Infective Endocarditis of the Tricuspid Valve

603 IMAGES IN CARDIAC SURGERY Infective Endocarditis of the Tricuspid Valve Jagdish Butany, M.B.B.S., M.S., F.R.C.P.C.∗ ,§, Varun Dev, B.H.Sc.,∗ Shaun W. Leong, B.Sc.,∗ Gursharan S. Soor, B.Sc.,∗ Molly Thangaroopan, M.D., F.R.C.S.C.,† and Michael A. Borger, M.D., F.R.C.S.C.‡ Departments of Pathology, †Cardiology, and ‡Cardiac Surgery, Toronto General Hospital/University Health Network, Toronto, Canada; §Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada ∗ ABSTRACT Infective endocarditis (IE) usually involves the left-sided valves, and IE involving the tricuspid valve (TV) is rare, often developing in intravenous drug users (IDU). We present a case of a 32-year-old male, an intravenous drug abuser (IDA), who presented with nonspecific septic symptoms, and was treated with TV conserving surgery. Pathological examination confirmed tissue destruction, friable thrombotic vegetations, and microorganisms in the leaflet tissue. doi: 10.1111/j.1540-8191.2006.00313.x (J Card Surg 2006;21:603-604) CASE REPORT A 32-year-old male with a history of myocarditis presented with nonspecific symptoms and multiple septic embolic events. Comorbidities included a history of intravenous/oral drug abuse (crack/oxycodone), a hepatitis C positive status, and a patent foramen ovale (PFO). Echocardiography revealed large vegetations on the tricuspid valve (TV) and blood cultures were positive for Staphylococcus aureus. Intraoperative transesophageal echocardiography (TEE) showed severe tricuspid regurgitation with large prolapsing vegetations (Fig. 1). The TV was repaired and the PFO closed. The posterior leaflet and the inferior half of the septal and anterior leaflets were resected. A neo-leaflet was constructed with autologous pericardium and Gore-tex sutures implanted as neo-chordae. Postoperative TEE revealed mild to moderate tricuspid stenosis and regurgitation. The patient is doing well nine months after the surgery. (Figs. 2–4), and abundant gram positive microorganisms (cocci) were seen (Figs. 3 and 4). The TV would have been significantly dysfunctional. DISCUSSION We report a case of infective endocarditis (IE) of the TV in an intravenous drug user (IDU), treated with valve sparing surgery. The damaged segments of leaflet tissue were excised and the leaflets reconstructed using autologous pericardium. Chordae tendineae were fashioned from synthetic suture material (Gore-tex, Newark, NJ, USA). PATHOLOGY The excised tricuspid leaflet segments (1.7 × 0.8 cm, 1.8 × 0.9 cm, and 2.0 × 0.8 cm, with the thickness ranging from 0.4 to 0.6 cm) were thickened and nodular, with focal calcification. The chordae tendineae were thickened and fused, and friable vegetations were present, mainly on the nonflow surfaces of the leaflet segments. There was evidence of tissue destruction Address for correspondence: Jagdish Butany, M.B.B.S., M.S., F.R.C.P.C., Department of Pathology E4-301, Toronto General Hospital, Toronto, ON, Canada M5G 2C4. Fax: 416 340 4213; e-mail: jagdish. butany@uhn.on.ca Figure 1. Transesophageal echocardiogram shows a large vegetation (white arrow) present on the posterior leaflet of the TV. 604 BUTANY, ET AL. TRICUSPID VALVE ENDOCARDITIS Figure 2. Photomicrograph of the TV leaflet showing extensive tissue damage and elastic tissue disruption. Thrombus is present on the nonflow surface (arrows), and blood and polymorphonuclear leukocytes were present in the substance of the leaflet ( ∗ ). The leaflet tissue is markedly thickened (Stain: Movat Pentachrome, original magnification = 16×). While 76% of endocarditis cases involving IDU occur on the right side, only 5% to 10% of all endocarditis cases occur on the right.1,2 Streptococcus viridans is the most common cause of IE overall, while S. aureus is the most common cause of IE in IDU.2-4 Frontera and Gradon hypothesize that IDU patients exhibit a greater expression of matrix molecules that bind to microbial surface components recognizing adhesive matrix molecules on the right-sided valvular surface, predisposing these valves to an increased S. aureus adherence.2 Our patient presented with septic pulmonary emboli (resulting from the dislodgment of vegetative material), and tricuspid regurgitation, which have been found to be common symptoms among tricuspid valve endocarditis (TVE) patients.1,5 The PFO likely contributed to higher blood flow and pressures on the right side of the J CARD SURG 2006;21:603-604 Figure 4. Photomicrograph showing abundant colonies of gram positive bacteria (arrowhead) in the significantly destroyed tricuspid leaflet tissue (Stain: Gram, original magnification = 200×). heart, resulting in thickening (fibrosis) and damage to the TV leaflets and chordae tendineae, further predisposing the TV to IE. In most cases, TVE can be controlled with antibiotics.1 However, as in our patient, surgery is warranted in cases with large vegetations, persistent sepsis, and tissue destruction.1 The patient’s PFO also warranted surgery. Because of extensive leaflet destruction, TV replacement may be the procedure of choice in most surgical centers. However, we strongly believe that TV replacement is associated with an increased risk of repeat infection, thrombosis, and structural valve failure; therefore, we avoid this procedure whenever possible. Our patient underwent a valve conserving and reconstruction procedure,1,6 and is doing well 9 months after the surgery. IE must be considered in patients presenting with nonspecific features of infection. In particular, TVE must be considered a possibility in an IDU when no other cause of symptoms is easily found. In many cases, TV repair is a viable alternative to replacement with a prosthetic valve. REFERENCES Figure 3. Photomicrograph showing significant tissue destruction ( ∗ ), vegetations (arrows), and colonies of gram positive cocci (arrowheads) are seen in the zona spongiosa (Stain: Movat Pentachrome, original magnification = 25×). 1. Chan P, Ogilby JD, Segal B. Tricuspid valve endocarditis. Am Heart J 1989;117(5):1140-1146. 2. Frontera JA, Gradon JD. Right-side endocarditis in injection drug users: Review of proposed mechanisms of pathogenesis. Clin Infect Dis 2000;30:374-379. 3. Netzer RO-M, Zollinger E, Seiler C, et al: Infective endocarditis: Clinical spectrum, presentation and outcome. An analysis of 212 cases 1980-1995. Heart 2000;84:25-30. 4. 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