OBJECTIVE
To develop a scale for predicting the risk of in-hospital adverse (lethal) outcome in patients undergoing redo surgery for structural dysfunction of diepoxy-treated mitral bioprostheses.
MATERIAL AND METHODS
There were 147 redo procedures of mitral valve replacement for dysfunction of bioprosthesis for the period 2005-2015. All interventions were carried out at the Research Institute for Complex Issues of Cardiovascular Diseases. The study included patients with mitral bioprosthesis dysfunction and age at the primary surgery ≥ 18 years. All re-operations were performed according to the technique of redo mitral valve replacement adopted in our hospital. Clinical, anatomical, biochemical (including markers of vascular inflammation) and echocardiographic characteristics of patients with and without a fatal outcome (217 variables) were compared in order to analyze the relationship between unfavorable outcome and possible predictors. We determined certain factors (preoperative, intraoperative and postoperative) as independent potential predictors of adverse event. A 30-day mortality was dependent variable. Preoperative risk of mortality was assessed using the EuroSCORE additive and logistic scales, STS calculator and ACEF scale. Postoperative risk was assessed using the SOFA and APACHE II scales.
RESULTS
Considering the data obtained, patients were divided into 4 categories of surgical risk: low (≤75 scores), medium (91-105 scores), high (106-128 scores) and very high (>128 scores). In-hospital mortality rate was 2.3%, 15.6%, 55.8% and 100%, respectively. The confidence interval (95% CI) for these categories was 2.3 (from 2.2 to 2.5), 16.3 (from 15.3 to 17.4), 56.2 (from 51.9 to 60,6) and 95.0 (from 92.8 to 97.2), respectively.
Mortality risk was assessed using the new scale. Its effectiveness was compared with the six previously established prognostic scales: EuroSCOREs, STS, ACEF, SOFA and APACHE II. Sensitivity, specificity, positive and negative prognostic values were determined for the identified threshold indicators. Our scale had very good accuracy in all subgroups with AUC=0.899. STS scale (AUC=0.847) was followed by SOFA (AUC=0.825), APACHE II (AUC=0.768), EuroSCORE II (AUC=0.754), EuroSCORE (AUC=0.714) and ACEF (AUC=0.699). Sensitivity, specificity and accuracy of the prognosis were similar to the results in the main sample. Confidence intervals of the probability of absence and occurrence of unfavorable (fatal) outcome do not overlap. Considering these data, the quality of the proposed model can be rated as very good.
CONCLUSION
Thus, high quality and easy application of this model were observed. Therefore, this scale may be applied to assess the likelihood of adverse (lethal) outcome in patients undergoing redo surgery for dysfunction of diepoxy-treated biological mitral prostheses.
