Nationwide trends in use and timeliness of diagnostic coronary angiography in acute coronary syndromes from 2005 to 2011: Does distance to invasive heart centres matter?

Aims: To examine trends in the use of diagnostic coronary angiography according to distance from home to the nearest invasive heart centre following implementation of fast-track protocols and extensive pre-hospital triaging of acute coronary syndrome patients. Methods and results: We performed a register-based cohort study of all patients admitted to Danish hospitals with incident acute coronary syndrome in 2005-2011. Diagnostic coronary angiography within 60 days of admission was investigated according to distance tertiles (DTs) calculated as range from each patient's home to the nearest invasive heart centre (short DT: <22 km, medium DT: 22-65 km, long DT: >65 km). Cox proportional hazards models were applied. Among the 52,409 patients included, diagnostic coronary angiography was increasingly used during 2005-2011 (short DT: 76% to 81%; medium DT: 74% to 81%; long DT: 69% to 78%; all p-values for trend <0.001). Using the short DT as reference the adjusted hazard ratios for medium DT were 0.87 (0.84-0.89) for 2005-2007, 0.94 (0.90-0.98) for 2008-2009 and 0.94 (0.90-0.98) for 2010-2011. Corresponding figures for long DT were 0.74 (0.72-0.76) for 2005-2007, 0.87 (0.83-0.90) for 2008-2009 and 0.94 (0.90-0.98) for 2010-2011. Length of hospital stay, time to coronary angiography, and 60-day mortality decreased in all DT. Conclusions: This nationwide study found significant increases in diagnostic coronary angiography use over time in incident acute coronary syndrome patients with a relatively larger increase in patients residing farthest from an invasive heart centre. Additionally, selected quality of care measures improved in the entire cohort, suggesting a benefit of national clinical protocols.