An abdominal aortic aneurysm (AAA) is a condition where the abdominal aorta becomes enlarged, either in a specific area or throughout its length, reaching 1.5 times its normal size. Most AAAs are found between the diaphragm and the point where the aorta splits into two branches. They can be classified into three types based on their location: suprarenal, pararenal, and infrarenal. Suprarenal AAAs involve the origin of one or more visceral arteries, pararenal AAAs involve the origins of the renal arteries, and infrarenal AAAs start below the renal arteries. The majority of AAAs (approximately 85%) are infrarenal. In individuals over 50 years old, a normal infrarenal aortic diameter is 1.7 cm in men and 1.5 cm in women. An infrarenal aorta with a diameter greater than 3 cm is considered to be an aneurysm. While most AAAs do not cause symptoms, an expanding aneurysm can sometimes lead to abdominal pain or pulsatile sensations. Symptomatic AAAs have a high risk of rupture. In the UK, elective surgery for AAAs is typically recommended if the aneurysm is larger than 5.5 cm in diameter or if it is larger than 4.5 cm in diameter and has increased in size by more than 0.5 cm in the past six months.

The NICE guidelines for suspected deep vein thrombosis (DVT) suggest considering the possibility of DVT if typical symptoms and signs are present, particularly if the person has risk factors like previous venous thromboembolism and immobility.

Typical signs and symptoms of DVT include unilateral localized pain (often throbbing) that occurs during walking or bearing weight, as well as calf swelling (or, less commonly, swelling of the entire leg). Other signs to look out for are tenderness, skin changes such as edema, redness, and warmth, and vein distension.

To rule out other potential causes for the symptoms and signs, it is important to conduct a physical examination and review the person’s general medical history.

When assessing leg and thigh swelling, it is recommended to measure the circumference of the leg 10 cm below the tibial tuberosity and compare it with the unaffected leg. A difference of more than 3 cm between the two legs increases the likelihood of DVT.

Additionally, it is important to check for edema and dilated collateral superficial veins on the affected side.

To assess the likelihood of DVT and guide further management, the two-level DVT Wells score can be used.

For more information, you can refer to the NICE Clinical Knowledge Summary on deep vein thrombosis.

Patients with active cancer and a confirmed deep-vein thrombosis (DVT) should be considered for treatment with a direct oral anticoagulant (DOAC) such as apixaban. If a DOAC is not suitable for the patient, alternative options should be offered. One option is the use of low-molecular-weight heparin (LMWH) alone. Another option is the combination of LMWH and a vitamin K antagonist (VKA) like warfarin, which should be given for at least 5 days or until the international normalized ratio (INR) reaches at least 2.0 on 2 consecutive readings. After achieving the desired INR, the patient can continue with a VKA alone. It is important to note that anticoagulation treatment should be offered for a period of 3-6 months. to the NICE guidance on the diagnosis and management of venous thromboembolism.

When managing a first episode of acute venous thromboembolism (VTE), it is recommended to start warfarin in combination with a parenteral anticoagulant, such as unfractionated heparin, low-molecular-weight heparin, or fondaparinux. The parental anticoagulant should be continued for a minimum of 5 days and ideally until the international normalized ratio (INR) is above 2 for at least 24 hours.

To prevent the extension of the blood clot and recurrence in calf deep vein thrombosis (DVT), at least 6 weeks of anticoagulant therapy is necessary. For proximal DVT, a minimum of 3 months of anticoagulant therapy is required.

For first episodes of VTE, the ideal target INR is 2.5. However, in cases where patients experience recurrent VTE while being anticoagulated within the therapeutic range, the target INR should be increased to 3.5.

The World Health Organisation Research into Global Hazards of Travel (Wright) Project found that the main factor contributing to deep venous thrombosis is being immobile, and the risk of developing a blood clot is higher when traveling for more than 4 hours. According to the Wright Study, the absolute risk of experiencing deep venous thrombosis during flights lasting over 4 hours was found to be one in 4656. For more information on this topic, you can refer to the guidance provided by the Civil Aviation Authority for medical professionals.

The current guidelines from NICE recommend that the first-line treatment for confirmed deep-vein thrombosis (DVT) or pulmonary embolus (PE) should be either apixaban or rivaroxaban, which are direct oral anticoagulants.

If neither of these options is suitable, the following alternatives should be considered:

1. LMWH (low molecular weight heparin) should be administered for at least 5 days, followed by dabigatran or edoxaban.

2. LMWH should be combined with a vitamin K antagonist (VKA), such as warfarin, for at least 5 days or until the international normalized ratio (INR) reaches at least 2.0 on 2 consecutive readings. Afterward, the VKA can be continued alone.

