Acute coronary syndrome
In medicine and cardiology, acute coronary syndrome (ACS) is a collection is medical signs and symptoms due to myocardial ischemia.[1]
Etiology/causes
Atheroclerotic obstruction
ACS is usually caused by obstruction in an epicardial coronary artery.[2] The obstruction may be due to a thrombus at the site of a ruptured atherosclerotic plaque.[3]
Rupture seems more likely to occur during the morning hours.[4] Rupture may be precipited by inflammation from non-cardiac infections.[5] Rupture may be triggered by vigorous exercise among individuals who do not ordinarily do vigorous exercise.[6]
Coronary vasospasm
Approximately 15% of NSTEMI and 2% of STEMI patients have no obstruction of coronary vessels and in about half of these patients, spasm can be induced of a coronary artery.[2]
Stress-induced (takotsubo) cardiomyopathy
Stress-induced (takotsubo) cardiomyopathy may occur during acute medical illness or after intense emotional or physical stress.[7] It may be caused by catecholamines.
Classification
| Electrocardiogram | Serum biomarkers | Typical appearance of culprit vessel at angioscopy[3] | |
|---|---|---|---|
| Unstable angina | "ST-segment depression or prominent T-wave inversion"[8] | Normal | Nonocclusive grayish-white thrombus (platelet-rich) |
| Non-ST segment elevation myocardial infarction (NSTEMI) |
"ST-segment depression or prominent T-wave inversion"[8] | Elevated | Primary NSTEMI: Nonocclusive grayish-white thrombus (platelet-rich) Secondary NSTEMI: no thrombus |
| ST segment elevation myocardial infarction (STEMI) |
ST-segment elevation | Elevated | Occlusive reddish thrombus (fibrin-rich) |
| Q-wave myocardial infarction | Q-waves | Elevated | Occlusive reddish thrombus (fibrin-rich) |
Unstable angina
Unstable angina is defined as "precordial pain at rest, which may precede a myocardial infarction".[9]
Myocardial infarction
A myocardial infarction is defined as "gross necrosis of the myocardium, as a result of interruption of the blood supply to the area".[10] It is usually caused by occlusion of an epicardial coronary artery.[11]
Non-ST segment elevation myocardial infarction (NSTEMI)
NSTEMI is usually caused by a grayish-white thrombus that is platelet-rich.[3]
ST segment elevation myocardial infarction (STEMI)
STEMI is usually caused by a reddish thrombus that is fibrin-rich.[3]
Diagnosis
History and physical examination
A helpful finding is reproduction of chest pain upon palpating the chest. In a patient whose other findings also suggest a non-cardiac course of their chest pain, this finding can help rule out coronary disease.[12]
Electrocardiogram
The electrocardiogram is a key part of decision making. For example, the presence of ST changes and q-waves determines therapy. Recently, isolated abnormalities of T-waves also confers worse prognosis.[13]
Laboratory tests
Clinical practice guidelines jointly written by multiple expert groups anchor the diagnosis on troponin blood assays obtained within 6 hours and again within 8-12 hours of a patient arriving for medical care.[8][14]
Clinical prediction rules
The Acute Cardiac Ischemia Time-Insensitive Predictive Instrument (ACI-TIPI), a clinical prediction rule, can help diagnose patients with chest pain and has been shown to improve medical care in a randomized controlled trial.[15][16]
The ACI-TIPI was studied up through 1993 before troponin assays were widely available and thus does not incorporate the troponin. However, the ACI-TIPI should retain its ability to use the medical history and the EKG to decide who should be observed for serial troponin levels. It is unclear why this role is not recognized by the ACC/AHA guidelines. One reason may be that the ACI-TIPI is patented.[17][18]
Treatment
Clinical practice guidelines address the treatment of unstable angina and non-ST-elevation myocardial infarction.[8][14]
Unstable angina
Among patients with unstable angina or NSTEMI, patients with ST-segment changes (e.g. depression or a transient elevation), a Thrombolysis in Myocardial Infarction (TIMI) risk score of 3 or more, elevated myocardial enzymes, and elderly patients may be most likely to benefit from invasive management (percutaneous transluminal coronary angioplasty) according to the TACTICS randomized controlled trial.[19][20]
Myocardial infarction
Prognosis
The Thrombolysis in Myocardial Infarction (TIMI) risk score can estimate prognosis and guide decisions.
The GRACE Risk Score and the Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) risk model can also help predict which patients will have complications.
References
- ↑ Anonymous (2024), Acute coronary syndrome (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ 2.0 2.1 Ong P, Athanasiadis A, Hill S, Vogelsberg H, Voehringer M, Sechtem U (August 2008). "Coronary artery spasm as a frequent cause of acute coronary syndrome: The CASPAR (Coronary Artery Spasm in Patients With Acute Coronary Syndrome) Study". J. Am. Coll. Cardiol. 52 (7): 523–7. DOI:10.1016/j.jacc.2008.04.050. PMID 18687244. Research Blogging.
