Nobody can debate that PCI is associated with better outcomes than fibrinolytics in patients with STEMI. However, it is reasonable to question the continual use of fixed time windows (90 minutes or 120 minutes) that the ACC/AHA recommends in choosing between fibrinolytics vs STEMI. Let's consider the case I presented at the beginning of this discussion. If the time to balloon inflation were going to be 119 minutes, would the patient truly be better served by following the new guidelines and thus letting him infarct myocardium for almost 2 additional hours awaiting balloon inflation when we could instead administer immediate fibrinolytics? Would the scenario change if the patient were 75 years old, had an inferior wall STEMI, and had been already having symptoms for 2 hours before the diagnosis?
For at least the past decade, some cardiology researchers have been evaluating the concept that the fibrinolytic vs PCI decision should be based on more than just using a single time window for every single patient. Instead, factors such as the location of infarction, duration of symptoms, age, cardiac risk factors, and so on should be incorporated into the decision regarding how long we should be willing to wait for balloon inflation in favor of fibrinolytics.
Pinto and colleagues published an example of this in 2006. In that study, the authors analyzed more than 190,000 patients from a national STEMI registry. When they looked at various combinations of age, location of infarct, and duration of symptoms, here's what they found (the times indicate how long we can wait for balloon inflation before we lose the survival advantage of PCI over fibrinolytics).
If the patient presents within 2 hours of symptom onset and:
Has an anterior STEMI and is < 65 years old: 40 minutes
Has an anterior STEMI and is > 65 years old: 107 minutes
Has a nonanterior STEMI and is < 65 years old: 58 minutes
Has a nonanterior STEMI and is > 65 years old: 168 minutes
If the patient presents beyond 2 hours of symptom onset and:
Has an anterior STEMI and is < 65 years old: 43 minutes
Has an anterior STEMI and is > 65 years old: 148 minutes
Has a nonanterior STEMI and is < 65 years old: 103 minutes
Has a nonanterior STEMI and is > 65 years old: 179 minutes
What is notable about these numbers is that if a patient < 65 years of age presents with an anterior STEMI, that patient has a survival advantage of PCI over fibrinolytics only if balloon inflation occurs within 40-45 minutes, not 90 or 120 minutes! At the other extreme, if a patient > 65 years of age presents with an inferior STEMI, we can choose PCI over fibrinolytics even if the delay to balloon inflation is almost 3 hours.
Please understand that I'm not trying to promote increased use of fibrinolytics in young patients with anterior STEMI, nor am I suggesting a laissez-faire approach to PCI in older patients. The numbers listed above surely would change with a reanalysis using more recent studies since 2006 reflecting improvements in interventional procedures. However, it appears that the continued use of a one-size-fits-all approach to the PCI vs fibrinolytics decision is flawed and is probably harming our patients. It's time for our national organizations to start producing guidelines that allow a more intelligent, evidence-based approach to the PCI vs fibrinolytics decision rather than simply dumbing it down to 120 minutes for every patient.
Medscape Emergency Medicine © 2013 WebMD, LLC
Cite this: Amal Mattu. New STEMI Guidelines: How Long Should We Wait for the Balloon? - Medscape - Jan 30, 2013.