Long term mortality of deep sternal wound infection after coronary artery bypass surgery.

BACKGROUND: Deep sternal wound infection and mediastinitis determine high in-hospital mortality. International studies show that these patients are also at increased cardiovascular mortality risk in long-term follow-up. However, data are scarce and there is no national data. OBJECTIVES: The aim of this study is to evaluate the mortality and incidence of cardiovascular events in long-term follow-up of patients suffering from deep sternal wound infection and mediastinitis. METHODS: Case-control study, matched by propensity score in a 1:1 proportion, in patients submitted to coronary artery bypass grafting between 2005 and 2008 at the Institute Dante Pazzanese of Cardiology (São Paulo, SP, Brazil). The primary outcome was death. As a secondary outcome, we analyzed the composite event of myocardial infarction, new revascularization, stroke or death. RESULTS: Of 1975 patients, 114 developed one of the infections. During the mean follow up of 3.6 years, deep sternal wound infection and mediastinitis increased the risk of death by 8.26 (95% CI 1.88-36.29, P = 0.005) and the incidence of combined end point by 2.61 (95% CI 1.2-5.69, P = 0.015). The Kaplan-Meier curves for both outcomes demonstrated that the greatest risk occurs in the first six months, followed by a period of stabilization and further increase in the incidence of events after 4 years of hospital discharge. The similarity between the curves of primary and secondary outcomes may be consequent to the predominance of death on the combined cardiovascular events. CONCLUSION: The presence of deep sternal wound infection or mediastinitis increased mortality in long-term follow-up in this sample of the Brazilian population according to the same pattern displayed by the developed countries.

Long term mortality of deep sternal wound infection after coronary artery bypass surgery / Mortalidade em longo prazo da infecção esternal profunda após cirurgia de revascularização do miocárdio

BACKGROUND: Deep sternal wound infection and mediastinitis determine high in-hospital mortality. International studies show that these patients are also at increased cardiovascular mortality risk in long-term follow-up. However, data are scarce and there is no national data. OBJECTIVES: The aim of this study is to evaluate the mortality and incidence of cardiovascular events in long-term follow-up of patients suffering from deep sternal wound infection and mediastinitis. METHODS: Case-control study, matched by propensity score in a 1:1 proportion, in patients submitted to coronary artery bypass grafting between 2005 and 2008 at the Institute Dante Pazzanese of Cardiology (São Paulo, SP, Brazil). The primary outcome was death. As a secondary outcome, we analyzed the composite event of myocardial infarction, new revascularization, stroke or death. RESULTS: Of 1975 patients, 114 developed one of the infections. During the mean follow up of 3.6 years, deep sternal wound infection and mediastinitis increased the risk of death by 8.26 (95% CI 1.88-36.29, P = 0.005) and the incidence of combined end point by 2.61 (95% CI 1.2-5.69, P = 0.015). The Kaplan-Meier curves for both outcomes demonstrated that the greatest risk occurs in the first six months, followed by a period of stabilization and further increase in the incidence of events after 4 years of hospital discharge. The similarity between the curves of primary and secondary outcomes may be consequent to the predominance of death on the combined cardiovascular events. CONCLUSION: The presence of deep sternal wound infection or mediastinitis increased mortality in long-term follow-up in this sample of the Brazilian population according to the same pattern displayed by the developed countries.

INTRODUÇÃO: A infecção esternal profunda e a mediastinite determinam elevada mortalidade intra-hospitalar. Estudos prévios demonstram que esses pacientes também apresentam maior mortalidade cardiovascular em longo prazo. No entanto, os dados são escassos para o Brasil. OBJETIVO: O objetivo deste estudo é avaliar a mortalidade e a incidência de eventos cardiovasculares em longo prazo em pacientes acometidos de infecção esternal profunda e mediastinite. MÉTODOS: Estudo de caso-controle com pareamento 1:1 por meio de propensity score, em pacientes submetidos à cirurgia de revascularização do miocárdio entre 2005 e 2008, no Instituto Dante Pazzanese de Cardiologia (São Paulo, SP, Brasil). O desfecho primário avaliado foi óbito. Como desfecho secundário, analisou-se o composto de infarto agudo do miocárdio, nova revascularização miocárdica, acidente vascular encefálico ou óbito. RESULTADOS: De 1975 pacientes avaliados, 114 desenvolveram infecção esternal profunda ou mediastinite. Durante o seguimento médio de 3,6 anos, as infecções conferiram razão de risco de óbito de 8,26 (IC 95% 1,88-36,29, P = 0,005), tendo sido a razão de risco de desfecho combinado de 2,61 (IC 95% 1,2-5,69, P = 0,015). A curva de Kaplan-Meier para ambos os desfechos demonstra que o maior risco ocorre nos primeiros 6 meses, seguindo-se um período de estabilização e novo aumento na incidência de eventos após 4 anos da alta hospitalar. A semelhança entre as curvas dos desfechos primário e secundário pode ser consequente à predominância do óbito sobre os demais eventos cardiovasculares. CONCLUSÃO: A presença de infecção esternal profunda ou de mediastinite aumentou a mortalidade em longo prazo nesta amostra da população brasileira, de acordo com o mesmo padrão exibido nos países desenvolvidos.