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National Clinical Guideline Centre – Acute and Chronic Conditions (UK). Venous Thromboembolism: Reducing the Risk of Venous Thromboembolism (Deep Vein Thrombosis and Pulmonary Embolism) in Patients Admitted to Hospital. London: Royal College of Physicians (UK); 2010. (NICE Clinical Guidelines, No. 92.)

Cover of Venous Thromboembolism

Venous Thromboembolism: Reducing the Risk of Venous Thromboembolism (Deep Vein Thrombosis and Pulmonary Embolism) in Patients Admitted to Hospital.

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20Spinal injury

20.1. Introduction

Spinal injury and, in particular, spinal cord injury is a significant cause of morbidity and mortality with younger age groups frequently affected. Spinal injury can occur without injury to the spinal cord and when nerve injury occurs at the level below the dorsal/lumbar junction (where the injury will be to the cauda equine and not the spinal cord). Even without injury to the spinal cord or nerve injury, patients with spinal injury may be at increased risk of VTE for reasons of prolonged immobility

Most patients with spinal injury are treated conservatively but a not insignificant proportion will require spinal stabilisation. Most patients recover to a greater degree but a not insubstantial number will have a permanent neurological deficit and require assessment, at least initially, in a Regional Spinal Injury Centre.

Non-traumatic causes of spinal cord compression are covered elsewhere, for example, in the NICE Metatastatic Spinal Cord Compression guideline 471. However, further evidence is evaluated in the Palliative care (Chapter 28) and Critical care (Chapter 29) sections of this document. The evidence for patients undergoing spinal surgery is presented in Chapter 14.

The major concern is the constantly changing balance between the initial risk of bleeding (a potential disaster within the enclosed space of the spinal column) and the subsequent increased risk of thrombotic events, particularly, with prolonged immobilisation. The small number of trials completed in this population recorded the baseline risk of DVT at between 40–50% in the absence of thromboprophylaxis. A risk assessment tool should be utilised as soon after admission as is practicable with constant clinical evaluation and re-evaluation depending on patient progress.

20.2. Evidence of methods of prophylaxis

20.2.1. Summary of comparisons identified for any outcome

Four randomised controlled trials which reported at least one of the three main outcomes were identified 233,234,442,616.

All included RCTs were either individually critically appraised to be of a high quality (level 1+ or level 1++) or came from systematic reviews of RCTs which had been critically appraised to be of a high quality (level 1+ or level 1++).

Figure 20-41. Number of studies which compared various types of prophylaxis methods.

Figure 20-41Number of studies which compared various types of prophylaxis methods

Numbers in boxes indicate the number of RCTs for each comparison. Boxes shaded grey indicates areas where no studies were identified.

GCS – anti-embolism/graduated compression stockings; IPCD/FID – intermittent pneumatic compression devices or foot impulse devices; LMWH – low molecular weight heparin; UFH – unfractionated heparin; Asp (HD) – high dose aspirin (>300mg), Asp (LD) - low dose aspirin (≤ 300mg); mech – mechanical prophylaxis (i.e. anti-embolism/graduated compression stockings, intermittent pneumatic compression devices or foot impulse devices); pharm – pharmacological prophylaxis

20.2.3. Additional information

20.2.3.2. Additional studies

The DVT and pulmonary embolism outcomes of a study which compared the safety and efficacy of a combination of UFH plus IPCD against LMWH had been excluded from the main analysis of DVT and PE because only 107/456 (23.5%) of patients were able to be evaluated for these outcomes 616. Major bleeding events were reported on an intention to treat basis and are presented in Table 20-101.

This study was followed with a rehabilitative phase study where patients were enrolled from week 2 for 6 additional weeks and were given UFH or LMWH prophylaxis 617. The study was excluded as the reported patient inclusion was unclear. The study did not find any significant difference in all cause mortality, DVT, symptomatic PE and major bleeding rates.

20.2.3.3. Additional outcomes

No studies reported heparin induced thrombocytopenia, post thrombotic syndrome or chronic thromboembolic pulmonary hypertension.

20.3. Network meta-analysis results

No network meta-analysis was completed for this population

20.4. Cost-effectiveness evidence

No cost effectiveness analysis was completed for this population.

20.5. Patient views

Only two patient view or adherence to treatment studies were found in this population, and both were conducted as RCTs 106,701.

In a United States study, patients received more than 99% of the prescribed LMWH doses, for both once or twice daily regimens (Evidence Table 62, Appendix D) 106. Most patients did not think getting the injections a “hassle” (compared to taking pills 3 times a day) or painful 106.

The other study compared FID vs IPCD among adults undergoing major thoracolumbar reconstructive spinal procedures (Evidence Table 61, Appendix D) 701. All participants also wore thigh-length stockings and the devices were started postoperatively and worn when in bed until discharge. There was a wide range of responses in both groups ranging from extremely comfortable to extremely uncomfortable. There was no difference in visual analogue scores for comfort between the FID and the IPCD groups.

For more information patient views and adherence on specific prophylaxis methods, see section 6.6, where information from different populations are presented.

