Acute coronary syndromes (STEMI, NSTEMI and unstable angina)

A 62-year-old smoker arrives with crushing central chest pressure radiating to both arms, diaphoretic and nauseous, breathless for the last hour. The ECG shows 3 mm ST elevation in V2 to V4. The cath lab is being called before his troponin comes back — because the ECG, not the biomarker, defines the emergency now.^[1]

Two questions decide his next hour, and they decide every ACS: is the artery occluded? (the ECG at first contact) and can I open it in time? (NICE 120 minutes from when fibrinolysis could have been given; DANAMI-2 two-hour transfer). Exclude dissection clinically first, give the bundle, then fork on the ECG — STEMI to reperfusion, NSTE-ACS to risk-stratified timing.^[1]

Definition and classification

ACS is classified by the ECG and by troponin. Unstable angina is ischaemia at rest or on minimal exertion without biomarker evidence of necrosis. NSTEMI is ischaemia with a rise or fall in cardiac troponin. STEMI is ischaemia with ST elevation or an ST-elevation equivalent on the ECG. The unstable-angina-versus-NSTEMI line is troponin; the NSTEMI-versus-STEMI line is the ECG. A separate entity, type 2 MI, is myocardial necrosis from a supply-demand mismatch (tachyarrhythmia, hypotension, sepsis, severe anaemia) without plaque rupture, and it must not be confused with the type 1 plaque-rupture ACS that drives the reperfusion pathway. ^[1]

