Myocardial infarction: a reduced ejection fraction, mitral regurgitation and old age increased the risk of dying.

Clinical bottom line (level 1b)

  1. One in eight patients with a myocardial infarction developed mitral regurgitation within 7 hours of symptom onset.
  2. One in twelve patients were dead at one year.
  3. Patients were at increased risk of dying in the next year with
    • an ejection fraction < 50%
    • increasing age
    • mitral regurgitation present within 7 hours of symptom-onset
    .
Lehmann et al: Annals of Internal Medicine 1992; 117 (1): 10-17
Expires March 2003

The study

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

Setting: 13 university hospitals, USA

206 patients (aged 21 to 75; mean 57, 83% male) with first myocardial infarction within 7 hours of symptom onset

Excluded if
  • aged > 75
  • chest pain for less than 30 minutes
  • cardiogenic shock, uncontrolled hypertension, left bundle branch block on presentation
  • previous MI, cardiac surgery or dilated cardiomyopathy
  • inadequate ventriculogram



Factors studied:
  • age, sex, ejection fraction, LV end diastolic pressure and volume, peak creatine kinase risk, systolic blood pressure, anterior infarction
  • mitral regurgitation within 7 hours of symptom onset
  • ejection fraction < 50%
  • increasing age


All patients received streptokinase.

A multivariate regression analysis was performed to adjust for confounding factors.

100% followed for 12 months
Outcomes studied:
  • mitral regurgitation
  • moderate to severe mitral regurgitation
  • death
  • death

The evidence

outcome time to outcome number of patients/total number %
(95% CI)		 NNF
(95% CI)
mitral regurgitation 7 hours 27/206 13%
(8.5% to 18%)		 8
(6 to 12)
moderate to severe mitral regurgitation 7 hours 5/206 2.4%
(0.33% to 4.5%)		 41
(22 to 310)
death 10 days 7/206 3.4%
(0.92% to 5.9%)		 29
(17 to 110)
death 12 months 16/206 7.8%
(4.1% to 11%)		 13
(9 to 24)

prognostic factor for
death 		time to outcome adjusted RR
(95% CI)		 NNF+
(95% CI)
mitral regurgitation within 7 hours of symptom onset 12 months 3.70
(1.10 to 12.1) 		7
(2 to 200)
ejection fraction < 50% 12 months 8.8
(1.8 to 42.7) 		3
(1 to 25)
increasing age 12 months 2.7
(1.2 to 6.2)
( to )

Comments

  1. A murmur suggestive of mitral regurgitation was only heard in two patients (1.0%: 95% CI: 0.0% to 2.3%).

Citation

  1. Lehmann KG, Francis CK, Dodge HT, et al: Mitral regurgitation in early myocardial infarction: incidence, clinical detection, and prognostic implications. Annals of Internal Medicine 1992; 117 (1): 10-17
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Contributor: Chris Ball and Clare Wotton, February 2000
Reviewer:

Clinical Question.
    Patient myocardial infarction
    Intervention or Exposure ejection fraction, mitral regurgitation
    Outcome death