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GHA GUIDELINES
Year : 2006  |  Volume : 7  |  Issue : 1  |  Page : 26-33 Table of Contents     

Guidelines on the management of acute coronary syndromes in patients presenting without ST-segment elevation


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Date of Web Publication17-Jun-2010

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How to cite this article:
Al Nozha M, Gaafar K, Kader FA, Al Rashdan I, Al Suwaidi J, Amin H, Al Khaja N, Al Mahameed W. Guidelines on the management of acute coronary syndromes in patients presenting without ST-segment elevation. Heart Views 2006;7:26-33

How to cite this URL:
Al Nozha M, Gaafar K, Kader FA, Al Rashdan I, Al Suwaidi J, Amin H, Al Khaja N, Al Mahameed W. Guidelines on the management of acute coronary syndromes in patients presenting without ST-segment elevation. Heart Views [serial online] 2006 [cited 2020 Jan 26];7:26-33. Available from: http://www.heartviews.org/text.asp?2006/7/1/26/63907


   Introduction Top


Acute coronary syndromes are a major health problem and represent a large number of hospitalizations annually world wide and the Gulf states are not an exemption.

The Gulf Countries, like many other developing countries, have witnessed a rapid development in many aspects of life during the last few decades. Epidemiological transition has already occurred; a sharp decline in infectious and nutritional deficiency diseases and a gradual increase in chronic diseases have occurred in these countries. The prevalence of cardiovascular risk factors has increased, the prevalence of diabetes mellitus is the highest worldwide approaching 15-25% of the adult population. More than 70% of the adult population have excess body weight (overweight or obese).Twenty six percent of the adult population are hypertensives, 54% have hypercholesterolemia and 13% -40% are smokers.

In the last decade of the 20th century, cardiovascular diseases, primarily coronary Atherosclerosis and heart failure, are the leading causes of morbidity and mortality in the Gulf States. The mean age of native patients with acute coronary syndrome in the Gulf is 62 yrs for women and 59 yrs for men. Diabetes mellitus is the commonest risk factor in these patients in over 50% of these patients, which is double the rate reported in other communities. Furthermore diabetes was more common in women than men (68.5% compared to 48%). Hypertension was present in 43%, hypercholesterolemia in 30% and smoking in 25% of patients. Acute coronary syndrome without persistent ST-segment elevation accounts for 50% of cases. Although there has been an increase in the use of appropriate therapeutic modalities in patients with acute coronary syndromes in our communities, their use remains sub-optimal, calling for the use development of evidence-based guidelines that are tailored to the needs of our patients. The GHA assigned a working group to develop an up- to- date guideline for the treatment of acute coronary syndrome, adopted from the latest update of both ESC and ACC/AHA guidelines .In the same vein a consensus based on the available data and practice present at the time of development of such guidelines, has been tailored to meet with the needs of our patients.

These guidelines refer to the management of patients with suspected acute coronary syndromes without persistent ST-segment elevation. The guidelines should be used as guidelines", which will apply to the majority of cases.

However it should be appreciated, that specific findings in individual patients may and should result in deviation from the proposed strategy. For every patient, the physician should make an individual decision taking into account the patient's history, presentation, findings during observation or investigation in hospital, and the available treatment facilities. In most patients, only chest discomfort (chest pain) might be present and suspicion of acute coronary syndrome is only a working diagnosis.

Initial Assessment & Evaluation

The initial assessment includes the four following steps.

  1. It is important to obtain a careful history and a precise description of the symptoms. A physical examination with particular attention to the possible presence of valvular heart disease (aortic stenosis), hypertrophic cardiomyopathy, heart failure, and pulmonary disease is required.
  2. An electrocardiogram is recorded: comparison with a previous ECG, if available, is very valuable, particularly in patients with preexisting cardiac pathology such as left ventricular hypertrophy or known coronary disease. The ECG allows differentiation of patients with a suspicion of ACS in two categories requiring different therapeutic approaches:


    1. ST-segment elevation signifies complete occlusion of a major coronary artery and immediate reperfusion therapy is usually indicated.
    2. ST-segment changes but without persistent Stsegment elevation or a normal ECG.
    3. In a few cases there is no definite characterization and there are undetermined ECG changes such as bundle branch block or pacemaker rhythm.
  3. In the latter two cases, biochemical markers are required for further characterization: Laboratory assessments should include haemoglobin (to detect anaemia) and markers of myocardial damage,preferably cardiac troponin T or cardiac troponin I. If concentrations of troponins or cardiac enzymes rise, irreversible cell damage will have occurred and these patients must be regarded as having had myocardial infarction.
  4. Then starts an observational period which includes a multi-lead ECG ischaemia monitoring. If the patient experiences a new episode of chest pain, a 12-lead ECG should be obtained and compared with a tracing obtained when symptoms have resolved spontaneously or after nitrates. In addition, an echocardiogram may be recorded to assess left ventricular function and to eliminate other cardiovascular causes of chest pain.
Troponin measurements should be repeated after 6 and 12 hours.

