Week 21 - Aneurysms, Ischaemic Limb, occulsions, arterial thrombosis, DVT Flashcards
what is an aneurysm
is an artery that has a localised dilation, with a permanent diameter of >1.5x that expected of the particular artery
what is a false aneurysm
other surrounding tissues form the wall of the aneurysm
where do pseudoaneurysms most commonly occur
in the femoral artery following a femoral artery puncture.
if there is inadequate pressure to the entry site of the puncture, then blood can spill out and form a haematoma. eventually the surrounding soft tissue will form the wall of the aneurysm
what is the difference between a psuedo and real aneurysm
the difference is that in a pseudoaneurysm there is still communication between the lumen and the fluid collection, but in a haematoma, there is either no connection or just a one way ‘leakage’ of fluid
what are the the two shapes of aneurysm
fusiform and sac-like
what is a fusiform aneurysm
describes a shape that is tapered at both ends (a bit like a raindrop with a pointy bit at both ends)
what is a sac like aneurysm
describes a more rounded characterisitc
what are the risk factors for aneurysmal disease
Hypertension
Smoking
Age
Diabetes
Obesity
High LDL levels
Sedentary lifestyle
Genetic factors – are more important in aneurysmal disease than in atherosclerotic disease, although they have a role in both.
10% of cases have a first-order relative also with the condition
what is the main risk of aneurysms
they have a tendency to dissect and rupture
where does an aortic aneurysm most commonly rupture into
the retroperitoneal space
what is used to ‘stage’ the aneurysm
ultrasound
it is accurate at assessing the site of the aneurysm, and easy to follow up cases to assess development
an aortic aneurysm of what size should be treated
an aneurysm that is greater than 5.5cm
what is thought to be a risk for rupture in an AAA
pain
what is an open laparotomy
the affected segment of aorta may be clamped and replaced by a prosthetic segment
what is the most common graft done in an open lapraotomy
a Dacron graft
what is EVAR
Endoluminal surgery – EVAR – Endovascular aneurysm repair
n aortic graft is inserted through the femoral artery, and up into the abdominal aorta. This method is generally preferred (lower mortality 1.2%) but many patients are not suitable. There must be at least 2.5cm normal aorta between the aneurysm and the renal arteries to securely fix the graft in place.
when does acute limb ischaemia happen
when there is a blockage of a peripheral artery, either from a thromboembolism, or sometimes from an embolic plaque
As the MI is to coronary artery disease, acute limb ischaemia is to peripheral vascular disease
what are the classic 6 P’s of acute limb ischaemia
Pulseless
Paraesthesia
Pain – muscles also become tender to palpation after about 6-8hours
Paralysis
Pallor
Perishing cold
what is seen on the skin in acute limb ischaemia that implies irreversibility
fixed mottling
how is diagnosis of acute limb ischaemia given
you can roughly localise the blockage by locating the bifurcation distal to the last palpable pulse
diagnosis is clinical
what percentage of cases of ACI are fatal
22%
what is given via the local arterial catheter in acute limb ischaemia
tissue plasminogen activator - thrombolytic agent
what can reperfusion injury lead to
compartment syndrome
where are the common sites for occlusion
splanchnic arteries
superior mesenteric
coeliac arteries
renal arteries
bifurcation of the aorta
what are the signs of renal artery occlusion
sudden onset flank pain
haematuria
what test should you perform on all suspected ischaemic bowel patients
lactate - normal lactate makes the condition unlikely
where does the thrombus travel in a DVT
travels from the deep veins, through the right side of the heart and into the lungs, where it becomes lodged in the pulmonary arteries
what happens when a DVT travels to the pulmonary arteries
it blocks blood flow to areas of the lungs and this is called a PE
what happens if the patient has a hole in their heart
the blood clot can pass through the left side of the heart and into the systemic circulation. it can travel to the brain and cause a large stroke
what are thrombophilias
conditions that predispose patients to develop blood clots
what are examples of thrombophilias
Antiphospholipid syndrome
Factor V Leiden
Antithrombin deficiency
Protein C or S deficiency
Hyperhomocysteinaemia
Prothombin gene variant
Activated protein C resistance
if you can remember one cause of recurrent VTE what should it be
antiphospholipid syndrome.
the common association you may come across in exams is recurrent miscarriage. the diagnosis can be made with a blood test for antiphopholipid antibodies
what is VTE prophylaxis usually in the hospital
low molecular weight heparin such as enoxaparin
what are the contraindications for VTE prophylaxis
active bleeding or existing anticoagulation with warfarin or a DOAC
what is the main contraindication for anti-embolic compression stockings
peripheral arterial disease
how does one examine for leg swelling
measure the circumference of the calf 10cm below the tibial tuberosity. more than 3cm difference between calves is significant
what is the scoring system used to predict risk of patient who is presenting with symptoms of having a DVT or PE
the Wells score
it includes risk factors such as a recent surgery, clinical findings such as unilateral calf swelling 3cm greater than the other leg
what is required to diagnose DVT
doppler ultrasound of the leg
NICE recommends repeating negative ultrasound scans after 6-8 days if a positive D dimer and Well’s score suggest a DVT is likely
what is initial management of a suspected or confirmed DVT or PE
starts with anticoagulation
what are two examples of anticoagulation
apixaban or rivaroxaban
what do NICE recommend considering for patients with a symptomatic iliofemoral DVT and symptoms lasting less than 14 days
catherter-directed thrombolysis
what are the options for long term anticoagulation in VTE
DOAC, warfarin or LMWH
what are DOACs
oral anticoagulants that do mot need monitoring
give four examples of DOACs
apixaban
rivaroxaban
edoxaban
dabigatran
what is warfarin
a vitamin K antagonist
what is the target INR for warfarin when treating PEs and DVTs
between 2 and 3
in which patients is warfarin first line
in patients with antiphospholipid syndrome
what is the first line anticoagulant in pregnancy
LMWH
how long do you continue anticoagulation if there is a reversible cause
3 months
how long do you continue anticoagulation if the cause is unclear, there is a recurrent VTE, or there is an irreversible underlying cause such as thrombophilia
beyond 3 months
how long do you continue anticoagulation for in patients with active cancer
3-6 months
what are inferior vena cava filters
devices inserted into the IVC, designed to filter the blood and catch any blood clots travelling from the venous system, towards the heart and lungs
they act as a sieve, allowing blood to flow through whilst stopping larger blood clots
when are inferior vena cava filters used
in unusual cases of patients with recurrent PEs or those who are unsuitable for anticoagulation
what is investigated when patients have their first VTE witihout a clear cause,
NICE guidlines recommend reviewing the medical history, baseline blood results and physical examination for evidence of cancer
