Surgery for infective endocarditis on mitral annulus calcification.

BACKGROUND AND AIM OF THE STUDY: The study aim was to assess the characteristics of bacterial endocarditis complicating mitral annulus calcification, and to evaluate the surgical results.

METHODS

Twenty-four patients (mean age 64 years) underwent surgery for mitral insufficiency secondary to mitral endocarditis with annulus calcification (acute, n = 18; healed, n = 6). Surgery was performed as an emergency in seven cases for septic (n = 3) or cardiogenic (n = 4) shock. An aortic prosthesis had previously been placed in three cases. Comorbidities noted included chronic renal insufficiency/dialysis (n = 8), cancer (n = 6), coronary disease (n = 6), and obstructive cardiomyopathy (n = 1). Nine patients suffered an embolic complication, such as stroke (n = 7, of which three had coma), splenic (n = 3), or lower limb (n = 1). The microorganism present was identified as Staphylococcus aureus (n = 9), Streptococcus/ Enterococcus sp. (n = 12), or others (n = 3). The left atrial diameter was 48 mm, the ejection fraction 63%, and the septal thickness 13 mm.

RESULTS

The mean severity score of annulus calcifications (range: 1 to 5) was 1.9. The anatomical lesions included: vegetations (n = 16, of which eight were > 10 mm), leaflet perforation (n = 9), chordae rupture (n = 9), aortic abscess (n = 2) and mitral annular abscess (n = 9), and one fistulation into the pericardium. The valve was repaired in 15 cases, and replaced in nine (seven bioprostheses, two mechanical). Associated procedures included aortic valve replacement (n = 7) and coronary artery bypass (n = 3). The in-hospital mortality was 29% (n = 7); all patients who died were operated on during the acute phase. All patients who presented with septic shock or coma died. After a mean follow up of 46 months, six patients had died (overall survival was 46% at 33 months), and 11 were in NYHA class I/II. One recurrence of endocarditis was treated medically.

CONCLUSION

Bacterial endocarditis complicating mitral annulus calcification has a poor prognosis due to the frequent comorbidity and severity of the infectious complications. Patients in septic shock or coma do not appear to be suitable candidates for surgery. Valve repair was possible in two-thirds of the present patients; otherwise, a bioprosthetic replacement was the option of choice.