Fever, dyspnea, and a new heart murmur
MITRAL VALVE ANEURYSM IN AORTIC VALVE ENDOCARDITIS
Aortic valve endocarditis often also involves the mitral valve; mitral valve endocarditis is seen in 17% of patients undergoing surgery for aortic valve endocarditis.3 Proposed mechanisms for this association include jet lesions from aortic regurgitation, vegetation prolapse with direct contact between the aortic valve and anterior mitral leaflet (“kissing lesions”), and direct local spread of infection.4–7
One of every five patients with mitral valve involvement in aortic valve endocarditis has a mitral valve aneurysm.3 This is a serious finding, as it can lead to septic embolization. Also, the weakened lining of the mitral valve aneurysm can rupture, resulting in severe mitral regurgitation, acute pulmonary edema, and precipitous cardiopulmonary decompensation.5
,Transesophageal echocardiography is more sensitive than transthoracic echocardiography for detecting mitral valve aneurysm.8 On two-dimensional echocardiography, the lesion appears as a narrow-necked, saccular echolucency with systolic protrusion into the left atrium. Color Doppler imaging often shows turbulent, high-velocity flow.
Differential diagnosis of mitral valve aneurysm
Differential diagnostic considerations include a valvular blood cyst, a congenital cardiac diverticulum, and mitral valve prolapse.
Valvular blood cysts are extremely rare in adults.9 These benign, congenital tumors are most often found on the atrioventricular valves in infants, in whom the reported incidence is between 25% and 100%. In almost all cases, these cysts are believed to regress spontaneously with time.
In almost all reported cases, the cyst involved the valvular apparatus or papillary muscle of the tricuspid, pulmonary, or mitral valve.10 Cysts consist of a benign diverticulum lined with flattened, cobblestone-shaped endothelium and are filled with blood. They can cause heart murmurs in otherwise asymptomatic patients.
On echocardiography, a blood cyst appears as an oval mass (often at the interatrial septum), often with normal cardiac function. In the rare case in which a blood cyst is found incidentally during echocardiography, the hemodynamic impact, if any, should be determined by Doppler techniques.
When benign, a valvular blood cyst can be safely monitored with echocardiographic follow-up.11 Treatment involves surgical resection of the mass in symptomatic patients in whom cardiac function is impaired by the presence of the cyst.
Congenital cardiac diverticuli are extremely rare, most often seen in children, and associated with a midline thoracoabdominal defect. Echocardiography can differentiate a ventricular diverticulum from an aneurysm or a pseudoaneurysm.
A ventricular diverticulum has a fibrous, narrow neck connecting with the ventricle, and a small circular echo-free space that communicates with the ventricle via this narrow neck.2 Doppler imaging shows systolic flow from the diverticulum to the ventricle, and systolic contractility may also be seen during cardiac catheterization. Congenital diverticulum is typically confused with ventricular aneurysm and, to a lesser degree, with mitral valve aneurysm.
Mitral valve prolapse is characterized by interchordal ballooning or hooding of the mitral valve leaflets that occurs when one or both floppy, enlarged leaflets prolapse into the left atrium during systole.
BACK TO OUR PATIENT
The patient underwent open heart surgery, with successful repair of the aortic root, replacement of the aortic valve, and repair of the mitral valve. An abscess was found within the aneurysmal cavity.
