SCMR 22nd Annual Scientific Sessions
Description of Clinical Presentation:
A 14-year old male with history of a systolic murmur is found to have aortic stenosis and a severely dilated ascending aorta on transthoracic echocardiogram. It was difficult to decipher if his aortic valve was bicuspid or unicuspid, thus CMR was performed to further evaluate his aortic valve and ascending aorta. He engaged in light jogging and light body weight exercises (push-ups and sit-ups) without any cardiac symptoms. He denied a family history of congenital heart disease. His physical exam was notable for a soft systolic ejection click followed by a 4/6 crescendo-decrescendo systolic murmur throughout the precordium with a thrill on palpation, and a soft 1/6 decrescendo diastolic murmur at the right sternal boarder. A CMR with MRA of the aorta was performed which showed a dilated aorta at the tubular portion measuring up to 46 mm, unicuspid aortic valve with moderate aortic stenosis (AS), and mild aortic regurgitation (AR).
Diagnostic Techniques and Their Most Important Findings:
CMR was performed on a Siemens 1.5 T scanner. Steady state free precession (SSFP) cine images (2A, 2B) of the short axis view of aortic valve during systole and diastole respectively demonstrated a thickened unicuspid valve. Gradient-echo cine image (2F) of the left ventricular outflow tract view demonstrated aortic stenosis along with an ascending aorta aneurysm. Magnitude image (2C) and phase image (2G) of the aortic valve were obtained to quantify peak velocity (3 m/s), peak gradient (36 mm Hg) and regurgitant fraction (15%) consistent with moderate AS and mild AR. Magnetic resonance angiography (MRA) was obtained (2D) which demonstrated an ascending aortic aneurysm at the tubular portion measuring 46 mm in diameter. 4 chamber SSFP cine (2E) shows normal LV cavity size and wall thickness with calculated EF 65%.
Learning Points from this Case:
A unicuspid aortic valve results from the absence of two out of the three commissures. The prevalence is only around 0.02% in adult population. Aortic stenosis is the most predominant associated hemodynamic lesion which on average requires surgical treatment during the third decade of life. About 1/2 also have a coexisting ascending aorta aneurysm. Current ACC/AHA statement for competitive athletes states that patients with moderate AS can participate in low and moderate static or low and moderate dynamic competitive sports however those with a bicuspid aortic valve and markedly dilated aorta (>45 mm) should not participate in any competitive sports due to concern for aortic dissection. Unicuspid aortic valves are too rare to have specific guideline recommendations. This case illustrates the importance of CMR as an adjunct to echocardiography for evaluating valvular morphology and hemodynamics as well as aortopathy.