|Prophylactic anticoagulation to prevent venous thromboembolism in traumatic intracranial hemorrhage: a decision analysis.|
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|PMID: 20406444 Owner: NLM Status: MEDLINE|
|INTRODUCTION: Patients with intracranial hemorrhage due to traumatic brain injury are at high risk of developing venous thromboembolism including deep vein thrombosis (DVT) and pulmonary embolism (PE). Thus, there is a trade-off between the risks of progression of intracranial hemorrhage (ICH) versus reduction of DVT/PE with the use of prophylactic anticoagulation. Using decision analysis modeling techniques, we developed a model for examining this trade-off for trauma patients with documented ICH. METHODS: The decision node involved the choice to administer or to withhold low molecular weight heparin (LMWH) anticoagulation prophylaxis at 24 hours. Advantages of withholding therapy were decreased risk of ICH progression (death, disabling neurologic deficit, non-disabling neurologic deficit), and decreased risk of systemic bleeding complications (death, massive bleed). The associated disadvantage was greater risk of developing DVT/PE or death. Probabilities for each outcome were derived from natural history studies and randomized controlled trials when available. Utilities were obtained from accepted databases and previous studies. RESULTS: The expected value associated with withholding anticoagulation prophylaxis was similar (0.90) to that associated with the LMWH strategy (0.89). Only two threshold values were encountered in one-way sensitivity analyses. If the effectiveness of LMWH at preventing DVT exceeded 80% (range from literature 33% to 82%) our model favoured this therapy. Similarly, our model favoured use of LMWH if this therapy increased the risk of ICH progression by no more than 5% above the baseline risk. CONCLUSIONS: Our model showed no clear advantage to providing or withholding anticoagulant prophylaxis for DVT/PE prevention at 24 hours after traumatic brain injury associated with ICH. Therefore randomized controlled trials are justifiable and needed to guide clinicians.|
|Damon C Scales; Jay Riva-Cambrin; Dave Wells; Valerie Athaide; John T Granton; Allan S Detsky|
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|Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-04-20|
|Title: Critical care (London, England) Volume: 14 ISSN: 1466-609X ISO Abbreviation: Crit Care Publication Date: 2010|
|Created Date: 2010-06-18 Completed Date: 2010-11-10 Revised Date: -|
Medline Journal Info:
|Nlm Unique ID: 9801902 Medline TA: Crit Care Country: England|
|Languages: eng Pagination: R72 Citation Subset: IM|
|Department of Critical Care Medicine, Sunnybrook Health Sciences Centre, Room D108, Toronto, ON, Canada. firstname.lastname@example.org|
|APA/MLA Format Download EndNote Download BibTex|
administration & dosage,
Decision Support Techniques*
Heparin, Low-Molecular-Weight / administration & dosage, therapeutic use*
Intracranial Hemorrhage, Traumatic / complications*, physiopathology
Venous Thromboembolism / prevention & control*
|//Canadian Institutes of Health Research|
|0/Anticoagulants; 0/Heparin, Low-Molecular-Weight|
|Crit Care. 2010;14(3):153
Journal ID (nlm-ta): Crit Care
Publisher: BioMed Central
Copyright ?2010 Scales et al.; licensee BioMed Central Ltd.
Received Day: 5 Month: 10 Year: 2009
Revision Received Day: 10 Month: 3 Year: 2010
Accepted Day: 20 Month: 4 Year: 2010
Print publication date: Year: 2010
Electronic publication date: Day: 20 Month: 4 Year: 2010
Volume: 14 Issue: 2
First Page: R72 Last Page: R72
Publisher Id: cc8980
PubMed Id: 20406444
|Prophylactic anticoagulation to prevent venous thromboembolism in traumatic intracranial hemorrhage: a decision analysis|
|Damon C Scales123||Email: email@example.com|
|Jay Riva-Cambrin45||Email: firstname.lastname@example.org|
|Dave Wells1||Email: email@example.com|
|Valerie Athaide6||Email: firstname.lastname@example.org|
|John T Granton17||Email: email@example.com|
|Allan S Detsky89||Email: firstname.lastname@example.org|
1Department of Critical Care Medicine, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Room D108, Toronto, ON M4N 3M5, Canada
2Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Room G157, Toronto, ON M4N 3M5, Canada
3Interdepartmental Division of Critical Care Medicine and Department of Medicine, University of Toronto, 30 Bond Street, Toronto, ON M5B 1W8, Canada
4Department of Neurosurgery, Primary Children's Medical Centre, 100 N. Mario Capecchi Dr., Suite. 1475, Salt Lake City, Utah 84113, USA
5Department of Neurosurgery, University of Utah, 30 N. 1900 E, Salt Lake City, Utah 84132, USA
6Faculty of Medicine, University of British Columbia, 17 - 2194 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
7Departments of Medicine and Critical Care, University Health Network, 11-1170 CSB, 585 University Ave, Toronto, ON M5G 2C4, Canada
8Department of Medicine, Mount Sinai Hospital, 600 University Avenue, Suite 429, Toronto, ON M5G 1X5, Canada
9Department of Health Policy, Management and Evaluation, University of Toronto, 155 College Street, Suite 425, Toronto, ON M5T 3M6, Canada
It is estimated that more than 1.5 million people in the United States sustain traumatic head injury each year . Radiologic evidence of intracranial hemorrhage at the time of presentation is present in up to 45% of cases and is associated with a markedly poorer prognosis [2,3]. Traumatic intracranial hemorrhage encompasses cerebral contusion, subdural hematoma, subarachnoid hemorrhage, epidural hematoma and intracerebral hemorrhage. These are characterized by a relatively high risk of bleeding progression, especially within the first 24 hours [2,4-6].
