Development and validation of a clinical risk score to predict mortality after percutaneous coronary intervention

Objective: To develop and validate a contemporary clinical risk score to predict mortality after percutaneous coronary intervention (PCI).

Methods: Using data collected from patients undergoing PCI at the South Yorkshire Cardiothoracic Centre, Sheffield, UK between January 2007 and September 2013, a risk score was developed to predict mortality. Logistic regression was used to evaluate the effect of each variable upon 30-day mortality. A backwards stepwise logistic regression model was then used to build a predictive model. The results were validated both internally and externally with data from Manchester Royal Infirmary, UK. 30-day mortality status was determined from the UK Office of National Statistics.

Results: The development dataset comprised 6,522 patients from Sheffield. Five risk factors, including cardiogenic shock, procedural urgency, history of renal disease, diabetes mellitus and age, were statistically significant to predict 30-day mortality. The risk score was validated internally on a further 3,290 patients from Sheffield and externally on 3,230 patients from Manchester. The discrimination of the model was high in the development (C-statistic = 0.82, 95% confidence interval (CI) 0.79-0.85), internal (C-statistic = 0.81, 95% CI 0.76-0.86) and external (C statistics =0.90, 95% CI 0.87-0.93) cohorts. There was no significant difference between observed and predicted mortality in any group.

Conclusion: This contemporary risk score reliably predicts 30-day mortality after PCI using a small number of clinical variables obtainable prior to the procedure, without knowledge of the coronary anatomy.