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Thromboprophylaxis following cast immobilisation for lower limb injuries—survey of current practice in United Kingdom
Injury, Int. J. Care Injured (2006) 37, 813—817
www.elsevier.com/locate/injury
Thromboprophylaxis following cast immobilisation for lower limb injuries–—survey of current practice in United Kingdom Sameer Batra *, Harish Kurup, Arif Gul, J.G. Andrew Department of Orthopaedics, Gwynedd Hospital, North West Wales NHS Trust, Bangor, Gwynedd, UK Accepted 14 March 2006
KEYWORDS Thromboprophylaxis; Cast immobilisation; Lower limb injuries
Summary The risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) is well documented in patients following cast immobilisation for injuries of lower extremities. There are no generally accepted approaches to preventing this complication and hence there remains substantial practice variation amongst surgeons regarding the use of anticoagulation measures. The present survey was conducted to investigate the current chemothromboprophylaxis practice among UK orthopaedic departments for patients immobilised with plasters for lower extremity injuries and establish any variations in practice. A telephone questionnaire survey was conducted on junior doctors (Senior House Officers and Registrars) in orthopaedic departments of 70 randomly selected hospitals in United Kingdom. This survey assessed the thromboprophylaxis practice for lower limb injuries in plaster casts. Our results show substantial variation amongst British orthopaedic surgeons in the use of chemothromboprophylaxis measures. Sixty-two percent of the departments do not use any DVT prophylaxis in this group of trauma. Furthermore, only 11.4% of the departments performed risk stratification on their patients. Ninety-nine percent of the respondents were unaware of any existing guidelines in this regard. Although the incidence of DVT in patients in plaster for lower extremity injuries is low compared to the Hip/Knee arthroplasty group, this is not insignificant. Both over and under treatment with thromboprophylaxis can have implications in terms of side effects and costs. One possible solution is to use risk stratification to identify individuals who are likely to benefit from prophylaxis. There is a substantial variation and inconsistency in practice among orthopaedic departments in United Kingdom due to a lack of clinical guidelines in this group of trauma and it remains underused even in high-risk group. # 2006 Elsevier Ltd. All rights reserved.
* Corresponding author at: 4, Llys Miaren, Gwynedd Hospital, Bangor, North Wales LL57 2PW, UK. Tel.: +44 7915053576. E-mail address: [email protected] (S. Batra). 0020–1383/$ — see front matter # 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2006.03.016
814
Introduction Venous thromboembolic disease (VTE) remains an enigma among health care professionals the world over. Data on increased risk of thrombosis in lower limb injuries immobilised in a plaster cast was presented as early as 19445 and confirmed in retrospective investigations,16,37 but it was not until 1993, when the first prospective study by Spannagel and Kujath22 reported significantly high thrombosis rates of 29% in lower extremity fractures and 11.4% in soft tissue injuries treated in plasters. Lassen et al.23 reported venographically proven thrombosis rates of 19% in patients without thromboprophylaxis compared to 9% in patients who were administered low molecular weight heparins (LMWHs) with over 75% of the thrombi developing in distal veins. Most other studies have reported significant reduction in the number of thromboembolic events with use of LMWHs.18,21—23 Scottish Intercollegiate Guidelines Network (SIGN) in their revised guidelines35 on thromboprophylaxis (2002) suggested that outpatient LMWH reduced the incidence of asymptomatic DVT in patients with plaster cast immobilisation citing two studies21,22 and to consider use of aspirin if LMWH were contraindicated. The British Committee for Standards in Haematology recommended7 LMWH prophylaxis for patients considered to be at high risk of VTE associated with lower limb plaster cast immobilisation. The clinical benefits9,24 and cost-effectiveness6,30 of prophylaxis in hospitalised patients with hip fractures or pelvic trauma13 are well documented. Despite many studies and recommendations to address the problem of VTE22,27,34 there is still no consensus and generally accepted recommendations on patient selection and choice of chemothromboprophylaxis in patients with lower limb injuries immobilised in a plaster cast.15 The aim of conducting this survey was to investigate the current thromboprophylactic practice of various orthopaedic departments for patients with lower limb injuries who are immobilised in plaster casts and to assess the need for concrete guidelines in this regard to bring uniformity in practice.