Traumatic intracranial hemorrhage is also associated with a high risk of thromboembolic complications . This risk is related to the immobility of head-injured patients arising from the underlying neurologic lesion itself, concomitant injuries following trauma, or the use of sedatives and neuromuscular blocking agents. The reported incidence of deep vein thrombosis (DVT) ranges between 18 and 58% in the absence of anticoagulant prophylaxis [8-11]. DVT is associated with increased morbidity and mortality, including risk of fatal pulmonary embolism (PE) .
Anticoagulant prophylaxis to prevent DVT is recommended for trauma patients without intracranial or other serious hemorrhage . This therapy is also effective in post-operative neurosurgical patients undergoing brain tumour excision . Only one small quasi-randomized clinical trial has studied anticoagulant prophylaxis versus pneumatic compression devices in patients with intracranial hemorrhage following trauma. This trial found no benefit or harm associated with use of anticoagulant prophylaxis, but only had sufficient sample size to detect very large differences in rates of venous thromboembolism or intracranial hemorrhagic progression . One observational study reported rates of hemorrhagic progression in 150 patients with intracranial hemorrhage that were treated with low molecular weight heparin prophylaxis 24 hours after the initial head injury . One quarter already had radiological evidence of intracranial hemorrhagic progression at the time anticoagulant prophylaxis was started, but only six patients (4%) subsequently developed progression in the 24 hours following initiation of anticoagulation prophylaxis. The study lacked a control group limiting inferences regarding the safety and efficacy of this therapy.
Many physicians report routinely withholding anticoagulation prophylaxis in patients with traumatic intracranial hemorrhage because of concerns that it may increase the risk of potentially devastating intracranial hemorrhagic progression [16,17]. Observational studies have also documented variable practice patterns for anticoagulation prophylaxis in such patients. A small retrospective study of 88 patients with traumatic brain injury observed that only 42% ever received low-molecular weight heparin prophylaxis, and the mean time to initiation of therapy was 14 days . Similarly, a multicentre retrospective study of trauma patients with ICU length of stay greater than seven days found that prophylaxis was initiated within two days in only 25% of patients, and another quarter did not receive prophylaxis until at least one week following injury . Thus, the use and timing of anticoagulation prophylaxis in these patients remains uncertain and controversial, and most are treated with more conservative and less effective measures such as graduated compression stockings, intermittent pneumatic compression devices, and physiotherapy [13,16].
The lack of persuasive evidence to guide decisions about using anticoagulant prophylaxis in patients with traumatic intracranial hemorrhage implies that clinicians must make decisions based on their own assessments of the risks and benefits. Our objective was to explore the decision to use or withhold anticoagulant prophylaxis in a common clinical scenario characterized by competing risks of hemorrhagic versus thromboembolic complications. We used decision analysis modeling techniques to compare the risks of progression of intracranial hemorrhage following trauma versus the potential benefits of reducing venous thromboembolism with anticoagulant prophylaxis. Decision analysis involves identifying the most important available clinical choices and determining probabilities of all important potential outcomes following each of these choices . This methodology has been used previously to evaluate the risks and benefits of anticoagulant prophylaxis in neurosurgical patients undergoing craniotomy , but to our knowledge has not specifically been used to evaluate patients with traumatic intracranial hemorrhage.
We searched Medline (OVID Technologies, New York, NY, USA; 1950 to March 2008) for studies concerning intracranial hemorrhage and anticoagulant thromboprophylaxis using the search terms brain injury, acute; craniocerebral trauma; cerebral hemorrhage, traumatic, anticoagulation, and heparin. We used natural history studies and controlled clinical trials performed in both post-operative neurosurgical and trauma patients to estimate the incidence of DVT [9-12,22]. We estimated the risk of hemorrhagic progression using natural history studies that reported the absolute risk at 24 hours following the neurological injury . The risk of systemic bleeding complications was estimated from rates of major gastrointestinal hemorrhage in critically-ill patients . We used clinical trials of anticoagulation prophylaxis in elective neurosurgical patients to estimate the effectiveness of anticoagulant prophylaxis in preventing DVT and its potential impact on subsequent intracranial bleeding [12,24,25].
