Management of acute coronary syndrome

Source: Wikipedia, the free encyclopedia.

Management of acute coronary syndrome
heart muscle is blocked, eventually causing cell death.
Specialtycardiology
]

Management of acute coronary syndrome is targeted against the effects of reduced blood flow to the affected area of the

electrocardiogram, which classifies cases upon presentation to either ST segment elevation myocardial infarction (STEMI) or non-ST elevation acute coronary syndrome (NST-ACS); the latter includes unstable angina and non-ST elevation myocardial infarction (NSTEMI). Treatment is generally more aggressive for STEMI patients, and reperfusion therapy is more often reserved for them. Long-term therapy is necessary for prevention of recurrent events and complications.[1]

General principles

Acute coronary syndromes are caused by sudden and critical reduction of blood flow in one of the coronary arteries, the vessels that supply oxygenated blood to the myocardium (heart muscle), typically by a blood clot. The principal symptom is typically chest pain, known as angina pectoris; people who present with angina must prompt evaluation for possible acute coronary syndrome.[2]

Acute coronary syndromes are classified to two major categories, according to the patient's electrocardiogram, and specifically the presence or absence of persistent (>20 min)

ST segment elevation (or left bundle branch block).[2] Patients with acute coronary syndrome and ST elevation are said to have ST-elevation myocardial infarction (STEMI) and they tend to have one of their coronary arteries totally blocked.[3] Damage is reversible for approximately 20[4]-30[5] minutes after complete obstruction of blood flow; thereafter myocardial cell death ensues and progresses as time passes. Therefore, complete and sustained restoration of blood flow must be as prompt as possible to ensure maximum salvage of functional myocardium, a principle expressed in the maxim "time is muscle".[6] This is achieved with reperfusion therapy, which is based on invasive reopening of the affected coronary artery with primary percutaneous coronary intervention, or non-invasive breaking up of the responsible blood clot with a thrombolytic drug.[7]

Patients without ST segment elevation are said to have non-ST-elevation acute coronary syndrome and tend not to have full occlusion of a coronary artery. If there is evidence of myocardial cell death (especially elevated

coronary angiography and, if necessary, revascularization with percutaneous coronary intervention or coronary artery bypass surgery.[9]

Medical therapy for acute coronary syndromes is based on drugs that act against ischemia and resultant angina and limit the infarct size (i.e., the area of myocardium that is affected), as well as drugs that inhibit clot formation. The latter include antiplatelet agents, which block the activation and aggregation of platelets (cellular blood components that contribute to clot formation), and anticoagulant agents (which attenuate the coagulation cascade). Long-term therapy in acute coronary syndrome survivors is targeted against recurrence and long-term complications (secondary prevention).[1]

Women are taken less seriously than men when they have a heart attack leading to higher mortality among women.[10]

Patient-dependent initial measures

Information card writing: "Heart Attack: Know the Symptoms. Take Action. Call 911" and depicting people holding their chest in pain
Information card published by the National Heart, Lung, and Blood Institute urging people with symptoms of angina to call the emergency medical services.

Because of the relationship between the duration of myocardial ischemia and the extent of damage to heart muscle, public health services encourage people experiencing possible acute coronary syndrome symptoms or those around them to immediately call emergency medical services.[11][12][13]

It is advised that the patients remain relaxed in a position that is comfortable for them. In case of heart attack,[14] the best position is not usually horizontal (lying down), but sitting down or sitting down with folded knees (but the patients would notice it by themselves).

Patients with known

nitroglycerin should promptly take one dose, and call emergency medical services if their symptoms do not improve within 2–5 minutes. Taking aspirin is encouraged (unless there are contraindications),[15]
chewable non-enteric-coated aspirin and effervescent aspirin dissolved into pieces act sooner.

Patients should not be transported to hospital by private vehicles instead of an ambulance, unless evacuation by land or air ambulance is impossible (e.g., dangerous weather in a very remote area), and if they must be, it should be done if possible with someone trained in cardiac first aid.

