Unstable angina: patients with new rest pain or pain lasting a long time had a worse outcome.

Clinical bottom line (level 2b)

  1. Dividing patients into five prognostic groups may help predict which ones have a worse outcome.
  2. Patients with new onset pain at rest, or pain that persistently lasts more than 20 minutes (with ECG changes) were at increased risk of dying, having intractable angina or an infarct.
Rizik et al: American Journal Of Cardiology 1995; 75: 993-997
Expires July 2003

The study

Retrospective cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: two acute hospitals, USA

1387 patients (aged mean 66 years, 53% male) unstable angina diagnosed by typical anginal pain and one of:
  • rest pain >10 minutes
  • pain on less exertion than previously
  • unresponsive to usual anti-anginal therapy
  • ECG changes with ST depression or T-wave inversion in two or more leads, ST elevation, hyperacute T waves or both. If ECG normal, then known coronary artery disease


Excluded if
  • ST elevation diagnostic MI (including posterior infarction)
  • evolving MI (CK raised twofold above upper limit of normal with CK-MB fraction raised) within 12 hours of admission
  • non-cardiac diagnosis


    • Patients received aspirin, heparin, nitrates, beta-blockers and calcium channel blockers as required. More patients with severe angina were on heparin.

    ?100% followed for length of hospital stay
    Outcomes studied:
  • intractable angina: Ia
  • intractable angina: Ib
  • intractable angina: II
  • intractable angina: III
  • intractable angina: IV
  • MI: Ia
  • MI: Ib
  • MI: II
  • MI: III
  • MI: IV
  • death: Ia
  • death: Ib
  • death: II
  • death: III
  • death: IV

    • Retrospectively categorised into the following groups by blinded cardiologist:
      • Ia- acceleration of previously chronic stable angina without new ECG changes (n=198)
      • Ib- acceleration of previously chronic stable angina with new onset ECG changes (n=219)
      • II- exertional angina of new onset (n=279)
      • III- new onset resting angina (n=408)
      • IV- protracted chest pain >20 minutes duration per episode with persistent abnormalities of subendocardial ischaemia (n=283)

    The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    intractable angina: Ia length of hospital stay 0/219 0.0%
    (% to %)
    intractable angina: Ib length of hospital stay 7/198 3.5%
    (% to %)
    intractable angina: II length of hospital stay 11/279 3.9%
    (% to %)
    intractable angina: III length of hospital stay 45/408 11%
    (% to %)
    intractable angina: IV length of hospital stay 54/283 19.1%
    (% to %)
    MI: Ia length of hospital stay 6/219 2.7%
    (% to %)
    MI: Ib length of hospital stay 11/198 5.6%
    (% to %)
    MI: II length of hospital stay 16/279 5.7%
    (% to %)
    MI: III length of hospital stay 36/408 8.8%
    (% to %)
    MI: IV length of hospital stay 50/283 17.7%
    (% to %)
    death: Ia length of hospital stay 0/219 0.0%
    (% to %)
    death: Ib length of hospital stay 0/198 0.0%
    (% to %)
    death: II length of hospital stay 0/279 0.0%
    (% to %)
    death: III length of hospital stay 6/408 1.5%
    (% to %)
    death: IV length of hospital stay 18/283 6.4%
    (% to %)

    Comments

    1. Needs to be prospectively validated in another set of patients to assess its clinical validity, although many other studies have consistent results.

    Citation

    1. Rizik DG, Healy S, Margulis A, et al: A new clinical classification for hospital prognosis of unstable angina pectoris. American Journal Of Cardiology 1995; 75: 993-997
    Contributor: Nick Shenker and Chris Ball, July 2000
    Reviewer: Dwight Peretz

    Clinical Question.
    Patient unstable angina
    Intervention or Exposure clinical features, ECG changes
    Outcome death, MI, recurrent angina