Table 1 summarizes the probabilities used in the decision analysis. We obtained utility values (Table 2) from previous publications and the Cost-Effectiveness Analysis Registry from the Institute for Clinical Research and Health Policy Studies, Tufts Medical Center [26-35]. We considered the baseline utility for our study (0.96) to be less than a perfect state of health (1.00) because all patients in our model would have already suffered a major trauma with associated head injury . We subtracted utilities associated with temporary states in our model, such as deep vein thrombosis, from the baseline utility, but we considered events having long-term morbidity, such as disabling neurological deficit, by multiplying the associated utility by the baseline utility . The most severe event that could be encountered in the model was death (utility = 0), and the worst outcome that could be experienced while alive was a severe disabling neurological deficit after progression of intracranial hemorrhage.
We also performed sensitivity analyses considering estimates of benefits and risks of anticoagulant prophylaxis reported on our recent survey of Canadian neurosurgeons and neuro-intensivists . We chose the three most frequent estimates of risk-category selected by survey respondents for risk of intracranial hemorrhagic progression and for risk of DVT/PE with and without anticoagulant prophylaxis. We considered the upper and lower boundaries defined by these three response categories to be the range of plausible values, and chose the median from the most frequent response risk-category to be the point estimate for sensitivity analyses.
The base case for our model was an adult trauma patient (? 18 years of age) with intracranial hemorrhage. The single decision node was whether or not to treat with LMWH anticoagulant prophylaxis at 24 hours after head injury and continued until hospital discharge. We assumed that all patients were treated with graduated compression stockings, but we did not consider sequential compression devices because our recent survey of Canadian practice showed these are seldom used in this patient population .
We considered the main advantage of anticoagulation prophylaxis to be a reduction in the risk of major thromboembolic complications, including DVT, pulmonary embolism, and death. We considered the disadvantages to be an increased risk of intracranial hemorrhagic progression, other bleeding complications, and the pain of subcutaneous injections. A disabling neurological deficit was defined as being equivalent to a stroke with a Modified Rankin Score ? 3, and a non-disabling neurological deficit was defined as being equivalent to a stroke with a Modified Rankin Score ? 2 . We considered the risks of developing major outcomes during the first thirty days of hospital admission.
We used TreeAge Pro 2008 (TreeAge Software Inc., Williamstown, MA, USA) to perform the decision analysis. The subtrees in our model are shown in Figures 1, 2 and 3. We created a linkage term to represent the effectiveness of anticoagulant prophylaxis at reducing the risk of DVT, calculated as follows: effectiveness of anticoagulant prophylaxis = ((probability of DVT without LMWH) - (probability of DVT with LMWH))/(probability of DVT without LMWH) (Figure 1) . We used the complement of this effectiveness term (1-effectiveness) in the anticoagulant prophylaxis subtree to ensure that no probabilities would ever have values greater than 1.0, and to guarantee that the risk of DVT would always be highest in patients not receiving anticoagulation. Similarly, we used two linkage terms within the DVT subtree (Figure 2) and the No DVT subtree (Figure 3) to reflect effectiveness of withholding anticoagulant prophylaxis to reduce the risk of systemic bleeding complications or of intracranial bleeding complications. Symmetry was maintained at all major branches of our model and trade-offs at each node were identical for both strategies . The expected utility for each branch was determined by multiplying all of the probabilities along the branches to obtain the probability of being in each state of the terminal nodes. These products of probabilities were then used as the weights to derive the expected value by multiplying the product of probabilities by each of the utilities and then summing these over all outcomes for each branch . Sensitivity analyses were performed across all plausible values for all variables.
The expected value associated with withholding anticoagulation prophylaxis (0.90) was similar to that associated with the LMWH strategy (0.89; Figure 4). A threshold value was reached within our range of estimates for the effectiveness of anticoagulant prophylaxis for preventing DVT (threshold 0.80, range of estimates 0.33 to 0.82; Figure 5), suggesting that providing LMWH would have a greater expected value than withholding LMWH only if its effectiveness for preventing DVT exceeded 80%. Similarly, the variable representing the effectiveness of withholding anticoagulant prophylaxis for reducing the risk of intracranial hemorrhagic progression also reached a threshold value within our range of estimates (threshold 0.05, range of estimates 0.001 to 0.990; Figure 6), suggesting LMWH would become the preferred strategy if it increased the risk of ICH progression by no more than 5% above the baseline risk.
