The delay in diagnosing and treating HITT between 2 and 9 January
22. Mrs F says the Trust failed to identify a blood clot following a CT scan done on 2 January 2024. She says she continued to be unwell, so the Trust re-reviewed this scan on 9 January. This is when it identified the blood clot.
23. She says the Trust’s failure to identify the blood clot meant she suffered with abdominal pain and vomiting for longer and formed more life-threatening blood clots. As a result, she needed more care and treatment and had to stay in hospital longer.
24. She also says she now takes seven different tablets a day and is still undergoing treatment. She says this could have been avoided had the Trust identified and treated the initial blood clot earlier. She says the whole experience has caused her and her family significant distress.
25. On 24 December 2023 Mrs F suffered a right hip fracture. The Trust admitted her and the plan was to perform hip surgery.
26. BNF ‘Venous thromboembolism (VTE)’ guidelines suggest pharmacological prophylaxis (the use of medications) to be considered in patients undergoing general or orthopaedic surgery when the risk of VTE outweighs the risk of bleeding. VTE includes both deep-vein thrombosis (DVT) and pulmonary embolism (PE) and refers to a blood clot that forms in a vein which partially or completely obstructs blood flow.
27. NICE ‘VTE in over 16s: reducing the risk of hospital-acquired DVT or PE’ says pharmacological VTE prophylaxis with low molecular weight heparin is suitable to use in all types of general and orthopaedic surgery and should be given for 28 days. It says to consider pre‑operative VTE prophylaxis with low molecular weight heparin for people with fragility fractures of the pelvis or hip if surgery is delayed beyond the day after admission and to give the last dose no less than 12 hours before surgery.
28. The records show the Trust gave Mrs F routine VTE prophylaxis with low molecular weight heparin in the form of enoxaparin (an injectable anticoagulant) and this was first given at 6pm on 25 December.
29. Our haematology adviser says enoxaparin was appropriately given to reduce Mrs F’s risk of developing VTE as she was undergoing orthopaedic surgery. This was in line with the BNF guidance.
30. Due to the high number of acute and trauma patients admitted to the hospital that required treatment before Mrs F, the Trust began enoxaparin on 25 December prior to her surgery. This was done in line with NICE VTE guidance because her surgery was delayed beyond the day after her admission.
31. The Trust performed Mrs F’s hip surgery the following day, 26 December, and transferred her onto one of its wards for recovery. The records indicate the plan was for her to be given low molecular weight heparin prophylaxis for 28 days in line with NICE VTE guidance.
32. NICE ‘How should I interpret platelet count results?’ guidance says normal laboratory reference range for platelets is 150–450 × 109/L. Thrombocytopenia is a platelet count below 150 × 109/L. Lower platelet counts are further sub-divided into mild, moderate, and severe thrombocytopenia.
33. On 31 December, Mrs F’s platelet count was 287 x 109L, which is considered normal.
34. On 1 January 2024, Mrs F began to experience abdominal pain and was vomiting. She had a fall in her platelet count to 94 x 109/L, which according to NICE platelet count guidance is moderate thrombocytopenia.
35. On 2 January, due to Mrs F’s condition, the Trust conducted a CT scan. On the morning of 3 January, the Trust’s consultant orthogeriatrician discussed the scan report with the imaging services team.
36. This discussion concluded the dark spots seen on the scan were a distortion of the image. The consultant’s plan was to continue to monitor Mrs F and repeat her blood tests. As her platelet count was low, the consultant decided to stop enoxaparin.
37. By 4 January, Mrs F’s platelet count was 37 x 109/L. This indicates ‘severe thrombocytopenia’ as per NICE platelet count guidance.
38. BSH ‘Diagnosis and management of HIT’ guidance says HIT typically occurs five to 14 days after exposure to heparin and is associated with a significantly increased risk of thrombosis (blood clots) causing the condition HITT. Blood clots can occur at any time and in any region or organ of the body.
39. Further, this BSH guidance says to use a 4T scoring system to predict a patient’s risk of HIT. The 4T scoring system evaluates four clinical parameters: • thrombocytopenia - the degree of platelet count drop • timing - the timing of the platelet count fall in relation to heparin exposure • thrombosis - the presence of thrombosis or other sequelae (after effect or complication) making the condition HITT • other explanations - the absence of other explanations for thrombocytopenia.
40. The system gives a score between zero and eight. The scores are interpreted as zero to three being low, four to five being intermediate, and six to eight being a high probability for HIT.
41. Mrs F’s platelet count dropped by 67% from 31 December to 1 January. It dropped a further 60% between 1 and 4 January. This would have given her a thrombocytopenia score of two.
42. She was first given heparin on 25 December and the fall in this platelet count began seven days after exposure to heparin. This would have given her a further score of two.
43. There was a presence of thrombosis, although not identified. If identified, it would have given her a score of two. If suspected a score of one.
44. Mrs F’s low platelet count could have been due to liver dysfunction so there was a possible other cause. This would have given her a score of one.
45. Her score without the presence or suspicion of thrombosis would have been five. This would have increased to six with suspicion, and seven had the thrombosis been identified at the time.
