Sun, 02 Dec 2018
Venous thromboembolism (VTE)
What is it?
- Formation of a blood clot (a thrombus) in a vein
- Most commonly in the deep veins of the legs or pelvis deep vein thrombosis (DVT)
- Common and potentially preventable
- Accounts for thousands of deaths annually in NHS
- Fatal pulmonary embolism (PE) a common cause of in-hospital mortality
- Management of risk now changed: all patients should now undergo routine VTE risk assessment.
- Post-DVT risk of post-thrombotic syndrome
- 'VTE' includes both DVT and PE
- Hospital-acquired VTE refers to VTE that occurs in hospital within 90 days after a hospital admission.
Those at risk
- Those with a history of DVT
- age over 60 years
- prolonged travel, acute medical illness, cancer, immobility
- Thrombus can dislodge and travel in the blood, particularly to the pulmonary arteries to form a PE.
- Can be fatal if PE - blood supply to lungs blocked by the thrombus.
- Non-fatal VTE can cause serious long-term conditions such as post-thrombotic syndrome.
- Thrombophilia (increased tendency to form blood clots) a major risk factor: an inherited or acquired state that predisposes to VTE
- Failure to diagnose and treat VTE correctly can result in fatal PE.
- Treatment associated with considerable cost
- 2005: VTE underlying cause of death in more than 6,500 patients (figure thought to be an underestimate).
- By July 2013 96% of adult admissions to NHS funded acute care hospitals were risk assessed for VTE compared with less than 50% of patients in July 2010
- Not always straightforward.
- “Venous thromboembolic diseases: diagnosis, management and thrombophilia testing”: Clinical guideline [CG144];
- Venous thromboembolism in adults: diagnosis and management. Quality standard [QS29]
The new VTE client and claim
- From our perspective, the first step should be to understand how competent medical professionals protect the patient against the risk of VTE. One starting point is to understand the control of VTE risk in patients admitted to hospital, although of course other primary care providers (GPs) have a corresponding duty to be alert to the risk of VTE within their practice.
- Go to NICE Guidance: Venous thromboembolism in adults: reducing the risk in hospital QS3 to understand current best practice. It consists of a list of 7 practice statements which should be read as a primer before delving into the detail of liability expert evidence, and ideally, before the first detailed face-to-face meeting or instructions from the client: –
List of statements (reducing risk of VTE in hospital)
Statement 1 Medical, surgical or trauma patients have their risk of VTE and bleeding assessed using a national tool as soon as possible after admission to hospital.
Statement 2 Patients who are at increased risk of VTE, are given information about VTE prevention on admission to hospital.
Statement 3 Patients provided with anti-embolism stockings have them fitted and monitored in accordance with NICE guidance.
Statement 4 Medical, surgical or trauma patients have their risk of VTE reassessed at consultant review or if their clinical condition changes.
Statement 5 Patients assessed to be at risk of VTE are offered VTE prophylaxis in accordance with NICE guidance.
Statement 6 Patients/carers are offered verbal and written information on VTE prevention as part of the discharge process.
Statement 7 Patients are offered extended (post hospital) VTE prophylaxis in accordance with NICE guidance.
- QS3 is modest on detail, but a springboard to another vital document to peruse before the first detailed meeting with the client. This is NICE Guideline: Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism NG89 (published March 2018).
- The obligation to be alert to the risk of VTE in patients is no less acute in general practice, where the shortness of patient interaction (10 minutes?) places demands on the GP to assess signs and symptoms, and on the patient to provide relevant history. For the client that presents with a potential VTE claim which involves a GP, NICE Guidance: Venous thromboembolism in adults: diagnosis and management QS29 is essential reading. Again, the format is a list of quality statements, applicable to hospital admissions, but of particular relevance to GPs.
List of quality statements (diagnosis and management)
Statement 1 People with suspected deep vein thrombosis are offered an interim therapeutic dose of anticoagulation therapy if diagnostic investigations are expected to take longer than 4 hours from the time of first clinical suspicion.
Statement 2 People with suspected deep vein thrombosis have all diagnostic investigations completed within 24 hours of first clinical suspicion.