We performed sensitivity analyses using the most frequently reported risk estimates obtained from our survey of Canadian neurosurgeons and neurointensivists. These analyses did not produce any additional threshold variables and the results did not qualitatively change our findings. We also considered sequential compression devices as a third strategy for preventing DVT. For this analysis, we considered the effectiveness of sequential compression devices for preventing DVT to be between that of LMWH and no anticoagulation prophylaxis (effectiveness 0.19, equivalent to point estimate of DVT incidence of 26%) and the risk of intracranial hemorrhagic progression to be the same as no anticoagulation prophylaxis. The expected value of the sequential compression device strategy was 0.90, similar to that of the other strategies (results not shown, but available upon request).
Our results suggest that the decision of whether or not to use anticoagulant thromboprophylaxis 24 hours after traumatic intracranial hemorrhage is a toss-up. Although the no prophylaxis strategy was associated with a slightly higher expected value (0.90 versus 0.89), this difference is unlikely to be clinically important. For example, the magnitude of this difference is equivalent to the disutility associated with administering a subcutaneous injection of anticoagulant prophylaxis.
Despite the similar expected values associated with each strategy, anticoagulant thromboprophylaxis became the preferred approach only in situations where the incremental risk of hemorrhagic progression was very low, or when its effectiveness in preventing venous thromboembolism was very high. These situations reflect the limits of our plausible risk estimates, and therefore seem unlikely to apply to most clinical situations. Considering the uncertainty, routinely withholding anticoagulant prophylaxis seems an appropriate strategy based on our findings, especially in the early phase when risk of hemorrhagic progression is perceived to be highest .
Our results are consistent with the findings of our recent survey of Canadian practice . Of the 160 intensivists and neurosurgeons surveyed, almost two-thirds (60%) of intensivists and neurosurgeons indicated they would use, at some time, anticoagulant thromboprophylaxis in patients with intracranial hemorrhage due to traumatic brain injury. However, only one-third (34%) of these respondents reported that they would start this thromboprophylaxis within two days of the surgery, reflecting their concerns about risk of hemorrhagic progression. However, slightly more than half (57%) would start anticoagulation within four days and most (80%) by one week, suggesting that the perceived risk of hemorrhagic progression decreases over time. We lacked sufficient data to evaluate the risks and benefits of initiating anticoagulant prophylaxis after more than 24 hours, but this could be the topic of future research. We only considered anticoagulant prophylaxis with LMWH rather than unfractionated heparin, reasoning that most available studies in neurosurgical patients used the former and that direct comparisons of these two types of prophylaxis have yielded similar results .
Instead of considering anticoagulant prophylaxis, some clinicians may choose to routinely screen patients with ultrasound or other imaging modalities to identify patients with DVT who require treatment with vena cava filters or full-dose anticoagulation, but we did not consider this to be a strategy for DVT prophylaxis. Similarly, depending on available resources some clinicians may choose to use sequential compression devices to prevent DVT while withholding anticoagulation to avoid intracranial hemorrhagic progression. However, this strategy would have important cost considerations and did not yield an apparent benefit in our decision analysis or reduce DVT incidence in a recent large clinical trial in stroke patients .
A limitation of all decision analyses is that they rely on having accurate estimates of probabilities of outcomes following clinical choices, and such estimates often are lacking in the literature for the clinical scenario of interest. For example, a limitation of our decision analysis was the difficulty quantifying the incremental risk of intracranial hemorrhagic progression at 24 hours with anticoagulant prophylaxis. Our only estimate was derived from a single prospective study that lacked a control group, so we used a very wide confidence interval in sensitivity analysis. These analyses suggest that anticoagulant prophylaxis would still only become the most effective strategy if the true incremental risk of hemorrhagic progression were less than 5% above baseline. Furthermore, the expected values associated with clinical choices in a decision analysis will depend on the utilities that are assigned to each clinical outcome, and different patients and clinicians may weigh such outcomes differently in the real world.
Our model showed no clear advantage to providing or withholding anticoagulant prophylaxis for DVT/PE prevention at 24 hours after traumatic brain injury associated with intracranial hemorrhage. In the context of such a toss-up, and given that the most disastrous event (other than death) encountered in this model is the development of a disabling neurological deficit, we would recommend against the use of routine anticoagulant prophylaxis at 24 hours for these patients. However, considering that both strategies were associated with nearly equivalent expected values, our model would suggest that it should be ethical to conduct a randomized, controlled, clinical trial to evaluate the safety and efficacy of using anticoagulant prophylaxis in patients with traumatic brain injury and intracranial hemorrhage.