References32ShowHide

1. [1]Byrne RA, Rossello X, Coughlan JJ, et al. 2023 ESC Guidelines for the management of acute coronary syndromes Eur Heart J, 2023.PMID 37622654
2. [2]Wallentin L, Becker RC, Budaj A, et al. Ticagrelor versus clopidogrel in patients with acute coronary syndromes N Engl J Med, 2009.PMID 19717846
3. [3]Wiviott SD, Braunwald E, McCabe CH, et al. Prasugrel versus clopidogrel in patients with acute coronary syndromes N Engl J Med, 2007.PMID 17982182
4. [4]Stub D, Smith K, Bernard S, et al. Air Versus Oxygen in ST-Segment-Elevation Myocardial Infarction Circulation, 2015.PMID 26002889
5. [5]Thiele H, Zeymer U, Thelemann N, et al. Intraaortic Balloon Pump in Cardiogenic Shock Complicating Acute Myocardial Infarction: Long-Term 6-Year Outcome of the Randomized IABP-SHOCK II Trial Circulation, 2019.PMID 30586721
6. [6]Poldervaart JM, Reitsma JB, Backus BE, et al. Effect of Using the HEART Score in Patients With Chest Pain in the Emergency Department: A Stepped-Wedge, Cluster Randomized Trial Ann Intern Med, 2017.PMID 28437795
7. [7]Yusuf S, Zhao F, Mehta SR, et al. Effects of clopidogrel in addition to aspirin in patients with acute coronary syndromes without ST-segment elevation N Engl J Med, 2001.PMID 11519503
8. [8]Van de Werf F, Adgey J, Ardissino D, et al. Single-bolus tenecteplase compared with front-loaded alteplase in acute myocardial infarction: the ASSENT-2 double-blind randomised trial Lancet, 1999.PMID 10475182
9. [9]Armstrong PW, Gershlick AH, Goldstein P, et al. Fibrinolysis or primary PCI in ST-segment elevation myocardial infarction N Engl J Med, 2013.PMID 23473396
10. [10]Antman EM, Morrow DA, McCabe CH, et al. Enoxaparin versus unfractionated heparin with fibrinolysis for ST-elevation myocardial infarction N Engl J Med, 2006.PMID 16537665
11. [11]Fox KA, Dabbous OH, Goldberg RJ, et al. Prediction of risk of death and myocardial infarction in the six months after presentation with acute coronary syndrome: prospective multinational observational study (GRACE) BMJ, 2006.PMID 17032691
12. [12]Montalescot G, Bolognese L, Dudek D, et al. Pretreatment with prasugrel in non-ST-segment elevation acute coronary syndromes N Engl J Med, 2013.PMID 23991622
13. [13]Andersen HR, Nielsen TT, Rasmussen K, et al. A comparison of coronary angioplasty with fibrinolytic therapy in acute myocardial infarction N Engl J Med, 2003.PMID 12930925
14. [14]Hofmann R, James SK, Jernberg T, et al. Oxygen Therapy in Suspected Acute Myocardial Infarction N Engl J Med, 2017.PMID 28844200
15. [15]Thiele H, Akin I, Sandri M, et al. PCI Strategies in Patients with Acute Myocardial Infarction and Cardiogenic Shock N Engl J Med, 2017.PMID 29083953
16. [16]Hochman JS, Sleeper LA, Webb JG, et al. Early revascularization in acute myocardial infarction complicated by cardiogenic shock N Engl J Med, 1999.PMID 10460813
17. [17]Granger CB, Goldberg RJ, Dabbous O, et al. Predictors of hospital mortality in the global registry of acute coronary events Arch Intern Med, 2003.PMID 14581255
18. [18]Thiele H, Zeymer U, Neumann FJ, et al. Intraaortic balloon support for myocardial infarction with cardiogenic shock N Engl J Med, 2012.PMID 22920912
19. [19]Mehta SR, Granger CB, Boden WE, et al. Early versus delayed invasive intervention in acute coronary syndromes N Engl J Med, 2009.PMID 19458363
20. [20]Jaeger C, Wildi K, Twerenbold R, et al. One-hour rule-in and rule-out of acute myocardial infarction using high-sensitivity cardiac troponin I Am Heart J, 2016.PMID 26699605
21. [21]Sgarbossa EB, Pinski SL, Barbagelata A, et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block N Engl J Med, 1996.PMID 8559200
22. [22]Smith SW, Dodd KW, Henry TD, et al. Diagnosis of ST-elevation myocardial infarction in the presence of left bundle branch block with the ST-elevation to S-wave ratio in a modified Sgarbossa rule Ann Emerg Med, 2012.PMID 22939607
23. [23]Meyers HP, Limkakeng AT, Jaffa EJ, et al. Validation of the modified Sgarbossa criteria for acute coronary occlusion in the setting of left bundle branch block Am Heart J, 2015.PMID 26678648
24. [24]de Zwaan C, Bär FW, Wellens HJ Characteristic electrocardiographic pattern indicating a critical stenosis high in left anterior descending coronary artery in patients admitted because of impending myocardial infarction Am Heart J, 1982.PMID 6121481
25. [25]Verouden NJ, Koch KT, Peters RJ, et al. Persistent precordial hyperacute T-waves signify proximal left anterior descending artery occlusion Heart, 2009.PMID 19620137
26. [26]ISIS-2 (Second International Study of Infarct Survival) Collaborative Group Randomised trial of intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2 Lancet, 1988.PMID 2899772
27. [27]Hobl EL, Stimpfl T, Ebner J, et al. Morphine decreases clopidogrel concentrations and effects: a randomized, double-blind, placebo-controlled trial J Am Coll Cardiol, 2014.PMID 24315907
28. [28]Goldstein JA Pathophysiology and management of right heart ischemia J Am Coll Cardiol, 2002.PMID 12225706
29. [29]Kinch JW, Ryan TJ Right ventricular infarction N Engl J Med, 1994.PMID 8139631
30. [30]Antman EM, Cohen M, Bernink PJ, et al. The TIMI risk score for unstable angina/non-ST elevation MI: A method for prognostication and therapeutic decision making JAMA, 2000.PMID 10938172
31. [31]Subherwal S, Bach RG, Chen AY, et al. Baseline risk of major bleeding in non-ST-segment-elevation myocardial infarction: the CRUSADE Bleeding Score Circulation, 2009.PMID 19332461
32. [32]National Institute for Health and Care Excellence Acute coronary syndromes (NG185) NICE, 2020.Source