Patients and methods A telephone questionnaire survey was conducted on 73 junior doctors (Senior House Officers and Registrars) working in orthopaedic departments in a random selection of hospitals in England, Wales and Scotland. A structured anonymysed questionnaire was used to obtain information in relation to use of VTE prophylaxis in their department for patients
S. Batra et al. who were treated with an above or below knee plaster for lower limb injuries.
The questionnaire 1. Do you prescribe thromboprophylaxis for patients with lower limb injuries in plaster casts? If used selectively, indicators for usage (from most important to least likely) (a) Foot fractures (b) Ankle fractures (c) Tibial/fibular fractures (d) Tendoachilles ruptures 2. If yes, what is the agent used? (a) LMWH/aspirin/warfarin (b) For whom: all patients/high risk (c) If high risk only: is a risk stratification protocol used? (d) Duration of prophylaxis 3. Do you think there is a need for thromboprophylaxis in these patients? If yes which category: (a) Specific injury/age group (b) High medical risk of DVT (c) All the patients 4. Are you aware of any guidelines by SIGN/British society of Haematology guidelines on above?
Results A total of 70 SHOs and Specialist registrars from orthopaedic departments in England, Scotland and Wales participated in the survey. Three refused to take part mainly because of time constraints giving a response rate of 96%. In 61.42% (n = 43) departments no VTE prophylaxis protocol existed for this group of trauma. In 11.4% (n = 8) departments, a risk stratification was performed for all the orthopaedic inpatients on the basis of a scoring system and not necessarily just for patients in plasters; the patients who were classed as high risk were prescribed prophylaxis. High-risk factors were defined as age over 40 years, previous DVT, obesity and use of the oral contraceptive pill. Table 1 shows the prophylactic anticoagulation measures prescribed by various departments based on type of injury sustained or whether there was a high-risk stratification done. Table 2 shows the methods of VTE prophylaxis used in various departments. In 52.9% of the departments no prophylaxis in any form was prescribed to these patients at all. There was no consistent pattern among the departments who used prophylaxis, however a greater tendency to prescribe thrombo-
Thromboprophylaxis following cast immobilisation for lower limb injuries
815
Table 1 Prophylactic anticoagulation measures based on type of injury sustained Injury sustained
To all the patients (%)
No
Foot fracture Ankle fracture Tibia/fibula fractures Tendoachilles rupture
8.6% 8.6% 12.9% 14.3%
75.7% 62.8% 52.8% 54.3%
(n = 6) (n = 6) (n = 9) (n = 10)
(n = 53) (n = 44) (n = 37) (n = 38)
Table 2 Prophylactic anticoagulation measures for patients wearing plaster casts for lower limb injuries Type of prophylaxis
Number of orthopaedic departments %
No measures irrespective of injury/hospitalisation LMWH throughout the period of immobilization Aspirin throughout the period of immobilization In hospital LMWH followed by aspirin throughout the period of immobilization In hospital LMWH followed by warfarin Warfarin only High risk only (irrespective of type of injury) received LMWH
52.9 (n = 37) 12.9 (n = 9) 15.7 (n = 11) 10.0 (n = 7)
2.8 (n = 2) 1.4 (n = 1) 4.3 (n = 3)
prophylaxis for patients with fractures than soft tissue injuries was observed. There was significant variation within the departments with individual consultants practicing varying measures. Amongst the cohort who chose to give prophylaxis to their patients, the majority (59%) employed the chosen mode of prophylaxis until the patient was mobilised with the plaster on while the rest continued their patients on prophylaxis till the plaster came off. When asked their views on who should be prescribed prophylaxis, 80% respondents maintained that they would use chemoprophylaxis in the high-risk group while only 2% felt that this group did not need any prophylaxis at all. 98.57% of the respondents were unaware of any existing guidelines in this regard.