Statement 3 People with suspected pulmonary embolism are offered an interim therapeutic dose of anticoagulation therapy if diagnostic investigations are expected to take longer than 1 hour from the time of first clinical suspicion.
Statement 4 (mechanical interventions) This statement has been removed.
Statement 5 People with unprovoked deep vein thrombosis or pulmonary embolism who are not already known to have cancer are offered timely investigations for cancer.
Statement 6 People with provoked deep vein thrombosis or pulmonary embolism are not offered testing for thrombophilia.
Statement 7 People with active cancer and confirmed proximal deep vein thrombosis or pulmonary embolism are offered anticoagulation therapy.
Statement 8 People without cancer who receive anticoagulation therapy have a review within 3 months of diagnosis of confirmed proximal deep vein thrombosis or pulmonary embolism to discuss the risks and benefits of continuing anticoagulation therapy.
Statement 9 People with active cancer who receive anticoagulation therapy have a review within 6 months of confirmed proximal deep vein thrombosis or pulmonary embolism to discuss the risks and benefits of continuing anticoagulation therapy.
- If we understand the NICE guidelines/best practice, we may better follow and understand the management of the client’s condition and have an index to assist in our preliminary evaluation of the medical care provided. This surely is a useful cross reference to test expert liability evidence, when it becomes available.
Identifying potential breaches of duty: admitted hospital patients
The VTE risk assessment
- There is an obligation throughout the NHS to assess all admitted hospital patients (medical and surgical) and identify risk of VTE and bleeding, particularly those in the high risk groups. The touchtone principle is that patients are to be risk assessed as soon as possible after admission or by the time of first consultant review.
- The Department of Health provides a VTE risk assessment tool for medical practitioners which can be found online and applies to all patient risk categories (search: “Department of Health VTE risk assessment tool”). The importance for us, as legal advisers is to understand what in practical terms the patient/client should have expected after admission or at first consultant review. The assessment tool, amongst other templates, is useful when preparing instructions and questions to the liability expert.
- The clinician’s task may include balancing risk of VTE against risk of bleeding when deciding whether to offer pharmacological thromboprophylaxis to patients.
- If the case is to be based on a failure or delay in provision of VTE prophylaxis, NG89 guidance is that in cases where there is an assessed risk of VTE, prophylaxis provision should start as soon as possible and within 14 hours of admission unless otherwise stated in population-specific recommendations.
- Pregnant women and women who have given birth or had a miscarriage or termination in the past 6 weeks are regarded as potentially vulnerable to VTE. Women taking oestrogen-containing oral contraceptives or hormone replacement therapy are at particular risk. The Department of Health VTE risk assessment tool, from our perspective, is another useful initial guide as to how the risk to this particularly vulnerable group of patients should have been assessed.
Reassessment of risk
- NG89 recommends reassessment of risk of VTE and the need for thromboprophylaxis in all patient groups. Was there any reassessment at the point of consultant review or when the client’s clinical condition changed?
The continuing duty: discharge from hospital
- In appropriate cases, and where there is an risk of VTE: –
- is/was there evidence of significantly reduced mobility?
- was the client (and possibly also, in appropriate cases his/her family/carers) provided with verbal and written information before offering VTE prophylaxis?
- Was the client provided on discharge with VTE prophylaxis along with written information on the importance of correct use (for example compression stockings), with information on treatment signs and symptoms?
- Was any verbal or written advice or information given as part of the discharge plan on:-
- the signs and symptoms of DVT and PE?
- how the risk can be reduced?
- the need to seek help if DVT, PE or other adverse events are suspected?
Gathering the evidence
- Medical records As always, the starting point, but particularly so in this category of case, where much will depend upon the paperwork trail. In hospital admission cases, do you have the following in the hospital notes: –
- nursing and clinical notes
- prescription charts
- VTE risk assessment record / risk management record (my generic term, but you should recognise them if they are there)
- discharge letter
- discharge summary
- On those records which have relevance to the VTE issue, look for timed/date entries, and work the timeline from admission / assessment to the time of the adverse event. Check the history taken/given on admission, and if any relevant references are made. Is history taken adequate? Has it been followed up, where necessary, if taken by a junior doctor?
