (5 cm around the level of the pulmonary bifurcation). MSDR was determined as the maximum minus the minimum acceleration in systole over the corresponding time interval (Figure 1a). Aortic growth rate (GR) was defined as the difference between final and initial aortic diameters obtained by angio-CT over the period of follow-up. Population was divided into tertiles based on GR.

Results

Demographic, clinical variables or basal aortic diameter did not show differences among GR groups (Table 1). MSDR was statistically different in patients with a GR <1mm/year (group 1) compared to fast-dilating patients (groups 2, 3) (Figure 1c). MSDR showed a positive linear correlation with GR resulting in a Pearson's correlation of 0.481 (p=0.008) (Figure 1b).

Table 1. Demographic and other variables Tertile 1 Tertile 2 Tertile 3 p-value Age (year) 63.4 (±13.5) 62.5 (±13.6) 64.6 (±6.7) 0.902 BSA (m2) 2.0 (±0.2) 1.8 (±0.2) 1.9 (±0.1) 0.213 Men 6 (86%) 4 (57%) 4 (100%) 0.210 Hypertension 4 (66%) 5 (71%) 4 (100%) 0.438 Atherosclerosis 1 (17%) 1 (14%) 0 (0%) 0.699 Initial diameter 45.0 (±7.69) 36.0 (±4.2) 37.0 (±6.5) 0.078 Final diameter 49.5 (±6.74) 44.9 (±5.7) 59.2 (±9.8) 0.049* Follow-up (year) 11.8 (±8.79) 7.9 (±3.3) 8.1 (±4.0) 0.921 Aortic GR (mm/year) 0.3 (±0.3) 1.2 (±0.3) 2.6 (±1.0) 0.001* MSDR (cm/s3) 1212 (±468) 2411 (±1034) 2558 (±1098) 0.005* Values are mean (±SD) or n (%).

Conclusion

MSDR of flow in the FL derived from 4D-flow RM is related to GR of dissected descending aorta. It is useful to discriminate mild vs. significant aorta enlargement and identify patients who may benefit from earlier therapy.

P1821Proximal aorta longitudinal but not circumferential strain predicts aortic events and aortic root dilation rate in marfan syndrome patients

Background

The most common cardiovascular complications in Marfan syndrome (MFS) are aortic root dilation and type A aortic dissections. Elective aortic root surgery is indicated when maximum aortic diameter is larger than a defined threshold or in the case of fast-progressing dilation. However, maximum aortic diameter is limited for the prediction of aortic events. Indeed, a large international registry of acute aortic syndromes reported that as much as 40% of aortic dissections happen with maximum aortic diameter lower than 50 mm. Consequently, there is a need for new, non-invasive biomarkers to improve the prediction of aortic complications.

Purpose

The aim of the present study was to assess if proximal aorta circumferential and longitudinal strain and ascending aorta distensibility were associated with progressive aortic dilation and incidence of aortic events in Marfan syndrome patients.

Methods

Eighty seven Marfan syndrome patients free from previous cardiac/aortic surgery or dissection, were prospectively included in a multicenter follow-up. Patients were diagnosed by original Ghent criteria. Proximal aorta longitudinal and circumferential strain and distensibility were computed from baseline cine CMR images by means of feature-tracking. The predictive capacity of each stiffness biomarkers was separately tested with multivariable linear regression analysis (aortic growth) and with Cox logistic regression analysis (aortic events), both corrected for clinical and demographic variables, including baseline maximum aortic diameter.

Results

During a follow-up of 81.6±17 months, mean diameter growth-rate was 0.65±0.67 mm/year and z-score growth rate was 0.07±0.13 / year. Elective aortic root replacement was performed in 11 patients while two patients presented type A aortic dissection.Baseline proximal aorta longitudinal strain was independently related to diameter growth-rate (p=0.001), z-score growth-rate (p=0.018) and aortic events (p=0.018). Conversely, neither circumferential strain nor distensibility were independent predictors of diameter growth-rate (p=0.385 and p=0.381, respectively), z-score growth-rate (p=0.515 and p=0.484, respectively) and aortic events (p=0.064 and p=0.205, respectively).

Conclusions

Proximal aorta longitudinal strain predicts aortic root dilation and major aortic events in Marfan syndrome patients beyond aortic root diameter and clinical and demographic characteristics.

Acknowledgement/Funding

ISCIII PI14/0106, La Maratό de TV3 (20151330) and CIBERCV. Guala A. FP7/People n° 267128

6126Peripheral aneurysms in Marfan patients are common and are related to age and advanced aortic disease

Background

Peripheral aneurysms are not included in the diagnostic criteria for Marfan syndrome (MFS); however, their real prevalence in MFS is unknown. Furthermore, they are commonly seen in other genetic entities such as Loeys-Dietz syndrome.

We aimed to investigate the prevalence of peripheral aneurysm in Marfan syndrome.