Discussion Prospective investigations in outpatients with nonweight-bearing long-leg casts have reported venographically proven thrombosis rates of 9% versus 19% in patients with and without LMWH,22,23,36 respectively. In the venographic study by Lassen et al.23 in 2002, 75% of these thrombi were detected in the
Only if admitted
Only high risk
Depends on consultant
11.4% 17.2% 17.2% 15.7%
4.3% 5.7% 8.6% 11.4%
— 5.7% (n = 4) 8.6% (n = 6) 4.3% (n = 3)
(n = 8) (n = 12) (n = 12) (n = 11)
(n = 3) (n = 4) (n = 6) (n = 8)
distal veins and the remainder appeared in the proximal veins or distal veins or both. Kujath et al.22 found a significant overall DVT reduction from 16.5% to 4.8% with LMWH. The thrombosis rates in the subgroup of patients with fractures were 29% and 10%, respectively, for control subjects and LMWH patients ( p < 0.05). They recommended prophylaxis for all patients immobilised in a plaster for lower extremity injuries irrespective of age and other risk factors such as smoking, obesity, contraception and history of thrombosis in their study. Our study was aimed at highlighting the extensive variation and inconsistency in practice and opinion among orthopaedic departments regarding what constituted proper prophylaxis, type of agent used, the timing and duration of the prophylaxis, or in the availability and adherence to a single, acceptable protocol. The survey highlighted concern about the failure to implement any kind of thromboprophylaxis even in the high risk group in a routinely performed procedure in Accident & Emergency and outpatient departments. The finding that 62% (n = 43) departments had no VTE prophylaxis protocol for these patients while most of them follow a consistent protocol based on local/national guidelines for hip fracture or elective Hip/Knee arthroplasty patients, was alarming. Only 11% departments used general risk stratification for all orthopaedic inpatients and high-risk patients received prophylaxis irrespective of them being in plaster or not. There was no predominant method used for prophylaxis, instead the distribution is random and seems rather empirical. Although almost 80% of the respondents were aware of the associated risks and would think of using some form of prophylaxis especially in high-risk group, the pattern was random and inconsistent. Over 98% of the respondents were unaware of any existing guidelines in United Kingdom this regard. What constitutes the best thromboprophylaxis is subject to debate and controversy. Aspirin was preferred by over a quarter of the departments mainly because of ease of administration. However it is not generally recommended10,11,39 or used33,2 for the prevention of venous thromboembolism, although it has been shown unequivocally to reduce the risk of myocardial infarction, ischaemic stroke and other
816 major occlusive arterial events in a wide range of circumstances.3,4 The pulmonary embolism prevention (PEP) Trial Collaborative Group in a randomised, blinded, placebo-controlled trial in patients undergoing surgery for hip fracture found aspirin to provide a 29% relative risk reduction in symptomatic DVT, and 58% relative risk reduction in fatal PE31 and that the baseline risk of thromboembolism in a particular patient is likely to be a key determinant of the absolute benefits of aspirin prophylaxis. But this has subsequently been criticised.8,25 LMWH was the most preferred agent used for inpatients in our study. The LMWH as a class of drugs, have been shown to reduce the risk of proximal and distal DVT by at least 70%15 and have been used in most studies18,21—23 primarily due to advantages of better bioavailability and no need for laboratory monitoring of the intensity of anticoagulation or dose adjustment when compared to standard heparins. Warfarin was the least preferred primary thromboprophylactic agent for outpatients being prescribed by just 1.4% and as a continuation following in-hospital LMWH by 2.8%. Both DVT and PE manifest very few specific symptoms and clinical diagnosis is often inadequate and unreliable.14,19 The fact that its occurrence is commonly concealed especially in patients in plasters and its consequences are delayed makes it even more pertinent and outlines the need for extending the prophylaxis to the outpatient setting, in view of the decreasing lengths of hospitalisation, to further reduce the incidence of VTE. The frequency of venous thrombosis detected by phlebography, after tibial fractures has been reported to be ranging from 27%29 to as high as 73%.1 The risk of thrombosis appears to be low when there is no fracture.21,22,32 Isolated calf vein thrombosis is often thought of as a benign entity with most attention given to proximal vein thrombosis, and its risk of pulmonary embolism and potential fatality,26 but it has been shown that calf thrombi may propagate to proximal veins.28 There is no doubt that unrecognised and untreated post-traumatic vein thromboses can lead to longterm damage in the form of post-thrombotic syndrome or pulmonary embolism.20 Even in mediumrisk patients, fatal pulmonary embolism rates of 0.01—1% have been described12 and no simple parameter allows the prediction of this potential evolution. The incidence of post-thrombotic syndrome has been reported to be 35—69% at 3 years after DVTand 49—100% at 5—10 years.17 Venous ulcers develop in at least 300 per 100,000 population and the proportion due to DVT is approximately 25%. The annual cost of treating venous ulcers has been estimated to be 400 million pounds for the UK.17 It is beyond the scope of this survey to decide on merits of what is best practice. This survey is limited
S. Batra et al. by its small sample size and its reliance on junior doctors representing their departmental practices. However junior doctors work with different consultants in the same department and are responsible for prescribing prophylaxis in wards or outpatients, we thought this was likely to be representative of common attitudes and practice. The inconsistent use of DVT prophylaxis can lead to under or over treatment; the former putting the patient at risk of pulmonary embolism, recurrent DVT, chronic venous insufficiency and post-phlebitic syndrome38 while the latter results in undesirable side effects with its associated cost implications.30 The substantial variation shown in our survey reflects the lack of guidelines on which to base good practice. Some might argue that because the incidence of DVT is not as high as following hip fractures or arthroplasty, administration of thromboprophylaxis may not be necessary or cost effective. The available evidence in the literature appears to be strong enough to support the use of thromboprophylaxis in at least the high-risk group of patients. Selection is dependent on a patients, risk level and contraindications related to an individual’s clinical condition and surgeon’s choice.
