JJ 16 Heparin for ACS and STEMI

Where I work, when a 60 year old man rolls into the resuscitation room with crushing chest pain and diaphoresis and I get handed the EMS ECG showing an obvious anterior STEMI, it’s kind of a no-brainer: Call a “Code STEMI” and tick off a bunch of boxes so that the nurses can go ahead a give a bunch of meds before the patient is whisked off to the cath lab. On that tick box list is ASA, with a NNT of 42 to prevent death [1].  Next on the list is heparin. I’ve been ticking that box for just about every patient with a STEMI, but now that I’ve reviewed the literature, I’m not so sure I should always be ticking that box - especially in the patient with more than a zero HAS-BLED score. What about NSTEMI or unstable angina? Does heparin - LMWH or unfractionated heparin - benefit the patient with, say, a pretty good story for angina with a bump in their troponin and some ST depression in the lateral leads? I think we’re expected to routinely give heparin for all these NSTEMI and unstable angina patients with any ischemic changes seen on the ECG, right? But should we?.... Podcast production by Justin Morgenstern, Rory Spiegel and Anton Helman. Podcast editing and sound design by Katrina D'Amore & Anton Helman. Blog summary by Anton Helman, Jan 2020. Cite this podcast as: Helman, A. Morgenstern, J. Spiegel, R. Journal Jam 16 - Heparin for ACS and STEMI. Emergency Medicine Cases. January, 2020. https://emergencymedicinecases.com/journal-jam-heparin-acs-stemi. Accessed [date] Heparin for ACS: NSTEMI and unstable angina Cochrane review 2014 [2] Heparin, for NSTEMI, when compared to placebo resulted in No change in mortality No change in revascularization No change in recurrent angina A small decrease in non-fatal MI A small increase in major bleeding 8 RCTs on heparin for ACS [3-10] Early studies in the late 1980's and early 1990's showed a small decrease in the rate of MI while on heparin that disappeared after the heparin is stopped. Subsequent studies asked if there was any benefit to continuing heparin for 30 days. They found that while the combined outcomes of recurrent angina/MI/death looked promising for benefit, when looked at separately, there was no mortality benefit, no recurrent MI benefit, and only some recurrent angina benefit - a subjective outcome. At 30 days they found an increase in major bleeding complications. Some of these trials noticed a benefit during the first week which led to further studies in the mid-1990's that suggested a slight decrease in non-fatal MI in the first week balanced against an increased risk of major bleeding complications at one month of about 1 in 33. Based on the totality of this data, it appears that heparin is not a life-saving medication in ACS and that it is unlikely to benefit NSTEMI or unstable angina patients, except perhaps those who are at very low risk for bleeding complications for the first week after the event.  Heparin for STEMI and/or PCI with or without thrombolytics Does heparin benefit STEMI patients who are going to the cath lab for PCI without thrombolytics? The surprising answer is: we don’t know. It has never been adequately studied. The AHA guideline [12] does recommend heparin for patients with STEMI going to the cath lab, however this is based on a level C recommendation (consensus expert opinion). They state “This recommendation does not come specifically from empirical data”. For patients with stable CAD undergoing elective PCI there has been only a single double-blind RCT of 700 which found that placebo was statistically noninferior to heparin for the primary outcome of a composite of death, MI and revascularization at 30 days, with more periprocedural MIs as well as bleeding complications in the heparin group. Does heparin benefit STEMI patients who are treat...