Aortic flow patterns by 4D flow CMR in Marfan and Loeys-Dietz patients before and after valve sparing aortic root replacement: a comparison with healthy volunteers

Introduction

Abnormal aortic flow patterns in patients with a connective tissue disorder (CTD), such as Marfan or Loeys-Dietz syndrome, may contribute to aortic root dilation [1,2]. Valve sparing aortic root replacement, which is effective in reducing the risk of aortic dissection in case of severe dilation, may also normalize flow patterns beyond the replaced aorta and potentially slow its progressive aortic dilation.

Purpose

To assess aortic flow dynamics in patients with a CTD by 4D flow cardiovascular magnetic resonance (CMR) before and after valve sparing aortic root replacement, and to compare the results with those of healthy volunteers (HV).

Methods

Patients with Marfan or Loeys-Dietz syndrome underwent two non-contrast enhanced 4D flow CMR, one before and another after undergoing valve sparing aortic root replacement. Healthy volunteers matched for age, sex and BSA were also included for comparison. Maximum velocity, in-plane rotational flow (IRF), systolic flow reversal ratio (SFRR) and wall shear stress (WSS) magnitude and its axial and circumferential components were obtained at 24 planes covering the thoracic aorta from the sinotubular junction to the descending aorta at the diaphragmatic level [3–5].

Results

Sixteen patients and 21 healthy volunteers were included. Demographic and clinical data is presented in Table. The mean time between the CMR prior and posterior to surgery was 15 months. Compared to HV, patients with CTD before intervention presented lower maximum velocity at the proximal ascending aorta (Fig. 1A), lower IRF and circumferential WSS at the arch and the proximal descending aorta (Fig. 1B and F), lower magnitude and axial WSS at the proximal ascending and descending aorta (Fig. 1E and D), and increased SFRR at the proximal descending aorta (Fig. 1C). The intervention completely restored maximum velocity and partially-restored physiological helical flow and circumferential WSS, but barely improved axial WSS and SFRR.

Conclusion

Valve sparing aortic root replacement in patients with Marfan or Loeys-Dietz syndrome partially restore to physiological level both in-plane rotational flow and circumferential wall shear stress in the descending aorta. This flow normalization may contribute to prevent progressive dilation after the surgery.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III (Spain) (PI17/00381)Spanish Society of Cardiology (SEC/FEC-INV-CLI 20/015)

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)

Mitral valve prolapse but no mitral annular disjunction is related to mitral regurgitation progression in patients with Marfan syndrome

Funding Acknowledgements

Type of funding sources: None.

Background

Mitral annular disjunction (MAD) is a structural abnormality of the mitral annular fibrosus characterized by a separation between the atrial wall-mitral valve junction, and the left ventricular attachment (1,2). It has been associated with mitral valve prolapse (MVP). Limited data is available regarding the impact of the presence of MVP on the evolution of mitral regurgitation in these syndromic entities.

Purpose

To evaluate the prevalence of MAD, PMV, and the combination of both in patients with syndromic hereditary thoracic aortic disease (HTAD) including Marfan (MFS), Loeys-Dietz (LDS), and vascular Ehlers-Danlos syndromes (vEDS), and its relationship with mitral regurgitation (MR) severity and the need for mitral surgery at the follow-up.

Methods

Adult patients with syndromic HTAD seen at our specialized unit were retrospectively included. The presence of MAD, MVP, and significant MR at the first echocardiogram were evaluated. Electronic medical records were reviewed to register the need for mitral surgery. The last echocardiogram available was also assessed to evaluate MR progression. 

Results

A total of 295 patients were included (235 MFS, 42 LDS, and 18 vEDS). The mean age at baseline was 39.0+-14.4 and 52.9% were female. MAD was present in 87 (37.0%) of MFS, 6 (14.3 %) of LDS and was not present in vEDS (p< 0.001). MVP was found in 105 (44.7%) of MFS, 6 (14.3%) of LDS and 0 in vEDS (p< 0.001).

In MFS, MAD was significantly associated with MVP (p= <0.001) (Table 1). Concretely, 73 (31.1%) of the MFS patients had the concurrence of MAD and MVP and 14 (6.0%) of patients had isolated MAD (Table 2). At baseline, significant MR was observed in 30 (12.8%) of the MFS and in 18 (24.7%) of patients with concurrent MAD and MVP. Interestingly, significant MR was absent in patients with isolated MAD (Figure 1). MVP (OR 16.85 CI 4.43 – 64.07) but not MAD (p = 0.607), was associated with significant MR in the multivariate analysis.

