Acute Coronary Syndrome is a clinical symptom complex caused by a sudden reduction in blood flow in the coronary arteries that is tasked with supplying the heart with oxygen and nutrients. Consequently, ischemia within the heart muscle may lead to its necrosis, i.e. a heart attack.

Acute coronary syndromesare one of the manifestations of the broadly understood ischemic heart disease associated with pathological changes in the arteries of the heart, i.e. coronary heart disease. Apart from acute coronary artery disease, we can also distinguish stable coronary syndromes. As the name suggests, this division is mainly due to the different dynamics of the course. More than 98% of the underlying cause of coronary artery disease is atherosclerosis.

Atherosclerosis is a chronic inflammatory disease of the arteries leading to the formation of the so-called atherosclerotic plaques within their walls. The mature plaque consists of a cover made of muscle cells and collagen, and a lipid core. They lead to a narrowing of the lumen of the arteries. Atherosclerosis within the coronary arteries may limit blood flow, which in the states of increased demand for oxygen of the heart, e.g. during exercise, may lead to ischemia manifested by chest pain. The described mechanism is the cause of stable angina (or angina pectoris), which is a stable coronary syndrome.

ACS, on the other hand, is most often caused by a rupture of an atherosclerotic plaque and a sudden obstruction of the coronary artery. The flow restriction may be caused by an embolic material from a plaque fracture or by a thrombosis that develops on the basis of the fracture. The causes of acute syndromes are more often the so-called unstable plaques. They may be small and not cause the symptoms of stable angina, but have a thin cover and a relatively large core, which makes them more prone to breakage.

Growing thrombosis in an artery does not have to completely obstruct its lumen. The effects also largely depend on its location in the coronary circulation. As a result, people affected by such an event constitute a heterogeneous group of patients, and acute coronary syndromes can be divided into:

  • unstable angina(UA unstable angina) - plaque damage causes an impaired flow in the coronary artery, but it is notcompletely closed
  • non-ST segment elevation myocardial infarction - NSTEMI- may be a consequence of UA, but in this case myocardial cells are damaged due to ischemia;
  • ST-segment elevation - STEMI- a thrombus on a ruptured plaque usually completely closes the lumen of the artery, leading to myocardial necrosis

Acute coronary syndrome can occur in a person with pre-existing coronary problems or be the first manifestation of ischemic heart disease, which requires chronic treatment.

Rare, non-atherosclerotic causes of a heart attack are any condition that can upset the balance between the heart's need for oxygen and otherwise restrict the flow in the coronary arteries. These include :

  • heart defects (aortic stenosis or regurgitation)
  • carbon monoxide poisoning
  • sepsa
  • deep anemia
  • hypertensive crisis
  • prolonged hypotension
  • thyroid crisis
  • heart rhythm disturbance
  • blockage
  • cocaine use and much more

Symptoms of ACS

The main symptom of the most common symptom is chest pain. It is usually crushing, squeezing, although it can be prickly at times. Typically, it is located behind the sternum and can run with a characteristic radiation - most often to the mandible, left shoulder and upper arm. It appears suddenly and generally lasts longer than 20 minutes. Sublingual administration of nitroglycerin does not relieve symptoms. These features distinguish infarct pain from stable angina pain. Contrary to a heart attack, pain is caused by physical exertion (or severe stress) and lasts up to several minutes - it is resolved at rest or after administration of nitroglycerin.

Clinical practice clearly shows that the symptoms of acute coronary syndrome do not always have to be such a suggestive, obvious picture. For example, in elderly or diabetic people, pain may be less severe or even absent.

Symptoms accompanying a heart attack may include :

  • weakness, pale skin and increased sweating
  • palpitations (caused by sinus tachycardia or ischemic arrhythmias)
  • shortness of breath (may be the only symptom of ACS, constituting the so-called "mask" of pain; may result from impaired function of the left ventricle and pulmonary edema due to an extensive infarction; it may be accompanied by spitting out a foamy, blood-colored discharge)
  • epigastric pain, nausea and vomiting (maybeoccur especially in an infarction of the lower wall of the heart)
  • severe anxiety and anxiety

ACS diagnostics

The diagnosis of ACS is determined primarily by the symptoms reported by the patient, but additional tests are performed to verify the suspicion. An electrocardiographic test, or EKG, is of key importance here. It is performed routinely by a called emergency medical team. A characteristic feature of the "infarct ECG" is the so-called Parde's wave, i.e. ST segment elevation (hence the term STEMI infarction). This picture differs from that seen in UA or NSTEMI infarction. Interpreting the ECG record, however, is not always so simple. The record during the infarction may undergo specific changes over time - the infarction evolves, hence the captured changes may be less characteristic. This often requires testing to be repeated at intervals. It is worth noting that in many cases of unstable angina and NSTEMI infarction, the resting ECG recording may be correct.

Laboratory determination of cardiac troponins is a very important test performed in the case of acute coronary syndromes. Troponins are proteins found in the cells of the heart muscle that play an indispensable role in its contraction. Necrosis caused by ischemia causes a significant increase in their blood levels. It is the presence of "positive" troponins - markers of myocardial necrosis that allows us to define acute coronary syndrome as a heart attack (in unstable angina, the cardiac troponins are below the lower limit of the norm). Their concentration begins to increase only after approx. 3 hours after the artery is closed. Hence, it is important to perform two or more determinations that can show the characteristic growth dynamics.

An additional examination may also be an imaging test such as heart ultrasound, i.e. heart ECHO. May visualize myocardial contraction abnormalities caused by ischemia and necrosis.

