Ascending aorta dilatation in patients with bicuspid aortic valve stenosis: a prospective CMR study

Comparison of manual and artificial intelligence based quantification of myocardial strain by feature tracking-a cardiovascular MR study in health and disease

OBJECTIVES

The analysis of myocardial deformation using feature tracking in cardiovascular MR allows for the assessment of global and segmental strain values. The aim of this study was to compare strain values derived from artificial intelligence (AI)-based contours with manually derived strain values in healthy volunteers and patients with cardiac pathologies.

MATERIALS AND METHODS

A cohort of 136 subjects (60 healthy volunteers and 76 patients; of those including 46 cases with left ventricular hypertrophy (LVH) of varying etiology and 30 cases with chronic myocardial infarction) was analyzed. Comparisons were based on quantitative strain analysis and on a geometric level by the Dice similarity coefficient (DSC) of the segmentations. Strain quantification was performed in 3 long-axis slices and short-axis (SAX) stack with epi- and endocardial contours in end-diastole. AI contours were checked for plausibility and potential errors in the tracking algorithm.

RESULTS

AI-derived strain values overestimated radial strain (+ 1.8 ± 1.7% (mean difference ± standard deviation); p = 0.03) and underestimated circumferential (- 0.8 ± 0.8%; p = 0.02) and longitudinal strain (- 0.1 ± 0.8%; p = 0.54). Pairwise group comparisons revealed no significant differences for global strain. The DSC showed good agreement for healthy volunteers (85.3 ± 10.3% for SAX) and patients (80.8 ± 9.6% for SAX). In 27 cases (27/76; 35.5%), a tracking error was found, predominantly (24/27; 88.9%) in the LVH group and 22 of those (22/27; 81.5%) at the insertion of the papillary muscle in lateral segments.

CONCLUSIONS

Strain analysis based on AI-segmented images shows good results in healthy volunteers and in most of the patient groups. Hypertrophied ventricles remain a challenge for contouring and feature tracking.

CLINICAL RELEVANCE STATEMENT

AI-based segmentations can help to streamline and standardize strain analysis by feature tracking.

KEY POINTS

• Assessment of strain in cardiovascular magnetic resonance by feature tracking can generate global and segmental strain values. • Commercially available artificial intelligence algorithms provide segmentation for strain analysis comparable to manual segmentation. • Hypertrophied ventricles are challenging in regards of strain analysis by feature tracking.

Aortic Dilatation in Patients With Bicuspid Aortic Valve

Bicuspid aortic valve (BAV) is the most common congenital cardiac abnormality. BAV aortic dilatation is associated with an increased risk of adverse aortic events and represents a potentially lethal disease and hence a considerable medical burden. BAV with aortic dilatation warrants frequent monitoring, and elective surgical intervention is the only effective method to prevent dissection or rupture. The predictive value of the aortic diameter is known to be limited. The aortic diameter is presently still the main reference standard for surgical intervention owing to the lack of a comprehensive understanding of BAV aortopathy progression. This article provides a brief comprehensive review of the current knowledge on BAV aortopathy regarding clinical definitions, epidemiology, natural course, and pathophysiology, as well as hemodynamic and clinically significant aspects on the basis of the limited data available.

Thoracic and abdominal aortic diameters in a general population: MRI-based reference values and association with age and cardiovascular risk factors

OBJECTIVES

To generate reference values for thoracic and abdominal aortic diameters determined by magnetic resonance imaging (MRI) and analyse their association with cardiovascular risk factors in the general population.

METHODS

Data from participants (n = 1759) of the Study of Health in Pomerania were used for analysis in this study. MRI measurement of thoracic and abdominal aortic diameters was performed. Parameters for calculation of reference values according to age and sex analysis were provided. Multivariable linear regression models were used for determination of aortic diameter-related risk factors, including smoking, blood pressure (BP), high-density lipoprotein cholesterol (HDL-C).

RESULTS

For the ascending aorta (β = -0.049, p < 0.001), the aortic arch (β = -0.061, p < 0.001) and the subphrenic aorta (β = -0.018, p = 0.004), the body surface area (BSA)-adjusted diameters were lower in men. Multivariable-adjusted models revealed significant increases in BSA-adjusted diameters with age for all six aortic segments (p < 0.001). Consistent results for all segments were observed for the positive associations of diastolic BP (β = 0.001; 0.004) and HDL (β = 0.035; 0.087) with BSA-adjusted aortic diameters and for an inverse association of systolic BP (β = -0.001).

