To The Editor:
When writing history, including medical history, it would seem of some
importance to be as correct as possible. After reading the review article by Lieberman, et al on prevention of thrombo-embolism after total hip or knee arthroplasty, I should like to provide some additional historical perspective.
The inspiration to evaluate the efficacy of extended duration of prophylaxis
was based on two observations: the occurrence of late fatal pulmonary embolism after surgery
(1); and the occurrence of post hospital discharge deep vein thrombosis after major
abdominal surgery (2). These observations formed the background to design
studies to evaluate the possible role of prolonged prophylaxis, and elective hip surgery was considered
a relevant experimental clinical model because it represents a fairly standardized surgical trauma event with
a high frequency of thrombosis.
The first such studies were published in 1996 (3, 4), and preceeded the
study by White, et al (5). They verified the presence of
late venous thromboembolism following arthroplasty and showed a reduction in venographically detected deep vein thrombosis when prophylaxis with molecular weight heparin was extended to approximately one month.
Later many studies have confirmed these results (6-9).
Lieberman and Hsu cite two studies by Planes, et al (4,10)(their references nos. 92 and 120), but the best summaries are found in two meta-analyses
which were made in parallel and published the same year (11, 12).
Lieberman and Hsu only refer to one of them (12). The value of prolonged
prophylaxis was later confirmed by Prandoni, et al (13) and Samama, et
al (14).
Several of the studies listed by Lieberman and Hsu to support the use of
prolonged prophylaxis have nothing to do with prolonged prophylaxis.
Turpie, et al (15) compared placebo with enoxaparin for 14 days; Warwick
(16) compared enoxaparin with control for three days; Kalodiki (17) compared control, enoxaparin and enoxaparin
combined with stockings for 8-12 days; and Leclerc (18),evaluated the use of
enoxaparin for a mean of 9 days.
A major problem that Lieberman and Hsu correctly raise is that
symptomatic venous thromboembolism was not assessed in the majority of
studies. However, we (3) reported a significant reduction in this complication, and Hull et al (11) found
significant reductions in clinical VTE.
References:
1. Bergqvist D, Lindblad B. A 30-year survey of pulmonary embolism
verified at autopsy: an analysis of 1274 surgical patients. Br J Surg
1985;72(2):105-8.
2. Scurr JH, Coleridge-Smith PD, Hasty JH. Deep venous thrombosis: a
continuing problem. Bmj 1988;297(6640):28.
3. Bergqvist D, Benoni G, Bjorgell O, et al. Low-molecular-weight heparin
(enoxaparin) as prophylaxis against venous thromboembolism after total hip
replacement [see comments]. N Engl J Med 1996;335(10):696-700.
4. Planes A, Vochelle N, Darmon JY, Fagola M, Bellaud M, Huet Y. Risk of
deep-venous thrombosis after hospital discharge in patients having
undergone total hip replacement: double-blind randomised comparison of
enoxaparin versus placebo. Lancet 1996;348(9022):224-8.
5. White RH, Romano PS, Zhou H, Rodrigo J, Bargar W. Incidence and time
course of thromboembolic outcomes following total hip or knee
arthroplasty. Arch Intern Med 1998;158(14):1525-31.
6. Dahl OE, Andreassen G, Aspelin T, et al. Prolonged thromboprophylaxis
following hip replacement surgery--results of a double-blind, prospective,
randomised, placebo-controlled study with dalteparin (Fragmin) [see
comments]. Thromb Haemost 1997;77(1):26-31.
7. Lassen MR, Borris LC, Anderson BS, et al. Efficacy and safety of
prolonged thromboprophylaxis with a low molecular weight heparin
(dalteparin) after total hip arthroplasty--the Danish Prolonged
Prophylaxis (DaPP) Study. Thromb Res 1998;89(6):281-7.
8. Hull RD, Pineo GF, Francis C, et al. Low-molecular-weight heparin
prophylaxis using dalteparin extended out- of-hospital vs in-hospital
warfarin/out-of-hospital placebo in hip arthroplasty patients: a double-
blind, randomized comparison. North American Fragmin Trial Investigators.
Arch Intern Med 2000;160(14):2208-15.
9. Comp PC, Spiro TE, Friedman RJ, et al. Prolonged enoxaparin therapy to
prevent venous thromboembolism after primary hip or knee replacement.
Enoxaparin Clinical Trial Group. J Bone Joint Surg Am 2001;83-A(3):336-45.
10. Planes A, Vochelle N, Darmon JY, et al. Efficacy and safety of
postdischarge administration of enoxaparin in the prevention of deep
venous thrombosis after total hip replacement. A prospective randomised
double-blind placebo-controlled trial. Drugs 1996;52 Suppl 7:47-54.
11. Hull RD, Pineo GF, Stein PD, et al. Extended out-of-hospital low-
molecular-weight heparin prophylaxis against deep venous thrombosis in
patients after elective hip arthroplasty: a systematic review. Ann Intern
Med 2001;135(10):858-69.
12. Eikelboom JW, Quinlan DJ, Douketis JD. Extended-duration prophylaxis
against venous thromboembolism after total hip or knee replacement: a meta
-analysis of the randomised trials. Lancet 2001;358(9275):9-15.
13. Prandoni P, Bruchi O, Sabbion P, et al. Prolonged thromboprophylaxis
with oral anticoagulants after total hip arthroplasty: a prospective
controlled randomized study. Arch Intern Med 2002;162(17):1966-71.
14. Samama CM, Vray M, Barre J, et al. Extended venous thromboembolism
prophylaxis after total hip replacement: a comparison of low-molecular-
weight heparin with oral anticoagulant. Arch Intern Med 2002;162(19):2191-
6.
15. Turpie A, Levine M, Hirsh J, et al. A randomized controlled trial of a
low-molecular-weight heparin (enoxaparin) to prevent deep-vein thrombosis
in patients undergoing elective hip surgery. N Engl J Med 1986;315(15):925
-9.
16. Warwick D, Bannister GC, Glew D, et al. Perioperative low-molecular-
weight heparin. Is it effective and safe. J Bone Joint Surg Br
1995;77(5):715-9.
17. Kalodiki EP, Hoppensteadt DA, Nicolaides AN, et al. Deep venous
thrombosis prophylaxis with low molecular weight heparin and elastic
compression in patients having total hip replacement. A randomised
controlled trial. Int Angiol 1996;15(2):162-8.
18. Leclerc JR, Gent M, Hirsh J, Geerts WH, Ginsberg JS. The incidence of
symptomatic venous thromboembolism during and after prophylaxis with
enoxaparin: a multi-institutional cohort study of patients who underwent
hip or knee arthroplasty. Canadian Collaborative Group. Arch Intern Med
1998;158(8):873-8.
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