Patients can then be classified as follows:

  • Myocardial infarction (with elevated markers of necrosis),
  • Unstable angina (ECG changes but no signs of necrosis)
  • Other causes of chest pain.
Once diagnosed, acute coronary syndromes without persistent STsegment elevation (ST-segment depression, negative T-waves, pseudo normalisation of T-waves or normal ECG) initially require medical treatment including:

  • Aspirin Initial dose of 150 - 325 mg followed by 75-150 mg/d
  • Clopidogrel (loading dose of 300mg followed by 75mg/day).
  • LMWH or unfractionated heparin.
  • Beta-blocker
  • Oral or intravenous nitrates in case of persistent or recurrent chest pain.
  • Calcium antagonists may be preferred over beta-blockers in those patients who have contraindications to, or who are known not to tolerate a beta-blocker.
In the subsequent observational period (8-12 hours) specific attention should be given to recurrence of chest pain during which an ECG will be recorded.

Signs of hemodynamic instability should be carefully noted (hypotension, pulmonary crackles) and treated.

Within this initial period, risk assessment can be performed based on the clinical, electrocardiographical and biochemical data, and a further treatment strategy can be selected.


   Strategies according to risk stratification Top



   Clinical Suspicion of ACS Top


3.1 - Patients judged to be at high risk for rapid progression to myocardial Infarction or death:

High risk patients include those:

  1. with recurrent ischaemia either recurrent chest pain or dynamic ST-segment changes (in particular ST-segment depression, or transient ST-segment elevation).
  2. with early post-infarction unstable angina. odynamic instability within the observation period.
  3. with elevated troponin levels.
  4. who develop hemodynamic instability within the observation period.
  5. with major arrhythmias (repetitive ventricular tachycardia, ventricular fibrillation).
  6. with diabetes mellitus.
  7. with an ECG pattern which precludes assessment of ST-segment changes.


In these patients the following strategy is recommended:

  1. Coronary angiography should be Planned as soon as possible, but without undue urgency. A relatively small group of patients will require a coronary angiogram within the first hour. This includes patients with severe ongoing ischaemia, major arrhythmias, and hemodynamic instability.


  2. Coronary angiography is to be performed within at least the hospitalisation period. In patients with lesions suitable for myocardial revascularization, the decision regarding the most suitable procedure will be made after careful evaluation of the extent and characteristics of the lesions, where appropriate, in consultation with surgical colleagues. In general, recommendations for the choice of a revascularization procedure in unstable angina are similar to those for elective revascularization procedures.
  3. While waiting and preparing for coronary angiography, treatment with LMWH Or UFH should be continued.
Administration of GP/IIb/IIIa receptor inhibitor should be started and continued for 12 (abciximab) or 24 (tirofiban, eptifibatide) hours after the procedure if PCI is performed.

In hospitals without onsite cardiac interventional facilities, high risk patients should be managed as above and arrangement made for transfer to hospital with interventional facilities.

3.2 - Patients considered to be at low risk for rapid progression to myocardial infarction or death.

Low risk patients include those:

  1. who have no recurrence of chest pain within the observational period.
  2. without ST-segment depression or elevation but rather flat Twaves or a normal ECG.
  3. without elevation of troponin or other biochemical markers of myocardial necrosis on the initial and repeat measurement (performed between 6-12 hours).
In these patients, oral treatment should be recommended, including aspirin, clopidogrel (loading dose of 300mg followed by 75mg daily), beta-blockers and possibly nitrates or calcium antagonists.

Secondary preventive measures should be instituted as discussed below. Low molecular weight heparin or UFH may be discontinued when, after the observational period, no ECG changes are apparent and a second troponin measurement is negative.

A stress test is recommended preferably prior to discharge. The purpose of such a test is firstly, to confirm or establish a diagnosis of coronary artery disease and secondly, to assess the risk for future events in patients with coronary artery disease.

In patients with significant ischaemia during the stress test, coronary angiography and subsequent revascularization, should be considered, particularly when this occurs at a low workload on the bicycle or treadmill.

Patients with an ECG pattern that would interfere with interpretation of the ST segment should have an exercise test with imaging. Patients who are unable to exercise should have a pharmacological stress test with imaging

3.3 Recommendation for the Diagnosis of Noncardiac Causes of Symptoms

The major objectives of the physical examination are to identify potential precipitating causes of myocardial ischemia (eg, uncontrolled hypertension or thyrotoxicosis), evidence of other cardiac disease (eg, aortic stenosis or hypertrophic cardiomyopathy), and comorbid conditions (eg, pulmonary disease) and to assess the hemodynamic impact of the ischemic event.

