Arquivos de Neuro-Psiquiatria (Jun 1997)
Fatores determinantes da letalidade após cirurgia para endocardite infecciosa Postoperative mortality in infective endocarditis: determinant factors
Abstract
Estudamos a influência de dados demográficos, fatores predisponentes, aspectos clínicos, variáveis operatórias sobre a evolução em 39 pacientes operados por endocardite infecciosa (EI). Utilizamos os testes t de Student, X²ou exato de Fisher em análises univariadas, regressão logística para determinação de fatores adversos independentes. O impacto do número destes fatores sobre a evolução foi estudado pelo teste exato de Fisher. Valvas mais afetadas: aórtica (20) e mitral (16); germes mais comuns: Staphylococcus aureus (12) e Streptococcus sp (10). Cirurgia de emergência e a presença de coma seis horas após a operação elevaram a letalidade (p=0,001 e p=0,0015), bem como infecção pelo S.aureus (p=0,023) e presença de complicações neurológicas (p=0,097). A concomitância de dois ou três destes fatores elevou particularmente a letalidade (>76,9%). Pacientes com EI devem receber cuidadosa avaliação quanto a indicação cirúrgica nas fases iniciais da doença, já que a concomitância de variáveis adversas e cirurgias em caráter de emergência elevam fortemente a letalidade por EI.The factors leading to high postoperative mortality in active infectious endocarditis (IE) are poorly defined. We studied patients operated at an University Hospital between March 1978 and April 1992. We hipothesized that the summation of potential adverse factors would strongly increase mortality after surgery. We studied 39 patients (28 men), age range 13-70 years (mean±SD =32±16) operated during active IE (time from onset 52+48 days). Predisposing factor: rheumatic valvar disease in 14 cases, intravenous drug use in 5. Affected valves: aortic in 14, mitral in 10, tricuspid in 8, multiple structures in 7. In most cases, S aureus (12) or Streptoccocus sp (10) was isolated in blood cultures. Surgery was indicated in most patients because of heart failure (30), multiple embolic complications (17) or treatment failure (14). The possible adverse influence of specific demographic characteristics, clinical features and surgical variables was assessed by the Student t test or the %² test. Also, multple regression analysis was performed in order to identify independent adverse factors for increased mortality. Positive correlations were further investigated with the X² test to assess whether an increasing number of adverse factors could identify a special subset of patients with markedly elevated death risk. Fourteen patients (36%) died after surgery. Emergency surgery (p = 0.001), the presence of coma 6 hours after surgery (p = 0.0015) and S. aureus infection (p = 0.023) were all associated with increased mortality. The presence of neurological complications was correlated with a high mortality (54% vs. 27%). However this increase was of dubious statistical significance (p = 0.097). Multiple regression analysis confirmed S. aureus and emergency surgery as independent adverse factors for increased mortality. When put together, an increasing number of adverse factors was highly predictive of a fatal outcome, even after exclusion of that evaluated after surgery (level of consciousness). Patients with two or three adverse factors had a very high mortality rate (>76.9%). Mortality following surgery for active IE is increased in patients operated on an emergency basis especially if the infection is caused by S. aureus. The presence of neurological complications may also be associated with worse outcome. Early consideration of surgery should reduce the high mortality in patients with active IE.
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