When it comes to regionalized STEMI care, we treat all STEMI patients the same. But are they the same?
The answer is, "No!"
Most EMS protocols include a maximum ground transport time of 30-60 when bypassing non-PCI hospitals (AHA Mission: Lifeline calls them "STEMI Referral Hospitals").
The idea is that when the "first medical contact-to-balloon" interval exceeds 90 minutes, the patient would be better served by transport to a non-PCI hospital for fibrinolytics.
Is this true?
The answer is, "Maybe!"
Consider Hospital delays in reperfusion for ST-elevation myocardial infarction: implications when selecting a reperfusion strategy. Circulation. 2006 Nov 7;114(19):2019-25
According to this table, the three variables to consider are:
- Symptom duration ( 120 min.)
- Age of the patient ( 65 years)
- Infarction location (anterior vs. non-anterior)
For early presenters (< 120 min. symptom onset) the point at which primary PCI loses its benefit over fibrinolytic therapy is an additional 94 minutes (that's door-to-balloon minus door-to-needle or D2B-D2N).
For late presenters (> 120 min. symptom onset) primary PCI loses its benefit at 190 min. (D2B-D2N).
For patients 65 years of age primary PCI loses its benefit at 155 min. (D2B-D2N).
For anterior infarction primary PCI loses its benefit at 115 minutes (D2B-D2N)
For non-anterior infarction primary PCI loses it benefit at 112 minutes (D2B-D2N).
The following graph illustrates how these variables interact.
This suggets that young patients who present early with anterior STEMI should probably receive fibronolytics prior to transfer.
On the other hand, late presenters and/or patients > 65 years of age should probably be transferred for primary PCI even when transport times are prolonged.
An elderly patient who presents early with acute anterior STEMI is right on the edge (assuming other "high risk" criteria are not met) at 107 minutes (D2B-D2N).