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The Three-Part Series on Stroke (III)
According to medical literature, most strokes are caused by congenital or acquired structural abnormalities in the brain or neck blood vessels. A smaller proportion of strokes are attributed to blood or cardiac conditions. In the previous article, we discussed the prevention of strokes caused by congenital cerebrovascular abnormalities. This article focuses on preventing strokes resulting from acquired cerebrovascular abnormalities.
Cerebrovascular Degeneration as the Leading Cause of Acquired Abnormalities
There are many causes of acquired cerebrovascular abnormalities, most of which are related to the degeneration of blood vessel structures in the brain. Based on clinical experience, strokes caused by acquired vascular abnormalities can occur in individuals as young as 28 years old, dispelling the misconception that strokes are exclusive to middle-aged or older individuals. Factors such as obesity, high cholesterol, high blood pressure, high blood sugar (the "three highs"), and smoking accelerate vascular degeneration. While these factors may have genetic links, many stroke patients do not have a family history of the condition. Notably, some couples have experienced strokes within a few years of each other, likely due to shared dietary habits over time.
Many stroke patients have normal cholesterol levels in their blood tests, highlighting that blood tests alone cannot fully assess vascular health. Cholesterol, like the oil in a bowl of soup, adheres to vessel walls rather than circulating freely in the bloodstream. This buildup leads to vascular narrowing, occlusion, and ischemic stroke. Additionally, cholesterol weakens the vascular wall, increasing the risk of aneurysms and haemorrhagic strokes. The human body, much like a car, requires routine maintenance to ensure optimal functioning and prevent accidents. Blood tests alone, akin to testing a car's fuel, cannot reflect the wear and tear or safety of internal components. Therefore, a comprehensive assessment using three-dimensional (3D) cerebrovascular imaging is crucial. Regular screening with 3D imaging allows neurosurgeons to detect congenital or acquired abnormalities before symptoms appear, enabling timely intervention to mitigate future stroke risks.
Case Study 1: A 39-Year-Old Healthy Female
Miss Wong, a 39-year-old with a history of good health, underwent annual health check-ups that consistently returned normal results. After learning about a friend's death from haemorrhagic stroke, she sought advice from a neurosurgeon to proactively mitigate her stroke risk. Despite having no symptoms of headaches or dizziness, normal blood pressure, and no family history of strokes, she wanted reassurance about her health. The neurosurgeon recommended magnetic resonance imaging (MRI) with 3D cerebrovascular imaging. The results revealed a 1–2 mm aneurysm in the ICA artery on the right side of her brain.
According to medical literature and clinical experience, even small aneurysms carry a 1–2% annual risk of rupture, potentially causing life-threatening subarachnoid haemorrhages. Over the next 50 years, Miss Wong faced a cumulative rupture risk of 50–100%. After consulting her family, she opted for a minimally invasive endovascular stent placement. Neurosurgeons used a puncture through her thigh to insert a 3D-guided flow diversion stent, reinforcing the artery and redirecting blood flow away from the aneurysm, effectively preventing a future haemorrhagic stroke.
Miss Wong’s cerebral "ticking time bomb" was defused, altering her fate and preventing the potential occurrence of a future haemorrhagic stroke.
Case Study 2: A 52-Year-Old Athlete
Mr Ho, a 52-year-old athlete with a healthy lifestyle—non-smoker, non-drinker, and balanced diet—consulted a neurosurgeon for sciatica. In addition to an MRI for lumbar nerves, the neurosurgeon recommended a 3D cerebrovascular imaging scan for stroke screening. The lumbar MRI revealed a mild disc herniation causing the sciatica, manageable with medication, physiotherapy, or chiropractic care. However, the cerebrovascular scan detected a 4 mm aneurysm at the bifurcation of the middle cerebral artery. The annual rupture risk of this aneurysm was 1–2%, translating to a cumulative risk of 30–60% over the next 30 years.
The neurosurgeon advised preventive surgical intervention. Due to the aneurysm's location, a minimally invasive stent posed a risk of occluding normal branch vessels. Thus, an open craniotomy with microsurgical clipping was recommended. During the 3–4-hour procedure, the neurosurgeon carefully isolated the aneurysm under a microscope and secured it with a titanium clip, effectively eliminating the risk of rupture (see below). Mr Ho was discharged the following day and continued conservative treatment for sciatica.
Relying solely on exercise, healthy eating, abstinence from smoking and alcohol, and regular blood tests or electrocardiograms can slow but not entirely prevent cerebrovascular degeneration. Even individuals with an active and healthy lifestyle, like Mr Ho, are not immune to stroke risks. Comprehensive assessments, including advanced imaging techniques, are essential for early detection and prevention of potentially life-threatening cerebrovascular events.