Dr Kevin McCarroll
Medical Matters
Speed is of the essence when faced with a stroke. The latest figures for life expectancy in Ireland have once again improved with the average age of death for males now at 79.9 years and females 83.6 years. This puts life expectancy for males here at higher than the EU average and on par with that for females.
Indeed, overall mortality has reduced by 14.9% since 2008 though the rate of improvement is slowing as in many other countries. However, life expectancy in the UK has levelled off and fallen in some areas and in the US there has been a downward trend which appears to be partly explained by higher rates of drug overdose.
Significant improvements in cancer and cardiac care and management of strokes has been a big driver in the reduction in mortality. There are about 8,000 strokes every year in Ireland that occur at the average age of 74 though importantly about 30% affect those under 65.
While stroke can lead to severe disability and is the third leading cause of death in Ireland, a significant proportion of stroke survivors continue to lead active lives .
Clot
About 85% of strokes occur when a clot blocks off an artery in the brain cutting off blood supply and thereby causing brain damage. The remaining 15% result from a haemorrhage into brain tissue when a blood vessel ruptures .
The extent of disability after a stroke varies hugely depending on its location and size. Some strokes are quite small and recovery can be quick within days.
Some of the biggest risk factors for stroke are high blood pressure, smoking, diabetes and high cholesterol which all cause the build-up of plaque on the arteries supplying blood either to or within the brain. As well as causing narrowing of these vessels, they can become acutely blocked when a plaque ruptures leading to a clot forming, so it is important to keep a close eye on your blood pressure and cholesterol and avoid smoking. Watch out too for your alcohol intake, as in excess it is also a risk factor for haemorrhagic strokes.
Another very important cause, which accounts for about a third of all strokes is atrial fibrillation (a type of irregular heart beat). This causes clots to form in the heart which can embolise and block arteries in the neck or brain. Atrial fibrillation occurs in about10% of those aged over 65 and can also happen intermittently.
Indeed, many are not aware of having it yet treatment with blood thinning medications can reduce the risk of stroke by about 70%. For a long time warfarin was the main drug used, but there are now several newer medications which are equally as effective but have a more predictable response and need less monitoring.
Most importantly, if you ever get symptoms or signs suggestive of a stroke then you should go immediately to the hospital. This may include facial droop, weakness in the arms or legs, poor balance, co-ordination and altered speech or vision. The FAST campaign based on F: face droop, A: arm weakness, S: speech disturbance, T: time to call ambulance significantly increased stroke awareness and early presentation to hospital. Crucially, early interventions in acute stroke can make a huge difference.
Clot busting drugs can be delivered in the hospital (thrombolysis) within 4.5 hours of having stroke signs or symptoms provided certain other criteria are met. It can result in an improvement in about 35% of patients. In some cases, its benefits are so great that in its early days of use it was described as the ‘Lazarus effect’.
Last year about 11% of strokes that presented to hospital in Ireland received clot-busting drugs. But time is of the essence, as every minute millions of brain cells are dying so it is vitally important to get to the hospital as early as possible.
CT brain imaging can also identify larger clots in bigger vessels that will not dissolve with medications.These may account for up to 20% of all stroke cases but may be amenable to a mechanical procedure to remove the clot (thrombectomy). This can double the rate of recovery to independent living and half the risk of death.
In fact, many patients who would have otherwise had very disabling strokes have been left with minimal deficits after thrombectomy. Ireland now ranks above the EU average in terms of its thrombectomy rate with over 250 cases being performed last year. There are two centres offering this service which is available in Dublin on a 24-hour basis (accounts for about 85% of all cases) and in Cork during defined hours on week days.
Whilst thrombectomy can be performed in selected cases up to 12 hours and beyond after stroke onset, the benefit diminishes significantly with time. In fact, for every minute you save in removing a clot, you gain a week of healthy living post stroke.
In summary, there’s a lot can be done for stroke. Make sure to address the important risk factors and get to hospital quickly if you ever get stroke symptoms!
Dr Kevin McCarroll is a Consultant Physician in Geriatric Medicine, St James’s Hospital, Dublin.