Influence of different approaches of aortic valve replacement on the incidence of post-operative delirium in intermediate risk patients - a matched pair analysis.

OBJECTIVES: Evaluation of the risk for post-operative delirium (POD) after surgical or transfemoral aortic valve replacement (AVR) as an additional decision parameter for the choice of treatment in patients with an EuroScore (ES) between 10% and 20%.
BACKGROUND: POD is well known as a not infrequent side effect of cardiac surgery necessitating extracorporeal circulation. In Germany a tendency to treat patients with ES <20% with transfemoral AVR (TF) instead of surgical AVR (SAVR) was observed in 2013. The risk of POD may influence the decision of physician and patient as to which procedure would be appropriate in the individual case. Therefore we performed an analysis of the incidence of POD in patients with comparable risk treated either with surgical or transfemoral aortic valve replacement.
METHODS: Patients with elective or urgent need for AVR and EuroScore between 10% and 20% were extracted from the database of all isolated AVR procedures in Germany of 2013. As a result 3407 cases, 771 SAVR patients and 2636 TF patients with EuroScore 10-20%, were extracted from the complete data-base of the German quality insurance registry for heart surgery. Two homogeneous groups with regard to the risk predicted by ES were built by case-control matches and compared for available variables. In a second step two groups with identical risk/co-morbidity profile for 10 variables were identified and analyzed with respect to POD and in-hospital mortality.
RESULTS: A total of 763 pairs with EuroScore of 13.5% each could be determined. Mean age was 75.6 years (SAVR, 51.6% male) and 78.8 years (TF, 56.5% male). Incidence of POD with need for therapy (POD-T) was 12.8% after SAVR and 3.8% after TF, resulting in numbers needed to harm of 8 and 26 respectively. In-hospital death rate of patients with POD-T was 5.1% after SAVR and 3.3% after TF, and nearly identical compared with patients without POD-T. POD-T had a negative influence on the regular discharge procedure. Further matching resulted in two groups of 470 patients each with identical co-morbidities and an age difference of 1 year but POD-T rates of 14.5% (SAVR) and 4.9% (TF); in-hospital mortality was 6.2% (SAVR) and 2.3% (TF). LIMITATIONS: The dataset contains valid data only for the period of hospital stay until discharge. Therefore conclusions about the duration and reversibility of POD, which are important parameters of quality of life and resource consumption as well as midterm consequences, cannot be estimated. The documentation of the German Federal Council asks only for POD and POD-T, a predefined definition of POD is not given; this may have some influence on the data. We therefore confined the analysis to only POD-T. In addition only a limited number of co-morbidities are documented.
CONCLUSION: In patients with intermediate risk according to EuroScore (10-20%) the risk of post-operative delirium and in-hospital mortality is significantly higher after surgical aortic valve replacement than after transfemoral procedure. This may be considered for patient guidance and the decision as to which procedure is able to achieve the best result including minimizing side effects.