Unstable angina pectoris

Unstable angina pectoris (NAP) is an acute coronary syndrome without ST elevation' on ECG.

Among acute coronary syndromes (ACS) we include:


 * 1) unstable angina pectoris;
 * 2) acute myocardial infarction without ST segment elevations (NSTEMI);
 * 3) acute myocardial infarction with ST segment elevations (STEIMI).

These conditions are an acute manifestation of ischemic heart disease and need to be addressed urgently. A patient with NAP must be hospitalized in a coronary unit.

Etiopathogenesis
The pathophysiological essence of all ACS is intracoronary thrombosis superimposed on a superficially damaged (rupture, erosion, fissure), unstable atherosclerotic plaque. In the case of NAP, the resulting obstruction of the coronary artery is incomplete, so myocardial necrosis does not occur, so the levels of cardiospecific markers do not increase.

The causes of NAP include:


 * non-occluding thrombosis encroaching on an unstable atherosclerotic plaque;
 * progressing atherosclerotic process;
 * progressive neointimal hyperplasia with the emergence of restenosis;
 * focal epicardial coronary artery spasm (Prinzmetal's AP);
 * inflammation of the coronary artery wall;
 * a number of extracardiac mechanisms (tachycardia, thyrotoxicosis, fever, anemia, hypoxemia, hypotension).

Clinical forms and classification

 * {| class="wikitable" align="right"
 * {| class="wikitable" align="right"
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! colspan="2" |Classification of AP degree according to CCS (Canadian Cardiovascular Society)
 * CCS I||AP only during heavy exertion, sports activities, fast or long-lasting load
 * CCS II||AP when walking uphill, patient ascends to 1st floor and above without pain/stopping
 * CCS III||AP even when walking on the level, the patient does not go up to the 1st floor without pain/stopping
 * CCS IV||AP while walking around the apartment, resting angina
 * }
 * }
 * CCS IV||AP while walking around the apartment, resting angina
 * }
 * }
 * }

Clinical symptoms
Patients report pressure/tightening/burning pain in the chest (angina), the pain can radiate to the neck, lower jaw, upper limbs, back and abdomen. The pain usually subsides within 20 minutes. In addition, anxiety, nausea, vomiting, sweating, dizziness, a feeling of fainting, a feeling of shortness of breathi may be present.

Diagnosis

 * History: risk factors (smoking, hyperlipoproteinemia, DM, hypertension)?, positive family history?, CHD?, previous MI?, exertional AP?, coronary angioplasty?, intracoronary stent?, aortocoronary bypass? other diseases? permanent medication? allergies?.
 * Physical examination: mostly normal. Tachycardia and increased blood pressure (sympathetic activation) may be present.
 * Nitroglycerin test: Nitroglycerin is given for chest pain. If the pain subsides within 2 minutes, it is probably angina pectoris. Pain relief after more than 10 minutes is non-specific.
 * ECG: ST segment depression, T wave inversion, new A-V block?, new bundle branch block?. Outside of an anginal attack, the ECG is usually completely normal. If the ECG picture is normal even during an angina attack, this usually indicates against NAP (possibly against acute ischemia).
 * Biochemical markers of myocardial necrosis: are negative in NAP (myocardial necrosis does not occur in NAP).
 * Selective coronary angiography: should be performed in all patients with NAP. For hemodynamically stable patients, we perform it early, i.e. within 48–72 hours. We perform it immediately in hemodynamically unstable patients. Diagnostic coronary angiography can be followed by PCI (percutaneous coronary intervention) or CABG (coronary artery bypass grafting).

Differential diagnosis
Differential diagnostics should exclude:


 * other causes of chest pain (STEMI, NSTEMI, ischemia of non-coronary origin, aortic dissection, aortic aneurysm, pericarditis, myocarditis, pulmonary embolism, pneumothorax, vertebrogenic algic syndrome etc.).

Treatment
A patient with NAP must be hospitalized in an intensive care unit with permanent monitoring of vital signs and ECG (preferably in a coronary unit).


 * {| class="wikitable"

! colspan="2" |Initial treatment of a patient with ACS. Taken from. introduction of i.v. cannulas recording of a 12-lead ECG
 * continuous monitoring of vital functions and ECG
 * continuous monitoring of vital functions and ECG
 * oxygen delivery 4–8 l/min
 * oxygen delivery 4–8 l/min
 * blood sampling for the determination of markers of myocardial necrosis
 * analgosedation (opiates)
 * ASA 150–300 mg i.v. or p.o.
 * heparin 5000 j i.v./enoxaparin 1 mg/kg s.c./i.v.
 * clopidogrel 300–600 mg i.v. (consider IIb/IIIa inhibitors)
 * metoprolol i.v. according to the clinical condition
 * }
 * heparin 5000 j i.v./enoxaparin 1 mg/kg s.c./i.v.
 * clopidogrel 300–600 mg i.v. (consider IIb/IIIa inhibitors)
 * metoprolol i.v. according to the clinical condition
 * }
 * metoprolol i.v. according to the clinical condition
 * }


 * Antithrombotic treatment: ASA, clopidogrel, IIb/IIIa inhibitors.
 * Anticoagulation treatment: heparin, low molecular weight heparin.
 * Antiischemic treatment: β-blocker (metoprolol), nitrate, calcium channel blocker (amlodipine, felodipine).
 * Hypolipidemic treatment: statin.

Related Articles

 * Angina pectoris
 * Prinzmetal's angina pectoris
 * Heart-attack
 * Ischemic heart disease