Infective endocarditis of native cardiac valves: 22 years' surgical experience

Most previous studies on surgery for endocarditis included cases of both prosthetic and native valve endocarditis (NVE), which clearly differ in their course and prognosis.

Between February 1979 and July 2000, 199 patients underwent surgical treatment for NVE. The native valve was replaced in 185 patients, and repaired in 14. Correlations between previous heart disease and site of NVE, site and etiology, site and embolism, and etiology and extracardiac infection were analyzed. Viability of echocardiography to identify NVE features was compared with surgical inspection. Risk factors for hospital, late mortality and recurrence were assessed by multivariate analysis, including preoperative, operative and postoperative variables.

Streptococci were found in 52 cases (26.1%), mostly spreading from splanchnic (n = 10) and cutaneous (n = 9) infections; Staphylococci were found in 43 cases (21.6%), mostly from cutaneous foci (n = 20). Tricuspid valve endocarditis was due to Staphylococcus sp. in all documented cases (11/15; p <0.001), while Streptococcus sp. predominated in the mitral (p = 0.026) position. Echocardiography was reliable in identifying anatomic features of NVE, except for periannular abscess (13 versus 31 found at surgery; p <0.001). Hospital mortality was 6% (n = 12): preoperative NYHA class IV (p = 0.034) and emergency surgery (p = 0.001) were significant predictors of mortality. Average follow up was 57.2+/-4.4 months and was 96.3% complete. There were 27 late deaths (15%). Actuarial survival was 75.7% at 10 years and 60.3% at 20 years. Low social status (p = 0.022), diabetes mellitus (p = 0.003), fever at time of surgery (p = 0.041) and persistent postoperative fever (p = 0.0002) were predictors for late mortality. Endocarditis recurred in 28 patients (15.5%), with 74.1% freedom at 10 years and 68.7% at 20 years. Drug abuse (p = 0.001), mitral endocarditis (p = 0.002), positive blood cultures (p = 0.0003), homograft implantation (p = 0.0012) and persistent postoperative fever (p <0.0001) were significant predictors for recurrence.

Preoperative conditions of patients with NVE significantly affect early and long-term outcomes. Prognosis is worsened by delayed diagnosis and operation during the active septic process.