Blood pressure is the force within the blood vessels that moves blood throughout the body. It is measured in millimeters of mercury (mmHg) and is separated into a systolic and diastolic measurement. Systolic blood pressure is measured when the heart chambers are contracting, and diastolic is measured when the heart muscle is relaxed.
A healthy blood pressure is less than 120 mmHg (systolic) and 80 mmHg (diastolic). A measurement above 130-139 mmHg systolic and 80-89 mmHg diastolic is considered hypertension (high blood pressure).
About 120 million adults in America have hypertension. High blood pressure can result in stroke and heart disease and does not always cause symptoms. These characteristics have led to the disease being called the "silent killer." High blood pressure is more common in men and African Americans.
Hypertension rates also vary geographically; the southern United States has more cases of high blood pressure than other regions. This article will explain blood pressure in more detail, specifically high systolic and low diastolic measurements.
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Understanding Blood Pressure Readings
Even though hypertension does not always cause symptoms, when blood pressure becomes dangerously high (180/120 mmHg), some signs and symptoms may manifest. These symptoms include:
- Difficulty breathing
- Vision abnormalities
- Cognitive changes
- Nausea
- Vomiting
- Speech difficulties
- Weakness
- Numbness
- Chest pain
If you or someone you know is experiencing these symptoms or signs of stroke or heart attack, it is critical to seek immediate medical attention.
High Systolic and Low Diastolic Blood Pressure
In some cases, the systolic number is high, and the diastolic reading is normal or low, showing abnormalities in the heart's ability to contract and relax, known as isolated systolic hypertension (ISH). Typically, this diagnosis is made if the systolic blood pressure is >140 mmHg and diastolic is <90 mmHg.
Elevated systolic blood pressure can increase mortality risk, so the patient must be treated appropriately. However, a normal or low diastolic blood pressure can make treatment difficult. A high systolic with a normal or low diastolic reading often means that the large arteries have stiffened.
Other causes may include thyroid disease, obesity, and heart valve dysfunction. Isolated systolic hypertension is the most common form of high blood pressure after age 50. In this condition, the diastolic blood pressure may be lower than normal. If this reading is <70 mmHg, diastolic blood pressure is low.
Risk Factors
Understanding risk factors for blood pressure abnormalities can aid in prevention. Some risk factors cannot be changed (non-modifiable), such as race or sex at birth. Others can be changed (modifiable), like diet and exercise.
Risk factors for high blood pressure include:
Risk factors for ISH include:
- Older age
- Female gender
- Diabetes mellitus
Root Causes
Several factors can cause the systolic blood pressure to rise while the diastolic reading stays the same or lowers. Possible root causes include:
Young Adults
ISH is more common in older adults (mostly likely due to artery stiffness), but this condition is becoming more common in young adults. If high blood pressure occurs earlier in life, treatment is crucial to prevent strokes and heart attacks.
Certain risk factors in young adulthood can increase the risk of isolated systolic hypertension; these include:
Health Implications
A high systolic/high diastolic and a high systolic/low diastolic reading require medical attention and treatment. ISH increases the risk of:
- Left ventricular hypertrophy
- Kidney dysfunction
- Cardiovascular events
- Stroke
Diagnostic Approach and Lab Tests
An initial assessment includes asking about family history, health history, and symptoms. Blood pressure is then measured and confirmed with multiple readings. High blood pressure results in the clinic can be confirmed through home and ambulatory monitoring (blood pressure over 24 hours).
Lab testing can help detect the root causes of isolated systolic hypertension. Helpful testing can include checking for anemia and thyroid function. Other diagnostic testing may include cholesterol levels, blood glucose, and kidney function tests.
A urinalysis can detect abnormal levels of protein or glucose in the urine. An electrocardiogram (ECG) can assess the heart rhythm.
Additional Testing
In some cases, more in-depth diagnostic testing is necessary for isolated systolic hypertension, including:
- Stress testing to see how the heart reacts to activity
- Ultrasound of the carotid arteries
- Computed tomography (CT)
- Magnetic resonance imaging (MRI) of the vessels
- Ankle-brachial index (ABI) compares blood pressure between the upper and lower extremities
Treatment and Management
Treating blood pressure abnormalities is vital for preventing adverse events such as heart attacks and strokes. The treatment for younger and older adults is similar. However, older adult treatment protocols must address patient health status to avoid increasing frailty (e.g., not restricting calories).
Address Underlying Causes
The first step in treating ISH is correcting underlying causes, such as anemia and heart valve dysfunction. Laboratory testing and imaging (e.g., echocardiogram) can help diagnose these contributing factors.
Lifestyle Interventions
Lifestyle changes are an effective initial intervention if blood pressure is not critically high. These lifestyle changes may include:
- Sodium reduction
- Increased potassium intake
- Exercise
- Reduce alcohol consumption
- Stopping smoking
- Weight loss
- Dietary changes
- High-quality sleep
- Reduce stress
- Reduce inflammation
Medication Therapy
If blood pressure is very high or lifestyle interventions alone do not lower blood pressure, medication intervention may be necessary. Many medication choices are available, and the choice of drug depends on the patient's history and demographic data. The drug selection in isolated systolic hypertension also depends on the diastolic blood pressure.
Common hypertension medications include:
- Beta-blockers
- Diuretics
- Angiotensin II receptor blockers (ARB)
- Calcium channel blockers
- ACE inhibitors
Multiple medications can be combined for increased efficacy if blood pressure is very high. Treating blood pressure with lifestyle interventions and pharmacologic therapy significantly decreases the risk of heart attack, stroke, and death.
The blood pressure goal for patients at a higher risk of cardiovascular disease is <130/80 mmHg. If patients are not at high risk for cardiovascular disease, their blood pressure goal may be below <130/80 mmHg. A treating provider can help establish blood pressure goals depending on individual risk factors.
Monitoring
Regular monitoring and follow-up are important to assess blood pressure treatment and ensure it does not drop too low.
Patient education should include how to perform home blood pressure monitoring, signs of hypertensive crisis (e.g., vision changes, dizziness), and signs of low blood pressure (e.g., dizziness, fainting). Patients with recent medication changes should follow up with their provider monthly to assess blood pressure and side effects.
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Key Takeaways
- High systolic and low diastolic blood pressure (isolated systolic hypertension) should be treated by a healthcare professional to avoid cardiac events and stroke.
- This condition is not necessarily an emergency. However, a blood pressure of 180/120 mmHg or higher is critically high and is an emergency. Critically high blood pressure and symptoms such as chest pain, shortness of breath, weakness, or vision changes require immediate medical attention.
- Risk factors for isolated systolic hypertension include diabetes, age, obesity, sedentary lifestyle, smoking, and excess alcohol intake.
- Treatment for this condition includes addressing root causes, lifestyle interventions, and medication therapy.
- Most people can lower their blood pressure through these interventions and reduce their risk for cardiac disease and stroke.
- Regular blood pressure monitoring is essential for early detection and diagnosis of hypertension.
- Providers should stay current on guidelines for preventing, assessing, diagnosing, and treating isolated systolic hypertension.
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