46. BSH guidance says HIT should be suspected if a person’s platelet score falls by 30% or more and/or if they develop a new thrombosis between days four and 14 of exposure to heparin. If a patient has suspected HIT, and at least an intermediate probability 4Ts score (more than four), all sources of heparin (including low molecular weight heparin) must be discontinued, and a non-heparin anticoagulant should be initiated while specialist blood tests are performed to see whether there are abnormal antibodies present to confirm the diagnosis.
47. Our haematology adviser says, in Mrs F’s case, her 4T score was at least five on 2 January even without the suspicion of thrombosis. A patient scoring four or above would indicate the need for further discussion with the haematology team for non-heparin anticoagulant advice and to test for HIT.
48. In line with the BSH guidance, the Trust appropriately stopped enoxaparin (low molecular weight heparin) on 3 January. However, as Mrs F’s score was at least five on 2 January, even if the CT scan was not clear, a non-heparin anticoagulant should have been started, and a blood test should have been performed to test for HIT. The Trust did not do this, and we consider this to be a failing.
49. When Mrs F’s platelet count dropped again by 4 January indicating severe thrombocytopenia, both our haematology and complex thrombotic advisers said this was a further sign that more investigations, and the involvement of haematology, were needed.
50. This was a further missed opportunity for the Trust to involve haematology, start a non-heparin anticoagulant, and perform a blood test for HIT in line with the BSH guidance. The Trust did not do this, and we consider this to be a further failing.
51. Although Mrs F appeared to be improving, her blood test results did not, and she continued to have a low platelet count. On 9 January, the blood tests also showed liver deterioration.
52. This prompted the Trust to re-review the previous scan from 2 January. It was at this stage where it identified that the dark spots on the scan were in fact hepatic portal vein thrombosis. The consultant referred to haematology for advice on selecting anticoagulation. HIT screening then began and it was confirmed on 10 January.
Care and treatment provided from 9 January
53. BSH guidance says alternative parenteral anti-coagulants to heparin, such as argatroban, bivalirudin, danaparoid and fondaparinux, should be used in the acute management of patients with HIT.
54. On 9 January, following haematology involvement, the Trust started Mrs F on a non-heparin anticoagulant called fondaparinux. Although HIT was not confirmed until 10 January, our haematology adviser says this was appropriate and in line with BSH guidance because the re-review of the CT scan had shown the presence of a blood clot.
55. NHS ‘Pulmonary Embolism’ guide explains that symptoms of a pulmonary embolism include difficulty breathing that comes on suddenly and chest pain that is worse when you breathe in.
56. Mrs F had begun to experience breathing difficulties, so a CT scan was done on 10 January. This confirmed bilateral PE with some right heart strain and a soft plaque or thrombus in the thoracic descending aorta (chest down to the abdomen). The fondaparinux (injection) was then switched to argatroban (IV).
57. The Trust’s ‘Management of HIT’ guidelines say to use the treatment argatroban when a diagnosis of HIT is confirmed. Therefore, when HITT was confirmed on 10 January, the fondaparinux (injection) was then switched to argatroban (IV) in line with the Trust’s guidelines.
58. BSH guidance has a protocol on when to adjust argatroban infusion rates. The rate is dependent on the activated partial thromboplastin time (APTT). APTT is a measure of the time taken for blood to clot via the intrinsic pathway.
59. The records give clear instructions to monitor the APTT very closely and adjust the argatroban infusion rate accordingly.
60. Our haematology adviser says this is a very complex protocol and can take some time to reach desired levels. The records indicate the medical team followed the protocol as closely as it was possible with liaison with the haematology team as needed.
61. The Trust’s ‘Management of HIT’ guidelines say to start warfarin (another anticoagulant medication) when platelet count is above 150 x 109/L. There should also be an overlap period of at least five days where both argatroban and warfarin are given.
62. On 15 January, Mrs F’s platelet count was 213 x 109/L and the records show that in line with the Trusts guidelines she was given warfarin alongside argatroban. The records state to continue the overlap for at least five days as per the Trust’s HIT guidance.
63. Our haematology adviser says the overlap period is needed as warfarin can lead to prothrombotic state. This means it is prone to developing clots due to abnormalities in the coagulation (clotting) system.
64. NICE CKS ‘Anticoagulation – oral: Scenario: Warfarin’ says warfarin-related skin necrosis is rare but is an adverse effect of taking the medication. It is more likely in people with HIT or in people with pre-existing protein C or protein S deficiency. Treatment with warfarin should be stopped if warfarin-related skin necrosis is suspected.
65. On 17 January, the Trust discovered that Mrs F had developed a thrombus in her right common femoral vein, superficial femoral vein (blood vessels in the thigh) and popliteal vein (vein of the lower limb).
66. The records indicate the haematology team thought Mrs F’s new blood clot had developed because of the warfarin treatment, which can happen in rare occasions.
67. The Trust stopped Mrs F’s warfarin treatment. The argatroban rate was changed and new target ranges implemented with a monitoring plan in place for this. This was also discussed with specialist at the tertiary centre for haematologists who agreed with the plan.
