Lesson topic №24. ОКС (Acute Coronary Syndrome )

Acute Coronary Syndrome

Gorban V.V., D.M. Department of polyclinic therapy with course of general medical practice (family medicine)

Acute Coronary Syndrome

• Acute coronary syndrome (ACS) refers

to the spectrum of clinical presentations

ranging from ST-segment elevation myocardial infarction (STEMI) to non–ST- segment elevation myocardial infarction (NSTEMI) to unstable angina (ie, acute coronary syndrome without release of enzymes or biomarkers of myocardial necrosis).

Pathophysiology

Atherosclerosis is primarily responsible for acute coronary syndrome.

Most cases of acute coronary syndrome occur from disruption of a previously nonsevere

lesion (an atherosclerotic lesion that was previously hemodynamically insignificant yet

vulnerable to rupture).

The vulnerable plaque is typified by a large lipid pool, numerous inflammatory cells, and a thin fibrous cap.

New modalities, such as optical coherence tomography (OCT), palpography, and virtual

histology, are being studied to identify vulnerable plaques.

History

Factors that predispose individuals to develop acute coronary syndrome include the

following:

Age older than 70 years

Male sex

Diabetes mellitus

Known history of coronary artery disease, including myocardial infarction

Family history of premature coronary artery disease

Hypertension

Hyperlipidemia

Tobacco use

Principal presentations

Principal presentations of unstable angina include the following findings:

Rest angina that occurs at rest and that usually lasts >20 minutes

New-onset angina at least as severe as Canadian Cardiovascular Society (CCS) class III (ie, marked limitation of ordinary physical activity)

Increasing (crescendo) angina, ie, previously diagnosed angina that has become distinctly more frequent, longer in duration, or lower in threshold (ie, increased by ≥1 CCS class to at least

CCS III severity)

Shortness of breath, which might be an anginal equivalent or a symptom of heart failure.

Physical examination

Physical findings can vary from normal to any of the following:

Hypotension or hypertension

Diaphoresis

Pulmonary edema and other signs of left heart failure

Extracardiac vascular disease

Fourth heart sound (S4), which may be heard in patients with ischemia or systolic murmur secondary to mitral regurgitation. (This is frequently present, especially in patients with inferior-wall ischemia.)

Other findings (eg, cool, clammy skin and diaphoresis in patients with cardiogenic shock)

Systolic murmur related to dynamic obstruction of the left ventricular outflow tract (This is caused by hyperdynamic motion of the basal left ventricular myocardium and may be heard in patients with an apical infarct.

Other causes of NSTEMI acute coronary syndrome include the following:

Dynamic obstruction (coronary spasm or vasoconstriction)

Cocaine or amphetamine use, which increases myocardial oxygen demand and which may cause coronary vasospasm

Use of certain medications, such as selective serotonin reuptake inhibitors (SSRIs)

Progressive mechanical obstruction

Inflammation4 and/or infection

Embolic occlusion of the coronary arteries

Congestive heart failure

Underlying coronary artery disease, which severe anemia or hypoxemia might precipitate

Coronary artery dissection (spontaneous or iatrogenic)

Coronary artery injury during blunt or penetrating chest trauma

Coronary artery anomaly, such as a left anterior descending coronary artery originating from the pulmonary trunk or a left main coronary artery originating from the right coronary sinus of the aortic valve with a course between the great vessels

Differential diagnoses

Aortic dissection

Aortic stenosis

Esophageal spasm

Gastroesophageal reflux disease

Myocarditis

Pneumothorax

Pulmonary embolism

Other problems to consider

Acute cholecystitis

Hypertensive emergency

Panic attack

Pericarditis