Mitral valve surgery for mitral regurgitation caused by Libman-Sacks endocarditis: a report of four cases and a systematic review of the literature

Abstract

Libman-Sacks endocarditis of the mitral valve was first described by Libman and Sacks in 1924. Currently, the sterile verrucous vegetative lesions seen in Libman-Sacks endocarditis are regarded as a cardiac manifestation of both systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS). Although typically mild and asymptomatic, complications of Libman-Sacks endocarditis may include superimposed bacterial endocarditis, thromboembolic events, and severe valvular regurgitation and/or stenosis requiring surgery. In this study we report two cases of mitral valve repair and two cases of mitral valve replacement for mitral regurgitation (MR) caused by Libman-Sacks endocarditis. In addition, we provide a systematic review of the English literature on mitral valve surgery for MR caused by Libman-Sacks endocarditis. This report shows that mitral valve repair is feasible and effective in young patients with relatively stable SLE and/or APS and only localized mitral valve abnormalities caused by Libman-Sacks endocarditis. Both clinical and echocardiographic follow-up after repair show excellent mid- and long-term results.

Figure 1

Verrucous vegetations seen in Libman-Sacks endocarditis of the mitral valve. The sterile fibrofibrinous vegetations seen in LS endocarditis of the mitral valve may vary in size and typically have a wart-like morphology. They can be found near the edge of the leaflets along the line of closure; both on the atrial and ventricular sides of the leaflets. They can even be found on the chordae and the endocardium. In this case several microthrombi are present on the free edge of the leaflet and on the chordae. Reproduced with permission from Dr. S. Gonzalez. Copyright 2009, department of Pathology, Pontifical Catholic University of Chile, Santiago, Chile.

Figure 2

Microscopic histopathological examination of excised mitral valve tissue in patient 2 (A,B), 3 (C,D), and 4 (E,F). (A) Photomicrograph of patient 2. Haematoxylin and Eosin (HE) stain of the atrial surface of the excised mitral valve anterior leaflet. Orginal magnification × 25. (B) Magnified section of A. Original magnification × 400. Fibrinoid changes and neovascularization at the base of the vegetation. The vegetation consists of fibrin-platelet thrombi and shows signs of acute and chronic inflammation with neutrophil and mononuclear cell infiltration. (C) Photomicrograph of patient 3. HE stain of the atrial surface of the excised mitral valve posterior leaflet. Orginal magnification × 50. (D) Magnified section of C. Original magnification × 400. Fibrinoid and hyaline changes at the base of the vegetation. The vegetation itself shows signs of fibroblastic organization of fibrin-platelet thrombus and an inflammatory infiltrate with neutrophils. (E) Photomicrograph of patient 4. HE stain of the atrial surface of the excised mitral valve posterior leaflet. Orginal magnification × 50. (F) Magnified section of E. Original magnification × 200. Fibrinoid and myxoid degenerative changes at the base of the vegetation. The vegetation shows signs of organization of fibrin-platelet thrombus without an evident inflammatory reaction. Sporadically, several neutrophils and mononuclear cells can be found in this section. Black transparant rectangles outline magnified sections shown in the right-hand column. V: vegetation.

Figure 3

Two-dimensional TTE examination and intra-operative inspection of the mitral valve in patient 3. (A) Parasternal long-axis view, systolic. (B) Apical four-chamber view, systolic. Morphologic examination of the mitral valve leaflets in both views revealed several structural abnormalities, such as leaflet thickening and vegetations on the edges of both leaflets. (C) Severe MR as determined by jet area (13.4 mm²) divided by left atrial area (25.9 mm²) (= 52%) and the vena contracta width (= 6 mm, not shown). (D) Superior view of the excised posterior mitral valve leaflet (as seen from the left atrium). (E) Frontal view of the excised posterior mitral valve leaflet. Both views show marked thickening and calcification of the posterior mitral valve leaflet and several thrombotic vegetations on the edge of the leaflet. Ao: aorta, LA: left atrium, LV: left ventricle, MR: mitral regurgitation and V: vegetations.

Figure 4

Two-dimensional TTE examination and intra-operative inspection of the mitral valve in patient 4. Morphologic examination of the mitral valve in both views revealed a 0.8 × 1.0 cm tumor on the posterior mitral valve leaflet; (A) Parasternal long-axis view, mid-diastolic; (B) Apical four-chamber view, end-diastolic. (C) Mild-to-moderate MR as determined with colour-Doppler TTE; apical four-chamber view, systolic. (D) Intra-operative inspection of the mitral valve (transseptal approach): a verrucous thrombotic tumor was found on the P2 section of the posterior mitral valve leaflet. (E) The verrucous thrombotic tumor was removed with a quadrangular resection of P2. Ao: aorta, LA: left atrium, LV: left ventricle, MR: mitral regurgitation and T: tumor.