- ↑ 3.0 3.1 3.2 3.3 Mizuno K, Satomura K, Miyamoto A, et al (January 1992). "Angioscopic evaluation of coronary-artery thrombi in acute coronary syndromes". N. Engl. J. Med. 326 (5): 287–91. PMID 1728732. [e]
- ↑ Muller JE, Stone PH, Turi ZG, et al (November 1985). "Circadian variation in the frequency of onset of acute myocardial infarction". N. Engl. J. Med. 313 (21): 1315–22. PMID 2865677. [e]
- ↑ Harskamp RE, van Ginkel MW (2008). "Acute respiratory tract infections: a potential trigger for the acute coronary syndrome". Ann. Med. 40 (2): 121–8. DOI:10.1080/07853890701753672. PMID 18293142. Research Blogging.
- ↑ Siscovick DS, Weiss NS, Fletcher RH, Lasky T (October 1984). "The incidence of primary cardiac arrest during vigorous exercise". N. Engl. J. Med. 311 (14): 874–7. PMID 6472399. [e]
- ↑ Kurowski V, Kaiser A, von Hof K, et al (September 2007). "Apical and midventricular transient left ventricular dysfunction syndrome (tako-tsubo cardiomyopathy): frequency, mechanisms, and prognosis". Chest 132 (3): 809–16. DOI:10.1378/chest.07-0608. PMID 17573507. Research Blogging.
- ↑ 8.0 8.1 8.2 8.3 8.4 Anderson JL, Adams CD, Antman EM, et al (2007). "ACC/AHA 2007 guidelines for the management of patients with unstable angina/non-ST-Elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines for the Management of Patients With Unstable Angina/Non-ST-Elevation Myocardial Infarction) developed in collaboration with the American College of Emergency Physicians, the Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation and the Society for Academic Emergency Medicine". J. Am. Coll. Cardiol. 50 (7): e1–e157. DOI:10.1016/j.jacc.2007.02.013. PMID 17692738. Research Blogging.
Executive summary Summary at National Guidelines Clearinghouse Cite error: Invalid
<ref>tag; name "pmid17692738" defined multiple times with different content Cite error: Invalid<ref>tag; name "pmid17692738" defined multiple times with different content - ↑ National Library of Medicine. Unstable angina. Retrieved on 2007-10-28.
- ↑ National Library of Medicine. Myocardial infarction. Retrieved on 2007-10-28.
- ↑ DeWood MA, Spores J, Notske R, et al (October 1980). "Prevalence of total coronary occlusion during the early hours of transmural myocardial infarction". N. Engl. J. Med. 303 (16): 897–902. PMID 7412821. [e]
- ↑ Bruyninckx R, Aertgeerts B, Bruyninckx P, Buntinx F (February 2008). "Signs and symptoms in diagnosing acute myocardial infarction and acute coronary syndrome: a diagnostic meta-analysis". Br J Gen Pract 58 (547): 105–11. DOI:10.3399/bjgp08X277014. PMID 18307844. Research Blogging.
- ↑ Lin KB, Shofer FS, McCusker C, Meshberg E, Hollander JE (June 2008). "Predictive value of T-wave abnormalities at the time of emergency department presentation in patients with potential acute coronary syndromes". Acad Emerg Med 15 (6): 537–43. DOI:10.1111/j.1553-2712.2008.00135.x. PMID 18616439. Research Blogging.
- ↑ 14.0 14.1 Braunwald E, Antman EM, Beasley JW, et al (2002). "ACC/AHA 2002 guideline update for the management of patients with unstable angina and non-ST-segment elevation myocardial infarction--summary article: a report of the American College of Cardiology/American Heart Association task force on practice guidelines (Committee on the Management of Patients With Unstable Angina)". J. Am. Coll. Cardiol. 40 (7): 1366–74. PMID 12383588. [e]
- ↑ Selker HP, Beshansky JR, Griffith JL, et al (1998). "Use of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI) to assist with triage of patients with chest pain or other symptoms suggestive of acute cardiac ischemia. A multicenter, controlled clinical trial". Ann. Intern. Med. 129 (11): 845–55. PMID 9867725. [e] Online calculator at InfoRetriever
- ↑ Selker HP, Griffith JL, D'Agostino RB (1991). "A tool for judging coronary care unit admission appropriateness, valid for both real-time and retrospective use. A time-insensitive predictive instrument (TIPI) for acute cardiac ischemia: a multicenter study". Med Care 29 (7): 610–27. PMID 2072767. [e]
- ↑ Selker HP et al.. Continuous monitoring using a predictive instrument. Retrieved on 2007-11-29.
- ↑ Selker HP et al.. Continuous monitoring using a predictive instrument. Retrieved on 2007-11-29.
- ↑ Cannon CP, Weintraub WS, Demopoulos LA, et al (2001). "Comparison of early invasive and conservative strategies in patients with unstable coronary syndromes treated with the glycoprotein IIb/IIIa inhibitor tirofiban". N. Engl. J. Med. 344 (25): 1879-87. PMID 11419424. [e]
- ↑ Bach RG, Cannon CP, Weintraub WS, et al (2004). "The effect of routine, early invasive management on outcome for elderly patients with non-ST-segment elevation acute coronary syndromes". Ann. Intern. Med. 141 (3): 186-95. PMID 15289215. [e]