Acute Mitral Regurgitation Due to a Torn Porcine Bioprosthetic Cusp
A 46-year-old man presented with a 48-hour history of fevers, sweats, and dyspnea. He had bacterial endocarditis of the native mitral valve 12 years earlier with subsequent mitral valve replacement (MVR) with a Hancock II porcine valve (Medtronic Inc). Examination revealed a Grade 3/6 holosystolic murmur at the apex radiating into the axilla with crackles heard halfway up both lung fields. A diagnosis of infective endocarditis with acute mitral regurgitation (MR) was made and serial blood cultures drawn. Transesophageal echocardiogram (TEE) revealed severe MR (Figure 1). The MR was transvalvular with no perivalvular leak.1–3⇓⇓ A large mobile linear echodense mass (length=2.0 cm) was seen in the left ventricle and this prolapsed across the valve into the left atrium (LA, Figure 2 through 4⇓⇓) along with partial prolapse of one of the leaflets of the valve (Figure 3 and 4⇓). The patient underwent urgent mitral valve replacement where the tissue bioprosthesis was replaced with a 29-mm St Jude Medical bileaflet mechanical valve (St Jude Medical Inc). The left atrium was closed with a patch. Postoperatively, the patient developed complete heart block and required a permanent pacemaker. Blood and tissue cultures were sterile.
The Hancock II porcine bioprosthesis showed degeneration of the porcine aortic valve cusps (Figures 5 through 7⇓⇓) and focal nodular calcification (Figures 5 and 6⇓) close to one commissural region. A second cusp showed a 0.7-cm, verti-cal, commissural region tear, a horizontal tear from commissure to commissure, and a 0.4-cm long vertical tear at the opposite commissural region (Figure 6). This torn strip (2.5-cm long×0.6-cm wide) of cuspal tissue was attached to the prosthesis by a 0.2-cm strip of cuspal tissue (Figure 6). This allowed it to flop into the ventricle and float up into the atrium (the “highly mobile mass” on TEE), leading to the significant acute MR noted on TEE. There was no evidence of infection in or around the bioprosthesis. Acute bioprosthesis failure was due to tissue degeneration and may also be related to the significant pannus that covered the stent posts (Figure 5 and 7⇓) and extended onto the adjacent part of the cusps with resultant stress aggregation at the cusp pannus interface.4
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
Circulation encourages readers to submit cardiovascular images to the Circulation Editorial Office, St Luke’s Episcopal Hospital/Texas Heart Institute, 6720 Bertner Ave, MC1-267, Houston, TX 77030.
- ↵Naqvi TZ, Siegel RJ, Buchbinder NA, et al. Clinical, echocardiographic, and pathologic features of aortic wall dehiscence of porcine bioprosthetic valves: a cause of rapidly progressive mitral regurgitation and heart failure after bioprosthetic mitral valve replacement. J Am Soc Echocardiogr. 1998; 11: 720–728.