Case Report:
A 29-year-old male with a past medical history of intravenous drug abuse
and hepatitis C was transferred from an outside hospital for evaluation
of fever, heart murmur, and concerns for infective endocarditis. On
arrival, the patient had mild chest pain and dyspnea. Blood cultures
were positive for Serratia marcescens. Transthoracic echocardiogram
(TTE) revealed large vegetations on the aortic valve with severe aortic
regurgitation. His hospital course was complicated by acute
encephalopathy and an acute left middle cerebral artery territory
embolic stroke. The patient completed a 6-week course of antibiotics and
underwent an uncomplicated aortic valve replacement with a 23 mm Magna
Ease bioprosthetic valve. TTE prior to discharge showed a normal
functioning prosthetic valve, with normal left ventricular size and
function. Although initially symptom free, the patient began
experiencing attacks of transient dizziness two weeks before a scheduled
3-month follow-up visit. A two-dimensional transthoracic echocardiogram
was obtained demonstrating severe aneurysmal change within the aortic
root (Figure 1). Ejection fraction was 55% and showed no evidence of
aortic regurgitation. Peak instantaneous pressure gradient across the
prosthetic valve was 7 mmHg with a mean pressure gradient of 4 mmHg. A
cardiac CT was performed using a Somatom Force Scanner (Siemens,
Erlangen, Germany). Images were reconstructed from the end diastolic
phase using a soft vascular kernel and a model based iterative algorithm
utilizing a small field of view and interpolative techniques to achieve
a fine spatial resolution. Image post processed was performed with an
advanced image postprocessing server (Aquarius Intuition, Terarecon,
Foster City, CA).
The cardiac CT revealed complete dehiscence of the surgical valve from
the LVOT, with a gap of 2 cm, and a massive circumferential
pseudoaneurysm. A ribbonlike remnant of the membranous interventricular
septum was all that tethered the aortic root to the heart. The coronary
arteries were stretched but not compressed by the pseudoaneurysm.
Fortuitously, there was no communication with the right ventricle or
atrium. The bioprosthetic aortic valve leaflets, surprisingly, appeared
normal. (Figure 2) Volume rendering with blood pool inversion technique
allowed for delineation of the pseudoaneurysm’s boundaries and its
relation to the aortic prosthetic valve, atria, ventricles, and
pulmonary veins. (Figure 3 and Cine.1)
While initially reluctant, the patient opted for surgical reintervention
during a one month follow up visit after a repeat TTE revealed a new
anterior wall motion abnormality assumed to be due to effacement of the
lumen of the left main coronary artery. Repeat surgery required
extensive debridement and replacement of the Magna Ease pericardial
prosthesis with a Medtronic Freestyle porcine root. Following the
surgery, the anterior wall motion abnormality resolved, and the patient
was transported to the intensive care unit in stable condition.