Some ideas simply sound good. A cell starved of oxygen dies. Acute coronary occlusions starve cells of oxygen. Timely resolution of the occlusion restores oxygenated blood. Time is myocardium. Happy myocardium results in fewer deaths.
This is still true – but, not on the order of minutes. This is a retrospective evaluation from the CathPCI registry, 1,400 hospitals in the U.S. that gather data for elective and emergency PCI. They looked specifically at patients who received primary PCI at the presenting hospital for STEMI, with door-to-balloon times less than three hours. Overall, between 2005 and 2009 – owing to door-to-balloon time as a quality measure – the median time decreased from 83 minutes to 67 minutes.
Unadjusted mortality? 4.8% at the beginning of the study period, 4.7% at the end. They also did a risk-adjusted analysis – as there was some gradually decrease of healthy substrate over the study period. This also showed no significant improvement in mortality. Essentially, lots of graphs with door-to-balloon times decreasing, and mortality staying flat.
It is retrospective & observational, and there are always potential unmeasured confounders. With 96,000 patients, however, chances are good they’re evenly distributed across groups. Treatments have also changed over the last five years – although, one would expect those treatments would only contribute to improved mortality in the unadjusted analysis, if anything.
Just today, I was just listening to Stuart Swadron ranting away on Emergency Medical Abstracts about the endless process improvement meetings they have to shave fractions of time off door-to-balloon times for STEMI – he felt symptom-to-reperfusion was more important. I’m sure he’s feeling in some way vindicated today. Clearly on the micro-level, door-to-balloon probably doesn’t matter. Use as a quality measure is probably overblown – particularly given the unanticipated consequences and resource utilization associated with these efforts. More expenditure seems to have been less, again.
“Door-to-Balloon Time and Mortality among Patients Undergoing Primary PCI”
http://www.nejm.org/doi/full/10.1056/NEJMoa1208200
Thanks for this. The hype surrounding D2B times really grinds my gears.
Actually, the focus on this study is mortality. Does D2B time have any affect on morbidity? On my phone, so I didn't really investigate that question prior to posting (sorry).
Thanks for this. The hype surrounding D2B times really grinds my gears.
Actually, the focus on this study is mortality. Does D2B time have any affect on morbidity? On my phone, so I didn't really investigate that question prior to posting (sorry).