Although stroke is known as the “silent killer,” there are some things you can do to reduce your risk and even prevent strokes before they happen. Thomas Madaelil, MD, a neurointerventional surgeon on the medical staff at Baylor Scott & White Medical Center – Plano, tells us how.
Ischemic strokes (aka the most common type)
Most common causes
The most common type of stroke, accounting for nearly 85% of all strokes, is known as ischemic stroke. This type of stroke happens when a clot blocks blood flow to the brain. There are five main causes of acute ischemic stroke, which you can remember using the menmonic: CAUSE
- C stands for cardioembolic, which means from your heart. Atrial fibrillation, or an irregular heartbeat, is often closely linked to stroke.
- A is for atherosclerotic large vessel disease, which occurs when cholesterol builds up in the big arteries that go to your head, neck and eventually, your brain.
- U stands for undetermined etiology or cryptogenic, both fancy ways of saying “We don’t know what caused it.” Dr. Madaelil said that if physicians can’t determine the cause of an ischemic stroke, a patient will get a thorough multidisciplinary workup with neurologists and cardiologists that involves imaging, a cardiac workup, and sometimes placement of a Holter monitor, which you wear for several days to evaluate for cardiac abnormalities.
- S is small vessel disease, which means that tiny blood vessels in your brain get blocked off from a microvascular perspective.
- E is basically everything else.
Biggest risk factors
Dr. Madaelil said that the main risk factors for ischemic stroke are all the things your primary care doctor typically screens for:
- High blood pressure
- High cholesterol
“These are the things that really can increase the risk for an ischemic stroke in the same way that they do for cardiovascular disease,” he said. “The heart and brain are closely connected, so if you’ve had an artery problem in your heart, then chances are you also have an artery problem somewhere in your brain or you could be at risk for it.”
Preventing ischemic strokes
Thanks to improvements in medications that help manage and minimize the main risk factors for ischemic stroke, people are better able to keep their cholesterol, blood pressure and blood sugar under control. Those actions help reduce stroke risk significantly.
If a patient does present with a blockage in the carotid artery, which goes through the neck, they may be a candidate for a surgical procedure called a carotid endarterectomy to open the artery and remove the plaque. Another interventional option for select patients is an endovascular procedure to place a carotid artery stent, which basically props the artery open and remodels the blood vessel.
Although cardiologists frequently put stents in narrowed arteries in the heart, the vessels in the brain are much more delicate.
“The things you can do to the arteries in the heart can be really aggressive,” Dr.Madaelil said. “But the arteries in the brain have a lot of perforators that come off the arteries, and if you put stents and balloons in them, you can actually cause strokes.”
Most common causes
Hemorrhagic strokes, or bleeding strokes, can occur in the brain itself (intracerebral) or in the space around the brain (subarachnoid hemorrhage). Intracerebral hemorrhages account for about 75% of bleeding strokes. The other 25% of hemorrhagic strokes—or about 5% of all strokes—are caused by a subarachnoid hemorrhage.
The no. 1 cause of intracerebral hemorrhage is hypertension, or high blood pressure.
“These usually happen when people haven’t been seen by a doctor for a long period of time,” Dr. Madaelil said. “That’s why we call high blood pressure a silent killer. You don’t know about it until it hurts you and usually it’s when you have a hypertensive related intracerebral hemorrhage.”
The most common cause of subarachnoid hemorrhage is a ruptured brain aneurysm, or a spontaneous, non-traumatic hemorrhage not related to hitting your head.
Biggest risk factors
Dr. Madaelil said that unruptured aneurysms are relatively common.
“There are about 10 to 12 million Americans walking around with an intracranial aneurysm, and most of them don’t know about it,” he said. “The good news is that 50 to 80% of them are so small, and they don’t rupture in a patient’s lifetime.”
The biggest contributing risk factors for hemorrhagic stroke include:
- Family history
- Tobacco use
- High blood pressure
- Age also can play a role in risk. A 75-year-old with no other risk factors will have a slightly increased risk of having an aneurysm rupture than a younger person
But the no. 1 indicator of whether an aneurysm will rupture is size.
“The larger the aneurysm, the bigger the problem,” Dr. Madaelil said.
Preventing hemorrhagic strokes
For patients with unruptured aneurysm—especially those 7 mm and larger—there are several options for preventing a rupture and the resulting stroke.
“I tell patients that an aneurysm is like a pothole on the road and the road is the artery in the brain,” Dr. Madaelil said. “One day, the pothole becomes a sinkhole, and the whole road collapses. And when that happens, you have bleeding in the brain.”
To fix the “pothole” before it becomes a sinkhole, you should get specialized care from a neurointerventionalist.
Often, people will discover they have an unruptured aneurysm when they experience “the worst headache of their lives.” If you have a severe sudden-onset headache or a family history of aneurysms, it’s essential that you are screened appropriately.
“When patients first get this diagnosis, it’s important for them to get plugged in to the right doctors who specifically focus on patients with a history of unruptured aneurysms,” Dr. Madaelil said. “We see them longitudinally and follow up with imaging and risk stratification. We can show patients images of their brain and really spend time with them to help allay any fears.”
There are many endovascular or minimally invasive techniques to treat aneurysms. Treatment for ruptured and unruptured aneurysms usually involves three options:
- Observation or no treatment. This can either be in cases where a ruptured aneurysm has already caused severe damage to the brain and treatment would not be helpful, or if an older patient has a smaller unruptured aneurysm that isn’t causing any problems.
- Open surgical clipping. Thanks to neurointerventional advances, this procedure (which involves opening the cranium to access and fix the aneurysm), isn’t as common as it used to be.
- Minimally invasive aneurysm embolization. Dr. Madaelil estimates that today, 90-95% of aneurysms can be treated endovascularly, or through the artery, which means no cutting open the cranium. This results in a much easier recovery.
Patients with ruptured or unruptured aneurysms should choose a Comprehensive Stroke Center, like Baylor Scott & White Medical Center – Plano, Baylor University Medical Center or Baylor Scott & White Medical Center – Temple. Comprehensive Stroke Centers have a multidisciplinary team that includes neurologists, neurosurgeons and neurointerventionalists who can provide advanced care for all stroke patients, both hemorrhagic and ischemic.