Methods

Patients with clinical criteria of Marfan syndrome and identified FBN1 mutation were evaluated. Only patients with either MRI or CT angiography assessing peripheral vessels were included in this study. MRI and CT angiography studies were retrospectively evaluated to detect the presence of peripheral aneurysms. Aortic dissection-related arterial dilations were excluded. Aortic events and those related to aneurysm complications were collected during follow-up.

Results

Two hundred and nine patients with Marfan and FBN1 mutation were evaluated. Of these 136 (65.1%) had undergone either MRA or CTA with peripheral artery study during follow-up. Mean age at the last follow-up visit was 42.4±14.1yrs; 54.4% were men, and mean follow-up 7.3±3.1 years. Sixty-six aneurysms were identified in 42 (30.9%) patients. The most common locations were the iliac arteries in 23. The rest were: renal (7), vertebral (5), splenic (5), coeliac (3), brachiocephalic (1), subclavian (3), carotid (3), axillary (2), internal mammary (3), femoral (2), hypogastric (3), bronchial (2), coronary (1), hepatic (1), lumbar (1), gastroduodenal (1) and popliteal (1). Twenty-six patients (61.9%) had more than one peripheral aneurysm, and only 4 required surgery.

Patients with peripheral aneurysms were older (47.2±14.3yrs vs 40.2±13.6yrs, p=0.06) and more frequently men (69.0% vs 47.9% p=0.026). Although patients with peripheral aneurysms did not more frequently have aortic dissection (16.7% vs 17.0%, p=0.586), they did more frequently have aortic surgery (73.8% vs 47.9% p=0.05).

Conclusions

Peripheral aneurysms are present in one third of Marfan syndrome patients and are related to age and more advanced aortic disease. Systematic use of whole-body vascular assessment in Marfan patients can provide a comprehensive evaluation of the entire arterial system, identifying other sites of vascular involvement at risk of potential complications, and the subgroup of patients with more aggressive vascular disease expression.

Overview of mitral regurgitation in Europe: results from the European Registry of mitral regurgitation (EuMiClip)

Aims

To determine the prevalence of mitral regurgitation (MR) in a large cohort of consecutive patients undergoing clinically indicated echocardiography and to examine the distribution of primary and secondary MR.

Methods and results

All patients undergoing an echocardiographic study in 19 European centres within a 3-month period were prospectively included. MR assessment was performed as recommended by the European Association of Cardiovascular Imaging (EACVI). MR was classified according to mechanism as primary or secondary and aetiologies were reported. A total of 63 463 consecutive echocardiographic studies were reviewed. Any degree of MR was described in 15 501 patients. Concomitant valve disease of at least moderate grade was present in 28.5% of patients, being tricuspid regurgitation the most prevalent. In the subgroup of moderate and severe MR (n = 3309), 55% of patients had primary MR and 30% secondary MR. Both mechanisms were described in 14% of the studies. According to Carpentier's classification, 26.7% of MR were classified as I, 19.9% of MR as II, 22.4% of MR as IIIa, and 31.1% of MR as IIIb.

Conclusion

To date, this is the largest echocardiography-based study to analyse the prevalence and aetiology distribution of MR in Europe. The burden of secondary MR was higher than previously described, representing 30% of patients with significant MR. In our environment, degenerative disease is the most common aetiology of primary MR (60%), whereas ischaemic is the most common aetiology of secondary MR (51%). Up to 70% of patients with severe primary MR may have a Class I indication for surgery. However, the optimal therapeutic approach for secondary MR remains uncertain.

Frequency, Mechanism and Severity of Mitral Regurgitation: Are There any Differences Between Primary and Secondary Mitral Regurgitation?

BACKGROUND AND AIM OF THE STUDY

Although mitral regurgitation (MR) is a well-recognized prognosis factor, its true prevalence is probably underestimated and its etiology and mechanisms have not been sufficiently explored. The study aim was to evaluate the burden of MR, focusing attention on its frequency, severity, etiology, mechanism, and other associated conditions.

METHODS

Between February and June 2015, a total of 39,855 consecutive echocardiographic studies was performed at nine tertiary hospitals, and were prospectively included in the study. MR severity was graded into four groups, ranging from none or trace to severe MR, in accordance with the recommendations of the European Association of Cardiovascular Imaging. Patients with moderate to severe MR were selected for the analysis.

RESULTS

MR was detected in 22.6% of cases. MR severity was mild in 82.5% of patients (n = 7,376), moderate in 11.7% (n = 1,048), and severe in 5.8% (n = 521). Concomitant valvular heart disease was present in 3,544 patients (39.7%), with tricuspid regurgitation the most frequently encountered (21.6%). Among moderate and severe MR, primary MR was more frequent than secondary MR (58.8% versus 23.5%), with degenerative valve disease being the most common cause of primary MR (49.2%). A third group composed of mixed forms of MR was described in 17.8% of cases.

CONCLUSIONS

MR is a common finding on echocardiography, and is frequently associated with other valvular heart disease. Most MRs are of degenerative origin. The primary and secondary forms of MR differ significantly in their clinical presentation with regard to gender, age, and ventricular function. There appears to be a gap for a 'mixed' group, though further studies are needed to confirm this suggestion.