- What is the quality of the documentary evidence in hospital notes on VTE risk assessment, and where necessary, prophylaxis?
- Crosschecking Do the records appear to be complete in so far as they touch upon VTE risk assessment? Ask the client. Do they accord with his/her recollection and instructions?
- Beyond the admission records In surgical cases, look at the operation record/notes. To what extent has the surgeon relied upon what was done in the background, i.e., on admission or on Ward? Has the surgeon checked (ie. is it noted) that a VTE risk assessment was undertaken and that, where appropriate, prophylaxis given? You may not be able to answer this from perusal of the notes: it may need following up with the expert.
- Discharge If the claim relates to a VTE event after discharge:-
- what evidence in the notes is there of a mobility assessment prior to discharge?
- Is there evidence of significantly reduced mobility?
- Was the client (and possibly also, in appropriate cases family/carers) provided with verbal and written information before offering VTE prophylaxis?
- Was the client provided on discharge with VTE prophylaxis along with written information on the importance of correct use (for example compression stockings) and information on treatment signs and symptoms?
- Was any verbal or written advice or information given on the signs and symptoms of DVT and PE and on how the risk can be reduced and need to seek help if DVT, PE or other adverse events are suspected?
Causation: back to the principles
- It is trite principle that, where possible, defendants should only be held liable for that part of the claimant’s ultimate damage to which they can be causally linked. Similarly, where a defendant has been found to have caused or contributed to an indivisible injury, it will be held fully liable for it, even though there may well have been other contributing causes.
- We should all be familiar with Hotson v East Berkshire Health Authority  AC 750, where the young claimant fell from a tree and fractured his left femoral epiphysis. He was taken to hospital, where for several days his injury was not properly diagnosed or treated. He suffered avascular necrosis of the epiphysis, leaving him with a permanent disability. The House of Lords held that on proper analysis of the evidence the avascular necrosis must have been caused in one or other of two ways. Either it was caused by irreparable rupture of the blood vessels to the epiphysis at the moment of the fall, or it was caused by later pressure within the joint from bruising or internal bleeding. There was no room for finding that the avascular necrosis was caused by a combination of the two factors. The trial judge’s findings were to the effect that on the balance of probabilities the cause was the original traumatic injury. The claim therefore failed.
- Unless a claimant proves on a balance of probabilities that the alleged negligent treatment was at least a contributory cause of his (indivisible) injury and damage, he will fail on causation. Where the sole cause of the damage was non-negligent the claimant will lose.
- But where negligent treatment is a material contributory factor:-
Lord Bridge in Hotson:
“…if the plaintiff had proved on a balance of probabilities that the authority’s negligent failure to diagnose and treat his injury promptly had materially contributed to the development of avascular necrosis, I know of no principle of English law which would have entitled the authority to a discount from the full measure of damage to reflect the chance that, even given prompt treatment, avascular necrosis might well still have developed.”
- Where on the balance of probabilities an invisible injury is caused by two (or more) factors operating cumulatively, one (or more) of which is a breach of duty, it is immaterial whether the cumulative factors operate concurrently or successively.
- Two relatively recent decisions are of importance on “but for” and “material contribution”: Bailey v Ministry of Defence and Williams v The Bermuda Hospitals Board.
Bailey v Ministry of Defence  1 WLR 1052
- In Bailey, the claimant underwent a surgical procedure, following which her treatment and care were negligent. As a result, she had to undergo further major procedures which should not have been necessary, and which led to her being in a weakened state. Later, in ITU, she vomited in her sleep and aspirated the vomit, causing her to suffer a cardiac arrest and hypoxic brain damage. Foskett J. held that the Claimant’s weakened state was partly due to pancreatitis for which the hospital was not responsible, and partly due to their negligence i.e. that there were two components of her weakness. He could not say whether the contribution made by the negligent component was more or less than that made by the non-negligent pancreatitis, but he did say that each contributed materially to the overall weakness and it was the overall weakness that caused the aspiration. The claim succeeded. The Defendant’s appeal failed but, significantly, the Court of Appeal thought that the case involved a departure from the “but-for” test.