Conclusions There is a substantial variation and inconsistency in practice among orthopaedic departments in the United Kingdom due to a lack of clinical guidelines in this group, and thromboprophylaxis remains underused even in high-risk patients. Most of the departments do not use prophylaxis for these patients and no concrete national guidelines are in place. The patients who are immobilised in plasters for lower extremity injuries appear to have a significant incidence of clinically occult distal DVT especially in those with fractures. Thus patients should be carefully assessed for risk of developing DVT before application of plaster and appropriate thromboprophylaxis prescribed accordingly. Further research is needed to identify safe and effective prophylactic regimens against thrombosis that can be used alone or in combination with reliable screening strategies in this group of patients.
References 1. Abelseth G, Buckley RE, Pineo GE, et al. Incidence of deepvein thrombosis in patients with fractures of the lower extremity distal to the hip. J Orthop Trauma 1996;10:230—5. 2. Anderson FA, Wheeler HB, Goldberg RJ, et al. Physician practices in the prevention of venous thromboembolism. Ann Intern Med 1991;115:591—5.
Thromboprophylaxis following cast immobilisation for lower limb injuries 3. Antiplatelet Trialists’ Collaboration. Collaborative overview of randomised trials of antiplatelet therapy. I. Prevention of death, myocardial infarction, and stroke by prolonged antiplatelet therapy in various categories of patients. BMJ 1994; 308:81—106. 4. Antiplatelet Trialists’ Collaboration. Collaborative overview of randomised trials of antiplatelet therapy. II. Maintenance of vascular graft or arterial patency by antiplatelet therapy. BMJ 1994;308:159—68. 5. Bauer G. Thrombosis following leg injuries. Acta Chir Scand 1944;90:229—49. 6. Bergqvist D, Matzsch T, Jendteg S, et al. The cost-effectiveness of prevention of post-operative thromboembolism. Acta Chir Scand Suppl 1990;556:36—41. 7. British Committee for Standards in Haematology. http:// www.bcshguidelines.com/pdf/Heparin_070705.pdf. 8. Cohen A, Quinlan D. PEP trial. Pulmonary embolism prevention. Lancet 2000;356(9225):247. 9. Collins R, Scrimgeour A, Yusuf S, Peto R. Reduction in fatal pulmonary embolism and venous thrombosis by perioperative administration of subcutaneous heparin: overview of results of randomised trials in general, orthopaedic, and urologic surgery. N Engl J Med 1988;318:1162—73. 10. Consensus Conference. Prevention of venous thrombosis and pulmonary embolism. JAMA 1986;256:744—9. 11. Consensus Statement (Guidelines according to scientific evidence). Prevention of venous thromboembolism. Angiology 1997;16:3—38. 12. Encke A. Thromboembolieprophylaxe in der Allgemeinchirurgie. Chiurg 1992;63:264—70. 13. Geerts WH, Code KI, Jay RM, et al. A prospective study of venous thromboembolism after major trauma. N Engl J Med 1994;331(24):1601—6. 14. Geerts WH, Heit JA, Clagett GP. Prevention of venous thromboembolism. Chest 2001;119:132S—75S. 15. Hirsh J, Dalen J, Guyatt G. The sixth (2000) ACCP guidelines for antithrombotic therapy for prevention and treatment of thrombosis: American College of Chest Physicians. Chest 2001;119:Suppl US-2S. 16. Hjelmstedt A, Bergvall U. Incidence of thrombosis in patients with tibial fractures. Acta Chir Scand 1968;134:209—18. 