Renal Function as a Prognostic Factor in Infective Endocarditis Surgery

Research Article

Austin Cardiol. 2017; 2(1): 1009.

Renal Function as a Prognostic Factor in Infective Endocarditis Surgerys

Kaufman R¹*, Geller M³, Caetano Kuschnir MC2,4, Aurelio Santos M², Gomes de Sá RM¹, Aquino Xavier RM² and Pereira Azevedo VM²

¹State Institute of Cardiology - Rio de Janeiro, Brazil

²National Institute of Cardiology - Rio de Janeiro, Brazil

³Federal University of Rio de Janeiro, Brazil

4Faculty of Medical Sciences - State University of Rio de Janeiro, Brazil

*Corresponding author: Renato Kaufman, State Institute of Cardiology - Rio de Janeiro, Brazil

Received: May 15, 2017; Accepted: September 19, 2017; Published: September 26, 2017


Introduction: Infective Endocarditis (IE) is a serious disease with a high mortality rate if not diagnosed early. Most patients are subjected to antimicrobial therapy alone with a good cure rate, but there is a group of more severely affected patients requiring an associated surgical approach. Pre-operative renal dysfunction is a marker of mortality, as well as worsening of renal function in surgical patients.

Objective: To evaluate preoperative and postoperative renal function, using serum creatinine as a marker of mortality, in surgical patients with IE.

Methods: We analyzed 59 consecutive patients undergoing cardiac surgery for the treatment of EI associated with antibiotic therapy in the period from Jan/2005 to Dec/2008. Serum creatinine was measured six times: on admission, the day before surgery, and 24h, 48h, 72h and 1 week postsurgery. Creatinine clearance was calculated from serum creatinine using the Cockroft-Gault formula. The variables were analyzed using ANOVA for repeated measures, Pearson correlation, and ROC curve; the alpha value used was 0.05.

Results: Repeated measurements showed that creatinine was higher in patients who died compared with those who survived (p=0.00608), which was not observed with creatinine clearance (p=0.24).

Conclusion: Renal dysfunction worsens the prognosis for patients undergoing cardiac surgery. Impaired renal function in the immediate postoperative period was an important predictor of death in these patients. Serum creatinine was a preoperative prognostic marker of death within 30 days after cardiac surgery for IE. However, creatinine clearance showed no prognostic value in this cohort.

Keywords: Endocarditis; Acute renal insufficiency; Cardiac surgical procedures; Valvular disease; Mortality


Infectious endocarditis is a complex disease with several clinical presentations, and its prognosis worsens with delays in diagnosis and treatment. Is estimated the in hospital mortality rate as high as 30% [1-4].

It occurs mainly in the cardiac valves and presents high morbidity and mortality, and can be fatal if not diagnosed and treated adequately. Due the diversity of the clinical presentations, the disease has a large prognosis spectrum, ranging from resolution with no complications to development of congestive heart failure and sepsis, sometimes with need for inotropic support and intra-aortic balloon [1,2].

There are some patients in which isolated antibiotic therapy is not effective, and surgical approach is needed. All patients with refractory heart failure due to endocarditis should be considered for surgery, since the ventricular dysfunction in these patients is related to a poor prognosis when antimicrobial therapy is used alone [2-5].

In patients undergoing surgery, pre-operative renal function is a marker for mortality, and renal dysfunction in the immediate postoperative period also influences the prognosis.

The aim of this study was to evaluate the prognosis of patients undergoing cardiac surgery for the treatment of infective endocarditis and the role of renal function, represented by serum creatinine and by estimated creatinine clearance, as marker of in-hospital death.


This was a case study, time series, which analyzed the data in the medical records of all consecutive in-hospital patients of both genders with infective endocarditis that underwent cardiac surgery as an adjunctive treatment to antibiotics in the National Institute of Cardiology, Rio de Janeiro, Brazil, from January 2005 to December 2008. All patients were older than 18 years old.

The inclusion criteria were: patients with clinical, laboratory and echocardiographic infective endocarditis diagnosis by the Duke criteria [1]. Exclusion criteria were patients on renal dialysis prior to the episode of Infective Endocarditis.

The following variables related to exposure and outcomes were analyzed: a) demographics (age at diagnosis, gender and ethnicity, weight, height, Body Mass Index (BMI), and Body Surface Area (BSA)); b) history of previous heart disease, and congenital or acquired risk factors for cardiovascular disease; c) complete blood count; d) serum creatinine, measured six times: on admission, the day before surgery, and 24h, 48h, 72h and 1 week post-surgery; e) creatinine clearance calculated by the Cockroft-Gault formula; f) heart failure classified according to the New York Heart Association Criteria (NYHA); g) medicines used before surgery (antibiotics, digitalis, furosemide, thiazide, spironolactone, Angiotensin-Converting Enzyme (ACE) inhibitors, and aspirin); h) echocardiographic parameters (Left Atrium Dimension (LAD), Left Atrium Dimension/ Body Surface Area Relation (LAD/BSA), Left Ventricle Ejection Fraction (LVEF), Left Ventricular End Systolic Volume (LVESV), Left Ventricular End Diastolic Volume (LVEDV), Systolic Pulmonary Artery Pressure (SPAP), presence and quantification of valvular insufficiency or stenosis, vegetation dimension, type, and location); i) surgical parameters (time of Cardio Pulmonary Bypass (CPB) and aortic clamping, use of Intra-Aortic Balloon (IAB) and valve repair by valvuloplasty, or use of biological or mechanical prosthesis); j) postoperative parameters (mechanical ventilation time, need for reintubation, use of packed red cells, plasma, or cryoprecipitate); and k) outcome: death within 30 days after cardiac surgery.

Statistical analysis was carried out with the Statistica 8.0 software from Statsoft Inc. Descriptive continuous data were expressed as mean and Standard Deviation (SD) or median and quartiles as appropriate, and by percentages for categorical data. To discriminate differences between outcome groups we used the Student’s t-test for continuous variables and the chi-square or Fisher exact test as appropriate for categorical variables. The analysis of continuous variables measured along time was performed by Analysis of Variance (ANOVA) for repeated measures. We used an alpha value of 0.05. The project was approved by the Institutional Research Ethics Committee, accredited by the National Committee for Ethics in Research, number 0185/181207.


During the study period 59 patients met the criteria for inclusion and exclusion. The demographic and laboratory characteristics of the population studied are summarized in (Table 1). Thirty-four patients (57.6%) were male. When analyzing age, the highest incidence was in the 3rd decade of life with a stable incidence from 4th to 6th decade followed by a significant decline. In relation to self-reported ethnicity, 57% of patients were identified as Caucasian, and 43% afro-Brazilian.