The National Registry of Myocardial Infarction (NRMI) was a large, prospective US registry, running from 1990 to 2006, which collected data on reperfusion therapy, including door-to-needle (D2N) and door-to-balloon (D2B) times, and outcomes of more than 2.5 million patients with acute myocardial infarction, of which 1,374,232 patients had ST-elevation myocardial infarction (STEMI).
Patients were selected if they had a diagnosis of acute ST-elevation myocardial infarction and/or left bundle branch block on initial ECG and <12 h after onset of symptoms, and also if they received reperfusion therapy – either primary percutaneous coronary intervention (PPCI) or thrombolysis – at a NRMI hospital.
NRMI: Selection criteria
A key finding of the NRMI has been the documentation of changes in the use and type of reperfusion therapy for patients with ST-segment elevation myocardial infarction (STEMI) and changes in door-to-needle (D2N) times for fibrinolysis and door-to-balloon (D2B) times for primary percutaneous coronary intervention (PPCI).
Over the duration of the study, the proportion of STEMI patients eligible for but not receiving reperfusion therapy decreased significantly, from 44.9% in 1990 to 28.1% in 2006 (p <0.001).
In 1990, the predominant reperfusion therapy was fibrinolysis (52.5%), with primary PCI used in only a very small proportion of patients (2.6%). However, by 2006, primary PCI had overtaken fibrinolysis as the predominant form of reperfusion therapy (43.2% versus 27.6%). These findings mirror results from the international GRACE registry.
NRMI: Trends in reperfusion for reperfusion-eligible STEMI patients, 1990 to 2006
Among eligible STEMI patients that were treated with fibrinolysis, the D2N time decreased from 59 min in 1990 to 29 min in 2006 (p <0.001 for trend). This corresponded to a decrease in in-hospital mortality for patients treated with fibrinolysis from 7.0% in 1994 to 6.0% in 2006 (p <0.001 for trend). The relative improvement in mortality attributable to reductions in D2N was estimated to be between 14.3 and 16.3%.
Among eligible STEMI patients that were treated with primary PCI, the D2B time decreased from 120 min in 1994 to 87 min in 2006 (p <0.001 for trend). For non-transfer patients, D2B time decreased from 111 to 79 min, whereas for patients transferred from other hospitals or emergency departments, D2B time decreased from 226 to 139 min. This corresponded to a decrease in in-hospital mortality for patients treated with pPCI from 8.6% in 1994 to 3.3% in 2006. The relative improvement in mortality attributable to reductions in D2B was estimated to be between 5.8% and 7.5%.
NRMI: Trends in door-to-needle (D2N) times, 1990 to 2006, and door-to-balloon (D2B) times, 1994 to 2006
NRMI: Changes in in-hospital mortality for STEMI patients receiving thrombolysis or PPCI (1994 to 2006)
- The rate of overall reperfusion for patients diagnosed with ST-elevation myocardial infarction increased from 1990 to 2006, with proportionally more patients receiving PPCI than thrombolysis in 2006.
- There were significant reductions in D2N and D2B times for STEMI patients eligible for reperfusion therapy over the duration of the NRMI, which resulted in a significant improvement in in-hospital mortality for all reperfusion strategies.
- French WJ, et al. Transforming quality of care and improving outcomes after acute MI. Lessons from the National Registry of Myocardial Infarction. JAMA 2012;308:771-772.
- Gibson CM, et al. Trends in reperfusion strategies, door-to-needle and door-to-balloon times, and in-hospital mortality among patients with ST-segment elevation myocardial infarction enrolled in the National Registry of Myocardial Infarction from 1990 to 2006. Am Heart J 2008;156:1035-1044.
- Pinto DS, et al. Hospital delays in reperfusion for ST-elevation myocardial infarction. Implications when selecting a reperfusion strategy. Circulation 2006;114:2019-2025.