17. International Consensus Statement. Prevention of venous thromboembolism. London: Med-Orion Publishing; 1997. 18. Jorgensen PS, Warming T, Hansen K. Low molecular weight heparin (Innohep) as thromboprophylaxis in outpatients with a plaster cast: a venografic controlled study. Thromb Res 2002;15;105(6): 477—80. 19. Kakkar VV. Prevention and management of venous thrombosis. Br Med Bull 1994;50(4):871—903. 20. Kakkar W. Prevention of venous thromboembolism. In: Bloom AL, Forbes CD, Thomas DP, Tuddenham EGD, editors. Haemostasis and thrombosis. 3rd ed., Edinburgh: Churchill Livingstone; 1994. p. 1361—79. 21. Kock H-J, Schmit-Neuerburg KP, Hanke J, et al. Thromboprophylaxis with low-molecular-weight heparin in outpatients
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with plaster-cast immobilisation of the leg. Lancet 1995; 346:459—61. Kujath P, Spannagel U, Habscheid W. Incidence and prophylaxis of deep venous thrombosis in outpatients with injury of the lower limb. Haemostasis 1993;23(Suppl 1):20—6. Lassen MR, Borris LC, Nakov RL. Use of the low-molecularweight heparin reviparin to prevent deep-vein thrombosis after leg injury requiring immobilization. N Engl J Med 2002;347(10):726—30. Leizorovicz A, Haugh MC, Chapuis FR, et al. Low molecular weight heparin in prevention of perioperative thrombosis. BMJ 1992;305:913—20. Mahe I, Bergmann JF, Mahe E, Caulin C. PEP trial. Pulmonary Embolism Prevention. Lancet 2000;356(9225):248. Moser KM, LeMoine JR. Is embolic risk conditioned by location of deep vein thrombosis. Am Intern Med 1981;94: 439—44. Nesheiwat F, Sergi AR. Deep venous thrombosis and pulmonary embolism following cast immobilization of the lower extremity. J Foot Ankle Surg 1996;35(6):590—4. Nicolaides A, Kakkar W, Field E, Renney JT. The origin of deep vein thrombosis: a venographic study. Br J Radiol 1971;44: 653. Nylander G, Semb H. Veins of the lower part of the leg after tibial fractures. Surg Gynecol Obstet 1972;134:974—6. Oster G, Tuden RL, Colditz GA. A cost-effective analysis of prophylaxis against deep-vein thrombosis in major orthopedic surgery. JAMA 1987;257:203—8. Pulmonary Embolism Trial Collaborative Group. Prevention of pulmonary embolism and deep vein thrombosis with low dose aspirin: pulmonary embolism prevention (PEP) trial. Lancet 2000;355(9212):1295—302. Reilmann H, Weinberg AM, Forster EE, Happe B. Prevention of thrombosis in ambulatory patients [in German]. Orthopade 1993;22:117—20. Rodgers A, Gray H, MacMahon S. Pharmacological thromboprophylaxis in hip and knee surgery: a survey of New Zealand orthopaedic surgeons. Aust NZ J Surg 1994;64:167—72. Samama MM. An epidemiologic study of risk factors for deep vein thrombosis in medical outpatients: the Sirius study. Arch Intern Med 2000;160(22):3415—20. Scottish Intercollegiate Guidelines Network (SIGN). http:// www.sign.ac.uk/guidelines/fulltext/62/index.html. Spannagel U, Kujath P. Low molecular weight heparin for the prevention of thromboembolism in outpatients immobilized by plaster case. Semin Thromb Hemost 1993;19(Suppl 1): 131—41. Spieler U, Peter B, Brunner U. Traumatische Thrombosen im tiefen Venensystem bei frischen Unterschenkelfrakturen. Sehweiz med Wschr 1972;102:1535—40. THRiFT II. Risk of and prophylaxis for venous thromboembolism in hospital patients. Phlebology 1998;13:87—97. Thromboembolic Risk Factors (THRIFT) Consensus Group. Risk of and prophylaxis for venous thromboembolism in hospital patients. BMJ 1992;305:567—74.
