Dr Pradeep Rowji, neurologist based at Milpark Hospital in Johannesburg
When faced with the critical decision between thrombectomy and thrombolysis in the management of ischaemic stroke, it is essential to understand the personalised nature of these treatments. Each option offers distinct advantages, depending on the patient's unique anatomy, the characteristics of the clot, and the location of the occlusion.
One of the primary reasons to choose thrombectomy over thrombolysis lies in the ability to provide a highly personalised treatment. As experienced neuroradiologists emphasise, the approach can be tailored specifically to the patient's vascular anatomy, particularly in older patients who often present with abnormally deformed vasculature. This personalisation begins with the choice of access, whether right or left radial, depending on the patient's vessel architecture.
Thrombectomy allows for precision in navigating the sometimes-murky territory of the brain's vasculature. The goal is to precisely reach the occluded vessel and remove the clot causing the stroke. Early investigations guide the intervention, ensuring that the procedure is both efficient and effective. When the clot is successfully removed and blood flow is restored, the result is often described as perfection in stroke treatment.
Thrombectomy is particularly advantageous when dealing with large vessel occlusions, such as those involving the carotid arteries or the anterior circulation vessels. These occlusions can lead to anterior ischaemic strokes, where a significant portion of the brain's blood supply is compromised. In these cases, the decision between thrombectomy and thrombolysis becomes crucial.
Thrombectomy is often the preferred choice when faced with complex occlusions, such as those involving the internal carotid artery (ICA) and the middle cerebral artery (MCA). These occlusions can take on a T shape (involving the ICA, MCA, and anterior cerebral artery) or an L shape (involving the ICA and MCA).
The challenge with thrombolysis alone in these cases is that long segment thrombi, often measuring several centimetres, are resistant to lytic agents. While thrombolysis may work in rare cases with specific types of clots, it is generally less effective in these scenarios.
Thrombectomy is considered a game-changer in stroke treatment, especially when compared to thrombolysis. The success of mechanical thrombectomy is reflected in the number needed to treat (NNT), a key metric in medical treatment.
For thrombolysis, the NNT has historically been around eight, meaning that eight patients need to be treated for one to benefit. However, with advances in thrombectomy techniques and technology, the NNT has been reduced to as low as 2.8 in some cases. This means that nearly one in every three patients treated with thrombectomy will have a positive outcome, a figure unmatched by other interventions, including cardiac or trauma surgery.
The precision and effectiveness of thrombectomy in removing clots and restoring blood flow lead to better tissue perfusion and significantly improved outcomes for patients. This approach reduces the risk of partial vessel opening, a common issue with thrombolysis, which can lead to higher mortality rates at three months post-treatment.
The success of thrombectomy also hinges on the timely recognition and treatment of stroke. Time is brain, and the faster a patient receives treatment, the better the outcome. When a patient arrives at the hospital, the first step is to assess their NIHSS score, which helps determine the severity of the stroke and the urgency of intervention. Patients with a score above 15 typically require immediate thrombectomy, while those with lower scores may be monitored or treated differently.
Advanced imaging, including NCCT scans or more sophisticated techniques, plays a crucial role in guiding the decision-making process. In settings with limited resources, even basic imaging can be sufficient to identify candidates for thrombectomy.
Not Your Typical Stroke - Challenging Cases and Whether to Thrombolyse
Dr Naeem Brey, neurologist with special interests in clinical neurology, electrophysiology and neuro-immunology
Strokes represent a significant global health issue, with ~22 million cases occurring annually. Developing countries, such as South Africa and India, are particularly affected, and the increasing incidence of strokes among younger populations has necessitated a re-evaluation of how these cases are defined and managed. Traditionally, stroke care has focused on older populations, generally those ≥80-years. However, younger patients, often defined as those <55-years, are a growing concern.
In this context, Dr Brey presented a challenging case involving a 25-year-old woman who suffered a severe stroke 35 hours after giving birth. Safety in pregnancy and lactation has not been established with the alteplase. The patient had high blood pressure (BP) and exhibited severe stroke symptoms, including hemiparesis and dysarthria.
Initial imaging revealed extensive damage, and the case posed a significant dilemma regarding the use of thrombolysis - a treatment that can be risky due to the potential for bleeding, especially in postpartum women.
