Non-Q MI and Unstable Angina


 

New AHA/ACC Unstable Angina Guideline

See Circulation Sep 5, 2000. 102(10): 1193-1209

This guideline is of tremendous interest to all Emergency physicians and internists.  It is written by Eugene Braunwald and other big shots in Cardiology.  I will summarize the guideline and highlight the most important changes to previous guidelines from the perspective of a ER physician/ hospitalist. The bottom line is there is not much that you didn't know before.   The reader is referred also to the excellant chapter in Tintainalli's Emergency Medicine: A comprehensive study guide for the basics.

Summary:

1.  All chest pain patients at rest x 20 min, hypotension, or syncope/pre-syncope should be seen in ER/chest pain unit. (No surprise here!)

2.  TAll patients should be classifed as to their likelihood for ischemic heart disease (low/intermediate/high) and the risk (low, intermediate, high).

2a.  The risk classification of the new guideline has subtle changes compared to the NHLBI guideline in 1994: (a) troponin is also used for risk classification: normal suggests low risk, slightly elevated suggests intermediate risk, markedly elevated=high risk).  (b) Also note the new age cut off! (>75 yo= high risk; 70-75=intermediate);  (c) New onset CCSC[1] III or IV angina in the past 2 weeks with moderate or high likelihood of CAD is now "low risk", but I think this is a mistake, but then I am not Braunwald!

The NHLBI CLASSIFICATION:

Likelihood
 
High likelihood
(e.g., 0.85-0.99)
Intermediate likelihood
(e.g., 0.15-0.84)
Low likelihood
(e.g., 0.01-0.14)
Any of the high or following features:  Absence of high likelihood features and any of the following:  Absence of intermediate likelihood features but may have:
History of prior MI or sudden death or other known history of CAD 
Definite angina: males > 60 or females > 70 years of age 
Transient hemodynamic or ECG changes during pain 
Definite angina: males < 60 or females < 70 years of age 
Probable angina: males > 60 or females > 70 years of age 
Chest pain probably not angina in patients with diabetes 
Chest pain classified as probably not angina 
One risk factor other than diabetes 
T-wave flattening or inversion < 1 mm in leads with dominant R waves 
Variant angina (pain with reversible ST-segment elevation)  Chest pain probably not angina and two or three risk factors other than diabetes[1]  Normal ECG
ST segment elevation or depression > 1 mm 
Marked symmetrical T-wave inversion in multiple precordial leads 
Extracardiac vascular disease 
ST depression 0.05 to 1 mm 
T-wave inversion > 1 mm in leads with dominant R-waves 

Short-term risk of death or nonfatal myocardial infarction in patients with unstable angina

 
High risk Intermediate risk Low risk
At least one of the following features must be present:  No high-risk feature but must have any of the following:  No high- or intermediate- risk feature but may have any of the following features: 
Prolonged ongoing (>20 mins) rest pain  Prolonged (> 20 mins) rest angina, now resolved, with moderate or high likelihood of CAD  Increased angina frequency, severity, or duration 
Pulmonary edema, most likely related to ischemia  Rest angina (> 20 mins or relieved with rest or sublingual nitroglycerin)  Angina provoked at a lower threshold 
Angina at rest with dynamic ST changes > 1 mm  Nocturnal angina New onset angina with onset 2 weeks to 2 months prior to presentation 
Angina with new or worsening MR murmur 
Angina with S3 or new/worsening rales 
Angina with dynamic T-wave changes  Normal or unchanged ECG
Angina with hypotension  Pathologic Q waves or resting ST depression < 1 mm in multiple lead groups (anterior, inferior, lateral) New onset CCSC[1] III or IV angina in the past 2 weeks with moderate or high likelihood of CAD
Age>75, High Troponin Age >70 years,  Slightly high troponin Normal Troponin

3. Classify patients into the following:

4. Serial enzymes (CKMB, troponin are ideal) and 12 leads should be performed up to 8-12 hours from admission.

5. Must R/O noncoronary chest pain. (such as dissection, pneumothorax!)

6. Medical therapy: NTG sublingual> NTG iv> Morphine for pain relief and pulmonary edema> beta-blocker if not contra-indicated> Ca-blocker if beta-blocker contraindicated or Sx not adequately controlled with beta-blocker. Use ACEI for HTN.

7. New: ACEI for all post-ACS patients/  (My note: based on

8. ASA, but if contraindicated then use clopidogrel or ticlopidine.  (Note: despite pressure from drug rep, ASA is still first line.)

9 Heparin IV or LMWH should be used. (The guideline write-up did suggest LMWH is better, but the actual recommendation is conventional IV heparin).

10.  Glycoprotein IIbIIIa inhibitors should be used in high risk patients, ongoing ischemia, or when coronary intervention planned.  (The guideline is vague for which drugs to use.  In high risk patients going for PCI within 24 hours, use ReoPro; may or may not go for cath: use integrilin or aggrastat.  The reader is reminded that GUSTO 4 presented last week in European Society of Cardiology showed no difference for patients with unstable angina not going for intervention using ReoPro.  Hence Glycoprotein IIbIIIa should really be used only when PCI may be performed.)

11. High risk patients should be considered for early invasive approach (early PCI): recurrent CP on therapy, CHF/ worse MR, high risk non-invasive, EF<40%, hypotension, V Tach, PCI within 6 months, Prior CABG (All Class I).  Age> 65 may lean you towards early invasive (Class IIa).  For all other patients the choice between early invasive versus early conservative should be individualized (e.g. based on patient's preference).

12.  Non-invasive testing: low risk patient wait 12 hours before testing, medium risk wait 2 days.  Stress ECG without imaging OK if interpretable, otherwise imaging as per local expertise.  Cath for patients who fails to stabilizes on medical therapy.

13.  CABG vs PCI:  CABG for Left Main, 3 vessel disease EF<50%, 2 vessel with prox LAD and EF<50% (but PCI a Class 2b alternative).  (Class 1)

14.  All coronary interventions should be performed with glycoprotein inhibitors (Class 1)


Reprinted from http://www.acls2000.org/index.html