A stroke occurs when the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. High blood pressure is a major risk factor for both ischemic and hemorrhagic stroke. However, what happens to blood pressure during an acute stroke event? Let’s take a closer look.
Blood Pressure During an Ischemic Stroke
An ischemic stroke accounts for about 87% of all strokes. It happens when a blood clot blocks an artery leading to the brain. During the early stages of an ischemic stroke, blood pressure often rises. This is the body’s natural response, as it tries to pump more blood to the affected area of the brain.
Some key points about blood pressure and ischemic stroke:
- Blood pressure can go up by as much as 22/12 mm Hg in the first 48 hours after an ischemic stroke.
- About 75% of people have high blood pressure in the acute phase of an ischemic stroke.
- The rise in blood pressure is usually temporary, going back down within 7 days after the stroke.
The initial spike in blood pressure serves to maintain blood flow to the threatened tissue. However, an extremely high blood pressure (e.g., above 220/120 mm Hg) can be dangerous, leading to further damage and bleeding in the brain.
That said, medications are not typically given to lower blood pressure during an acute ischemic stroke (except in cases of very high BP). Research has shown that rapidly lowering blood pressure can actually decrease blood flow to the brain, potentially worsening the effects of the stroke.
Blood Pressure During Hemorrhagic Stroke
A hemorrhagic stroke accounts for about 13% of strokes. It occurs when a weakened blood vessel ruptures and bleeds into the surrounding brain. The main types are intracerebral hemorrhage (bleeding within the brain tissue) and subarachnoid hemorrhage (bleeding into the space surrounding the brain).
In contrast to ischemic stroke, blood pressure tends to be higher before a hemorrhagic stroke. Over time, uncontrolled high blood pressure can damage the smaller arteries and make them prone to rupture. Some key points about blood pressure and hemorrhagic stroke:
- Having high blood pressure is the most important risk factor for hemorrhagic stroke.
- Systolic blood pressure is usually >160 mm Hg before a hemorrhagic stroke occurs.
- The initial bleeding causes BP to rise even further due to increased pressure within the brain.
During the acute phase of a hemorrhagic stroke, the systolic blood pressure is often >200 mm Hg. This extremely high pressure can cause continued bleeding or re-bleeding. As a result, medications are used to lower blood pressure to a safer level (e.g., <140/90 mm Hg).
How High Blood Pressure Contributes to Stroke
High blood pressure, also known as hypertension, is the most significant risk factor for all types of stroke. Here’s an overview of how chronic high blood pressure affects the brain and contributes to stroke:
- Causes wear and tear on blood vessel walls. Higher pressure damages the lining of arteries over time.
- Leads to atherosclerosis. High BP accelerates the buildup of fatty deposits and plaque inside blood vessel walls.
- Increases risk of blood clots. The damaged and narrowed blood vessels are more likely to obstruct blood flow.
- Weakens blood vessels in the brain. Makes them more prone to bursting and causing hemorrhagic stroke.
- Reduces blood flow to the brain. Even before a stroke, elevated BP decreases circulation of oxygen and nutrients.
According to the American Heart Association, high blood pressure is linked to nearly 75-80% of all strokes. That’s why controlling hypertension is crucial for preventing strokes.
Normal Blood Pressure Range
Normal blood pressure is defined as a reading of less than 120/80 mm Hg. The top number (systolic pressure) reflects the pressure in arteries when the heart contracts. The bottom number (diastolic pressure) is the pressure when the heart relaxes between beats.
Blood Pressure Classifications
Here is a table summarizing the various categories of blood pressure readings:
| Blood Pressure Category | Systolic (mm Hg) | Diastolic (mm Hg) |
|---|---|---|
| Normal | Less than 120 | And less than 80 |
| Elevated | 120-129 | And less than 80 |
| Stage 1 Hypertension | 130-139 | Or 80-89 |
| Stage 2 Hypertension | 140 or higher | Or 90 or higher |
| Hypertensive Crisis | Higher than 180 | And/or higher than 120 |
Blood pressure between 120-129/80 is considered elevated. Readings of 130/80 or above are classified as hypertension, which is divided into Stage 1 and more severe Stage 2. A hypertensive crisis occurs when systolic BP is over 180 or diastolic is over 120.
Ideal Blood Pressure Goals
For individuals who have already had a stroke or transient ischemic attack (TIA), stricter blood pressure control is recommended. This helps reduce the risk of recurrent stroke.
Blood Pressure Goals After Stroke
| Population | Recommended BP Goal |
|---|---|
| Prior stroke or TIA | Less than 130/80 mm Hg |
| No history of stroke | Less than 140/90 mm Hg |
For those with a history of stroke or mini-stroke, getting the blood pressure down to 130/80 or below is ideal. Lifestyle changes like diet, exercise, and stress management can help lower BP, along with medication if needed.
Reaching an optimal blood pressure helps reduce the chances of a future stroke. It also decreases risk of other complications like heart attack, kidney failure, and dementia.
Medications to Lower Blood Pressure After Stroke
Several types of medications are used to control high blood pressure and prevent recurrent stroke. Common options include:
- Diuretics – Help flush excess sodium and fluid from the body. Examples are chlorthalidone and hydrochlorothiazide.
- ACE inhibitors – Block effects of angiotensin, a chemical that narrows blood vessels. Examples are lisinopril, ramipril, and enalapril.
- ARBs – Block angiotensin receptors directly. Examples are losartan, valsartan, and candesartan.
