Cardiac magnetic resonance assessed valve morphology and aortic distensibility in severe aortic stenosis
© Steadman and McCann; licensee BioMed Central Ltd. 2012
Published: 1 February 2012
We have shown that cardiac magnetic resonance (CMR) can accurately assess aortic valve morphology in severe aortic stenosis (AS) and this is associated with significant differences in aortic distensibility (AD) despite similar degrees of stenosis severity.
AD is known to be a prognostic marker in other diseases. The effect of valve morphology on AD has not been reported in patients with severe AS without coronary artery disease.
46 patients with severe AS without obstructive coronary artery disease awaiting aortic valve replacement were studied. Transthoracic echocardiography (TTE) was used to assess aortic valve area using the continuity equation, peak aortic velocity and mean valve gradient. CMR was used to assess aortic valve morphology and to enable planimetry of aortic valve area. Two SSFP cines of the aortic valve were taken; one planned from a 3-chamber cine at the level of the aortic annulus in end-diastole and one at the aortic valve tips in end-systole. The smallest planimetered valve area was used for analysis. A high temporal resolution cine of the ascending aorta was taken at the level of the pulmonary artery bifurcation with three blood pressure recordings taken at the same time; the average of the three readings was used for analysis. AD was calculated according to the formula (aortic area max - aortic area min/ aortic area max)*(systolic BP - diastolic BP).
Differences between valve morphologies
Bicuspid raphe present
Bicuspid raphe absent
Number of patients
Aortic valve area CMR (cm sq)
Aortic valve area TTE (cm sq)
Maximum aortic velocity (m/s)
Mean pressure gradient (mmHg)
Aortic distensibility (10-3 mmHg BP-1)
CMR is uniquely placed to assess aortic valve morphology and assess vascular function. We have demonstrated that significant numbers of severely stenosed aortic valves are functionally bicuspid and that these valves are associated with impaired vascular function when compared with trileaflet valves. Valves that are truly bicuspid are associated with further decreased AD. The prognostic implications of such findings warrant further study.
This study was funded by a Project Grant from the British Heart Foundation. Further support was received from the Leicester Cardiovascular Biomedical Research Unit.
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