2. BTS(1992)→3 Mths anticoagulation to pts
with pul: VTE(1st episode or no episodes
for previous 3 yrs)
UK,N.America,Europe→6 mths or more
BTS→compare outcomes of 3 & 6 mths
anticoagulation with warfarin after initial
heparin Rx
3. Methods & Design
Multicentre,prospective,randomised
controlled trial with f-up for 1 yr
Mid Sept,1999 to end of Dec,2002
137 Consultants fr 46 hospitals;810 pts
>18yr with suspected or proved DVT or
PE or both
369 pts in 3m & 380 in 6mth a/f exclusion
4. Methods & Design
Start warfarin on day 1 of the scheduled 5
days heparin
F-up at 3,6,& 12 mths from date of entery
INR to monitor anticoagulation
To acheve INR b/t 2 to 3.5
5. Methods & Design
Informations obtained
-failure of resolution
-extension or recurrence of DVT or PE
-results of INR
-dates of start & completion of Rx with
heparin & warfarin
-adverse events
6. Methods & Design
Predetermined adverse outcomes
-death from DVT or PE
-failure during Tx
-recurrence a/f end of Tx
-major haemorrhage during Tx
7. Methods & Design
Type of anticoagulation
-Low MW heparin
-oral anticoag→ warfarin or courmarin
Grading for anticoagulation
-good=INR b/t 2 to 3.5 on 2/3 occasions
-mod = 2 to 3.5 on >1/3 but <2/3 occasions
-poor=2 to 3.5 on<1/3 occasions
8. Methods & Design
Haemorrhage was defined as major if
-transfusion is necessary
-Hb ↓ by 20 g/l
-intracranial or retroperitoneal
-sufficiently serious to stop anticoag
9. Results
Warfarin Rx at 3m f-up,graded as poor in
-42 of 355 pts in 3mth group(13%)
-37 of 340 pts in 6mth group(11%)
-11(4%) in b/t 3 & 6m →control improved
b/t 3 & 6 mths
10. Results
During Tx →4 pts died from DVT or PE
-1 pt from 3mth group
-3 pts from 6mth group
-1 from 3 mth grp died from DVT or PE 1
mth after completion of Tx
Death fr hge duing Tx →0% for both grp
11. Results
During & a/f Tx →28 pts died from causes
other than DVT & PE
-12 pts from 3m group
-16 pts from 6m group
DVT or PE failed to resolve,extended or
recurred in
-6 in 3m grp without fatal consequences
-10 pts in 6m group
12. Results
Major nonfatal haemorrhage
-0 in 3 mth group
-10 pts in 6 mth group
Overall adverse outcomes
-31 pts(8%) in 3 mth group
-35 pts(9%) in 6 mth group
14. Comparism b/t previous studies &
this study
Regarding failure during Tx & recurrence
(1)100 pts with DVT/PE→9 to 17% a/f 6m
(2)1st BTS study(1992) →8% a/f 3 mth
(3)comparing 3 & 6 m Rx →8% in both
(4)comparing 6wk Tx & 6m Tx
-at 2 yrs →18% in 6wk & 9% in 6 mth
-at 6 yrs →28% in 6wk & 2% in 6 mth
-at 10 yrs →no sig: difference(31% & 27%)
15. (5)comparing 3m & 6m groups at 2 year
-12 to 16% in 3 mth group
-12 to 17% in 12 mth group
This study →fatal & nonfatal failure of
resolution,extension or recurrence during
& after Tx →8% in both
16. Regarding risk of major bleeding
Studies(1996,2000 & 2005) →death rate
from major hge=0.5% in 3m
Meta-analysis(2005) →same for both long
term & short term anticoagulation
This study →0% in 3m &2% in 6mth
17. Regarding mortality
1 yr mortality from DVT or PE
-previous trials →0 to 2.2%
-study in 1992 →1%
-studies in 1996 & 2000 →0.5%
-this study →0.7%
Death from major haemorrhage(b/t 1990-2005)
-0.1 to 0.4% for 3 mth
-0.1% for 6 mth
18. Summary
3 mth anticoag= same benefits as 6 mth
but lower incidence of hge during Tx
Tx beyond 6mth →not ↓ risk of recurrence
after warfarin is stopped
1st episode VTE →at least 3 mth warfarin
Distal VTE →6 wks is adequate
Continuing reversible risk factor →beyond
3 to 6m until risk=no longer present
19. For continuing Tx indefinitely
Pts with very high risk of recurrence
-> 1 episode of unprovoked thrombus
-cancer & thrombosis
-high risk thrombophilia
-severe post thrombotic syndrome
-strong preference for minimising risk of
recurrence by continuing anticoagulation