- Beta blockers – Reduce heart rate and decrease heart’s workload. Examples are metoprolol, carvedilol, and bisoprolol.
- Calcium channel blockers – Relax blood vessels by affecting calcium channels. Examples are amlodipine, diltiazem, and verapamil.
The choice of medications depends on age, medical history, type of stroke, and other individual factors. Most people need two or more drugs to adequately control blood pressure after stroke.
Lifestyle Changes to Help Lower Blood Pressure
In addition to medication, making certain lifestyle modifications can help lower blood pressure. Recommended changes include:
- Following a healthy diet such as the DASH (Dietary Approaches to Stop Hypertension) diet
- Reducing sodium intake
- Getting regular exercise (30 minutes per day, most days of the week)
- Losing weight if overweight or obese
- Limiting alcohol to 1 drink per day or less for women, 2 for men
- Quitting smoking and avoiding secondhand smoke
- Cutting back on caffeine
- Learning stress reduction techniques such as meditation
Adopting healthy habits provides benefits beyond just lowering BP – it also reduces stroke risk directly. So lifestyle changes should be considered an important component of secondary stroke prevention.
Treating High Blood Pressure in the Hospital After Stroke
Individuals who have a stroke are typically admitted to a hospital stroke unit for acute care. This allows close monitoring of neurological status, vital signs, and medical complications.
Blood pressure management in the hospital after stroke depends on the stroke type and severity:
- Ischemic stroke – BP is monitored but not usually lowered unless extremely high or medication is required for another medical reason.
- Hemorrhagic stroke – Medications are given to gradually lower BP to prevent re-bleeding and edema. Systolic BP goal is <140 mm Hg.
- Severely elevated BP – Intravenous medications may be administered to lower BP by 15-25% over the first 24 hours. Excessive lowering is avoided.
Once the acute phase has resolved, oral BP medications are initiated to achieve recommended long-term reduction. The transition to home medications usually occurs before hospital discharge.
Monitoring Blood Pressure After Leaving Hospital
After discharge following a stroke, frequent follow-up is essential. This includes:
- Seeing primary doctor within 7-14 days after hospital discharge
- Meeting with a neurologist to manage medications and monitor progress
- Checking blood pressure at home daily initially, then as often as recommended
- Undergoing blood tests as needed to monitor medication effects
- Having long-term lifestyle counseling to support healthy behaviors
Blood pressure goals are reassessed over time based on progress. Ongoing medication adjustments and lifestyle reinforcement are key to maintaining optimal BP control.
Proper follow-up helps ensure that blood pressure stays at the right level to prevent another stroke. It also empowers the patient to actively manage their health.
Tips for Monitoring BP at Home
Home monitoring is important for tracking blood pressure over time. Here are some tips for accurately measuring BP at home:
- Use a validated arm cuff monitor – check that it’s been validated for accuracy.
- Take readings at same time each day, like morning and evening.
- Sit quietly for 5 minutes before taking BP.
- Sit with back straight, feet flat, and arm supported.
- Take 2-3 readings each time, 1-2 minutes apart.
- Record all results with date and time.
- Bring monitor to doctor’s office to compare readings.
Consistent home monitoring provides valuable data on blood pressure fluctuations. Be sure to share results with your doctor to guide treatment decisions.
What To Do If BP Readings Are High
If home readings are consistently above your target blood pressure range, take these actions:
- Don’t panic – 1 or 2 high readings isn’t necessarily cause for concern.
- Recheck BP after 5-10 minutes of quiet rest.
- Make sure your technique and equipment are accurate.
- Review recent changes in diet, physical activity, stress, or medications.
- Document all concerning readings and contact your doctor promptly.
- Follow your doctor’s advice regarding additional monitoring or medication adjustments.
Sustained high blood pressure requires medical attention, so don’t hesitate to call your doctor if concerned. Getting BP back into the target zone is key for reducing future stroke risk.
Warning Signs of a Stroke
Along with tracking blood pressure, it’s vital to watch for signs of a potential stroke, including:
- Sudden numbness or weakness of the face, arm or leg, often on one side of the body
- Confusion, trouble speaking or difficulty understanding speech
- Vision problems in one or both eyes or double vision
- Dizziness, trouble walking or loss of balance and coordination
- Severe headache with no known cause
If any of these symptoms appear, call 911 right away. Timely treatment can minimize brain damage from a recurrent stroke.
Summary
In summary, high blood pressure is a major risk factor for all types of stroke. Blood pressure typically rises in the acute phase of stroke, especially hemorrhagic stroke. Rapid lowering of blood pressure is dangerous and can worsen outcomes.
After leaving the hospital, maintaining BP control through medications and lifestyle change is crucial. This requires frequent monitoring at home and with a doctor. Keeping blood pressure at the recommended target level reduces risk of recurrent stroke.
Conclusion
High blood pressure is intimately linked with increased risk of stroke. That’s why controlling hypertension is so important, both for prevention and after a stroke occurs.
During the acute phase of stroke, blood pressure may rise or fluctuate for various reasons. Cautious lowering is warranted only in certain situations due to risk of impairing blood flow to vulnerable brain tissue.
Later, tighter control of BP is needed to minimize chances of a future stroke. This involves medications, lifestyle changes, frequent monitoring, and sticking to recommended targets. Proper long-term blood pressure management requires commitment but pays off by optimizing health after stroke.