Coagulation questions

Question 1.

A patient who is on rivaroxaban for atrial fibrillation (CHA₂DS₂-VASc score 5) is undergoing a cholecystectomy in a few weeks time and you have been contacted by the anaesthetist for assistance in offering a bridging plan. This 60 year old lady weighs 85kg and her renal function is normal. Outline a bridging plan for the anaesthetist in the perioperative period and include advice to the patient about what to do when she is discharged from hospital. (10)

Question 2.

A 78 year old patient comes in overnight to the Emergency Department with a diagnosed small intracranial haemorrhage with no mass effect and is on apixaban 2.5mg BD for atrial fibrillation. He has a mild left hemiparesis. His last dose of apixaban was 17 hours ago and you are waiting for the patient’s renal function to come back. In the meantime, you have the coagulation results available (patient’s full blood count is normal). You are contacted at 3am to provide advice on further management.

PT 14s (NR 10-13s)

APTT 35s (NR 25-35s)

Fibrinogen 2g/L (NR 1.5-4g/L)

Outline your management plan for this patient, explaining your reasoning (8).

Question 3.

A 35 year old lady has been referred for a semi-elective nephrectomy for cancer and has no bleeding history. In the past, the pre-op nurse has noted some tooth extractions done with no problems. She is found to have a prolonged APTT and further tests were requested.

PT 13s (NR 9-14s)

APTT 59s (NR 24-36s) – 50/50 corrects to 42s (control 33s)

Fibrinogen 3.0/L (NR 1.5-4g/L)

FVIII 1.6IU/mL

FIX 0.94IU/mL

FXI 0.65IU/mL

FXII 0.8IU/mL

vWF Ag: 1.48IU/mL; vWF RCoF: 1.60IU/mL

a) Comment on the results and outline what further tests you would like to perform, and what you might expect to find. (3)

b) The FXI level has been repeated and it has come back at 0.68IU/mL. You have been asked by the urologists regarding thromboprophylaxis for this lady given the results – what would you advise? (2)

Unfortunately, in spite of adequate thromboprophylaxis she developed a swollen left leg and duplex scanning confirmed an above knee DVT and she was anticoagulated. Two repeat APTT samples using a lupus insensitive reagent were performed (both 62s).

c) Outline the reason for the abnormal APTT. (1)

d) Recommend a choice of anticoagulant here suggest a management plan including duration of anticoagulation. Justify your decision. (3)

Question 4.

You have been contacted in the evening by the Emergency Department F2 about a 44 year old man who has presented requiring an urgent appendicectomy and has previously lived in Italy and has only just moved to the UK for work. He claims to have ‘mild haemophilia’ but no level is given, and that he has never had treatment before and no past surgical problems. The F2 doctor has sent off the bloods and the lab have also done a FVIII level. The results are as follows:

Hb 135g/L, WCC 14x10^9/L, platelets 245x10^9/L

PT 10s (NR 9-14s)

APTT 40s (29-41s)

Fibrinogen 2.5g/L (NR 1.5-4g/L)

FVIII: 0.65IU/mL

a) Comment on the above results and suggest four alternative tests you may wish to perform, explaining your reasoning for requesting these tests. (5)

b) He requires some factor concentrate for his surgery - his chromogenic assay FVIII has come back at 0.20IU/mL. Suggest a choice of concentrate and a dose, plus aftercare post surgery. (3)

Question 5.

You are contacted by the general surgery team about a patient post hemicolectomy who had the following result, and was noted to have some oozing from his surgical wound. Unfortunately he did not have any pre-operative bloods and two years ago his FBC at his GP surgery was noted to have a mild thrombocytosis of 550x10^9/L. His result from today showed:

Hb 115g/L

WCC 12.6x10^9/L

Plt 790x10^9/L

PT 12s, APTT 50s (corrects to 34s – control 31s), fibrinogen 3.3g/L

FVIII 60IU/dL (NR 50-150IU/dL), FIX 90IU/dL, FXI 93IU/dL, FXII 79IU/dL

Blood film – variable size of platelets with occasional large forms seen, neutrophilia confirmed

a) Comment on the results, and highlight what further investigations you would like to perform, based on your differentials (4).

His results show vWF:Ag 45IU/dL, vWF:Ac (latex) 40IU/dL with some loss of high molecular weight multimers.

b) Suggest a diagnosis (1)

c) Recommend a management plan for this patient (4).

Question 6.

A 26 year old woman has presented with a thrombosis, and has no other significant thrombotic or bleeding history. Routine investigations show the following:

Hb 120g/L, WCC 4.6x10^9/L, Plt 223x10^9/L

PT 18s, APTT 43s, fibrinogen (Clauss) 0.6g/L

a) What further investigations would you recommend in this patient, and what differential diagnoses would you consider? (2)

b) She is found to be 14 weeks pregnant. Outline a peripartum delivery plan. (6)

Question 7.

A 78 year old man with a history of diabetes is admitted under the vascular surgeons and previously has had coronary artery bypass grafting approximately two years ago. He requires an angioplasty and stenting of a popliteal artery for his left leg, requiring anticoagulation before and after the procedure. He was previously diagnosed with heparin-induced thrombocytopenia and you have been given the results of some investigations.

Creatinine 230umol/L (NR 50-100), eGFR 28ml/min

Hb 90g/L, WCC 14.3x10^9/L, Plt 375x10^9/L

PT 12s, APTT 33s, fibrinogen 2.4g/L

anti-PF4 1.487 (NR 0-0.5).

a) Briefly outline the assays used to diagnose HIT. (4)

b) Outline a peri-procedural plan for this patient, given that he will require anticoagulation before and after the procedure. (4)

Question 8.

A man brings his 2 year old boy with increased nosebleeds and easy bruising which he has noticed since he has been more mobile at nursery. His blood results are shown below.

Hb 170g/L, WCC 5.4x10^9/L, Plt 350x10^9/L

PT 12s (NR 10-14), APTT 35s (NR 30-40), Clauss fibrinogen 2g/L

a) Suggest some differential diagnoses and further tests you may wish to request that are not listed below (3).

b) You request some further testing of PFA100 and platelet aggregation studies:

PFA: C/Epi >300s, C/ADP >300s

Platelet aggregation studies show normal response to ristocetin but absent secondary aggregation waves to AA, ADP, Adrenaline and collagen.

What is the diagnosis? (2)

Outline what you would recommend in future if the child requires dental extractions when he is older. (3)

For the answers please see Coagulation answers