Health care professionals are responsible for teaching their patients at risk of acute coronary syndrome what the symptoms of this condition are, and that it is imperative to seek urgent medical attention in case they present.[16]

Emergency services

Emergency Medical Services (EMS) Systems vary considerably in their ability to evaluate and treat patients with suspected acute myocardial infarction. Some provide as little as first aid and early defibrillation. Others employ highly trained paramedics with sophisticated technology and advanced protocols.

nitroglycerine, morphine, and aspirin. Some advanced paramedic systems can also perform 12-lead ECGs.[18] If a STEMI is recognized the paramedic may be able to contact the local PCI hospital and alert the emergency room physician, and staff of the suspected AMI. Some Paramedic services are capable of providing thrombolytic therapy in the prehospital setting, allowing reperfusion of the myocardium.[19][20]

With

ECG in the field and using this information to triage the patient to the most appropriate medical facility.[21][22][23][24] In addition, the 12-lead ECG can be transmitted to the receiving hospital, which enables time saving decisions to be made prior to the arrival of the patient. This may include a "cardiac alert" or "STEMI alert" that calls in off duty personnel in areas where the cardiac cath lab is not staffed 24 hours a day.[25] Even in the absence of a formal alerting program, prehospital 12-lead ECGs are independently associated with reduced door to treatment intervals in the emergency department.[26]

Initial diagnostic approach

non ST elevation myocardial infarction (NSTEMI) and unstable angina.[28][29][30]

Relief of angina

Relief of the pain of angina is of paramount importance, not only for humane reasons but because the pain is associated with

beta blockers and oxygen.[31]

Nitrates

Nitrates, like

sublingually. By relaxing blood vessels nitrates also reduce blood pressure, which must be carefully monitored; they must not be used if hypotension is present. They must also be avoided in patients who have taken sildenafil or other phosphodiesterase type 5 inhibitors (used for erectile dysfunction) within the previous 24–48 hours, as the combination of the two could cause a serious drop in blood pressure.[31][32][33] Intravenous nitrates are useful in patients with hypertension or pulmonary edema.[34]

Beta blockers

By reducing

congestive heart failure (e.g., Killip class II or above) or hypotension, along with other contraindications to beta blockers (slow heart rate, atrioventricular block); in the absence of contraindications beta blocker therapy should begin in the first 24 hours. It may be prudent to prefer oral rather than intravenous forms.[35]

Oxygen therapy

Initial administration of oxygen to all patients with acute coronary syndrome is common practice; however, there is no evidence to support or refute that supplemental oxygen might be harmful or beneficial for cardiac patients who do not need it.[36] It is currently recommended to give oxygen only to breathless patients or when blood oxygen saturation is low, e.g. <90%.[31][37]

Analgesics

Analgesic agents that are most commonly used are

Non-steroidal anti-inflammatory drugs are contraindicated for both categories of patients.[40][41]

Antiplatelet drugs

All patients with acute coronary syndrome must immediately receive

antiplatelet therapy, including aspirin and generally a second oral antiplatelet agent.[42] Bleeding is the most important side-effect of antiplatelets.[citation needed
]

Aspirin

Aspirin inhibits platelet aggregation and formation of blood clots. It is effective across the entire spectrum of acute coronary syndromes; it has been shown to reduce the rate of death in patients with STEMI and in patients presenting without ST elevation. Aspirin is contraindicated in patients with documented allergy or known platelet disorder. Patients who have had gastrointestinal symptoms while on long-term aspirin therapy are usually able to tolerate aspirin in the short term. For patients with true intolerance to aspirin clopidogrel is recommended. Lower doses need days to achieve full antiplatelet effect, therefore a loading dose is necessary for patients who are not already on aspirin.[43]

P2Y12 inhibitors

Aside from aspirin, three antiplatelet agents taken by mouth have been approved for use in acute coronary syndromes, clopidogrel,

adenosine phosphate receptor, on the surface of platelets. Not all three of them are equally indicated in all types of acute coronary syndromes. In patients with ST elevation the choice of P2Y12 inhibitor depends on reperfusion strategy; for patients undergoing primary percutaneous coronary intervention ticagrelor and prasugrel are considered superior to clopidogrel, as they are more potent and have more rapid onset of action, at the cost of some increase in bleeding risk; for STEMI patients who are treated with fibrinolysis and those who do not undergo reperfusion treatment only clopidogrel is indicated. Prasugrel must not be given to patients with a history of ischemic stroke or aged 75 years or older. In patients with non-ST elevation acute coronary syndrome current guidelines also recommend immediate administration of dual antiplatelet therapy upon diagnosis; clopidogrel and ticagrelor are indicated in this setting, with ticagrelor considered superior for patients undergoing early invasive strategy (see later). However, emerging evidence questions this strategy.[44] As with aspirin, it is necessary to administer a loading dose.[45][46]

Glycoprotein IIb/IIIa inhibitors

Glycoprotein IIb/IIIa inhibitors are a class of intravenous antiplatelet agents used in patients undergoing percutaneous coronary intervention, consisting of abciximab, eptifibatide and tirofiban. Patients presenting with ST elevation that will be reperfused with percutaneous coronary intervention may receive one of the above agents at the time of catheterization, or perhaps before. Administering eptifibatide or tirofiban may also be reasonable in patients presenting with NST-ACS who are considered of intermediate or high risk and are treated with early invasive strategy.[47][48]

