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Venous thromboembolism - Pulmonary Embolism-Low molecular weight heparin as effective as unfractionated heparin

Clinical Bottom Line:
Pulmonary Embolism-Low molecular weight heparin is as effective as unfractionated heparin in decreasing recurrent VTE

Citation: The Columbus Investigators. Low-molecular weight heparin in the treatment of patients with venous thromboembolism. NEJM 1997;337:657-62.

Three-part Question: In pts with PE, is low molecular weight heparin as effective as unfractionated heparin in decreasing recurrent venous thromboembolism?

Search Terms: "heparin", "pulmonary embolism" in MEDLINE

The Study:
Randomised controlled trial of consecutive pts with symptomatic DVT, PE or both; DVT could be in calf or proximal.

Controls (N=511) unfractionated heparin adjusted using a nomogram to a aPTT of 60-85s, coumadin started within first 48 hrs and continued for a total of 12 wks; heparin discontinued when INR >2 for 2 consecutive days

Experimental (N=510) low molecular weight heparin adjusted by pt weight, coumadin started within first 48 hrs and continued for a total of 12 wks; LMWH discontinued when INR >2 for 2 consecutive days

The Evidence:

Outcome

Time to Outcome

RRR

95% CI

ARR

95% CI

NNT

95% CI

recurrent VTE

12 wks

-8%

-63% to 47%

-0.004

-0.031 to 0.023

-250

NNH = 32 to INF; NNT = 43 to INF

major bleed ( fall in haemo-globin of >2 or transfu-sion of 2 units)

12 wks

-35%

-100% to 52%

-0.008

-0.028 to 0.012

-125

NNH = 36 to INF; NNT = 84 to INF

death

12 wks

7%

-36% to 49%

0.005

-0.027 to 0.037

200

NNH = 37 to INF; NNT = 27 to INF

Comments:

  1. included pts with calf DVT
  2. not blinded but outcome events reviewed by blinded adjudication committee
  3. fewer pts in LMWH group had calf DVT
  4. hospitalisation days-LMWH 6.4 days vs. 9.4 days in unfractionated heparin; some pts in LMWH group were treated at home
  5. in LMWH group - 3 fatal PE, 3 sudden deaths; in unfractionated heparin - 3 fatal PE, 2 sudden deaths and 2 fatal bleeds
  6. see also Simonneau et al. NEJM 1997;337:663-9 - no difference in recurrent VTE, bleeds or death between unfractionated and lmwh groups but 73% of pts allocated to lmwh received therapeutic doses of unfractionated heparin prior to randomisation

Appraised by: Straus, Thursday, September 04, 1997

Expiry date: Sept/98

 

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