Native versus primary prosthetic valve endocarditis: comparison of clinical features and long-term outcome in 353 patients

BACKGROUND AND AIM OF THE STUDY: The study aim was to compare preoperative and intraoperative features, and long-term outcome of patients operated on for native (NVE) and primary prosthetic valve endocarditis (PVE). METHODS: Between January 1978 and December 2002, 258 patients (mean age 47.5 +/- 16 years) were referred for NVE, and 95 for PVE. Demographics, clinical preoperative conditions, indications to surgery, microbiological data, surgical pathology, early postoperative course and long-term outcome were compared via hospital chart review and outpatient clinic follow up. RESULTS: Female sex prevailed in the PVE group (49.5%) versus NVE (27.1%; p < 0.0001). Mitral valve involvement was more common in PVE (46.3% versus 24.8%, p = 0.0001), and multivalvular in 16.3% of NVE patients versus 4.2% of PVE (p = 0.001). Active endocarditis (80.6% versus 58.9%, p = 0.00004) and preoperative embolism (29.5% versus 11.6%, p = 0.0002) were significantly prevalent in the NVE group. Emergency operation (21.1% versus 10.5%, p = 0.009) and preoperative NYHA class IV or V (40% versus 19.8%, p < 0.0001) were significantly more frequent in PVE. Overall hospital mortality was 11.3% (n = 40), with 6.6% among NVE patients and 24.2% among PVE (p < 0.0001). Mean follow up (94% complete) was 5.8 +/- 5.3 years (6.0 +/- 5.5 years for NVE versus 5.1 +/- 4.6 years for PVE, p = 0.191), and total follow up was 1,707.85 patient-years. Actuarial survival at 1, 5, 10 and 15 years was respectively 91, 82, 67.5 and 48.8% in NVE, and 79.7, 64.2, 33.5 and 33.5% in PVE (p = 0.0016). A significantly lower survival in PVE versus NVE was found for the mitral site subgroup (p = 0.018), but not for the aortic site (p = 0.14). Actuarial freedom from reoperation for recurrent endocarditis at 1, 5, 10 and 15 years was 97.5, 91.4, 80.5 and 49.4% in NVE versus 90.8, 84.9, 59.4 and 43.9% in PVE (p = 0.015). CONCLUSION: PVE patients were older, presented with more compromised clinical conditions, and had worse early and long-term outcomes than NVE patients. PVE had a higher incidence of recurrence and worse prognosis, especially if the mitral valve was involved.