When the brain is starved of oxygen, cell, and tissue damage begins to happen in a matter of minutes. It is, however, possible to reverse the damage to some extent or in full, with the help of mechanical thrombectomy.
Put simply, mechanical thrombectomy looks to treat brain stroke by dispelling the clot that causes the clogging of the arteries carrying blood to the brain.
In clinical terms, mechanical thrombectomy serves to treat patients of acute ischemic stroke i.e. brain stroke victims whose brain suffers from lack of blood flow.
Blood vessels to the brain may narrow down naturally over time due to the deposit of fats or plaque. This is why patients who have levels of cholesterol are supposed to get themselves screened regularly for clogs. This build-up, referred to as a clot, can clog the blood vessels in part or in full, reducing the normal blood flow to a trickle or blocking blood flow entirely. Imaging such as CT or MRI scan can help estimate the blockade so that a doctor can recommend whether the patient can use mechanical thrombectomy as a recourse for treatment.
Mechanical thrombectomy has to be carried out within 6 hours of the last known normal some cases up to 24 hours. This process proposes recanalization or re-opening and restoration of normal blood flow through the cranial arteries.
The factors working against mechanical thrombectomy are multi-fold:
- Logistical factors: Patients may not be aware of the brain stroke and the need for immediate treatment. The application of intra-arterial thrombectomy is required within the window of stroke. This window for treatment has been extended to a period of 24 hours from the last known normalcy – the condition of neurologic baseline readings.
- Another logistical factor is the availability of hospitals that are equipped to carry out mechanical thrombectomy. In sites where the resources and expertise required to conduct mechanical thrombectomy is not available, an intravenous intervention can be used as a stop-gap until the patient reaches a suitable facility.
Given the above constraints, and considering that not all ischemic stroke victims qualify for mechanical thrombectomy, the use of tPA is a recourse to be used – as a stop-gap or as an alternative. tPA stands for tissue plasminogen activator and is the only drug approved by the Food and Drug Administration agency of the United States Department of Health and Human Services.
Where tPA is ineffective, especially when the clot to be broken up is too large, Mechanical Thrombectomy is used in combination with a stent retriever.
The process involves introducing a catheter bearing a stent retriever into the site of the occlusion. X-ray powered imaging is carried out side-by-side so that the stent goes past the clot, expands, and retraces its path, bringing the clot out with it. This clears the path for the blood flow to resume.
The effects of mechanical thrombectomy are almost immediate in some cases and the patient can become mobile again. The patient will take 3 months to improve in the majority of the cases.