Anticoagulants

Anticoagulants in acute coronary syndrome are targeted against the coronary blood clot, as well as towards prevention of thrombotic complications, like formation of blood clots in the

activated partial thromboplastin time (APTT). In STEMI patients choice depends on the reperfusion strategy used (see below); bivalirudin is used when PCI is employed only, while in the same case fondaparinux is not preferred.[50] Similarly, in Non-STE ACS bivalirudin too is only used when an early invasive strategy is chosen.[51]

Reperfusion

Main article: Reperfusion therapy
ECG are presumed to have an occlusive thrombosis in an epicardial coronary artery. They are therefore candidates for immediate reperfusion, either with thrombolytic therapy, percutaneous coronary intervention (PCI) or when these therapies are unsuccessful, bypass surgery.[citation needed
]

Individuals without ST segment elevation are presumed to be experiencing either unstable angina (UA) or non-ST segment elevation myocardial infarction (NSTEMI). They receive many of the same initial therapies and are often stabilized with antiplatelet drugs and anticoagulated. If their condition remains (hemodynamically) stable, they can be offered either late coronary angiography with subsequent restoration of blood flow (revascularization), or non-invasive stress testing to determine if there is significant ischemia that would benefit from revascularization. If hemodynamic instability develops in individuals with NSTEMIs, they may undergo urgent coronary angiography and subsequent revascularization. The use of thrombolytic agents is contraindicated in this patient subset, however.[55]

The basis for this distinction in treatment regimens is that ST segment elevations on an ECG are typically due to complete occlusion of a coronary artery. On the other hand, in NSTEMIs there is typically a sudden narrowing of a coronary artery with preserved (but diminished) flow to the distal myocardium. Anticoagulation and antiplatelet agents are given to prevent the narrowed artery from occluding.[citation needed]

At least 10% of patients with STEMI do not develop myocardial necrosis (as evidenced by a rise in cardiac markers) and subsequent Q waves on EKG after reperfusion therapy. Such a successful restoration of flow to the infarct-related artery during an acute myocardial infarction is known as "aborting" the myocardial infarction. If treated within the hour, about 25% of STEMIs can be aborted.[56]

Rehabilitation

Additional objectives are to prevent life-threatening arrhythmias or conduction disturbances. This requires monitoring in a coronary care unit and protocolized administration of antiarrhythmic agents. Antiarrhythmic agents are typically only given to individuals with life-threatening arrhythmias after a myocardial infarction and not to suppress the ventricular ectopy that is often seen after a myocardial infarction.[57][58][59]

Cardiac rehabilitation aims to optimize function and quality of life in those affected by a heart disease. This can be with the help of a physician, or in the form of a cardiac rehabilitation program.[60]

stress and mood.[60] Some patients become afraid of exercising because it might trigger another infarct.[61] Patients are encouraged to exercise, and should only avoid certain exerting activities. Local authorities may place limitations on driving motor vehicles.[62] In most cases, the advice is a gradual increase in physical exercise during about 6–8 weeks following an MI.[63] If it doesn't feel too hard for the patient, the advice about exercise is then the same as applies to anyone else to gain health benefits, that is, at least 20–30 minutes of moderate exercise on most days (at least five days per week) to the extent of getting slightly short of breath.[63]

Some people are afraid to have

sex after a heart attack. Most people can resume sexual activities after 3 to 4 weeks. The amount of activity needs to be dosed to the patient's possibilities.[64]

Special cases

Cocaine

benzodiazepines should be administered early.[65] The treatment itself may have complications. If attempts to restore the blood flow are initiated after a critical period of only a few hours, the result may be a reperfusion injury instead of amelioration.[66]

Wilderness setting

In

cardiac arrest differs slightly from that carried out in an urban setting in that it is generally considered acceptable to terminate a resuscitation attempt after 30 minutes if there has been no change in the patient's condition.[citation needed
]

Air travel

Certified personnel traveling by commercial aircraft may be able to assist an MI patient by using the on-board

Cardiac monitors are being introduced by some airlines, and they can be used by both on-board and ground-based physicians.[68]