Despite the high risks associated with thrombolysis, including the potential for postpartum haemorrhage, Dr Brey and his team decided to proceed with the treatment. This decision was informed by a thorough review of existing literature and consultations with other stroke specialists.
The outcome was positive: Although the patient experienced mild bleeding, it resolved without further complications. Remarkably, her condition improved rapidly, and within five days, she was able to walk with minimal assistance and care for her newborn. By three months, she had made a complete recovery.
Current guidelines do suggest that thrombolysis may be appropriate within a four-and-a-half-hour window if the benefits outweigh the risks. Documented cases, such as the one presented by Dr Brey, generally show positive outcomes without a significant increase in bleeding risks.
Patient selection is crucial in stroke management. Factors such as age, comorbidities, BP, National Institutes of Health (NIH) Stroke Scale score, and imaging results should guide the decision-making process.
The advent of endovascular mechanical thrombectomy has also revolutionised stroke care, offering another treatment option that should not be withheld from pregnant patients. Studies have shown no significant difference in outcomes between pregnant and non-pregnant women, even though strokes during pregnancy tend to be more severe.
Dr Brey emphasised the importance of considering differential diagnoses in stroke-like presentations during pregnancy. Conditions such as Haemolysis, Elevated Liver Enzymes, Low Platelet Count, Posterior Reversible Encephalopathy, and Reversible Cerebral Vasoconstriction Syndromes can mimic stroke symptoms and must be ruled out.
These conditions can significantly influence treatment decisions and outcomes, particularly when considering thrombolysis in challenging situations.
The 2022 European Stroke Organization (ESO) guidelines are pivotal in navigating these complex decisions, even in scenarios lacking robust data. The ESO guidelines advocate for intravenous thrombolysis (IVT) and thrombectomy in eligible patients, even during atypical scenarios such as menstruation, pregnancy, and the postpartum period. They recommend considering these treatments even in menopausal patients, although the window for postpartum thrombolysis is generally limited to ten days.
In addition to the case of the young postpartum woman, Dr Brey also discussed a 94-year-old female patient with multiple comorbidities who presented with a high initial stroke score. Alteplase is not indicated for the therapy of acute stroke in children and adolescents <18-years or adults >80- years.
Despite significant improvement in her symptoms, her family chose not to proceed with thrombolysis due to the risks involved. The patient’s condition initially improved but later deteriorated due to sepsis, ultimately leading to her death.
This case underscores the complexities of decision-making in elderly patients, particularly those with multiple comorbidities. While initial improvements might suggest a favourable outcome, the risk of complications such as infection can drastically alter the prognosis.
The Third International Stroke Trial (2012), which expanded eligibility for thrombolysis to older patients, found that while mortality at seven days was higher for those treated with alteplase, long-term outcomes at six months were similar between treated and untreated groups.
More recent trials have confirmed that thrombolysis in patients >80-years offers significant benefits in terms of independence, with no increase in long-term mortality. The ESO guidelines support the use of IVT for patients >80-years, backed by strong evidence. Alteplase is not indicated for the therapy of acute stroke in children and adolescents <18-years or adults >80-years.
Thrombectomy also plays a crucial role in stroke management for older patients. American guidelines suggest that while thrombectomy can be beneficial in the elderly, selection criteria should be individualised. Data from the CT perfusion to Predict Response to Recanalization in Ischemic Stroke Project trial (2017) indicates that bleeding rates plateau >60-years, suggesting that age alone should not be a contraindication for thrombectomy.
Key messages
- Thrombectomy is a highly effective treatment for ischaemic stroke, particularly in cases involving large vessel occlusions. By physically removing the clot, thrombectomy rapidly restores blood flow to the brain, significantly improving outcomes. This procedure is especially beneficial when thrombolysis alone may be insufficient, offering a greater chance of recovery with fewer long-term disabilities. Thrombectomy's precision in targeting and removing the clot ensures that more patients experience positive outcomes, making it a critical intervention in modern stroke care.
- Stroke management must evolve to address the growing incidence of strokes among younger populations and the complexities of treating pregnant and elderly patients. Dr Brey’s case of a 25-year-old postpartum woman illustrates that thrombolysis, despite its risks, can lead to remarkable recovery when carefully considered. The 2022 ESO guidelines support thrombolysis and thrombectomy in diverse patient groups, including those with pregnancy-related strokes and older adults, highlighting the importance of tailored treatment strategies and thorough patient selection.