The symptoms resulting on presentation to the hospital were probably not caused by myocardial ischaemia, and additional investigations of other organ systems may be appropriate. In any case, the risk for cardiac events in such patients is very low.Therefore, additional tests can usually be performed at a later time, at the outpatient

Indication for Early Coronary Angiography in U.A & NSTEMI

4.1. An early invasive strategy is recommended in patients with UA/NSTEMI and any of the following

(I) high-risk indicators:

  1. Recurrent angina/ischemia at rest or with low-level activities despite intensive anti-ischemic therapy.
  2. Elevated TnT or TnI.
  3. New or presumed new ST-segment depression at presentation.
  4. Recurrent angina/ischemia with CHF symptoms, an S3 gallop, pulmonary edema, worsening crackles, or new or worsening mitral regurgitation.
  5. High-risk findings on noninvasive stress testing.
  6. Depressed LV systolic function (eg, ejection fraction [EF] < 0.40 on noninvasive study).
  7. Hemodynamic instability or angina at rest accompanied by hypotension.
  8. Sustained ventricular tachycardia.
  9. PCI within 6 months.
  10. Prior CABG.
In the absence of these findings, either an early conservative or an early invasive strategy in hospitalized patients without contraindications for revascularization should be adopted.

4.2. Coronary angiography is not recommended in

  1. patients with extensive co morbidities (eg, liver or pulmonary failure, cancer), in whom risks of revascularization are likely to outweigh the benefits.
  2. Patients with acute chest pain and a low likelihood of ACS.


Long term management

5.1. Aggressive risk factor modification is warranted in all patients following diagnosis of ACS. It is mandatory that patients stop smoking. Referral to smoking cessation clinic is recommended.

5.2. Blood pressure control should be optimised. 5.3. Aspirin (75-150mg) in addition to clopidogrel (75mg/day) should be prescribed for at least 9- 12 months.

Later on, Aspirin (75-150mg/day) will be continued for life Clopidogrel should replace aspirin in patients with hypersensitivity or major gastro-intestinal intolerance to aspirin

5.4. Beta-blockers improve prognosis in patient after myocardial infarction and should be continued after acute coronary syndromes.

5.5. Lipid lowering therapy should be initiated without delay and optimised particularly HMGCoA reductase inhibitors ( statins) .

5.6. ACE-inhibitors in secondary prevention of acute coronary syndromes should be considered in all patients especially those at high risk.

Since coronary atherosclerosis and its complications are multifactorial, much attention should be paid to treat all modifiable risk factors in an effort to reduce recurrence of cardiac events. [Figure 1], [Figure 2], [Figure 3], [Table 2], [Table 3] [4]

 
   References Top

1.Management of Acute Coronary Syndromes: Acute Coronary Syndromes without Persistent ST- Segment-Elevation. Task Force of the ESC, M.E. Bertrand (Chairperson) K.L. Simoons, K.A.A. Fox, L.C. Wallentin, C.W. Hamm, E. McFadden, P.J. De Feyter, G. Specchia, W. Ruzyllo Eur. Heart J. 2000; 21:1406-1432.  Back to cited text no. 1      
2.Management of Acute Coronary Syndromes in Patients Presenting without Persistent ST-segment Elevation. Task Force of the ESC. M.E. Bertrand (Chairperson) M.L. Simoons, K.A.A. Fox, L.C. Wallentin, C.W. Hamm, E. McFadden, P.J. De Feyter, G. Specchia, W. Ruzyllo Eur. Heart J. 2002;23:1809-1840.  Back to cited text no. 2      
3.Management of Acute Myocardial Infarction in Patients Presenting with ST-Segment Elevation. Task Force of the ESC. F. Van de Werf (Chairperson), D. Ardissino, A. Betriu, D.V. Cokkinos, E. Falk, K.A.A. Fox, D. Julian, M. Lengyel, F-J. Neumann, W. Ruzyllo, K. Thygesen, S.R. Underwood, A. Vahanian, F.W.A. Verheugt, W. Wijns. Eur. Heart J.2003; 24:28-66.  Back to cited text no. 3      
4.Myocardial infarction redefined - a consensus document of The Joint European Society of Cardiology/American College of Cardiology committee for the redefinition of myocardial infarction: The Joint European Society of C ardiology/American College of Cardiology Committee .E. Antman , J-P. Bassand, Wl. Klein, M . Ohman, J.L. Lopez sendon, L. Rydzn, M. Simoons and M. Tendera J.Am Coll. Cardiol. 2000; 36:959-969.  Back to cited text no. 4      


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 2], [Table 3]



 

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