Central blood pressure measurement gives a better view of cardiovascular health by checking pressure in the aorta. Basically, central blood pressure (aortic BP or CBP) is considered different from brachial BP due to something called the amplification effect. This happens because the pressure increases as the blood moves from the large, flexible arteries near the heart (like the aorta) to the smaller, stiffer arteries in your arms. It’s like water pressure increasing when it flows from a flexible hose into a stiff tube — as the stiffness of the tube helps keep the pressure higher. Because of this, blood pressure readings in the arm are usually higher than the pressure near the heart. Therefore, Central BP is considered a better indicator of cardiovascular risk [1].
What Does Central Blood Pressure Measure?
Central blood pressure is the pressure in the aorta, directly affecting vital organs like the heart, brain, and kidneys [2]. This pressure can be affected not just by the large arteries, but also by the smaller arteries throughout the body. So, both the big and small arteries play a role in determining Central BP [3].
Central Blood Pressure Thresholds:
The optimal central blood pressure (CBP) is 110 mmHg for systolic (SYS) and 80 mm Hg for diastolic (DIA). A CBP of 130 mmHg for SYS and 90 mmHg for DIA is considered the threshold for hypertension. This 130/90 mmHg cutoff is especially important because it has been shown to better predict long-term health risks, making it a key marker for identifying individuals at higher risk for cardiovascular events [4].
Professor Illyés, a highly respected expert in the field of arterial stiffness, emphasizes that under normal circumstances, aortic (central) systolic blood pressure (SBPao) should be physiologically lower than peripheral (brachial) systolic blood pressure. SBPao is considered normal when it is below 140 mmHg and at least 10 mmHg lower than the brachial systolic reading. Therefore, when central systolic blood pressure falls between 130 and 140 mmHg, special care should be taken to monitor and manage these individuals, as they may be at greater risk for cardiovascular issues [5].
Central Blood Pressure Measurement Methods:
Central blood pressure (CBP) measurement provides crucial insights into cardiovascular health. There are several methods used for assessing CBP, each with distinct advantages and limitations:
- Invasive Cardiac Catheterization
- Applanation Tonometry of the Carotid Artery
- Applanation Tonometry of the Radial Artery
- Cuff-Based Oscillometry at the Brachial Artery [6]
1. Invasive Cardiac Catheterization for CBP Measurement
Invasive cardiac catheterization is the most accurate method for measuring central blood pressure. However, it is rarely used in routine clinical practice due to associated risks such as infection, bleeding, and arterial damage. This method is primarily reserved for specialized cases where precise internal blood pressure monitoring is necessary.
2. Applanation Tonometry of the Carotid Artery for CBP Measurement
Carotid artery pressure is often used to estimate aortic pressure due to its proximity. Applanation tonometry captures carotid pressure waveforms, which are then calibrated using brachial artery mean and diastolic pressures. Despite its usefulness, this method has limitations:
- Requires significant operator skill.
- Challenging to use in obese patients.
- Potential overestimation of aortic pressure due to minor differences between carotid and aortic pressures.
3. Applanation Tonometry of the Radial Artery for CBP Measurement
Measuring CBP via the radial artery is another non-invasive approach. However, pressure differences between the arm and wrist can result in underestimating true central pressure. While advanced devices attempt to correct this issue, the method remains less reliable for precise aortic pressure measurements.
4. Cuff-Based Oscillometric Method for CBP Measurement
This method is widely used due to its ease of application, operator independence, and painless, quick measurement process. Its accuracy, however, depends heavily on the algorithm employed by the device. The Arteriograph device, recognized as the gold standard, has revolutionized non-invasive CBP measurement. It utilizes the Supra-Systolic technique, inflating the cuff 35 mmHg above systolic pressure to analyze pulse waves accurately, ensuring precise central blood pressure readings.
The Best Central Blood Pressure Measurement Device
Each CBP measurement method has its strengths and challenges. While invasive cardiac catheterization remains the most precise, non-invasive techniques such as applanation tonometry and oscillometry provide practical alternatives. Among these, the Arteriograph device stands out for its accuracy and ease of use, making central blood pressure assessment more accessible in clinical settings.
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