? Patients with traumatic brain injury associated with intracranial hemorrhage are at high risk for developing venous thromboembolism
? Anticoagulation prophylaxis is proven to decrease the risk of venous thromboembolism in other patient groups, but may increase the risk of progression of intracranial hemorrhage
? The decision to provide anticoagulation prophylaxis to these patients therefore represents a trade-off that can be examined using decision analysis techniques
? Our decision analysis model showed no clear advantage to providing or withholding anticoagulant prophylaxis for thromboembolic prophylaxis at 24 hours after traumatic brain injury associated with intracranial hemorrhage
? Randomized controlled trials of this study question are justifiable and needed to guide clinicians
CNS: central nervous system; DVT: deep vein thrombosis; ICH: intracranial hemorrhage; ICU: intensive care unit; LMWH: low-molecular weight heparin; PE: pulmonary embolism; SYS: systemic bleeding.
The authors declare that they have no competing interests.
DCS, JRC, JTG and ASD conceived of and designed the manuscript. DCS, JRC, VA and DW were responsible for data acquisition. DCS, JRC, DW and ASD were responsible for analysis and interpretation. DCS, JRC, DW, VA, JTG and ASD drafted and revised the manuscript. All authors read and approved the final manuscript.
DCS is supported by a New Investigator Award from the Canadian Institutes for Health Research.
|Rutland-Brown W,Langlois JA,Thomas KE,Xi YL,Incidence of traumatic brain injury in the United States, 2003J Head Trauma RehabilYear: 20062154454810.1097/00001199-200611000-0000917122685|
|Tabori U,Kornecki A,Sofer S,Constantini S,Paret G,Beck R,Sivan Y,Repeat computed tomographic scan within 24-48 hours of admission in children with moderate and severe head traumaCrit Care MedYear: 20002884084410.1097/00003246-200003000-0003810752839|
|Servadei F,Murray GD,Teasdale GM,Dearden M,Iannotti F,Lapierre F,Maas AJ,Karimi A,Ohman J,Persson L,Stocchetti N,Trojanowski T,Unterberg A,Traumatic subarachnoid hemorrhage: demographic and clinical study of 750 patients from the European brain injury consortium survey of head injuriesNeurosurgeryYear: 20025026126710.1097/00006123-200202000-0000611844260|
|Gudeman SK,Kishore PR,Miller JD,Girevendulis AK,Lipper MH,Becker DP,The genesis and significance of delayed traumatic intracerebral hematomaNeurosurgeryYear: 19795309313503290|
|Oertel M,Kelly DF,McArthur D,Boscardin WJ,Glenn TC,Lee JH,Gravori T,Obukhov D,McBride DQ,Martin NA,Progressive hemorrhage after head trauma: predictors and consequences of the evolving injuryJ NeurosurgYear: 20029610911610.3171/jns.2002.96.1.010911794591|
|Stein SC,Spettell C,Young G,Ross SE,Delayed and progressive brain injury in closed-head trauma: radiological demonstrationNeurosurgeryYear: 199332253010.1097/00006123-199301000-000048421553|
|Knudson MM,Ikossi DG,Khaw L,Morabito D,Speetzen LS,Thromboembolism after trauma: an analysis of 1602 episodes from the American College of Surgeons National Trauma Data BankAnn SurgYear: 200424049049610.1097/01.sla.0000137138.40116.6c15319720|
|Geerts WH,Jay RM,Code KI,Chen E,Szalai JP,Saibil EA,Hamilton PA,A comparison of low-dose heparin with low-molecular-weight heparin as prophylaxis against venous thromboembolism after major traumaN Engl J MedYear: 199633570170710.1056/NEJM1996090533510038703169|
|Joffe SN,Incidence of postoperative deep vein thrombosis in neurosurgical patientsJ NeurosurgYear: 19754220120310.3171/jns.1975.42.2.02011113155|
|Valladares JB,Hankinson J,Incidence of lower extremity deep vein thrombosis in neurosurgical patientsNeurosurgeryYear: 1980613814110.1097/00006123-198002000-000037366805|
|Zelikovski A,Zucker G,Eliashiv A,Reiss R,Shalit M,A new sequential pneumatic device for the prevention of deep vein thrombosisJ NeurosurgYear: 19815465265410.3171/jns.1981.54.5.06527229704|
|Agnelli G,Piovella F,Buoncristiani P,Severi P,Pini M,D'Angelo A,Beltrametti C,Damiani M,Andrioli GC,Pugliese R,Iorio A,Brambilla G,Enoxaparin plus compression stockings compared with compression stockings alone in the prevention of venous thromboembolism after elective neurosurgeryN Engl J MedYear: 1998339808510.1056/NEJM1998070933902049654538|
