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.