68. Our haematology adviser says, as Mrs F had been diagnosed with HITT and her test results also showed protein C and protein S deficiency, it was appropriate for the Trust to suspect skin necrosis and stop the warfarin treatment.
69. The Trust confirmed Mrs F’s ongoing hyponatraemia (low sodium level), adrenal insufficiency (where the adrenal glands do not produce enough of their hormones), and bilateral adrenal thrombosis (a blockage of both adrenal veins) on 22 January. The records show the Trust gave Mrs F the additional medication she needed to support her adrenal system.
70. On 23 January, the Trust appropriately discussed cautiously reintroducing warfarin with argatroban infusion because of its concerns about it contributing to her condition. The records suggest warfarin began again on 29 January and continued throughout her hospital admission. She was discharged home on 9 February with warfarin.
71. Therefore, we have found that the care provided to Mrs F from 9 January up until her discharge was appropriate and in line with the Trust’s ‘Management of HIT’ guidelines, the BSH guidance, and the NICE CKS.
Impact of initial delay in diagnosing and treating HITT between 2 and 9 January
72. Having taken everything into consideration, we are of the view that the development of Mrs F’s first blood clot (hepatic portal vein thrombosis -seen on the CT scan on 2 January) happened despite the Trust giving her appropriate post-operative care and treatment and there was nothing further it could have done to prevent this from happening.
73. We are of the view the Trust appropriately stopped enoxaparin (low molecular weight heparin) on 3 January in line with the BSH guidance.
74. Despite this, as Mrs F’s score was at least five on 2 January, even without the CT scan reporting the presence of a blood clot, BSH guidance is clear that a non-heparin anticoagulant should have been started, and a blood test should have been performed to test for HIT. This would have led to a diagnosis of HIT.
75. This did not happen until 9 January, therefore, we have found that there was a seven-day delay in the Trust diagnosing and treating Mrs F for HIT.
76. Our complex thrombotic adviser says, as Mrs F’s breathing issues developed around 10 January, it is likely the PE formed before 10 January, so when she was not receiving treatment for HITT.
77. Our complex thrombotic adviser also says the blood clots affecting Mrs F’s right leg, which were diagnosed on 17 January, were likely present earlier but not detected.
78. Our complex thrombotic adviser explained that a PE often happens when part of the blood clot dislodges itself from the leg and travels up to the lungs, causing a blockage. They explained as Mrs F developed a PE around 10 January, it is likely these leg clots were present before 9 January.
79. Our complex thrombotic adviser says further blood clots can occur despite the correct treatment. This typically occurs within the first one to two weeks of treatment.
80. Mrs F developed a bilateral adrenal thrombosis on 22 January. This was after she started receiving the correct treatment on 9 January.
81. Although we cannot say Mrs F would not have developed further clots had she been diagnosed and began treatment earlier, our complex thrombotic adviser said that if the Trust had started fondaparinux or argatroban seven days earlier, i.e. on 2 January, it would have reduced the likelihood of her developing the further blood clots and reduced the chance of her developing further clots to the extent she did.
82. Mrs F says she now takes seven different tablets a day and is still undergoing treatment, which may not have happened had the Trust identified the blood clot on 2 January and treated her earlier.
83. BMJ ‘Duration of anticoagulation for VTE’ study shows after anticoagulant treatment is stopped, VTE often recurs. Extending anticoagulant medications up to 12 or 24 months reduces the risk of recurrent VTE by more than 80%, but this benefit is lost after stopping anticoagulation.
84. Our complex thrombotic adviser says it is unlikely that Mrs F would need to take ongoing anticoagulant medication for HITT, but this may be required to prevent recurrent VTE.
85. As such, we cannot say, even on the balance of probabilities, whether Mrs F would still be required to take this medication long-term following the development of the first blood clot which she developed when she was receiving the correct care and treatment.
86. Also, as we cannot say that Mrs F would not have developed a clot in her adrenal gland if the correct care and treatment was provided, we cannot say that the long-term steroid medication would not be required due the injury sustained to her adrenal gland.
87. We appreciate the distress and frustration it causes Mrs F and her family having to attend multiple hospital appointments. That said, we are of the view that she would likely require ongoing medical appointments to monitor and review her condition. This is because she developed the initial blood clot despite appropriate post-operative care and treatment.
88. The records indicate Mrs F experienced abdominal pain and vomiting between 1 and 2 January. This seemed to improve the following day and then began to deteriorate again on 8 January. Our haematology adviser says these symptoms added to Mrs F’s already difficult situation. Our haematology adviser said this deterioration on 8 January could have potentially been avoided had HITT treatment begun earlier.
89. We are of the view the Trust missed two opportunities to diagnose Mrs F with HITT, which led to a seven-day delay in her receiving appropriate treatment. We have found that this failing increased her risk of developing further clots. Had the failing not occurred, we conclude that the further clots may not have developed to the extent they did. Further, she suffered pain and vomiting on 8 January, which could potentially have been lessened with earlier treatment.
90. Although we have found there was a delay in the diagnosis and treatment of HITT for seven days, we cannot say that this led to Mrs F having to stay in hospital for longer. This is because she still may have developed further blood clots and required the same hospital treatment due to the complex and progressive nature of the condition.