1657 Systematic Review and Meta-Analysis of Mortality Risk Prediction Models in Adult Cardiac Surgery

Background

The most used mortality risk prediction models in cardiac surgery are the European System for Cardiac Operative Risk Evaluation(EuroSCORE)(ES) and Society of Thoracic Surgeons(STS) score. There is no agreement on which score should be considered more accurate nor which score should be utilised in each population sub-group. We sought to provide a thorough quantitative assessment of these 2 models.

Method

We performed a systematic literature review and captured information on discrimination, as quantified by the area under the receiver operator curve(AUC), and calibration, as quantified by the ratio of observed-to-expected mortality(O:E). We performed random effects meta-analysis of the performance of the individual models as well as pairwise comparisons and sub-group analysis by procedure type, time and continent.

Results

The ES2(AUC 0.783[95%CI 0.765-0.800];O:E 1.102[95%CI 0.943-1.289]) and STS(AUC 0.757[95%CI 0.727-0.785];O:E 1.111[95%CI 0.853-1.447]) both showed good overall discrimination and calibration. There was no significant difference in the discrimination of the two models(Difference in AUC -0.016; 95%CI -0.034 to -0.002;p0.09). However, the calibration of ES2 showed significant geographical variations(p < 0.001) and a trend towards miscalibration with time(p0.0057). This was not seen with STS.

Conclusions

ES2 and STS are both reliable predictors of short-term mortality following adult cardiac surgery in the populations from which they were derived. STS may have broader applications when comparing outcomes across continents and time periods as compared to ES2.

1638 Decade-Long Trends in Surgery for Acute Type A Aortic Dissection

Background

Little is known about unwarranted variations in care and outcomes of patients who undergo surgical repair for type A acute aortic dissection(TAAD). We aim to investigate decade-long trends in TAAD surgical repair in England.

Method

Retrospective review of the National Institute for Cardiovascular Outcomes Research (NICOR) National Adult Cardiac Surgery Audit (NACSA) registry from January 2009 to December 2018 , which prospectively collects demographic and peri-operative clinical information for all adult cardiac surgery procedures in the UK.

Results

Over the 10-year period,3,686 TAAD patients underwent surgical repair in England. A steady doubling in the overall number of operations conducted in England was observed from 237 cases recorded in 2009 to 510 in 2018. Number of procedures per hospital per year also doubled, from 10 in 2009 to 21 in 2018. The risk profile of the operated patients remained unchanged. Overall, in-hospital mortality was 17.4% with a trend toward lower mortality in the most recent years (from 22.8% in 2009 to 14.7% in 2018). There was a significant variation in operative mortality across regions with a trend towards lower mortality in regions with a high-volume hospital.

Conclusions

Surgery is the only treatment for acute TAAD but is associated with high mortality. Prompt diagnosis and referral to a specialist center is paramount. The number of operations conducted in England has doubled in 10 years and the associated survival following surgery has improved. Regional variations exist in service provision with a trend towards better survival in high volume centers.