|Hirsh J,Guyatt G,Albers GW,Harrington R,Schunemann HJ,American College of Chest PhysiciansAntithrombotic and thrombolytic therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)ChestYear: 2008133110S112S10.1378/chest.08-065218574260|
|Kurtoglu M,Yanar H,Bilsel Y,Guloglu R,Kizilirmak S,Buyukkurt D,Granit V,Venous thromboembolism prophylaxis after head and spinal trauma: intermittent pneumatic compression devices versus low molecular weight heparinWorld J SurgYear: 20042880781110.1007/s00268-004-7295-615457363|
|Norwood SH,McAuley CE,Berne JD,Vallina VL,Kerns DB,Grahm TW,Short K,McLarty JW,Prospective evaluation of the safety of enoxaparin prophylaxis for venous thromboembolism in patients with intracranial hemorrhagic injuriesArch SurgYear: 200213769670110.1001/archsurg.137.6.69612049541|
|Cupitt JM,Cupitt JM,Prophylaxis against thromboembolism in patients with traumatic brain injury: a survey of UK practiceAnaesthesiaYear: 20015678078511493245|
|Scales DC,Riva-Cambrin J,Le TL,Pinto R,Cook DJ,Granton JT,Canadian Critical Care Trials GroupProphylaxis against venous thromboembolism in neuro-intensive care patients: survey of Canadian practiceJ Crit CareYear: 20092417618410.1016/j.jcrc.2009.03.01019501306|
|Denson K,Morgan D,Cunningham R,Nigliazzo A,Brackett D,Lane M,Smith B,Albrecht R,Incidence of venous thromboembolism in patients with traumatic brain injuryAm J SurgYear: 200719338038310.1016/j.amjsurg.2006.12.00417320539|
|Nathens AB,McMurray MK,Cuschieri J,Durr EA,Moore EE,Bankey PE,Freeman B,Harbrecht BG,Johnson JL,Minei JP,McKinley BA,Moore FA,Shapiro MB,West MA,Tompkins RG,Maier RV,The practice of venous thromboembolism prophylaxis in the major trauma patientJ TraumaYear: 20076255756210.1097/TA.0b013e318031b5f517414328|
|Last JM,A Dictionary of EpidemiologyYear: 20014New York, New York: Oxford University Press|
|Danish SF,Burnett MG,Ong JG,Sonnad SS,Maloney-Wilensky E,Stein SC,Prophylaxis for deep venous thrombosis in craniotomy patients: a decision analysisNeurosurgeryYear: 2005561286129210.1227/01.NEU.0000159882.11635.EA15918945|
|Geerts WH,Code KI,Jay RM,Chen E,Szalai JP,A prospective study of venous thromboembolism after major traumaN Engl J MedYear: 19943311601160610.1056/NEJM1994121533124017969340|
|Cook DJ,Griffith LE,Walter SD,Guyatt GH,Meade MO,Heyland DK,Kirby A,Tryba M,Canadian Critical Care Trials GroupThe attributable mortality and length of intensive care unit stay of clinically important gastrointestinal bleeding in critically ill patientsCrit CareYear: 2001536837510.1186/cc107111737927|
|Dickinson LD,Miller LD,Patel CP,Gupta SK,Enoxaparin increases the incidence of postoperative intracranial hemorrhage when initiated preoperatively for deep venous thrombosis prophylaxis in patients with brain tumorsNeurosurgeryYear: 1998431074108110.1097/00006123-199811000-000399802851|
|Macdonald RL,Amidei C,Baron J,Weir B,Brown F,Erickson RK,Hekmatpanah J,Frim D,Randomized, pilot study of intermittent pneumatic compression devices plus dalteparin versus intermittent pneumatic compression devices plus heparin for prevention of venous thromboembolism in patients undergoing craniotomySurgical NeurologyYear: 20035936337210.1016/S0090-3019(03)00111-312765806|
|Torrance GW,Utility approach to measuring health-related quality of lifeJ Chronic DisYear: 19874059360310.1016/0021-9681(87)90019-13298297|
|Center for the Evaluation of Value and Risk in Health. The Cost-Effectiveness Analysis Registryhttp://www.cearegistry.org|
|Naglie G,Krahn MD,Naimark D,Redelmeier DA,Detsky AS,Primer on medical decision analysis: Part 3--Estimating probabilities and utilitiesMed Decis MakingYear: 19971713614110.1177/0272989X97017002039107608|
|Fryback DG,Dasbach EJ,Klein R,Klein BE,Dorn N,Peterson K,Martin PA,The Beaver Dam Health Outcomes Study: initial catalog of health-state quality factorsMed Decis MakingYear: 1993138910210.1177/0272989X93013002028483408|
|Kaplan RM,Anderson JP,A general health policy model: update and applicationsHealth Serv ResYear: 1988232032353384669|
