Mechanical Thrombectomy

Most strokes are ischaemic: a clot blocks an artery and the part of the brain it supplies starts to die from lack of oxygen. When the blocked vessel is a large one, such as the internal carotid artery, the main trunk of the middle cerebral artery or the basilar artery, clot-dissolving medicine given into a vein often cannot clear it alone. Mechanical thrombectomy removes the clot physically. Under X-ray guidance, a catheter is passed from an artery in the groin or wrist to the neck, and a finer microcatheter is steered through and beyond the clot. Then either a stent retriever, a small self-expanding mesh tube that grips the clot, is pulled back into the catheter, or a wide aspiration catheter sucks the clot out, and the two methods are often combined. Once the artery is open, blood returns to the brain tissue that is still alive. Thrombectomy is often given together with clot-dissolving medicine, called thrombolysis, when a patient is eligible for both.

Thrombectomy is recommended for adults with an acute ischaemic stroke caused by a blockage in a large artery, confirmed on CT angiography or MR angiography, who arrive within a suitable time window. For most patients, treatment is offered within about 6 hours of the onset of symptoms or of the time the person was last seen well. Selected patients can benefit up to 24 hours after onset when advanced imaging shows that a substantial area of brain is still salvageable. The stroke team also considers how severe the symptoms are, the extent of damage already visible on the scan and the patient's level of independence before the stroke. The classic warning signs follow the word FAST: face drooping, arm weakness, speech difficulty and time to call emergency services. Sudden loss of vision, severe dizziness or loss of balance can also signal a stroke. Because the treatment is only available in centres with a round-the-clock interventional team, patients are sometimes transferred urgently between hospitals.

When a large vessel blockage is confirmed, the patient is taken straight to the angiography suite. The procedure may be done under local anaesthesia with sedation, which can save time, or under general anaesthesia when the patient is agitated, cannot protect their airway or needs to stay completely still. A sheath is placed in the artery at the top of the leg or at the wrist, and a guiding catheter is advanced to the neck. Contrast dye shows the exact position of the blockage. A microcatheter is passed across the clot, and a stent retriever is opened inside it, left for a few minutes to grip the clot and then withdrawn, often while suction is applied, or an aspiration catheter is pushed up against the clot to draw it out. Several passes may be needed. Each step is checked with fresh images until flow is restored. In some patients a narrowing in the neck artery is treated with a stent at the same time. The whole procedure often takes about 1 to 2 hours.

Unlike planned procedures, there is little time for preparation. In the emergency department, the stroke team checks blood sugar and blood pressure, performs a CT or MRI scan with imaging of the arteries and, if appropriate, starts clot-dissolving medicine while the angiography suite is prepared. The main factors that decide whether thrombectomy is offered are a confirmed large vessel blockage, the time since onset, the amount of brain still salvageable on imaging and the person's condition before the stroke. Families can help greatly by telling the team the exact time the person was last seen well, their usual medicines, especially blood thinners, and any previous illnesses. For international travellers, carrying a list of medicines and diagnoses, and having travel insurance details and an emergency contact to hand, saves time. Planned travel for care becomes relevant later, for secondary prevention, investigation of the cause of the stroke and rehabilitation.

After thrombectomy, patients are monitored closely in a stroke unit or intensive care for at least the first day, with checks of neurological function, blood pressure and the puncture site. A repeat scan looks for bleeding before blood-thinning treatment is started or adjusted. The cause of the stroke is investigated, for example an irregular heart rhythm or a narrowed neck artery, and prevention is tailored to it. If a stroke happens while you are travelling, treatment comes first at the nearest capable hospital; the journey home is planned only once the team confirms the condition is stable, often after at least one to two weeks, and sometimes with a medical escort arranged through travel insurance. Many people and families then look further for structured neurological rehabilitation, a specialist review of the cause and prevention plan, or follow-up imaging, and this is where planned treatment abroad can help, with full records and images shared between teams.

For eligible patients, large clinical trials have shown that thrombectomy gives many more people a chance of recovering independence than medicine alone, which is why it is a standard treatment for large vessel strokes. It still carries risks. The most serious is bleeding into the brain, which can happen as blood returns to damaged tissue, especially when clot-dissolving medicine has also been given. Other risks include injury to the artery wall, fragments of clot travelling to a new branch, bleeding or bruising at the puncture site, a reaction to contrast dye and, in some patients, failure to reopen the artery fully. The outcome depends mainly on how much brain was already damaged before the artery was reopened, the size and location of the stroke, the person's age and health, and the speed of treatment. Some people recover almost completely, while others are left with weakness, speech or memory problems that improve with rehabilitation over months.