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

Background and aim of the study: Most previous studies on surgery for endoc arditis included cases of both prosthetic and native valve endocarditis (NV E), which clearly differ in their course and prognosis. Methods: Between February 1979 and July 2000, 199 patients underwent surgic al treatment for NVE. The native valve was replaced in 185 patients, and re paired in 14. Correlations between previous heart disease and site of NVE, site and etiology, site and embolism, and etiology and extracardiac infecti on were analyzed. Viability of echocardiography to identify NVE features wa s compared with surgical inspection. Risk factors for hospital, late mortal ity and recurrence were assessed by multivariate analysis, including preope rative, operative and postoperative variables. Results: Streptococci were found in 52 cases (26.1%), mostly spreading from splanchnic (n = 10) and cutaneous (n = 9) infections; Staphylococci were f ound in 43 cases (21.6%), mostly from cutaneous foci (n = 20). Tricuspid va lve endocarditis was due to Staphylococcus sp. in all documented cases (11/ 15; p <0.001), while Streptococcus sp. predominated in the mitral (p = 0.02 6) 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 mo rtality. 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 a nd 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 recurre d in 28 patients (15.5%), with 74.1% freedom at 10 years and 68.7% at 20 ye ars. Drug abuse (p = 0.001), mitral endocarditis (p = 0.002), positive bloo d cultures (p = 0.0003), homograft implantation (p = 0.0012) and persistent postoperative fever (p <0.0001) were significant predictors for recurrence . Conclusion: Preoperative conditions of patients with NVE significantly affe ct early and long-term outcomes. Prognosis is worsened by delayed diagnosis and operation during the active septic process.