The importance of secondary mitral valve involvement in primary aortic valve endocarditis; the mitral kissing vegetation.

AIMS Secondary involvement of the mitral valve is well documented in primary aortic valve endocarditis. A poorly considered, but probably important causative mechanism, involving both left-sided valves, is 'mitral kissing vegetation'. This results from large aortic vegetations prolapsing into the left ventricular outflow tract and making contact with the ventricular aspect of the anterior mitral leaflet thus causing secondary infection. METHODS AND RESULTS In 192 consecutive patients with aortic valve endocarditis, two to 18 (7.6+/-2.6) serial transoesophageal echocardiographic examinations were analysed per patient to demonstrate the development of mitral kissing vegetation on initially competent, morphologically normal mitral leaflets. In 19 patients (9.9%) with aortic valve endocarditis, mitral kissing vegetation was diagnosed within 11.6+/-9.0 (range 1-31) days following primary transoesophageal echocardiography. In all patients with mitral kissing vegetation, vegetations attached to aortic cusps were >6 mm. On hospital admission, patients with aortic valve endocarditis plus mitral kissing vegetation presented more often with a positive sepsis score, embolic events, renal failure and had larger aortic valve vegetations (9.9+/-3.3 vs 5.7+/-2.3 mm). Prognosis of aortic valve endocarditis plus mitral kissing vegetation was unfavourable (P<0.005) when compared to patients with aortic valve endocarditis alone. CONCLUSION In aortic valve endocarditis early echocardiographic detection of mitral kissing vegetation and timely surgery may preserve the mitral valve apparatus, and favourably influence the long-term prognosis.