To STEMI or NSTEMI, That is the Question!

By Janie Liang

To STEMI or NSTEMI, That is The Question!: Treating Patients with Chest Pain and ECG Changes

CASE

History: 63 year old man with a PMH of appendiceal cancer s/p appendectomy and PAD s/p stent in L carotid and LLE, HF and alcohol use disorder presented to the ED via EMS with shortness of breath. Patient states that he was diagnosed with COPD in January of this year, in the past month, he has been having progressive shortness of breath when walking. His shortness of breath worsened overnight. He states that he had waxing and waning episodes of positional shortness of breath every 10 or so minutes that woke him up from sleep. Patient also endorses a sharp left side pain that comes and goes.

Physical Exam:

Vitals: BP 165/106 | Pulse 104 | Temp 36.9 °C (98.4 °F) | Resp 22 | SpO2 98% on 2L NC

Cardiovascular: Normal rate and regular rhythm. Decreased pulses in bilateral lower limbs

Pulmonary: Tachypnea present. No stridor. Wheezing and rales present bilaterally

Musculoskeletal: 2+ edema present on bilateral lower limbs

ED course + results:

Elevated troponin (115>110>120) and BNP of over 4,472
Initial ECG showed concerning ST elevation
ST elevation were present in previous ECG, no changes to ECG as compared to previous ECGs
CXR: Cardiomegaly, pulmonary edema and likely small pleural effusions.
Patient was given furosemide for diuresis
Admitted to internal medicine

Images:

Clinical Question: Is it adequate to use the dichotomy of STEMI vs NSTEMI to decide on PCI and whether adding OMI (obstructive MI) vs NOMI (non-obstructive MI) can add nuance to treating patients with chest pain and ECG changes.

Summary of Evidence

The AHA describes a STEMI using the following criteria (3):

New ST elevation at the J point of greater than 1 mm in two contiguous leads in all leads except V2-V3
In leads V2-V3, the cutoff is 2 mm in men greater than 40, 2.5 mm in men less than 40 and 1.5 mm in women of all ages

This definition is frequently used when determining whether a patient needs urgent PCI however is rather narrow and does not take into account the NSTEMI ECG patterns that could also benefit from PCI. In a paper in the American Heart Journal, researcher examined the patients from a trial in which the patients randomly received either lamifiban which is a Platelet IIb/IIIa Antagonist or a placebo. They specifically looked at the 1957 patients who presented with non-STEMI acute coronary syndrome and they found that 27% of them had occlusion in their arteries (4). This study is a retrospective study so the strength of evidence is limited.

Further review of available literature revealed a paper by Avdikos et al that compiled several observational studies and meta-analysis on the topic showed anywhere between 14% to 35% of total occlusions were being missed with the STEMI vs NSTEMI classification system (5). Furthermore, the paper found that death, recurrent MI and cardiogenic shock was statistically increased in NSTEMI with total occlusion than in NSTEMI without total occlusion, The strengths of this paper is that they were able to give sensitivity and specificity of certain ECG patterns in their ability to establish total occlusion. Examples of ECG patterns that strongly suggest total occlusive event without ST elevation include De Winter sign, Wellen syndrome’s, hyperacute T wave, posterior wall MI, occult LCx MI, South African Flag Sign (1,2)). Examples of ECG patterns that mimic ST elevation without indicating occlusive pattern. LBBB, left ventricular hypertrophy, left ventricular aneurysm. Previously, there was no concrete definition on which ECG patterns indicate an emergent PCI candidate beyond the STEMI vs NSTEMI classification. The decision to send a patient to PCI was then left to the discretion of the provider. One of the downfalls of this paper is that because it is a analysis of literature, it is subject to interpretation from the writer.

RECOMMENDATIONS

New onset STEMI that fulfill the AHA definition of STEMI can benefit from urgent revascularization (6,7)
High risk NSTEMI with ECG evidence highly suggestive of occlusion should be sent to PCI immediately (2)
High risk ECG patterns are Wellens pattern, De Winters pattern, posterior wall MI, right ventricular wall MI, occult LCx MI, hyperacute T waves, ST elevation in AVR
High risk NSTEMI with possible ECG evidence of occlusion should get a CT angiogram first (2)
Obstruction greater than 50% should get revascularization
Obstruction less than 50% can be managed medically
Low risk NSTEMI with no ECG evidence of occlusions can be managed medically

REFERENCES

Kontos, M, de Lemos, J. et al. 2022 ACC Expert Consensus Decision Pathway on the Evaluation and Disposition of Acute Chest Pain in the Emergency Department: A Report of the American College of Cardiology Solution Set Oversight Committee. JACC. 2022 Nov, 80 (20) 1925–1960.
Sankardas, M. A., Ramakumar, V., & Farooqui, F. A. (2021). Of occlusions, inclusions, and exclusions: Time to reclassify infarctions? Circulation, 144(5), 333–335. https://doi.org/10.1161/circulationaha.121.055827
Correction to: Fourth universal definition of myocardial infarction (2018). (2018). Circulation, 138(20). https://doi.org/10.1161/cir.0000000000000632
Wang TY, Zhang M, Fu Y, Armstrong PW, Newby LK, Gibson CM, Moliterno DJ, Van de Werf F, White HD, Harrington RA, Roe MT. Incidence, distribution, and prognostic impact of occluded culprit arteries among patients with non-ST-elevation acute coronary syndromes undergoing diagnostic angiography. Am Heart J. 2009 Apr;157(4):716-23. doi: 10.1016/j.ahj.2009.01.004. PMID: 19332201.
Avdikos G, Michas G, Smith SW. From Q/Non-Q Myocardial Infarction to STEMI/NSTEMI: Why It's Time to Consider Another Simplified Dichotomy; a Narrative Literature Review. Arch Acad Emerg Med. 2022 Oct 1;10(1):e78. doi: 10.22037/aaem.v10i1.1783. PMID: 36426169; PMCID: PMC9676707.
Pendell Meyers H, Bracey A, Lee D, Lichtenheld A, Li WJ, Singer DD, Rollins Z, Kane JA, Dodd KW, Meyers KE, Shroff GR, Singer AJ, Smith SW. Accuracy of OMI ECG findings versus STEMI criteria for diagnosis of acute coronary occlusion myocardial infarction. Int J Cardiol Heart Vasc. 2021 Apr 12;33:100767. doi: 10.1016/j.ijcha.2021.100767. PMID: 33912650; PMCID: PMC8065286.
Meyers HP, Bracey A, Lee D, Lichtenheld A, Li WJ, Singer DD, Kane JA, Dodd KW, Meyers KE, Thode HC, Shroff GR, Singer AJ, Smith SW. Comparison of the ST-Elevation Myocardial Infarction (STEMI) vs. NSTEMI and Occlusion MI (OMI) vs. NOMI Paradigms of Acute MI. J Emerg Med. 2021 Mar;60(3):273-284. doi: 10.1016/j.jemermed.2020.10.026. Epub 2020 Dec 9. PMID: 33308915.