www.elsevier.com/locate/injury
Thromboprophylaxis following cast immobilisation for lower limb injuries–—survey of current practice in United Kingdom Sameer Batra *, Harish Kurup, Arif Gul, J.G. Andrew Department of Orthopaedics, Gwynedd Hospital, North West Wales NHS Trust, Bangor, Gwynedd, UK Accepted 14 March 2006
KEYWORDS Thromboprophylaxis; Cast immobilisation; Lower limb injuries
Summary The risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) is well documented in patients following cast immobilisation for injuries of lower extremities. There are no generally accepted approaches to preventing this complication and hence there remains substantial practice variation amongst surgeons regarding the use of anticoagulation measures. The present survey was conducted to investigate the current chemothromboprophylaxis practice among UK orthopaedic departments for patients immobilised with plasters for lower extremity injuries and establish any variations in practice. A telephone questionnaire survey was conducted on junior doctors (Senior House Officers and Registrars) in orthopaedic departments of 70 randomly selected hospitals in United Kingdom. This survey assessed the thromboprophylaxis practice for lower limb injuries in plaster casts. Our results show substantial variation amongst British orthopaedic surgeons in the use of chemothromboprophylaxis measures. Sixty-two percent of the departments do not use any DVT prophylaxis in this group of trauma. Furthermore, only 11.4% of the departments performed risk stratification on their patients. Ninety-nine percent of the respondents were unaware of any existing guidelines in this regard. Although the incidence of DVT in patients in plaster for lower extremity injuries is low compared to the Hip/Knee arthroplasty group, this is not insignificant. Both over and under treatment with thromboprophylaxis can have implications in terms of side effects and costs. One possible solution is to use risk stratification to identify individuals who are likely to benefit from prophylaxis. There is a substantial variation and inconsistency in practice among orthopaedic departments in United Kingdom due to a lack of clinical guidelines in this group of trauma and it remains underused even in high-risk group. # 2006 Elsevier Ltd. All rights reserved.
* Corresponding author at: 4, Llys Miaren, Gwynedd Hospital, Bangor, North Wales LL57 2PW, UK. Tel.: +44 7915053576. E-mail address: [email protected] (S. Batra). 0020–1383/$ — see front matter # 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.injury.2006.03.016
814
Introduction Venous thromboembolic disease (VTE) remains an enigma among health care professionals the world over. Data on increased risk of thrombosis in lower limb injuries immobilised in a plaster cast was presented as early as 19445 and confirmed in retrospective investigations,16,37 but it was not until 1993, when the first prospective study by Spannagel and Kujath22 reported significantly high thrombosis rates of 29% in lower extremity fractures and 11.4% in soft tissue injuries treated in plasters. Lassen et al.23 reported venographically proven thrombosis rates of 19% in patients without thromboprophylaxis compared to 9% in patients who were administered low molecular weight heparins (LMWHs) with over 75% of the thrombi developing in distal veins. Most other studies have reported significant reduction in the number of thromboembolic events with use of LMWHs.18,21—23 Scottish Intercollegiate Guidelines Network (SIGN) in their revised guidelines35 on thromboprophylaxis (2002) suggested that outpatient LMWH reduced the incidence of asymptomatic DVT in patients with plaster cast immobilisation citing two studies21,22 and to consider use of aspirin if LMWH were contraindicated. The British Committee for Standards in Haematology recommended7 LMWH prophylaxis for patients considered to be at high risk of VTE associated with lower limb plaster cast immobilisation. The clinical benefits9,24 and cost-effectiveness6,30 of prophylaxis in hospitalised patients with hip fractures or pelvic trauma13 are well documented. Despite many studies and recommendations to address the problem of VTE22,27,34 there is still no consensus and generally accepted recommendations on patient selection and choice of chemothromboprophylaxis in patients with lower limb injuries immobilised in a plaster cast.15 The aim of conducting this survey was to investigate the current thromboprophylactic practice of various orthopaedic departments for patients with lower limb injuries who are immobilised in plaster casts and to assess the need for concrete guidelines in this regard to bring uniformity in practice.
Patients and methods A telephone questionnaire survey was conducted on 73 junior doctors (Senior House Officers and Registrars) working in orthopaedic departments in a random selection of hospitals in England, Wales and Scotland. A structured anonymysed questionnaire was used to obtain information in relation to use of VTE prophylaxis in their department for patients
S. Batra et al. who were treated with an above or below knee plaster for lower limb injuries.
The questionnaire 1. Do you prescribe thromboprophylaxis for patients with lower limb injuries in plaster casts? If used selectively, indicators for usage (from most important to least likely) (a) Foot fractures (b) Ankle fractures (c) Tibial/fibular fractures (d) Tendoachilles ruptures 2. If yes, what is the agent used? (a) LMWH/aspirin/warfarin (b) For whom: all patients/high risk (c) If high risk only: is a risk stratification protocol used? (d) Duration of prophylaxis 3. Do you think there is a need for thromboprophylaxis in these patients? If yes which category: (a) Specific injury/age group (b) High medical risk of DVT (c) All the patients 4. Are you aware of any guidelines by SIGN/British society of Haematology guidelines on above?
