Lesson topic №24. ОКС (Acute Coronary Syndrome )
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Guidelines for the diagnosis and treatment of non-ST-segment elevation acute
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The spectrum of acute coronary syndromes
Further Inpatient Care
Patients with unstable angina, ECG changes, or both should be admitted to a telemetry bed. A certain subset of patients with stable angina may be treated as outpatients with antianginal agents, but close follow-up is necessary.
Patients with symptoms refractory to aggressive medical treatment, shock, suspected or known aortic stenosis, or new or worsening mitral regurgitation are at high risk. Management for these patients should include the following:
o Admission to an intensive care unit setting o Cardiology consultation
Intra-aortic balloon pump (IABP) and early angiography to delineate anatomy should be considered.
Antiplatelet and antianginal medications initiated in the ED should be continued. Subsequent dosing is determined
by symptomatic response and tolerance of side effects.
The routine use of lidocaine as prophylaxis for ventricular arrhythmias in patients with ACS is not indicated. In MI, it has been shown to increase mortality rates. Lidocaine may be used for patients with complex ventricular ectopy or for patients with hemodynamically significant, nonsustained, or sustained ventricular tachycardia.
Further Outpatient Care
Patients with chronic stable angina may be considered for discharge after occurrence of the following: o Symptom duration is brief and identical to symptoms experienced in the past.
o ECG is normal or unchanged.
o Patient has access to timely follow-up with a primary care provider.
When in doubt, admit. The usual reason for a patient with chronic stable angina to present to the ED is a change in pattern or
severity of symptoms, which makes their angina unstable.
A study by Bartholomew et al may be helpful in making the decision to admit or discharge. This prospective thrombolysis in myocardial infarction risk score (TIMI-RS) used 7 variables in patients with suspected ACS: (1) age older than 65 years, (2) 3 or more cardiac risk factors, (3) ST deviation, (4) aspirin use within 7 days, (5) 2 or more anginal events over 24 hours, (6) history of coronary stenosis, and (7) elevated troponin levels. Patients were contacted at 30 days, and data were collected concerning major
adverse cardiac events.7
oIn patients presenting with chest pain, a higher TIMI-RS was associated with an increase in major adverse cardiac events within 30 days. The authors concluded that the 30-day event rate was 0% for a score of 1, 20% for a score of 2, 24% for a score of 3, 42% for a score of 4, 52% for a score of 5, and 70% for a score of 6 or 7 (p < 0.0001).
oThe TIMI-RS successfully differentiates early risk for major adverse cardiac events in a general population presenting with symptoms suggestive of ACS. A simple bedside calculation of the TIMI-RS provides rapid risk stratification, allowing facilitation of therapeutic decision-making in patients with symptoms suggestive of ACS and may be helpful with the patient's disposition.
Inpatient & Outpatient Medications
Aspirin
Use clopidogrel as a substitute for patients unable to take aspirin because of a history of hypersensitivity or bleeding. Use a 300-mg loading dose, then 75 mg qd.
Nitrates
o Use topical or oral nitrates for those who are discharged or for those who are stable inpatients.
oIntravenous infusion is preferable for those admitted with unstable symptoms.
Beta-blockers
oMetoprolol and propranolol are excellent choices for inpatient and outpatient management.
oUse esmolol for inpatient treatment, particularly those at risk for adverse effects from beta-blockade.
Heparin: Use heparin for inpatient management of unstable angina. Some preliminary data suggest that LMWH is a safe and effective alternative.
Significant clustering of recurrent ischemic events occurs within 24 hours after cessation of both short-term UFH and enoxaparin treatment, and patients should be carefully monitored during that period. This early rebound may be prevented by continuation of a fixed dose of enoxaparin.
Transfer
Consider transfer only for patients at particularly high risk and for those who are being evaluated in a center without access to timely cardiac catheterization, PTCA, or bypass.
High-risk criteria include the following:
o Symptoms refractory to medical management
o Hemodynamic instability, cardiogenic shock
o New or worsening mitral regurgitant murmur
oKnown or suspected severe aortic stenosis
The risks of transferring these unstable patients must be carefully weighed against the benefits of transfer.