References

  1. ^ a b Current management of acute coronary syndrome is based on guidelines, produced by national and international medical societies according to the principles of evidence-based medicine. Examples are the guidelines of the American Heart Association and American College of Cardiology (O'Gara 2013, Amsterdam 2014) and those of the European Society of Cardiology (Steg 2012, Hamm 2011).
  2. ^ a b Hamm 2011, p. 3004.
  3. ISBN 978-0-8089-2436-4
    ., p. 1092
  4. ISBN 978-0-8089-2436-4
    .
  5. ISBN 978-1-4160-3121-5.. Cited in Antman 2012a
    , p. 1093
  6. ^ See:
  7. ^ Antman 2012b, p. 1118.
  8. ^ Cannon 2012, p. 1178.
  9. ^ Cannon 2012, p. 1194.
  10. ^ Heart attack care dangerously unequal for women, study finds BBC
  11. PMID 11551867
    .
  12. ^ "What is a heart attack". National Institutes of Health. National Heart, Lung, and Blood Institute. Retrieved 30 September 2014.
  13. ^ "Heart attack - Symptoms". National Health Service. Retrieved 22 December 2014.
  14. ^ HealthCentral (2024-03-12). "Best Position to Be in During a Heart Attack". web.archive.org. Retrieved 2024-04-03.
  15. ^ O'Gara 2013, p. e369.
  16. ^ Antman 2012b, p. 1111.
  17. PMID 15358045
    .
  18. ^ Alberta Occupational Competency Profile EMT Paramedic Archived 2011-10-05 at the Wayback Machine. Alberta College Of Paramedics. Updated January 2007, Retrieved June 29, 2011.
  19. PMID 12103258
    .
  20. S2CID 20363018
    .
  21. PMID 16996830
    .
  22. PMID 18340140
    .
  23. PMID 15684279
    .T
  24. PMID 16580518
    .
  25. ^ Rokos I. and Bouthillet T., "The emergency medical systems-to-balloon (E2B) challenge: building on the foundations of the D2B Alliance," Archived 2007-08-09 at the Wayback Machine STEMI Systems, Issue Two, May 2007. Accessed June 16, 2007.
  26. ISBN 978-0-89603-552-2
    .
  27. PMID 22922414
    .p. 2553
  28. ^ a b Steg 2012, p. 2574.
  29. ^ Amsterdam 2014, p. 14.
  30. ^ O'Gara 2013, p. e370.
  31. ^ a b c d Antman 2012b, p. 1116.
  32. ^ Cannon 2012, p. 1185.
  33. PMID 9884398
    .
  34. ^ Steg 2012, p. 2598.
  35. ^ See:
  36. PMID 27991651
    .
  37. ^ Amsterdam 2014, p. 30.
  38. ^ Steg 2012, p. 2576.
  39. ISBN 978-0-07-176917-4
    .
  40. ^ a b Amsterdam 2014, p. 31.
  41. ^ O'Gara 2013, p. e391.
  42. ISBN 978-1-4557-3322-4
    .
  43. ^ See:
  44. PMID 25954988
    .
  45. ^ Amsterdam 2014, p. 37-40.
  46. ^ Steg 2012, p. 2583-2584, 2587-2588, 2591.
  47. ^ O'Gara 2013, p. 377-378.
  48. ^ Amsterdam 2014, p. 38.
  49. ^ Antman 2012b, p. 1029.
  50. ^ Steg 2012, p. 2584-5, 2587-91.
  51. ^ Amsterdam 2014, p. 41-43.
  52. PMID 22361039
    .
  53. PMID 7882472
    .
  54. PMID 7829790
    .
  55. PMID 7905143
    .
  56. PMID 16543251
    .
  57. PMID 1900101
    .
  58. S2CID 21284044
    .
  59. S2CID 24212782
    .
  60. ^
    National Heart, Lung and Blood Institute
    . Retrieved December 2, 2006.
  61. ^ Trisha Macnair. Recovering after a heart attack. BBC, December 2005. Retrieved December 2, 2006.
  62. ^ "Classification of Drivers' Licenses Regulations". Nova Scotia Registry of Regulations. May 24, 2000. Retrieved April 22, 2007.
  63. ^ a b Patient UK > After a Myocardial Infarction Archived 2010-07-22 at the Wayback Machine Reviewed: 19 May 2010
  64. ^ "Heart Attack: Getting Back Into Your Life After a Heart Attack Archived 2008-07-24 at the Wayback Machine". American Academy of Family Physicians, updated March 2005. Retrieved December 4, 2006.
  65. PMID 18347214
    .
  66. PMID 16450811
    .
  67. ^ Youngwith, Janice (2008-02-06). "Saving hearts in the air". Dailyherald.com. Retrieved 2008-06-12. [dead link]
  68. PMID 11090520
    .

Selected cited works

Retrieved from "https://en.wikipedia.org/w/index.php?title=Management_of_acute_coronary_syndrome&oldid=1216969108"