Chest pain: raised CK-MB increased the risk of cardiac complications.

Clinical bottom line (level 1b)

  1. Patients with a raised CK-MB (NNF = 3 for unknown) or troponin T (NNF = 4 for unknown) were at increased risk for cardiac complications in the next 2 months.
Sayre et al: Annals of Emergency Medicine 1998; 31: 539-549
Expires July 2003

The study

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

Setting: emergency department, university hospital, USA

667 patients (aged range 22 to 93 years; mean 53, 52% female) chest pain or other symptoms consistent with acute ischaemic heart disease

Excluded if
  • chest pain secondary to trauma
  • <25 years
  • unusable blood sample



Factors studied:
  • cardiac complications
  • highest troponin T within 24 hours <1 mcg/l
  • highest troponin T within 24 hours 1 to 2 mcg/l
  • highest troponin T within 24 hours 2 or more mcg/l
  • no CK-MB positive within 24 hours
  • at least one CK-MB positive within 24 hours




Multivariate logistic regression analysis was performed to adjust for other risk factors (eg. age, sex, race).

88% followed for 60 days
Outcomes studied:
  • cardiac complications

The evidence

outcome time to outcome number of patients/total number %
(95% CI)
cardiac complications 60 days 181/667 27%
(24% to 31%)

prognostic factor for
cardiac complications 		time to outcome control rate (%) adjusted OR
(95% CI)		 NNF+
(95% CI)
highest troponin T within 24 hours <1 mcg/l ? 23/442
(5.2%) 		1.0
( to )
( to )
highest troponin T within 24 hours 1 to 2 mcg/l 60 days 23/442
(5.2%) 		1.8
(0.7 to 4.8) 		26
(-6 to 67)
highest troponin T within 24 hours 2 or more mcg/l 60 days 23/442
(5.2%) 		6.9
(3.4 to 13.9) 		4
(3 to 10)

prognostic factor for
cardiac complications 		time to outcome adjusted RR
(95% CI)		 NNF+
(95% CI)
no CK-MB positive within 24 hours 60 days 1.0
( to )
( to )
at least one CK-MB positive within 24 hours 60 days 8.0
(3.6 to 17.7) 		3
(2 to 7)

  • 417 patients had a non-cardiac final diagnosis for chest pain (and 11 - 2.6% - had a cardiac complication within the time of the study)

Comments

  1. Low risk population for MI, and high number of cocaine users.
  2. No indication how long troponin done after onset of chest pain (more useful than arrival time in the emergency department).
  3. Patients had multiple tests- would fewer tests be as accurate?

Citation

  1. Sayre MR, et al: Measurement of cardiac troponin T is an effective method for predicting complications among emergency department patients with chest pain. Annals of Emergency Medicine 1998; 31: 539-549
Contributor: Chris Ball and Bob Phillips, July 2000
Reviewer: William Rhoton

Clinical Question.
Patient chest pain ?cardiac
Intervention or Exposure troponin T
Outcome cardiac complications