CONCLUSIONS

Some BSA-adjusted median aortic diameters are smaller in men than in women. All diameters increase with age, diastolic blood pressure and HDL-C and decrease as systolic BP increases.

KEY POINTS

• Median aortic diameter increases with age and diastolic blood pressure. • Median aortic diameter is larger in men than in women. • Some BSA-adjusted median aortic diameters are smaller in men than in women.

Imaging of cardiovascular risk in patients with Turner's syndrome

Turner's syndrome is a disorder defined by an absent or structurally abnormal second X chromosome and affects around 1 in 2000 newborn females. The standardised mortality ratio in Turner's syndrome is around three-times higher than in the general female population, mainly as a result of cardiovascular disorders. Most striking is the early age at which Turner's syndrome patients develop the life-threatening complications of cardiovascular disorders compared to the general population. The cardiovascular risk stratification in Turner's syndrome is challenging and imaging is not systematically used. The aim of this article is to review cardiovascular risks in this group of patients and discuss a systematic imaging approach for early identification of cardiovascular disorders in these patients.

Fused aortic valve without an elliptical-shaped systolic orifice in patients with severe aortic stenosis: cardiac computed tomography is useful for differentiation between bicuspid aortic valve with raphe and tricuspid aortic valve with commissural fusion

OBJECTIVE

The objective is to determine cardiac computed tomography (CCT) features capable of differentiating between bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) in severe aortic stenosis (AS) patients with fused cusp and without elliptical-shaped systolic orifices.

METHODS

We retrospectively enrolled 53 patients who had severe AS with fused cusps and without an elliptical-shaped systolic orifice on CCT and who had undergone surgery. CCT features were analyzed using: 1) aortic valve findings including cusp size, cusp area, opening shape, midline calcification, fusion length, calcium volume score, and calcium grade; 2) diameters of ascending and descending aorta, and main pulmonary artery; and 3) rheumatic mitral valve findings. The variables were evaluated using univariate and multivariate logistic regression analyses.

RESULTS

At surgery, 19 patients had BAV and 34 had TAV. CCT features including uneven cusp size, uneven cusp area, round-shaped systolic orifice, longer cusp fusion, and dilatation of ascending aorta were significantly associated with BAV (P < 0.05). In particular, fusion length (OR, 1.76; P = 0.001), uneven cusp area (OR, 10.46; P = 0.012), and midline calcification (OR, 0.08; P = 0.013) were strongly associated with BAV.

CONCLUSION

CCT provides diagnostic clues that helps differentiate between BAV with raphe and TAV with commissural fusion in patients with severe AS.

KEY POINTS

• Accurate morphologic assessment of the aortic valve is important for treatment planning. • It is difficult to differentiate BAV from TAV with a fused cusp. • CCT provides diagnostic clues for the differentiation of BAV and TAV.

Interactions between inflammatory activation and endothelial dysfunction selectively modulate valve disease progression in patients with bicuspid aortic valve

OBJECTIVES

Bicuspid aortic valve (BAV) is associated with increased risk of valvular degeneration and ascending aortic aneurysm formation and rupture. We sought to evaluate the roles of endothelial dysfunction and inflammatory activation in modulating these processes.

METHODS

We performed a case-control study of patients with BAV together with a multivariate analysis within the BAV group to identify factors associated with: development of significant valvular disease; dilatation of the ascending aorta; differential valve relative to aortic disease. Endothelial function of patients and controls was evaluated via flow-mediated dilatation (FMD) and plasma concentrations of asymmetric dimethylarginine (ADMA). Correlations with inflammatory markers and endothelial progenitor cell counts were also examined. Morphological and physiological assessment of the valve and ascending aorta was performed with transthoracic echocardiography and MRI.

RESULTS

Patients with BAV (n=43) and controls (n=25) were matched for age and gender. FMD was significantly lower in patients than controls (7.85±3.48% vs 11.58±3.98%, p=0.001), and these differences were age-independent. Within the BAV cohort, multivariate correlates of peak aortic valve velocity were plasma concentrations of ADMA and myeloperoxidase (MPO) (both p<0.01), while increasing age was an independent correlate of ascending aortic diameter (p<0.05). Furthermore, both low FMD and inflammatory activation were multivariate correlates of selectivity for valvular disease.

CONCLUSIONS

BAV is associated with endothelial dysfunction. The extent of inflammatory activation (specifically MPO release) and that of endothelial dysfunction impact primarily on integrity of the valve rather than aortic structure.