Results A total of 70 SHOs and Specialist registrars from orthopaedic departments in England, Scotland and Wales participated in the survey. Three refused to take part mainly because of time constraints giving a response rate of 96%. In 61.42% (n = 43) departments no VTE prophylaxis protocol existed for this group of trauma. In 11.4% (n = 8) departments, a risk stratification was performed for all the orthopaedic inpatients on the basis of a scoring system and not necessarily just for patients in plasters; the patients who were classed as high risk were prescribed prophylaxis. High-risk factors were defined as age over 40 years, previous DVT, obesity and use of the oral contraceptive pill. Table 1 shows the prophylactic anticoagulation measures prescribed by various departments based on type of injury sustained or whether there was a high-risk stratification done. Table 2 shows the methods of VTE prophylaxis used in various departments. In 52.9% of the departments no prophylaxis in any form was prescribed to these patients at all. There was no consistent pattern among the departments who used prophylaxis, however a greater tendency to prescribe thrombo-
Thromboprophylaxis following cast immobilisation for lower limb injuries
815
Table 1 Prophylactic anticoagulation measures based on type of injury sustained Injury sustained
To all the patients (%)
No
Foot fracture Ankle fracture Tibia/fibula fractures Tendoachilles rupture
8.6% 8.6% 12.9% 14.3%
75.7% 62.8% 52.8% 54.3%
(n = 6) (n = 6) (n = 9) (n = 10)
(n = 53) (n = 44) (n = 37) (n = 38)
Table 2 Prophylactic anticoagulation measures for patients wearing plaster casts for lower limb injuries Type of prophylaxis
Number of orthopaedic departments %
No measures irrespective of injury/hospitalisation LMWH throughout the period of immobilization Aspirin throughout the period of immobilization In hospital LMWH followed by aspirin throughout the period of immobilization In hospital LMWH followed by warfarin Warfarin only High risk only (irrespective of type of injury) received LMWH
52.9 (n = 37) 12.9 (n = 9) 15.7 (n = 11) 10.0 (n = 7)
2.8 (n = 2) 1.4 (n = 1) 4.3 (n = 3)
prophylaxis for patients with fractures than soft tissue injuries was observed. There was significant variation within the departments with individual consultants practicing varying measures. Amongst the cohort who chose to give prophylaxis to their patients, the majority (59%) employed the chosen mode of prophylaxis until the patient was mobilised with the plaster on while the rest continued their patients on prophylaxis till the plaster came off. When asked their views on who should be prescribed prophylaxis, 80% respondents maintained that they would use chemoprophylaxis in the high-risk group while only 2% felt that this group did not need any prophylaxis at all. 98.57% of the respondents were unaware of any existing guidelines in this regard.
Discussion Prospective investigations in outpatients with nonweight-bearing long-leg casts have reported venographically proven thrombosis rates of 9% versus 19% in patients with and without LMWH,22,23,36 respectively. In the venographic study by Lassen et al.23 in 2002, 75% of these thrombi were detected in the
Only if admitted
Only high risk
Depends on consultant
11.4% 17.2% 17.2% 15.7%
4.3% 5.7% 8.6% 11.4%
— 5.7% (n = 4) 8.6% (n = 6) 4.3% (n = 3)
(n = 8) (n = 12) (n = 12) (n = 11)
(n = 3) (n = 4) (n = 6) (n = 8)
distal veins and the remainder appeared in the proximal veins or distal veins or both. Kujath et al.22 found a significant overall DVT reduction from 16.5% to 4.8% with LMWH. The thrombosis rates in the subgroup of patients with fractures were 29% and 10%, respectively, for control subjects and LMWH patients ( p < 0.05). They recommended prophylaxis for all patients immobilised in a plaster for lower extremity injuries irrespective of age and other risk factors such as smoking, obesity, contraception and history of thrombosis in their study. Our study was aimed at highlighting the extensive variation and inconsistency in practice and opinion among orthopaedic departments regarding what constituted proper prophylaxis, type of agent used, the timing and duration of the prophylaxis, or in the availability and adherence to a single, acceptable protocol. The survey highlighted concern about the failure to implement any kind of thromboprophylaxis even in the high risk group in a routinely performed procedure in Accident & Emergency and outpatient departments. The finding that 62% (n = 43) departments had no VTE prophylaxis protocol for these patients while most of them follow a consistent protocol based on local/national guidelines for hip fracture or elective Hip/Knee arthroplasty patients, was alarming. Only 11% departments used general risk stratification for all orthopaedic inpatients and high-risk patients received prophylaxis irrespective of them being in plaster or not. There was no predominant method used for prophylaxis, instead the distribution is random and seems rather empirical. Although almost 80% of the respondents were aware of the associated risks and would think of using some form of prophylaxis especially in high-risk group, the pattern was random and inconsistent. Over 98% of the respondents were unaware of any existing guidelines in United Kingdom this regard. What constitutes the best thromboprophylaxis is subject to debate and controversy. Aspirin was preferred by over a quarter of the departments mainly because of ease of administration. However it is not generally recommended10,11,39 or used33,2 for the prevention of venous thromboembolism, although it has been shown unequivocally to reduce the risk of myocardial infarction, ischaemic stroke and other
