High-risk myocardial infarction patients appear to derive more mortality benefit from short door-to-balloon time than low-risk patients

Abstract

To evaluate reduction of door-to-balloon (DTB) time and its impact on in-hospital mortality of high-risk infarct patients in a collaboration of district general hospitals (DGH) with a physician-to-patient model. Primary percutaneous coronary interventions (PPCI) with short DTB time offer mortality benefit for ST-segment elevation myocardial infarction but literatures are conflicting on this benefit for high- vs. low-risk patients. In a unique model at Sandwell and West Birmingham Hospitals, five interventional cardiologists provide 24-h PPCI at whichever one of its two DGH that patients present to. A retrospective audit was performed on 3 years (July 2005-June 2008) of PPCI data in the British Cardiovascular Intervention Society database. Data were analysed in four periods corresponding to change from daytime-only to 24-h PPCI. DTB time and in-hospital mortality were the main outcome measures. Of the 459 patients, median DTB time improved from 89 min (interquartile range: 49-120) to 68 min (50-91) (p = 0.005) and proportion of patients achieving target 90-min DTB time increased from 53% (21/40) to 75% (93/124) (p = 0.005). In-hospital mortality was less for short DTB time [4.6% (13/284) vs. 11.5% (20/174); odds ratio (OR) 0.37, 95% confidence interval (CI): 0.18-0.75; p = 0.008]. With the proviso that our study was limited in power, long DTB time (> 90 min vs. < or = 90 min) was associated with higher in-hospital mortality in high-risk patients [15.6% (20/128) vs. 7.1% (12/168); OR 2.41, 95% CI: 1.14-5.06; p = 0.024] and not in low-risk patients [0% (0/46) vs. 0.9% (1/117); OR 0, 95% CI: 0-9.88; p = 1.000]. A collaboration of DGH with a physician-to-patient model can deliver timely PPCI that appear to translate into mortality benefit more so in high-risk patients. Low-risk patients would therefore probably tolerate delays associated with transfer to large centres while high-risk patients would not and need alternative strategy. A collaboration of smaller hospitals with a pool of mobile interventional cardiologists could be such an alternative.