20.6. Summary of evidence

Intervention(s)Comparison(s)Intervention favoured
DVTPEMB
Prophylaxis vs no prophylaxis
UFHNilNot sig--
Asp(HD) +/− antiplateletsNilNot sigNo events-
Single prophylaxis vs single
UFHLMWHNot sig--
Double prophylaxis vs single
IPCD + UFHLMWH--Not sig
Cost Effectiveness
There is no relevant cost-effectiveness evidence specifically for this population subgroup.

The prophylaxis strategy which is significantly more effective in reducing DVT or PE; or resulting in significantly less major bleeding is stated in bold.

Not sig - not statistically significant difference; ‘-’ = not reported; no events – nobody in the study had the outcome. MB = Major bleeding

Very few RCTs had been conducted in patients with spinal injury. The studies were mostly very small, and therefore may be unable to detect any difference in the effectiveness of different strategies, even if there was one.

20.7. Recommendations and link to evidence

RecommendationOffer combined VTE prophylaxis with mechanical and pharmacological methods tor patients with spinal injury. Regularly reassess the patient’s risks of VTE and bleeding.
Box 2. Bleeding Risk FactorsRegard hospitalised patients as being at risk of bleeding if they have any of the following risk factors:
  • Active bleeding
  • Acquired bleeding disorders (such as acute liver failure)
  • Concurrent use of anticoagulants known to increase the risk of bleeding (such as warfarin with international normalised ration [INR] higher than 2)
  • Lumbar puncture/epidural/spinal anaesthesia expected within the next 12 hours
  • Lumbar puncture/epidural/spinal analgesia within the previous 4 hours
  • Acute stroke
  • Thrombocytopenia (platelets < 75 × 109/l)
  • Uncontrolled systolic hypertension (≥ 230/120 mmHg)
  • Untreated inherited bleeding disorders (such as haemophilia and von Willebrand’s disease).
Relative values of different outcomesThe main outcomes considered were venous thromboembolic events (asymptomatic and symptomatic DVT, symptomatic pulmonary embolism and fatal pulmonary embolism), bleeding events (major bleeding, fatal bleeding and stroke) and other long term events occurring as a result of VTE (chronic thromboembolic pulmonary hypertension and post thrombotic syndrome).
Trade off between clinical benefit and harmsThe benefit of reducing the risk of venous thromboembolism and long term events occurring as a result of thromboembolism were considered against the risk of major bleeding.
Economic considerationsThere is no relevant cost-effectiveness evidence specifically for this population subgroup.
The implications for spinal injury patients developing VTE are similar to other groups of patients and the risk of VTE in this population is likely to be very high (40–47% in no prophylaxis arms of included RCTs). The results of our economic model for the general medical and surgical patients (Chapters 23 and 9) could therefore be extrapolated for this subgroup.
The model result suggests that LMWH is the most cost-effective for general medical patients. This was followed by unfractionated heparin. The model for general surgical patients suggests that a combination of mechanical prophylaxis and either unfractionated heparin or LMWH are most cost - effective where the risk of major bleeding is less than 1%.
It is likely that any major bleeding events have more severe consequences for this group of patients than for general medical or surgical patients from which the data have been extrapolated; especially if the bleeding occurs in the spinal cord. The importance of establishing bleeding risk before providing pharmacological prophylaxis is therefore very important.
Quality of evidenceAll included RCTs were either individually critically appraised to be of a high quality (level 1+ or level 1++) or came from systematic reviews of RCTs which had been critically appraised to be of a high quality (level 1+ or level 1++).
There was very little evidence available for this group of patients. All three studies where venous thromboembolism outcomes were included had small sample sizes (mean = 34, range 28 to 41), and would not have been powered to detect significant differences in VTE events or bleeding risks. Therefore, the quality of evidence is disadvantaged from lack of precision in the results. Moreover, only two of the studies masked patients and VTE investigators to the treatment.
Other considerationsDespite a lack of evidence which is specific to this group, it had been noted that the incidence of VTE is very high (40–47% in no prophylaxis arms of included RCTs). Based on evidence in other groups, prophylaxis should be offered, unless outweighed by the risk of bleeding. The Guideline Development Group recognised that it is difficult to determine a time point where the risk of bleeding would be significantly reduced based on the literature. This would need to be assessed individually for each patient.
There is little evidence available in terms of patients’ views. The study which was found in this population found LMWH could be administered without adherence problems in the hospital setting, and most patients did not find it a painful or an inconvenience (“hassle”).

20.7.1. Other recommendations of relevance

The specific recommendations for patients with spinal injury in this chapter should be read in conjunction with other relevant recommendations in the guideline. These are:

20.8. Recommendations for research

Although not identified as a top priority research recommendation the Guideline Development Group identified that information about prophylaxis in this group is sparse, particularly around the duration of prophylaxis and suggested that further research in this area would be helpful.

20.9. Summary of recommendations

Box Icon

Box 2

Bleeding Risk Factors. Active bleeding Acquired bleeding disorders (such as acute liver failure)

Copyright © 2010, National Clinical Guideline Centre - Acute and Chronic Conditions.

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Bookshelf ID: NBK116510

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