Cardiovascular magnetic resonance imaging for bicuspid aortic valve syndrome: the time is now

Cardiac Magnetic Resonance for Structural Aortic Valve Stenosis Procedures

The number of structural aortic valve procedures has increased significantly in recent years. Pre-procedural planning and follow-up with noninvasive testing are essential. Although cardiac magnetic resonance (CMR) is the gold standard for assessing left ventricular mass, volume, and function, it is not performed routinely in patients undergoing structural interventions. CMR can provide useful information for pre- and post-procedural assessment, including quantification of cardiac function, myocardial assessment, grading of the severity of valvular heart disease, and evaluation of extracardiac anatomy while avoiding the limitations of other non-invasive modalities. Here, we review the use cases, future perspectives, and limitations of CMR for patients undergoing structural aortic valve procedures.

Aortopathy and aortic valve surgery in patients with bicuspid aortic valve with and without raphe

AIM

To evaluate the association between raphe in bicuspid aortic valve (BAV) patients and valve dysfunction, aortopathy and aortic valve surgery in the REBECCA registry [REgistro della valvola aortica Bicuspide della Società Italiana di ECocardiografia e CArdiovascular Imaging (SIECVI)].

METHODS

Prevalence of aortic valve dysfunction and aortopathy was investigated in BAV patients with and without raphe. Aortic valve dysfunction (regurgitation or stenosis) was categorized as mild, moderate and severe. Aortopathy was defined as annulus ≥14 mm/m2; root ≥20 mm/m2; sinotubular junction ≥16 mm/m2; ascending aorta ≥17 mm/m2, and classified in Type A, isolated ascending aorta dilatation; Type B, aortic root and ascending aorta dilatation; and Type C, isolated aortic root dilatation.

RESULTS

Overall, 695 patients with BAV were enrolled; 520 (74.8%) with raphe and 175 (25.2%) without raphe. BAV patients with raphe presented more frequently with moderate or severe aortic stenosis than BAV patients without raphe (183 [35.2%] vs 34 [19.4%], p < 0.001). A higher prevalence of aortopathy, particularly Type B, was observed in patients with vs without raphe. At multivariable analysis, raphe was a predictor of aortic valve surgery at three-year follow-up (odds ratio 2.19, 95% confidence interval 1.08-4.44, p < 0.001).

CONCLUSIONS

Patients with BAV and raphe have a higher prevalence of significant aortic stenosis, aortopathy, especially Type B, and a higher risk of undergoing aortic valve surgery at three-year follow-up.

Misclassification of bicuspid aortic valves is common and varies by imaging modality and patient characteristics

BACKGROUND

Bicuspid aortic valve (BAV) is the most prevalent adult congenital heart defect. BAV causes lifelong progressive disease that can be prevented by early diagnosis and long-term surveillance, but may be compromised by misclassification of valve morphology.

METHODS

The study population was derived from the UTHealth Bicuspid Aortic Valve Registry, which includes serial images on more than 200 participants over a mean follow-up interval of 2.8 years. We abstracted descriptions of aortic valve morphology from transthoracic or transesophageal echocardiography, computed tomography angiography, and magnetic resonance angiography reports. We used chi-square and t tests to determine associations between reported valve morphologies (definitely bicuspid, possibly bicuspid, tricuspid, or uncertain) and clinical characteristics and assessed image quality using a validated tool.

RESULTS

About 40% of participants were misclassified in at least one imaging report. The mean interval between misclassification and correct diagnosis was 22 months. TEE, MR and CT were more sensitive than TTE and successfully reclassified 20% of participants, but were only used in 14% of patients. Misclassification was associated with age, the extent of valve calcification and image quality, but was not significantly associated with aortic regurgitation, gender, or cusp configuration.

CONCLUSION

Misclassification of BAV is prevalent, frequently leads to delayed diagnosis, and is more likely to occur in the most severely affected cases. TEE, CT and MR may increase diagnostic accuracy in up to half of BAV cases but are underutilized. Additional studies are needed to determine if misclassification of BAV patients leads to increased long-term morbidity and mortality.

MR Imaging of Thoracic Aortic Disease

A number of congenital defects and acquired disease processes affect the thoracic aorta, and traditionally, computed tomography (CT) has been the mainstay of imaging, especially in evaluation of the acute aorta. However, recent advances in magnetic resonance (MR) imaging such as electrocardiographically (ECG) triggered breath-hold sequences and ultrafast 3-dimensional MR angiography (MRA) are bringing MR imaging to the forefront of imaging of the thoracic aorta. By providing high-resolution morphological imaging and sophisticated vascular flow analysis for functional data, this modality can provide a comprehensive, reproducible evaluation of the thoracic aorta. In this review, we discuss the role of MR imaging in the evaluation of thoracic aorta pathology along with pertinent examples of aortic abnormalities.