Surgical treatment of prosthetic valve endocarditis in patients with double prostheses: is single-valve replacement safe?

OBJECTIVE: Bias against operating on patients with prosthetic valve endocarditis (PVE) who have multiple prostheses may preclude the use of life-saving valve replacement. We investigated the accuracy of the preoperative diagnosis of PVE in patients with both mitral and aortic prosthesis and the safety of single-valve replacement when only one valve seemed infected. METHODS: Patients with a diagnosis of active PVE who had mitral and aortic prosthesis in place were assessed. We looked at the methods for diagnosis, causative agents, indication for valve replacement, operative findings and outcome. RESULTS: Twenty patients, who had both mitral and aortic prostheses and a diagnosis of PVE, were assessed. Streptococci and staphylococci caused 70% of cases. By means of echocardiography, the valves involved were: mitral (11 patients), aortic (six patients), and in three cases both prosthetic valves seemed infected. Surgery was undertaken in 17 patients (85%). The positive predictive value of transesophageal echocardiogram (TEE) for the preoperative diagnosis of the site of infection was 100%. In 13 patients, only the prosthetic valve that seemed infected was replaced. Four of these patients died within a week after the procedure. Nine patients survived the surgical procedure, completed a course of antimicrobial therapy and were followed up for 15.78 months (95% CI: 12.83-18.72). All were considered cured and relapses were not observed. CONCLUSIONS: TEE allowed a diagnosis of site involvement that did correlate with the anatomic diagnosis obtained during the operation. This fact contributed to the management of patients and was of great help in guiding the surgical intervention. Echo-oriented single-valve replacement may be a safe strategy for patients with PVE and double prostheses.

The impact of hospital-acquired infections on the microbial etiology and prognosis of late-onset prosthetic valve endocarditis.

STUDY OBJECTIVES: To study the changing etiology of prosthetic valve endocarditis (PVE) and the impact of nosocomial acquisition of the infection on prognosis in a single hospital. METHODS: Retrospective review of 121 cases of PVE during a period of 34 years. Two different periods (the period from 1970 to 1986 [P1], and the period from 1987 to 2003 [P2]) were analyzed. RESULTS: During P1, 58 patients with PVE were treated (30 early PVE and 28 late PVE); during P2, 63 patients with PVE were treated (13 early PVE and 50 late PVE). The frequency of early-onset PVE decreased from 0.94% in P1 to 0.34% in P2 (p < 0.001), but the incidence rate of late-onset PVE did not change (0.33% and 0.42% per year, respectively). The microbiology of early PVE changed over the years: Gram-negative bacilli decreased from 40% during P1 to 7.7% in P2 (p = 0.033). Staphylococci remained the main causes of early PVE in both periods. The microbial etiology of late PVE also changed over the years with enterococci and Staphylococcus aureus as the leading causes during P2. Streptococcus viridans decreased from a leading position to a fourth position. Methicillin-resistant S aureus endocarditis appeared first in 1992. Eleven cases of late-onset PVE in P2 were hospital acquired (22%). In comparison, only two cases (7.1%) of hospital-acquired, late-onset PVE were seen in P1 (p = 0.11). Mortality of early-onset PVE decreased from 80% in P1 to 46% in P2 (p = 0.026). The overall mortality of late-onset PVE did not change between periods: 39% vs 34%. Mortality associated with nosocomial PVE in P2 was 63.6% (7 of 11 patients). In comparison, the mortality of community-acquired cases was 25.6% (10 of 39 patients; p = 0.03). In the multivariate analysis, the presence of comorbidities and hospital acquisition were associated with an excess of mortality (odds ratio [OR], 13.9; 95% confidence interval [CI], 1.23 to 158 [p = 0.033]; and OR, 10.8; 95% CI, 2.16 to 54.7 [p = 0.0037], respectively). CONCLUSION: Although the mortality associated with early-onset PVE has significantly decreased, in this series the mortality of patients with late-onset PVE remained high due mainly to an increasing number of patients with comorbidities who acquired the infection during admission for other diseases.

Prosthetic valve endocarditis due to Listeria monocytogenes. Report of two cases and reviews.

INTRODUCTION: Endocarditis due to Listeria monocytogenes is a rare but serious disease often leading to valve dysfunction and heart failure. Two cases of listerial prosthetic valve endocarditis are reviewed along with 66 cases previously reported. RESULTS: The mean age of patients with listerial endocarditis increased from 47.1 years in the decades from 1955-1984 to 65.5 years from 1985-2000. Chronic debilitating diseases, solid tumours and immunosuppression associated with organ transplantation, hematologic neoplasia or AIDS were found in 41.1% of cases. Listerial endocarditis was a vegetative and destructive process, with dehiscense of the prosthesis and occasionally, abscess formation, fistulization and pericarditis. Treatment with penicillin or ampicillin alone or combined with gentamicin was adequate therapy in most cases. Vancomycin together with gentamicin may be a reasonable alternative therapy. CONCLUSIONS: Despite problems associated with microbial persistence and relapses in other forms of human listeriosis, antimicrobial therapy alone may be a successful treatment for listerial endocarditis, including cases occurring on prosthetic valves. Valve replacement may be reserved for complicated cases with valve dehiscense, cardiac failure or myocardial abscess. Overall mortality was 35.3%, although most patients who died did so before 1985 and since then mortality has been significantly reduced to 12%.

Successful stent-grafting for perforation of the thoracic aorta by an intraaortic balloon pump.

Vascular complications associated with intraaortic balloon pump placement are quite common and predominantly related to femoral or iliac damage. Iatrogenic injury of the thoracic aorta is less usual and often fatal. Surgery for the lesions of the descending thoracic aorta still has a relatively high morbidity and mortality. Endovascular covered stentgraft prostheses have become a less invasive therapeutic approach to lesions of the thoracic aorta, especially in patients with high surgical risk. We describe a case of perforation of the thoracic aorta caused by an intraaortic balloon pump. The injury was confirmed by aortography and successfully repaired by implantation of an endovascular stent-graft via the left common iliac artery.