The NICE guidelines for suspected deep vein thrombosis (DVT) suggest considering the possibility of DVT if typical symptoms and signs are present, particularly if the person has risk factors like previous venous thromboembolism and immobility.

Typical signs and symptoms of DVT include unilateral localized pain (often throbbing) that occurs during walking or bearing weight, as well as calf swelling (or, less commonly, swelling of the entire leg). Other signs to look out for are tenderness, skin changes such as edema, redness, and warmth, and vein distension.

To rule out other potential causes for the symptoms and signs, it is important to conduct a physical examination and review the person’s general medical history.

When assessing leg and thigh swelling, it is recommended to measure the circumference of the leg 10 cm below the tibial tuberosity and compare it with the unaffected leg. A difference of more than 3 cm between the two legs increases the likelihood of DVT.

Additionally, it is important to check for edema and dilated collateral superficial veins on the affected side.

To assess the likelihood of DVT and guide further management, the two-level DVT Wells score can be used.

For more information, you can refer to the NICE Clinical Knowledge Summary on deep vein thrombosis.

An abdominal aortic aneurysm (AAA) is a localized or diffuse enlargement of the abdominal aorta, reaching 1.5 times its normal diameter. The majority of AAAs are found between the diaphragm and the aortic bifurcation. They can be classified as suprarenal, pararenal, or infrarenal, depending on which arteries are involved. About 85% of AAAs are infrarenal, with a normal diameter of 1.7 cm in men and 1.5 cm in women over 50 years old. An infrarenal aorta larger than 3 cm is considered an aneurysm. Risk factors for AAA development include age (most common in those over 65), male gender, smoking, hypertension, history of peripheral vascular disease, positive family history, and connective tissue disorders.

Most AAAs are asymptomatic, but an expanding aneurysm can cause pain or pulsatile sensations in the abdomen. Symptomatic aneurysms have a high risk of rupture. In the UK, elective surgery for AAAs is recommended if the aneurysm is larger than 5.5 cm or larger than 4.5 cm with a growth of more than 0.5 cm in the past six months.

Imaging modalities used to assess AAAs include ultrasound (best for unstable patients), CT scan with contrast (best for uncertain diagnosis), and MRI scan (suitable for stable patients in an elective setting). The most significant complication of AAA is rupture, which can result in sudden death. Only around 50% of patients with a ruptured AAA survive long enough to receive treatment. Common clinical features of a ruptured AAA include acute severe abdominal pain, flank pain (with pararenal AAAs), back pain (with more distal AAAs), unexplained syncope, and a pulsatile abdominal mass. Other less common complications include aortic branch involvement causing ischemia, distal embolization, rhabdomyolysis, and bacterial infection.

The current guidelines from NICE recommend that the first-line treatment for confirmed deep-vein thrombosis (DVT) or pulmonary embolism (PE) should be either apixaban or rivaroxaban, which are direct oral anticoagulants.

If neither of these options is suitable, the following alternatives should be considered:

1. LMWH (low molecular weight heparin) should be administered for at least 5 days, followed by dabigatran or edoxaban.

2. LMWH should be combined with a vitamin K antagonist (VKA), such as warfarin, for at least 5 days or until the international normalized ratio (INR) reaches at least 2.0 on 2 consecutive readings. Afterward, the VKA can be continued alone.

Acute limb ischaemia refers to a sudden reduction in blood flow to a limb, which puts the limb at risk of tissue death. This condition is most commonly caused by either a sudden blockage of a previously partially blocked artery by a blood clot or by an embolus that travels from another part of the body. Acute limb ischaemia is considered a medical emergency, and if not promptly treated with surgery to restore blood flow, it can lead to extensive tissue damage within six hours.

The classic signs of acute limb ischaemia are often described using the 6 Ps:
– Pain that is constant and persistent
– Absence of pulses in the ankle
– Pallor, cyanosis, or mottling of the skin
– Loss of power or paralysis in the affected limb
– Paraesthesia or reduced sensation, leading to numbness
– Feeling cold in the affected limb

It is important to be able to distinguish between ischaemia caused by a blood clot and ischaemia caused by an embolus. The following highlights the main differences:
Embolus Thrombus
– Onset is sudden, occurring within seconds to minutes – Onset is gradual, taking hours to days
– Ischaemia is usually severe due to the lack of collateral circulation – Ischaemia is less severe due to the presence of collateral circulation
– There is typically no history of claudication, and pulses may still be present in the other leg – There is often a history of claudication, and pulses may also be absent in the other leg
– Skin changes, such as marbling, may be visible in the feet. This can appear as a fine reticular blanching or mottling in the early stages, progressing to coarse, fixed mottling
– Skin changes are usually absent in cases of thrombus-induced ischaemia.