Unstable angina: enoxaparin reduced cardiac outcomes

Clinical bottom line (level 1b)

  1. In patients with unstable angina who received enoxaparin instead of standard heparin, there were fewer patients with MI, death or recurrent angina at 1 year (NNT = 14 at 12 months)
  2. Patients who received enoxaparin were less likely to require revascularisation (NNT = 17 at 12 months)
Goodman et al: J Am Coll Cardiol 2000; 36: 693-698
Expires November 2003

The study

Double-blinded concealed randomised trial with intention-to-treat
Setting: 176 acute hospitals, North and South America and Europe

3171 patients (aged 25 to 94; median 65,  66% male) recent onset angina at rest and underlying ischaemic heart disease, as evidenced by 1 or more of
  • new ST-depression of  at least 1 mm, or transient ST elevation or T-wave inversion in  at least 2 contiguous leads
  • documented previous MI or revascularisation procedure
  • results of previous tests demonstrating ischaemic heart disease


Excluded if
  • <18 years old
  • pregnancy
  • left bundle branch block or pacemaker
  • persistent ST-T elevation
  • angina with established cause (anaemia/ congestive heart failure)
  • contraindications to anticoagulation
  • creatinine clearance of less than 30 ml/min
  • refusal to give consent


Control Group: (n = 1564, 1446 analysed): intravenous heparin to ensure a therapeutic aPTT, with dummy s/c injections of saline
Experimental Group: (n = 1607, 1469 analysed): subcutaneous enoxaparin (1mg/kg) twice daily with dummy saline intravenous infusion

91.9% followed for 12 months
Outcome notes:
  • death, MI or recurrent angina : composite end-point
  • death or MI : composite end-point

The evidence

Outcome Time to outcome CER RR
(95% CI)		 NNT
(95% CI)
death, MI or recurrent angina 12 months 516/1446
(35.7%)		 0.87
(0.77 to 0.98) 		24
(14 to 156)
death or MI 12 months 195/1446
(13.5%)		 0.84
(0.69 to 1.02) 		46
(NNT = 24 to infinity;
NNH = 370 to infinity)
revascularization procedures 12 months 519/1446
(35.9%)		 0.84
(0.75 to 0.94) 		17
(11 to 46)

The RR described above are Hazard Ratios taken from an analysis of the event survival curves

Comments

  1. This one year follow-up confirms the results of the short-term outcomes of the original ESSENCE study.

Citation

  1. Goodman SG, Cohen M, Bigonzi F, et al: Randomized Trial of Low Molecular Weght Heparin (Enoxaparin) Versus Unfractionated Heparin for Unstable Coronary Artery Disease. J Am Coll Cardiol 2000; 36: 693-698
Search Terms: Reference from expert; and from ACP Journal Club other articles noted
Contributor: Bob Phillips, November 2000
Reviewer: Chris Ball

Clinical Question.
Patient unstable angina
Intervention or Exposure LMWH, enoxaparin
Comparison heparin, unfractionated heparin
Outcome death, reinfarction, reintervention, MI