Risk assessment for Venous ThromboEmbolism (VTE)

Venous thrombosis is a potentially life-threatening, but reversible pathological process. It can progress to thromboembolism, usually producing a pulmonary embolism. The risk of VTE is higher amongst certain patients, but the risk can be modified with pharmacological.

All patients should be risk assessed on admission to hospital. Patients should be reassessed within 24 hours of admission and whenever the clinical situation changes.

Patients who may require intervention include:

• All surgical patients
• Medical patients expected to have ongoing reduced mobility relative to normal state.

 

Factors which increase risk of thrombosis (may indicate anticoagulation)

• Active cancer or cancer treatment 
• Age > 60
• Dehydration
• Known thrombophilias
• Obesity (BMI > 30 kg/m2)
• Significant medical comorbidities
• Personal history or first-degree relative with a history of VTE
• Use of hormone replacement therapy
• Use of oestrogen-containing contraceptive therapy
• Varicose veins with phlebitis
• Pregnancy or < 6 weeks post-partum
• Significantly reduced mobility for 3 days or more
• Hip or knee replacement
• Hip fracture
• Total anaesthetic + surgical time > 90 minutes
• Surgery involving pelvis or lower limb with a total anaesthetic + surgical time > 60 minutes
• Acute surgical admission with inflammatory or intra-abdominal condition
• Critical care admission
• Surgery with significant reduction in mobility

 

Factors which increase bleeding risk (may contraindicate anticoagulation)

• Active bleeding
• Acquired bleeding disorders (such as acute liver failure)
• Concurrent use of anticoagulants known to increase the bleeding risk
• Acute stroke
• Thrombocytopoenia
• Uncontrolled systolic hypertension
• Untreated inherited bleeding disorders
• Neurosurgery, spinal surgery, or eye surgery
• Other procedure with high bleeding risk
• Lumbar puncture/epidural/spinal anaesthesia expected within the next 12 hours
• Lumbar puncture/epidural/spinal anaesthesia within the previous 4 hours

 

Example of an assessment form

References

1. National Institute for Health and Clinical Excellence (2010) Venous thromboembolism: reducing the risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) in patients admitted to hospital. NICE clinical guideline 92. London: National Institute for Health and Clinical Excellence.

Statins

Key examples

• Simvastatin
• Atorvastatin
• Pravastatin
• Rosuvastatin

 

Common indications

1. Primary prevention of cardiovascular disease: to prevent cardiovascular events in people over 40 years of age with a 10-year cardiovascular risk >20.
2. Secondary prevention of cardiovascular disease: first line alongside lifestyle changes, to prevent further cardiovascular events in those who already have evidence of cardiovascular disease.
3. Primary hyperlipidaemia: first line, in conditions such as primary hypercholesterolaemia, mixed dyslipidaemia and familial hypercholesterolaemia.

 

Mechanisms of action

• Statins reduce serum cholesterol levels. They inhibit 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG CoA) reductase, an enzyme involved in making cholesterol. They decrease cholesterol production by the liver and increase clearance of LDL-cholesterol from the blood, reducing LDL-cholesterol levels. 
• They also indirectly reduce triglycerides and slightly increase HDL-cholesterol levels. Through these effects they slow the atherosclerotic process and may even reverse it.

 

Important adverse effects

• Statins are generally safe and well tolerated. The most common adverse effects are headache and gastrointestinal disturbances. Potentially more serious are their effects on muscle. These can range from simple aches to more serious myopathy or, rarely, rhabdomyolysis. They can also cause a rise in liver enzymes (e.g. alanine transaminase [ALT]); drug-induced hepatitis is a rare but serious adverse effect.

 

Warnings

• Statins should be used with caution in patients with existing hepatic impairment. They are excreted by the kidneys, so the dose should be reduced in people with renal impairment. You should avoid prescribing statins to women who are pregnant (cholesterol is essential for normal fetal development) or breastfeeding.

 

Important interactions

• The metabolism of statins is reduced by cytochrome P450 inhibitors, such as amiodarone, diltiazem, itraconazole, macrolides and protease inhibitors. This leads to accumulation of the statin in the body, which may put patients at increased risk of adverse effects. Amlodipine has a similar interaction although the mechanism is less clear. 
• To reduce this risk you may need to reduce the dose of the statin or, if the other drug is being used for a short period only (e.g. a course of clarithromycin therapy), withhold the statin.