816 major occlusive arterial events in a wide range of circumstances.3,4 The pulmonary embolism prevention (PEP) Trial Collaborative Group in a randomised, blinded, placebo-controlled trial in patients undergoing surgery for hip fracture found aspirin to provide a 29% relative risk reduction in symptomatic DVT, and 58% relative risk reduction in fatal PE31 and that the baseline risk of thromboembolism in a particular patient is likely to be a key determinant of the absolute benefits of aspirin prophylaxis. But this has subsequently been criticised.8,25 LMWH was the most preferred agent used for inpatients in our study. The LMWH as a class of drugs, have been shown to reduce the risk of proximal and distal DVT by at least 70%15 and have been used in most studies18,21—23 primarily due to advantages of better bioavailability and no need for laboratory monitoring of the intensity of anticoagulation or dose adjustment when compared to standard heparins. Warfarin was the least preferred primary thromboprophylactic agent for outpatients being prescribed by just 1.4% and as a continuation following in-hospital LMWH by 2.8%. Both DVT and PE manifest very few specific symptoms and clinical diagnosis is often inadequate and unreliable.14,19 The fact that its occurrence is commonly concealed especially in patients in plasters and its consequences are delayed makes it even more pertinent and outlines the need for extending the prophylaxis to the outpatient setting, in view of the decreasing lengths of hospitalisation, to further reduce the incidence of VTE. The frequency of venous thrombosis detected by phlebography, after tibial fractures has been reported to be ranging from 27%29 to as high as 73%.1 The risk of thrombosis appears to be low when there is no fracture.21,22,32 Isolated calf vein thrombosis is often thought of as a benign entity with most attention given to proximal vein thrombosis, and its risk of pulmonary embolism and potential fatality,26 but it has been shown that calf thrombi may propagate to proximal veins.28 There is no doubt that unrecognised and untreated post-traumatic vein thromboses can lead to longterm damage in the form of post-thrombotic syndrome or pulmonary embolism.20 Even in mediumrisk patients, fatal pulmonary embolism rates of 0.01—1% have been described12 and no simple parameter allows the prediction of this potential evolution. The incidence of post-thrombotic syndrome has been reported to be 35—69% at 3 years after DVTand 49—100% at 5—10 years.17 Venous ulcers develop in at least 300 per 100,000 population and the proportion due to DVT is approximately 25%. The annual cost of treating venous ulcers has been estimated to be 400 million pounds for the UK.17 It is beyond the scope of this survey to decide on merits of what is best practice. This survey is limited
S. Batra et al. by its small sample size and its reliance on junior doctors representing their departmental practices. However junior doctors work with different consultants in the same department and are responsible for prescribing prophylaxis in wards or outpatients, we thought this was likely to be representative of common attitudes and practice. The inconsistent use of DVT prophylaxis can lead to under or over treatment; the former putting the patient at risk of pulmonary embolism, recurrent DVT, chronic venous insufficiency and post-phlebitic syndrome38 while the latter results in undesirable side effects with its associated cost implications.30 The substantial variation shown in our survey reflects the lack of guidelines on which to base good practice. Some might argue that because the incidence of DVT is not as high as following hip fractures or arthroplasty, administration of thromboprophylaxis may not be necessary or cost effective. The available evidence in the literature appears to be strong enough to support the use of thromboprophylaxis in at least the high-risk group of patients. Selection is dependent on a patients, risk level and contraindications related to an individual’s clinical condition and surgeon’s choice.
Conclusions There is a substantial variation and inconsistency in practice among orthopaedic departments in the United Kingdom due to a lack of clinical guidelines in this group, and thromboprophylaxis remains underused even in high-risk patients. Most of the departments do not use prophylaxis for these patients and no concrete national guidelines are in place. The patients who are immobilised in plasters for lower extremity injuries appear to have a significant incidence of clinically occult distal DVT especially in those with fractures. Thus patients should be carefully assessed for risk of developing DVT before application of plaster and appropriate thromboprophylaxis prescribed accordingly. Further research is needed to identify safe and effective prophylactic regimens against thrombosis that can be used alone or in combination with reliable screening strategies in this group of patients.
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