Acute coronary syndrome I24.9

Acute coronary syndrome (ACS) is an acutely occurring, life-threatening phase of coronary heart disease (Arntz 2000).

The ACS is divided into 2 groups:

1. Acute coronary syndrome with ST elevation. This includes the
   • ST-segmental elevation infarction (so-called STEMI; old nomenclature: transmural infarction [Stierle 2017])
2. Acute coronary syndrome without ST elevation. These include:
   • Non-ST-segmental elevation myocardial infarction (so-called NSTEMI; old nomenclature: non-transmural infarction [Stierle 2017]); by definition with myocardial necrosis
   • unstable angina pectoris (so-called NSTE- ACS = Non ST Elevation Acute Coronary Syndrome [Giannitsis 2007]), by definition without myocardial necrosis (Kasper 2015).

The differentiation between a NSTEMI and an unstable AP is only possible by determining the troponin (Giannitsis 2007).

In Germany, approximately 350,000-400,000 patients are admitted annually with an ACS without ST-segment elevation and approximately 300,000 patients with an acute STEMI. Relatively speaking, the incidence of NSTEMI is increasing compared with STEMI (Kasper 2015).

An ACS without ST elevation affects slightly more than 1/3 women, whereas in STEMI approximately ¾ are male (Kasper 2015). According to ESC 2015, the following causes are found in an emergency department in unselected patients with acute chest pain:

• 5 % - 10 % STEMI
• 15 % - 20 % NSTEMI
• 10 % unstable angina pectoris
• 15 % other cardiac diseases
• 50 % non-cardiac diseases (Roffi 2015).

Associated non-cardiac diseases:

• Iron deficiency (serum ferritin and transferrin saturation): Iron deficiency has significant prognostic significance. In one study, iron deficiency was shown to have a high prevalence to ACS. 29.1% of patients with ACS (including 42.8% women) had low levels. The risk of cardiovascular mortality and nonfatal myocardial infarction was increased by 73% in these patients during a 4-year follow-up period (Zeller 2018).

In ACS, all three manifestations (NSTEMI, STEMI, unstable angina pectoris) are based on a common pathomechanism (Arntz 2002). There is primarily an imbalance between oxygen supply and oxygen demand, which can be triggered by:

• a thrombus formation on coronary plaque
• an erosion of the coronary artery endothelium
• dynamic constrictions (e.g. due to coronary spasm)
• severe mechanical constrictions (e.g. due to coronary sclerosis)
• Increased myocardial oxygen demand for e.g.
  • Fever
  • Tachycardia
  • Thyrotoxicosis
  • severe anaemia (Arntz 2002)
  • Hypotension (Arntz 2002, Kasper 2015)

Only <3% of patients with ACS have a >70% reduction in coronary lumen. However, 75% of patients have ruptured atherosclerotic plaques that partially or completely occlude the coronary artery by thrombi. In the remaining cases, dynamic stenoses such as vasospasms, prinzmetal angina, microcirculatory angina, etc. are found. Secondary causes such as fever, hypotension, thyrotoxicosis etc. are extremely rare. (Arntz 2002).

Pathophysiologically, the following three mechanisms can be found:

• first, the rupture of an atherosclerotic plaque
• there are different degrees of additional thrombus formation
• distal embolization occurs (Stierle 2017)

ACS is characterized by the typical symptoms of angina pectoris at rest or under low stress, such as:

• retrosternal localized pain with radiation in
  • the neck/neck
  • Lower jaw
  • Teeth
  • Shoulder area
  • both (!) arms (with focus on the ulnar sides of the forearms), which can radiate into the ulnar fingertips (Kasper 2015)

In NSTEMI, thoracic pain persists for > 10 - 15 minutes, occasionally longer (Stierle 20017). In STEMI the pain symptoms last > 20 min. Often there are additional vegetative symptoms such as:

• Nausea
• Shortness of breath
• Vertigo (Herold 2020)
• cold, pale skin
• Sinus tachycardia
• Occurrence of a 3rd and/or 4th heartbeat (Kasper 2015)

Coronary CT

The coronary Ct plays a subordinate role in ACS, since:

• the diagnostic reliability is lower than with coronary angiography
• the radiation exposure is high
• in case of doubt, an additional coronary angiography is indispensable (Kasper 2015)

Heart catheter

Immediate indication for coronary angiography (and subsequent revascularization) exists in patients with:

• persistent ST- elevation of > 20 min. in ≥ 2 continuous recordings or
• a newly occurred left bundle branch block or
• Troponin elevation (Stierle 2017)

In the absence of ST elevation and troponin elevation, the cardiac markers should be checked again after 6 h - 9 h (or with a highly sensitive essay after 3 h). If the results are negative again, a stress test is required. If this test is positive, the usual diagnostic tests for acute angina pectoris are recommended. If the result is negative, further clarification can be carried out on an outpatient basis (Stierle 2017).

Troponin T:

• at STEMI ≥ 1.0
• from NSTEMI ≥ 0.01 to ≤ 1.0
• with unstable AP ≤ 0.01 (Stierle 2017)

Serum tits: often humiliated (Zeller 2018)

Transferrin saturation (see below transferrin): often lowered (standard value: 15-45%)

With the help of the so-called Grace Risk Score, a risk assessment can be made for an ACS. With a point value:

• < 108, the risk of dying in hospital is < 1%.
• between 109 - 140 the risk of dying in hospital is 1 % - 3 %
• > 140, the risk of dying in hospital is > 3 % (Herold 2020)

Inspection and palpation: Typically, patients hold the clenched fist in the middle of the sternum (Levine's sign) when describing pain, the hand is placed flat on the sternum or both hands, fingertips facing each other, are placed on the sternum from the side to indicate belt-shaped tightness. The sensitivity to cardiac pain is about 80%, the specificity is about 49% (Edmondstone 1995)

Auscultation: Occurrence of a 3rd and/or 4th heartbeat possible (Kasper 2015)

ECG:

STEMI may be present:

• persistent ST elevation of > 20 min. in ≥ 2 recordings
• newly appeared left thigh block (Stierle 2015)

With NSTEMI can be present:

• at 20 % - 25 % reductions of the ST line, which can persist for several days (Kasper 2015)
• transient ST elevations. T waves can be normal or negative (Stierle 2017)

With the unstable AP there are mostly:

• ST waves normal or decreased
• transient ST-lifts possible
• T waves reduced or normal (Stierle 2017)

Note: In the absence of ST elevation and troponin elevation, the cardiac markers should be checked again after 6 h - 9 h (or with a highly sensitive essay after 3 h). If the results are again negative, a stress test is required. If this test is positive, the usual diagnostic tests for acute angina pectoris are recommended. If the result is negative, further clarification can be carried out on an outpatient basis (Stierle 2017).

The so-called "big five" of thoracic pain include - in addition to ACS:

• Pulmonary embolism
• Aortic dissection
• Boerhaave syndrome (spontaneous rupture of the esophagus after severe vomiting)
• tension pneumothorax (Herold 2020)

Furthermore, differential diagnosis of the following diseases are possible:

1. cardiac chest pain caused by e.g.

• Dressler syndrome (so-called postmyocardial infarction syndrome)
• hemodynamically effective tachycardia
• hypertensive crisis
• aortic vitiation (such as aortic valve insufficiency or aortic valve stenosis)
• mitral valve prolapse
• hypertrophic cardiomyopathy
• Perimyocarditis
• Tako-Tsubo cardiomyopathy
• congenital anomalies of the coronaries
• Vasculitides such as:
  • panarteritis nodosa
  • Takayasu arteritis
  • Kawasaki syndrome (Herold 2020)
• Spontaneous coronary artery dissection (affects between 66%-80% women; in one-third, dissection occurs postpartum)
• Bland-White-Garland syndrome (the left coronary artery originates in the main trunk of the pulmonary artery - Apitz 2002)
• Marfan syndrome
• Homocystinuria
• Ehlers-Danlos syndrome (Pinger 2019).