Acute coronary syndromes: treatment

The mainstay of ACS treatment is currently coronary angiography with percutaneous coronary intervention (PCI). Coronary angiography (or coronary angiography) is an invasive method of imaging the coronary arteries. It involves the insertion of special catheters that apply a contrast agent to the coronary arteries through the femoral or radial arteries. X-ray observation of the heart allows for a dynamic image of the coronary circulation, which allows for the location of strictures and obstructions.

PCI includes several treatments:

  • percutaneous coronary angioplasty (PTCA) with or withoutstent implantation
  • and currently used less frequently in specific indications: cutting atherectomy, rotaablation and intravascular brachytherapy.

PTCA consists in restoring the resulting narrowing of the artery with a percutaneous balloon, and in the next stage of stent placement - a special coil with a mesh structure, which is used to increase and maintain the patency of the coronary artery. Increasingly, stenting is performed directly - without prior widening. Currently, stenting is the most common and effective method of PCI in acute coronary syndromes as well as in stable angina.

Any patient diagnosed with an acute STEMI (STEMI) based on symptoms and ECG should be transferred to the invasive cardiology unit as soon as possible for emergency primary PCI.

The situation is different in patients with unstable angina (UA) and ACS NSTEMI. The treatment strategy and the urgency of the procedure depend on, among others: the patient's condition, the dynamics of troponin changes, ECG, the image of the heart in the ECHO examination, etc.

An alternative to percutaneous coronary interventions in STEMI (only) is fibrinolytic therapy, which consists of intravenous administration of drugs designed to "dissolve" the clot formed on the ruptured atherosclerotic plaque. However, this treatment is less effective and carries a higher risk of complications - in particular, severe hemorrhages. However, due to the well-organized network of 24-hour hemodynamics laboratories, fibrinolytic treatment of myocardial infarction has been pushed to the margin in Poland.

Important

First aid for heart attack

When discussing the subject of acute coronary syndromes, it is worth devoting a few words to the basic principles of pre-hospital management of myocardial infarction.

MOST IMPORTANT:

  • in the event of severe chest pain, the patient (or someone from the environment) should immediately call an ambulance - 112 or 999
  • the patient should lie down in a semi-sitting position (with the torso slightly elevated), ensuring breathing comfort - e.g. unbutton the shirt collar, open the oncoat
  • you can give a preparation containing acetylsalicylic acid in a dose of 150-325 mg (preferably in the form of an uncoated tablet; you should chew it)
  • in a person who has been prescribed a sublingual preparation of nitroglycerin for the immediate relief of coronary ailments in a stable form of the disease, a single dose can be administered, no pain relief within 3-5 minutes or its intensification should result inimmediate ambulance call, if not done before

ATTENTION. The induced, compulsory cough in the case of suspected infarction is unfounded. The effectiveness of such proceedings is a myth, so its application is unfounded.

CAUTION: ACS can lead to cardiac arrest! Loss of consciousness and loss of breath obliges those around you to start CPR (cardiopulmonary resuscitation).

Complications of acute coronary syndromes

Acute coronary syndromes carry a risk of complications. The risk of complications that are dangerous to he alth and life is caused by a STEMI infarction in particular. The most dangerous of them include :

  • acute heart failure in the form of pulmonary edema or even cardiogenic shock (it is assumed that it may occur when the infarction affects>40% of the ventricular muscle mass),
  • ischemia recurrence / recurrent infarction,
  • mechanical complications within the heart: papillary muscle rupture, rupture of ventricular septum or free heart wall (these complications are rare; their frequency ranges from 1-2%)
  • cardiac arrhythmias, the most dangerous of which is ventricular fibrillation (15-20% of patients with STEMI), which is in fact a state of sudden cardiac arrest requiring CPR. An episode of ventricular fibrillation is associated with high mortality and significantly worsens the long-term prognosis.
  • heart aneurysm

Acute coronary syndrome: prognosis and rehabilitation

Surviving an acute coronary syndrome is associated with an increased risk of mortality in the early period following the incident and worsens the long-term prognosis. There is no doubt how important it is for early and late prognosis to be promptly diagnosed and treated. Nevertheless, proper management of a coronary incident is important. The role of non-pharmacological treatment aimed at inhibiting the progression of atherosclerosis, which is associated with the reduction of cardiovascular risk cannot be overstated. Its basic assumptions are:

  • smoking cessation (active and passive) - the risk of a repeat coronary event decreases by 50% one year after stopping smoking!
  • weight loss
  • introducing a diet - a patient after ACS should benefit from a dietary consultation; the basic principles are: qualitative change in food (eating more vegetables and fruits, whole grain bread, fish, lean meat), increasing the consumption of mono- and polyunsaturated fats at the expense of reducing saturated and trans fats, limited consumption of table s alt
  • increasing physical activity - it is especially recommendedmoderate aerobic exercise for 30 minutes, at least 5 times a week

A patient after a heart attack undergoes cardiac rehabilitation. Its first stage takes place in a hospital setting. The second stage may take place in stationary conditions - in a rehabilitation hospital, cardiac rehabilitation departments or outpatient, i.e. in day care departments. It covers multidisciplinary activities including the optimization of pharmacological treatment, educating the patient in the field of non-pharmacological management and creating optimal, individually tailored exercise programs.

Sources: 1. Acute coronary syndromes [in:] Gajewski P. (ed.), Interna Szczeklika 2016, Krakow, Medycyna Praktyczna, 20162. ESC guidelines for the management of acute coronary syndromes without persistent ST segment elevation in 2015

Category:

Cardiology