|Torrance GW,Measurement of health state utilities for economic appraisalJ Health EconYear: 1986513010.1016/0167-6296(86)90020-210311607|
|Brothers TE,Frank CE,Frank B,Robison JG,Elliott BM,Del Schutte H,Merrill KD,Friedman RJ,Is duplex venous surveillance worthwhile after arthroplasty?J Surg ResYear: 199767727810.1006/jsre.1996.49629070185|
|Kellett J,Clarke J,Kellett J,Clarke J,Comparison of "accelerated" tissue plasminogen activator with streptokinase for treatment of suspected myocardial infarction. (see comment). (Review) (145 refs)Medical Decision MakingYear: 19951529731010.1177/0272989X95015004018544674|
|Lee TT,Solomon NA,Heidenreich PA,Oehlert J,Garber AM,Cost-effectiveness of screening for carotid stenosis in asymptomatic persons[see comment]Annals of Internal MedicineYear: 19971263373469054277|
|Sarasin FP,Eckman MH,Management and prevention of thromboembolic events in patients with cancer-related hypercoagulable states: a risky businessJ Gen Intern MedYear: 1993847648610.1007/BF026001088410419|
|Kerridge RK,Glasziou PP,Hillman KM,The use of "quality-adjusted life years" (QALYs) to evaluate treatment in intensive careAnaesth Intensive CareYear: 1995233223317573919|
|van Swieten JC,Koudstaal PJ,Visser MC,Schouten HJ,van Gijn J,Interobserver agreement for the assessment of handicap in stroke patientsStrokeYear: 1988196046073363593|
|Detsky AS,Naglie G,Krahn MD,Redelmeier DA,Naimark D,Primer on medical decision analysis: Part 2: Building a treeMed Decis MakingYear: 19971712613510.1177/0272989X97017002029107607|
|Krahn MD,Naglie G,Naimark D,Redelmeier DA,Detsky AS,Primer on medical decision analysis: Part 4: Analyzing the model and interpreting the resultsMed Decis MakingYear: 19971714215110.1177/0272989X97017002049107609|
|Collen JF,Jackson JL,Shorr AF,Moores LK,Prevention of venous thromboembolism in neurosurgery: a metaanalysisChestYear: 200813423724910.1378/chest.08-002318641095|
|Dennis M,Sandercock PA,Reid J,Graham C,Murray G,Venables G,Rudd A,Bowler G,Effectiveness of thigh-length graduated compression stockings to reduce the risk of deep vein thrombosis after stroke (CLOTS trial 1): a multicentre, randomised controlled trialLancetYear: 20093731958196510.1016/S0140-6736(09)60941-719477503|
|Ginsberg JS,Management of venous thromboembolismN Engl J MedYear: 19963351816182810.1056/NEJM1996121233524078943165|
|Monreal M,Ruiz J,Olazabal A,Arias A,Roca J,Deep venous thrombosis and the risk of pulmonary embolism. A systematic studyChestYear: 199210267768110.1378/chest.102.3.6771516386|
|McLeod RS,Geerts WH,Sniderman KW,Greenwood C,Gregoire RC,Taylor BM,Silverman RE,Atkinson KG,Burnstein M,Marshall JC,Burul CJ,Anderson DR,Ross T,Wilson SR,Barton P,other investigators of the Canadian Colorectal Surgery DVT Prophylaxis TrialSubcutaneous heparin versus low-molecular-weight heparin as thromboprophylaxis in patients undergoing colorectal surgery: results of the canadian colorectal DVT prophylaxis trial: a randomized, double-blind trialAnn SurgYear: 200123343844410.1097/00000658-200103000-0002011224634|
|Rogers FB,Shackford SR,Wilson J,Ricci MA,Morris CS,Prophylactic vena cava filter insertion in severely injured trauma patients: indications and preliminary resultsJ TraumaYear: 19933563764110.1097/00005373-199310000-000218411290|
|Goldhaber SZ,Visani L,De Rosa M,Acute pulmonary embolism: clinical outcomes in the International Cooperative Pulmonary Embolism Registry (ICOPER)LancetYear: 19993531386138910.1016/S0140-6736(98)07534-510227218|
|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 randomized trials in general, orthopedic, and urologic surgeryN Engl J MedYear: 1988318116211733283548|
|Patel NY,Hoyt DB,Nakaji P,Marshall L,Holbrook T,Coimbra R,Winchell RJ,Mikulaschek AW,Traumatic brain injury: patterns of failure of nonoperative managementJ TraumaYear: 20004836737410.1097/00005373-200003000-0000110744271|
|Caroli M,Locatelli M,Campanella R,Balbi S,Martinelli F,Arienta C,Multiple intracranial lesions in head injury: clinical considerations, prognostic factors, management, and results in 95 patientsSurg NeurolYear: 200156828810.1016/S0090-3019(01)00540-711580939|
|Radberg JA,Olsson JE,Radberg CT,Prognostic parameters in spontaneous intracerebral hematomas with special reference to anticoagulant treatmentStrokeYear: 1991225715762028484|