2. non-cardiac chest pain caused by:

• pleural or pulmonary causes such as:
  • Pulmonary embolism
  • chronic cor pulmonale
  • Pleurisy (respiratory related pain)
  • Lung carcinoma
  • Pancoast tumor
  • pleurodynia due to e.g. Coxsackie B virus infection, Bornholm disease
  • Tension pneumothorax
• Diseases of the mediastinum or aorta such as:
  • Mediastinal tumor
  • Mediastinitis
  • Aortic dissection
  • intramural hematoma of the aorta
• Diseases of the esophagus and stomach such as:
  • Reflux disease
  • esophageal motility disorders such as diffuse esophageal spasm (Barsony- Teschendorf syndrome), nutcracker esophagus (hypertensive peristalsis [Siewert 2006]), achalasia
  • Mallory-Weiss syndrome (tearing of the mucosa and / or submucosa of the esophagus occurring after severe vomiting )
  • Boerhaave syndrome (spontaneous rupture of the esophagus after severe vomiting)
  • Ventricular ulcer (Pinger 2019)
• Diseases in the region of the ribs such as:
  • Tietze syndrome (pressure-dolled swelling of the ribs at the bone-cartilage junction)
  • Rib fracture
  • Thoracic trauma
• Diseases in the area of the spine such as:
  • Bechterew's disease
  • Cervical spine osteochondrosis
  • Osteochondrosis of the thoracic spine
• Diseases in the area of the nerves such as:
  • Zoster
• abdominal diseases that may radiate to the thorax such as:
  • Acute pancreatitis
  • Biliary colic
  • Cholecystitis
  • Roemheld syndrome (postprandial chest pain unrelated to CHD)
• functional thoracic pain such as:
  • Da-Costa syndrome (functional pain in the cardiac region without organic cause)
• genetic diseases such as:
  • severe pain in the thorax or upper abdomen in sickle cell disease (v. Schweinitz 2009)
  • Psychiatric disorders such as cardiac neurosis (Pinger 2019).

Acute treatment of a patient with ACS should consist of:

• elevation of the upper body (in case of respiratory distress)
• O2 administration of 4 - 8 l / min via nasal probe, if oxygen saturation is < 90%.
• Administration of nitroglycerin: outpatient sublingual 1 - 3 strokes, after reaching the clinic via perfusor (1mg - 5 mg / h i. v.); contraindications: systolic RR values < 90 mmHg, taking PDE- 5 inhibitors such as Viagra
• Morphine for severe pain (3 mg - 5 mg i. v., then 2 mg every 5 - 15 min. until pain relief is achieved; side effects: nausea, respiratory depression, hypotension)
• in case of nausea: administration of an antiemetic, e.g. metoclopramide
• if vagal reaction occurs, administration of atropine 0.5 mg i.v.
• Administration of a platelet aggregation inhibitor.
  • ASA (initially 160 mg - 325 mg parenterally or s. l., then 75 mg - 100 mg/ d p. o. [Stierle 2017])
  • Dual platelet inhibition: heparin in patients with STEMI and NSTEMI (e.g., enoxaparin 2 x 1 mg / kg bw / d s. c. - Stierle 2017; Herold 2020)
• Beta-blockers in symptomatic patients with systolic blood pressure values > 100 mmHg at a heart rate of > 55 / min; dosage: 5 mg - 15 mg i. v. (Stierle 2017).

After securing the diagnosis and validating the risk should be made:

In STEMI: In this case, there is an urgent indication for revascularization (for detailed information on revascularization, see coronary artery disease).

In NSTEMI: Patients with NSTEMI should undergo coronary angiography immediately (within 72 h).

In unstable angina pectoris: Patients with unstable angina pectoris (troponin values unremarkable on admission and also on control after 3 - 6 h) should undergo ischemia tests such as exercise ECG, stress echocardiography, myocardial scintigraphy in addition to primary stabilization. If the result is positive, there is an indication for coronary angiography (Herold 2020).

In case of existing iron deficiency: iron carboxymaltose i. v. (see above "Occurrence": Associated non-cardiac diseases) (Zeller 2018).

Mortality is dependent on the triggering disease of ACS.

The 30-day mortality for:

• STEMI 12.9%
• NSTEMI 10,4
• unstable AP 4,5 %

The 6-month leths lethality is:

• STEMI 19.2%
• NSTEMI 18,7
• unstable AP 8.6 % (Stierle 2017)

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