A second echocardiogram was available in 220 patients at > = 1 year (mean 4.1 +- 1.4 years). Overall, 25 (11.4%) presented significant progression of MR, 0 in the isolated MAD group, 13 (19.4%) in the MAD/MVP group and 6 (20.0%) of the isolated MVP (p = 0.007).

After a mean clinical follow-up of 7.5 +- 3.2yrs, 10 patients required mitral surgery (6 prostheses, 4 valvuloplasties).

After adjustment for the presence of MVP and time of follow-up, MAD was not associated with progression of MR (p= 0.529) but MVP was (OR 5.2 IC 1.70 - 15.93). Similarly, MVP (OR 5.6 CI 1.23 - 25.86)  but not MAD  (P= 0.096) was associated with the  need for mitral surgery ., 

Conclusions

The prevalence of MAD in syndromic HTAD is high, especially in Marfan syndrome, and absent in vEDS. In this retrospective observational study, the presence of MVP but not MAD was associated with mitral regurgitation evolution and the need for mitral surgery. Abstract Table 1  Abstract Figure 1

Clinical impact on treatment and prognosis of advanced cardiac imaging with echocardiography in the acute setting of a COVID-19 infection

Background and objectives

Despite myocardial injury being related to excess mortality in acute COVID-19 infection, its impact on imaging findings remains unclear. This study aimed to characterize transthoracic echocardiographic (TTE) findings in patients admitted with COVID-19 infections and its impact on management and prognosis.

Methods

A prospective observational cohort study was performed among 66 COVID-19 patients who were admitted to a tertiary center between March 1 and May 25, 2020 and underwent TTE. High-sensitivity troponin I (hs-cTnI) data, echocardiographic assessment of right and left ventricular (LV) functional parameters, strain, and myocardial work analysis were obtained.

Results

2025 patients were admitted with COVID-19 and in 200 a complete TTE study was performed. Due to poor image quality, only 66 studies were included in the final analysis. The median age was 62 years (IQR, 55–70) and 59.1% of patients were males. The most common comorbidity was hypertension (47%), followed by smoking history (30.3%), atrial fibrillation (9.1%), and chronic obstructive pulmonary disease (7.9%). More than half of the patients (39, 59%) were admitted to the ICU, and half of them (33, 50%) required invasive mechanical ventilation. TTE was mainly indicated because of concerns for systemic conditions (50%) and evaluation of hemodynamic assessment (30%). Thirty-six patients (54.5%) had an abnormal TTE result and 57% had elevated hs-cTnI levels. The most common cardiac abnormality was LV diastolic dysfunction in 33% of the patients, followed by right ventricular dysfunction (12%) and LV dysfunction (6%) (Figure 1). LV GLS was reduced in 48.5% of the cases. Myocardial work performance indices were all reduced in patients with an abnormal TTE (GWI 30%, GCW 30%, GWW 40%, and GWE 40%), although differences were not significant (P>0.2 for all parameters). Patients with an abnormal TTE were older and presented a higher cardiovascular risk profile. There were no significant differences in the levels of D-dimer, NTproBNP, and hs-cTnI between patients with and without diastolic dysfunction, RV, or LV dysfunction (P>0.3 for all parameters). Using Spearman rank correlation, there was an inverse relationship between hs-cTnI and LV strain and myocardial work analysis. TTE results impacted clinical management in 60 patients, mainly de-escalation of medical treatment (Figure 2). Abnormal TTE results did not impact in-hospital outcomes.

Conclusions

Severe echocardiographic abnormalities are uncommon in hospitalized patients with COVID-19 infections, presenting mostly with subclinical myocardial changes, such as diastolic dysfunction, reduced LV GLS, and myocardial work indices, both associated with high-sensitivity troponin I elevation. An echocardiographic study should be limited to rule out long-term ICU complications or to evaluate hemodynamic instability. Although TTE was a valuable tool for guiding management, it had no significant impact on prognosis.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Findings on TTE studies.Figure 2. Changes in management.

Mitral annular disjunction in patients with syndromic hereditary aorthopaties

Background

Mitral annular disjunction (MAD) is a structural abnormality of the mitral annular fibrosus characterized by a separation between the atrial wall-mitral valve junction, and the left ventricular attachment (1). It has been associated with mitral valve prolapse (MVP) (2) but also, with arrhythmias and sudden cardiac death (SCD) (3). There is no evidence of its prevalence and clinical significance in patients with syndromic hereditary aortopathies.