Deterrence/Prevention
Cessation of smoking
Assessment of lipid profile and dietary changes, where appropriate (Among patients who have recently had an ACS, an intensive lipid-lowering statin regimen provides greater protection against death or major cardiovascular events than a standard regimen.8 )
Blood pressure control
Compliance with medications, particularly aspirin
Comprehensive risk assessment by primary care provider, including exercise tolerance test (ETT) for individuals at high risk and identification of structural heart disease (eg, left ventricular hypertrophy [LVH], aortic stenosis)
Complications
Acute myocardial infarction
Cardiogenic shock
Ischemic mitral regurgitation
Arrhythmias
o Supraventricular arrhythmias (rare complication of ischemia, may actually precipitate ischemic events)
oVentricular arrhythmias; simple and complex premature ventricular contractions (PVCs), and nonsustained ventricular tachycardia (NSVT)
Atrioventricular nodal blockade
oUsually transient in setting of reversible ischemia
oTreatment guided by location of block and hemodynamic stability
Ventricular rupture occurs in the interventricular septum or the LV free wall. This represents a catastrophic event with mortality rates greater than 90%. Prompt recognition, stabilization, and surgical repair are crucial to any hope of survival. An echocardiogram will usually define the abnormality, and a right heart catheterization may show an oxygenation increase with septal rupture.
Prognosis
Patients with angina either proceed to infarct or have their disease stabilized by medical and/or interventional therapies. Patients with angina are a heterogeneous group; therefore, prognosis varies with respect to stability of disease, demographics, comorbidity, and current intervention.
Patients with ACS with atrial fibrillation (AF) are associated with increased morbidity and mortality.
Patients with ACS and diabetes mellitus, especially those with ST elevation, had increased in-hospital mortality rates. Among patients with ACS and diabetes mellitus, those receiving insulin had worse outcomes. Outcomes were similar for those on hypoglycemic medication or on diet alone.10
In chronic stable angina, prognosis is generally excellent. Factors that have been shown to impact prognosis include the following:
o Aspirin reduces progression to both nonfatal MI and cardiac death.
o Beta-blockers control anginal symptoms and reduce cardiac complications in patients with hypertension.
o PTCA and revascularization improve the prognosis in high-risk patients.
oPoor prognostic factors include male sex, diabetes, and hypertension.
In unstable angina, prognosis is determined by the ability to control symptoms acutely, preventing progression to AMI. Factors associated with a poorer prognosis include the following:
oEvidence of myocardial necrosis, as determined by elevated troponin T level
o Delays in angiography in patients at high risk (Early angiography allows for triage to medical therapy, PTCA, or revascularization.)
Patient Education
For patients being discharged home, emphasize the following:
o Timely follow-up with primary care provider
o Compliance with discharge medications, specifically aspirin and other medications
used to control symptoms
o Need to return to ED for any change in frequency or severity of symptoms
Medicolegal Pitfalls
Failure to consider the diagnosis - Groups at risk include the following: o Women, particularly premenopausal
o Patients with diabetes o Elderly patients
o Patients with cocaine-related ischemia
Inadequate risk stratification in ED
Failure to administer aspirin as first-line therapy
Overcautious use of beta-blockers in ED
Clinical
History
Typically, angina is a symptom of myocardial ischemia that appears in circumstances of increased oxygen demand. It is usually described as a sensation of chest pressure or heaviness, which is reproduced by activities or conditions that increase myocardial oxygen demand.
Not all patients experience chest pain. Some present with only neck, jaw, ear, arm, or epigastric discomfort.
Other symptoms, such as shortness of breath or severe weakness, may represent anginal equivalents.
A patient may present to the ED because of a change in pattern or severity of symptoms. A new case of angina is more difficult to diagnose because symptoms are often vague and similar to those caused by other conditions (eg, indigestion, anxiety).
Patients may have no pain and may only complain of episodic shortness of breath, weakness, lightheadedness, diaphoresis, or nausea and vomiting.