|Swash M,Oxbury J,Clinical NeurologyYear: 19913New York: Churchill-Livingstone|
|Daverat P,Castel JP,Dartigues JF,Orgogozo JM,Death and functional outcome after spontaneous intracerebral hemorrhage. A prospective study of 166 cases using multivariate analysisStrokeYear: 199122161987664|
|Siddique MS,Gregson BA,Fernandes HM,Barnes J,Treadwell L,Wooldridge TD,Mendelow AD,Comparative study of traumatic and spontaneous intracerebral hemorrhageJ NeurosurgYear: 200296868910.3171/jns.2002.96.1.008611794609|
|Lipper MH,Kishore PR,Girevendulis AK,Miller JD,Becker DP,Delayed intracranial hematoma in patients with severe head injuryRadiologyYear: 1979133645649504644|
|Shorr AF,Ramage AS,Enoxaparin for thromboprophylaxis after major trauma: potential cost implicationsCrit Care MedYear: 2001291659166510.1097/00003246-200109000-0000111546959|
|Gage BF,Cardinalli AB,Albers GW,Owens DK,Cost-effectiveness of warfarin and aspirin for prophylaxis of stroke in patients with nonvalvular atrial fibrillation[see comment]JAMAYear: 19952741839184510.1001/jama.274.23.18397500532|
|Tengs TO,Yu M,Luistro E,Health-related quality of life after stroke a comprehensive reviewStrokeYear: 20013296497211283398|
Probabilities used in the decision analysis
|Variables||Baseline probability||Range of plausible probabilities||Threshold value within published range||Threshold from 0 to 1|
|Probability of DVT||0.32 ||0.18 to 0.50 [ to [11,12]]||No||Yes (> 0.6*)|
|Probability of PE following development of DVT||0.1[42,43]||0.01 to 0.18 [22,24,44,45]||No||Yes (> 0.3*)|
|Probability of death from PE||0.17 ||0 to 0.50 ||No||No|
|Probability of a CNS bleed on LMWH||0.108 ||0.03 to 0.23 [24,44]||No||Yes (> 0.017+)|
|Effectiveness of LMWH in preventing DVT (e)||0.47 ||0.33 to 0.82 [12,42]||Yes (> 0.8*)||Yes (> 0.8*)|
|Probability of death from a CNS bleed||0.105 ||0.08 to 0.3 [49,50]||No||No|
|Probability of disabling neurological deficit after CNS bleed||0.17 ||0.16 to 0.33 [52,53]||No||No|
|Probability of an ICU-related systemic bleed||0.035 ||0.027 to 0.046 ||No||No|
|Probability of death from ICU-related systemic bleed||0.02 ||0.001 to 0.035 [23,46]||No||No|
|Effectiveness of not receiving LMWH in reducing CNS bleeds||0.315 [4,15]||0.001-0.99 [4-6,23,47,54]||Yes (> 0.05+)||Yes (> 0.05+)|
|Effectiveness of not receiving LMWH in reducing ICU-related systemic bleeds||0.146||0 to 0.66 [8,12,55]||No||No|
Table of probabilities and plausible ranges used for the decision analysis. The last two columns indicate variables for which a threshold value was identified in one-way sensitivity analysis. Values with an asterisk (*) indicate a threshold value above which providing anticoagulant prophylaxis becomes the preferred strategy. Values with a plus (+) indicate a threshold value above which withholding anticoagulant prophylaxis becomes the preferred strategy.
CNS: central nervous system; DVT: deep vein thrombosis; ICU: intensive care unit; PE: pulmonary embolism
Utilities used in the decision analysis
|Utility||Baseline value||Published ranges||Threshold value within published range||Threshold value reached between 0 and 1|
|Baseline||0.96 ||0.95 to 1.0*||No||No|
|LMWH prophylaxis||0.99 ||0.9 to 1.0*||No||No|
|Living with DVT||0.95 ||0.92 to 1.0*||No||Yes (> 0.9+)|
|Living with PE||0.7 ||0.6 to 0.9 ||No||No|
|Living with massive systemic bleed||0.7 ||0.6 to 0.8*||No||No|
|Living with a non-disabling ICH||0.75 [33,34]||0.6 to 0.8 [33,34,56,57]||No||No|
|Living with a disabling ICH||0.39 [33,34]||0.14 to 0.43 [33,34,57]||No||No|
Table of utilities and plausible ranges used for the decision analysis. Ranges with an asterisk (*) were generated from a consensus of authors. The last two columns indicate variables for which a threshold value was identified in one-way sensitivity analysis. Values with a plus (+) indicate a threshold value above which withholding anticoagulant prophylaxis becomes the preferred strategy. DVT: deep vein thrombosis; ICH: intracranial hemorrhage; LMWH: low molecular weight heparin; PE: pulmonary embolism
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