Purpose

To evaluate the prevalence of MAD, PMV, and the combination of both in patients with syndromic hereditary thoracic aortic disease (HTAD) including Marfan (MFS), Loeys-Dietz (LDS) and vascular Ehlers-Danlos syndromes (vEDS), and its relationship with arrhythmias, SCD, mitral regurgitation (MR) severity and the need for mitral surgery at the follow-up.

Methods

Adult patients with syndromic HTAD seen at our specialized unit were retrospectively included. The presence of MAD, MVP, and significant MR at first echocardiogram were evaluated. Electronic medical records were reviewed to register the occurrence of arrhythmic events and the need of mitral surgery. Last echocardiogram available was also assessed to evaluate MR progression.

Results

A total of 295 patients were included (235 MFS, 42 LDS and 18 vEDS). Mean age at baseline was 39.0±14.4 and 52.9% were female. MAD was present in 87 (37.0%) of MFS, 6 (14.3%) of LDS and was not present in vEDS (p<0.001). MVP was found in 105 (44.7%) of MFS, 6 (14.3%) of LDS and 0 in vEDS (p<0.001).

In MFS, the presence of MAD was significantly associated with MVP (p≤0.001) (Table 1). However, 14 (6.0%) of patients had isolated MAD (Table 2). At baseline, significant MR was observed in 18 (24.7%) of patients with concurrent MAD and MVP and was not present in patients with isolated MAD (Table 2). MVP (OR 16.85 IC 4.43 – 64.07) but not MAD (p=0.607), was associated with significant MR in the multivariate analysis.

A second echocardiogram was available in 220 patients at ≥1 year (mean 4.1±1.4 years). Overall, 25 (11.4%) presented significant progression of MR, 0 in the isolated MAD group, 13 (19.4%) in the MAD/MVP group and 6 (20.0%) of the isolated MVP (p=0.007).

After a mean clinical follow-up of 7.5±3.2 years, 10 patients required mitral surgery (6 prosthesis, 4 valvuloplasty), 22 (9.4%) presented atrial fibrillation, flutter or supraventricular tachycardia (SVT), and 2 (0.9%) SCD.

After adjustment for the presence of MVP and time of follow-up, MAD was not associated with progression of MR (p=0.529) need for mitral surgery (p=0.096), atrial fibrillation-flutter or SVT (p=0.510) nor SCD. (p=0.997).

Conclusions

The prevalence of MAD in syndromic HTAD is high, especially in Marfan syndrome, and absent in vEDS. In this retrospective observational study, the presence of MAD in Marfan was not associated with mitral regurgitation evolution or arrhythmic events.

Funding Acknowledgement

Type of funding sources: None. Characteristics of MFS patientsPresence of significant MR by groups.

Routine advanced echocardiography in the evaluation of cardiovascular sequelae of COVID19 survivors with elevated cardiovascular biomarkers

Background

COVID19 has been related to elevated CVB and biventricular dysfunction during hospitalization. However, it is unknown whether patients with biomarker elevation exhibit long-lasting abnormalities in cardiac function.

Purpose

To determine, using advanced echocardiography, the prevalence and type of cardiovascular sequelae after COVID19 infection with marked elevation of cardiovascular biomarkers (CVB), and their prognostic implications.

Methods

All patients admitted from March 1st to May 25th, 2020 to a tertiary referral hospital were included. Patients with cardiovascular disease antecedent, death during admission, or the first 30 days after discharge were excluded. Patients with hs-TnI >45 ng/L, NT-proBNP >300 pg/ml, and D-dimer >8000 ng/ml were separated based on each CVB elevation and matched with COVID controls (three biomarkers within the normal range) based on intensive care requirements and age.

Results

From a total of 2025 hospitalized COVID19 patients, 80 patients with significantly elevated CVB and 29 controls were finally included. No differences in baseline characteristics were observed among groups, but elevated CVB patients were sicker. Follow-up echocardiograms showed no differences among groups regarding LVEF or RV diameters, but TAPSE was lower if hs-TnI or D-dimer were elevated. Hs-TnI patients also had lower global myocardial work and global longitudinal strain. The presence of an abnormal echocardiogram was more frequent in the elevated CVB group compared to controls (23.8 vs 10.3%, P=0.123) but mainly associated with mild abnormalities in deformation parameters. Management did not change in any case and no major cardiovascular events except deep vein thrombosis occurred after a median follow-up of 7 months (Figure 1).

Conclusions

Minimal abnormalities in cardiac structure and function are observed in COVID19 survivors without previous cardiovascular diseases who presented a significant CVB rise at admission, with no impact on patient management or short-term prognosis. These results do not support a routine screening program after discharge in this population.

Funding Acknowledgement

Type of funding sources: None.

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.