Unstable angina: chest pain observation units had no clear benefit.

Clinical bottom line (level 1b-)

  1. Patients with unstable angina who were admitted to a chest pain observation unit had no clear difference in cardiovascular events, than those admitted to routine hospital care.
Farkouh et al: New England Journal of Medicine 1998; 339 (26): 1882-1888
Expires March 2003

The study

Unblinded ?concealed randomised trial ?with intention-to-treat
Setting: emergency department, USA

424 patients (aged mean 58 years, 56% male) unstable angina, defined as: symptoms of angina lasting >20 minutes; new-onset angina on exertion; recent acceleration of preexisting angina; post MI angina

Excluded if
  • obvious noncardiac cause for chest pain
  • residency outside the nine-county region
  • transfer from another hospital
  • non-English speaking
  • ST-segment elevation on ECG
  • unstable angina associated with a low or high risk according to AHCPR criteria
  • coexisting condition requiring hospitalisation


    • Note:
  • Patients were stratified according to age, sex, previous MI or undergone a revascularisation procedure.


    • Control Group: (n = 212, 212 analysed): routine hospital admission- monitored bed under the care of the cardiology service. Treatment was not standardised and patient care varied in diagnostic approach and therapy details.
    Experimental Group: (n = 212, 212 analysed): observation in the chest pain unit- four beds in a separate area of the emergency department, equipped with event monitors, continuous ST-segment monitoring and staffed by a full-time nurse. Patients were admitted to a monitored bed under the care of the cardiology service if their creatine kinase-MB rose above 9.6 ng/ml at any time. They were also admitted to hospital if they had symptoms of recurrent chest pain. Patients were given 325 mg aspirin and heparin iv if deemed necessary.

    100% followed for 6 months
    Outcome notes:
    • cardiovascular event : nonfatal MI, death, congestive heart failure, stroke or out-of-hospital cardiac arrest

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    cardiovascular event 6 months 18
    (8.49%)    		 14
    (6.60%)    		 22.0%
    (-52.0% to 60.0%)    		 1.89%
    (-3.14% to 6.91%)    		 53
    (NNT = 14 to infinity;
    NNH = 32 to infinity)

    Comments

    1. Unclear how discharged patients are included in this analysis (if at all).
    2. The trial was too small to show any clear difference in cardiovascular events between a chest pain observation unit and routine admission.

    Citation

    1. Farkouh ME, Smars PA, Reeder GS, et al: A clinical trial of a chest-pain observation unit for patients with unstable angina. New England Journal of Medicine 1998; 339 (26): 1882-1888
    Contributor: Clare Wotton and Musab Hayatli, January 2000
    Reviewer: Dwight Peretz

    Clinical Question.
    Patient unstable angina
    Intervention or Exposure admitted to chest pain observation unit
    Comparison routine hospital admission
    Outcome cardiovascular events