Mycotic Left Ventricular False Aneurysm at the Site of an Apical Vent Presenting 24 Years After Aortic Valve Surgery
A 48-year-old man presented with progressive exertional dyspnea, lethargy, and intermittent fever. He had undergone resection of subvalvular aortic stenosis at 12 years of age and subsequent resection of residual subaortic stenosis at 24 years of age when an apical vent had been placed in the left ventricle (LV) and closed with a pledgeted suture. The patient had recovered well after both operations and led an active life. Catheter coronary angiography and ventriculography 4 years before his current presentation showed no significant coronary arterial or LV pathology, except for a pullback gradient of 19 mm HG across the LV outflow tract. Echocardiography subsequently showed progression of mild to moderate subaortic stenosis, mild aortic valve stenosis, and moderate regurgitation.
On clinical examination, there was visible pulsation of the left chest and a large pulsatile mass palpable subcostally. The patient was anemic (hemoglobin, 7.5 g/dL). Methicillin-sensitive Staphylococcus aureus was cultured from blood samples, and antibiotics were given accordingly. A chest x-ray showed a large opacity apparently continuous with the apical region of the LV (Figure 1). An ECG showed T-wave inversion in leads V3 through V6 (Figure 2). A transthoracic echocardiogram showed a large multiloculated, heteroechogenic structure inferior to the apex with smooth-walled hypoechogenic areas showing spontaneous echo contrast (Figure 3A and Movie I). Color Doppler flow mapping showed flow in the hypoechogenic areas, with evidence of communication with the LV apex (Figure 3B and Movie II). The aortic valve appeared thickened and, by then, severely regurgitant. Cardiovascular magnetic resonance (CMR) showed a large, rounded mass (Figure 4A and 4B) measuring 11×8×9 cm. Cine imaging showed evidence of jet flow into and out of the loculated cavities of a false aneurysm in the upper half of the mass (Figure 4C and 4D). Below these, the mass showed intermediate signal intensity with a region of brighter signal on T2-weighted turbo spin-echo imaging (Figure 4B) suggestive of abscess formation. The mass extended down to and displaced the left hemidiaphragm. The anterior and lateral borders extended to the chest wall. The CMR study also showed a trileaflet aortic valve with mild subaortic stenosis and central aortic regurgitation, with a regurgitant fraction of 40% by phase-contrast velocity mapping.
The patient agreed to undergo cardiac surgery. Because of possibility of perforating the false aneurysm, the approach was first to expose the aorta and right atrium and establish bypass through a limited reopening of the previous median sternotomy. Closer inspection of the aortic valve showed a thickened and deformed right coronary cusp with suspected vegetation. The apex of the LV was then exposed and detached from the false aneurysm. Beyond it, a large abscess cavity was found, extending through the pericardial cavity into the pleural cavity above the diaphragm. The pus drained contained 2 large Teflon pledgets. The aortic valve was then replaced with a 21-mm Perimount pericardial valve, and the fibrous subaortic stenosis was resected. The resected aortic valve cusps had no obvious vegetations or perforations and no microscopic evidence of inflammation to suggest endocarditis. Histopathological analysis of tissue recovered from the drain site after surgery showed neutrophils and necrotic debris consistent with abscess formation (Figure 5). The patient recovered well, and his clinical status remains stable. Subsequent outpatient transthoracic echocardiography showed the replacement aortic valve to be well seated and no evidence of recurrent LV aneurysm or mass.
Although LV apical venting is common at open heart surgery and subsequent aneurysms have been reported,1–3 we have not found any previous report of late presentation with abscess formation. Because Teflon pledgets were found in the pus in this case, it is possible that they predisposed to the infection. The role of CMR in the presurgical and postsurgical evaluation of suspected ventricular true or false aneurysms is well recognized.4,5 In this case, the CMR identified the abscess and the false aneurysm, providing guidance for a cautious surgical approach.
The online Data Supplement is available with this article at http://circ.ahajournals.org/cgi/content/full/118/13/e501/DC1.