Which leads to:-
Williams v The Bermuda Hospitals Board  UKPC 4
- The Claimant Mr Williams went to Accident and Emergency complaining of abdominal pain. He had appendicitis. A CT scan was planned but was not carried out expeditiously. Consequently, there were significant delays in diagnosing and treating him. During the delay his appendix ruptured and sepsis incrementally ensued. The sepsis caused myocardial ischaemia. The causation issue was whether the negligent delay had caused the myocardial ischaemia. At first instance the court held that “but for” causation was not established. On appeal, the Court of Appeal of Bermuda reversed the lower court decision holding that the question was not whether the negligent delay was the cause of the myocardial ischaemia but whether it materially contributed to the injury. It was appealed to the Privy Council.
- Lord Toulson, giving the Opinion of the Privy Council, directly applied Bonnington, holding that the indivisible injury (myocardial ischaemia) was caused by sepsis of which there was "guilty" sepsis (attributable to the negligent delay) and "innocent" sepsis which had already begun irrespective of the delay. Unlike in Hotson, it could not be said that the myocardial ischaemia would have occurred in any event. Mr Williams succeeded on causation by proving that the negligence had materially contributed to the process and therefore materially contributed to the injury (myocardial ischaemia).
- Williams is of significance for claimants because the Privy Council declared that Foskett J. was right in Bailey v Ministry of Defence in his approach and conclusion, and disagreed with the Court of Appeal (in Bailey) that it was a departure from the “but for” test. The fact that the Claimant’s vulnerability in Bailey was heightened by her pancreatitis no more assisted the hospital’s case than if she had an egg shell skull. As a matter of principle, successive events are capable of each making a material contribution to the subsequent outcome.
Causation: claim fails
- Where a claim will fail is if the most that can be said is that the injury is likely to have been caused by one or more of a number of disparate factors, one of which was attributable to a wrongful act or omission of the defendant: Wilsher v Essex Area Health Authority  AC 1074.
- In such a case the claimant will not have shown as a matter of probability that the factor attributable to the defendant caused the injury, or was one of two or more factors which operated cumulatively to cause it. In Wilsher the injury was retrolental fibroplasia or RLF, to which premature babies are vulnerable. The condition may be caused by various factors, one of which is an over-supply of oxygen. The claimant was born prematurely and as a result of clinical negligence he was given too much oxygen. He developed RLF, but it was held by the House of Lords that it was not enough to show that the defendant’s negligence added to the list of risk factors to which he was exposed. The fact that the administration of excess oxygen was negligent did not warrant an inference that it was a more likely cause of the RLF than the various other known possible causes. The House of Lords distinguished the case from Bonnington in which the injury was caused by a single known process (the inhalation of dust).
Some observations on the relevance of VTE to quantum
- Where breach of duty and causation are established, consider:-
- risk of Post Thrombotic Syndrome (% risk)
- risk of further DVT (% risk)
- damage to deep veins
- chronic venous insufficiency
- provisional damages
 Source: NHS.uk
 NICE Guidance: “Venous thromboembolism in adults: reducing the risk in hospital” QS3
 Source: “Venous thromboembolism in adults: reducing the risk in hospital” Quality standard [QS3]
 Source: "Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism, March 2018
 Statement 4 on mechanical interventions (graduated compression stockings) has been removed. The source guidance for the statement (NICE's guideline on venous thromboembolic diseases: diagnosis, management and thrombophilia testing) was updated in November 2015 and the advice on using compression stockings has changed.
 NG89 2018
 NG89 2018 para 1.16
 This term is referred to repeatedly in NICE guidance, and it is of importance where the client’s instructions are that no or no adequate VTE prophylaxis, and advice/information were provided on discharge, in cases where there is significantly reduced mobility. NG89 defines “Significantly reduced mobility” as those people who are bedbound, unable to walk unaided or likely to spend a substantial proportion of their day in bed or in a chair.
 Defined in NG89 as applying to people who are bed bound, unable to walk unaided or likely to spend a substantial proportion of their day in bed or in a chair.
 Page 783
 See Lord Simon of Glaisdale in McGhee v National Coal Board  1 WLR 1, 8. Referring to Bonnington Castings Ltd v. Wardlaw  A.C. 613