Standard blood pressure measurement identifies the force of blood pushing against artery walls, which is recorded as two numbers. The first, systolic pressure, measures the force as the heart pumps blood. The second, diastolic pressure, is the force between heartbeats. A newer concept, “High-Definition Blood Pressure,” or HD BP, refers to more advanced monitoring that captures a greater level of detail about cardiovascular function.
Defining HD BP
The term “HD BP” is not a standardized medical classification but is used by some device manufacturers to describe technology that goes beyond a basic reading. A traditional cuff measures blood pressure in the arm’s brachial artery at two moments, providing a snapshot of the pressure extremes within the cardiac cycle.
In contrast, HD BP technology analyzes the entire blood pressure waveform for each heartbeat. A pressure waveform is a graphical representation of the rise and fall of arterial pressure during one complete cardiac cycle. This method captures the continuous fluctuation of pressure, offering a more detailed view of what is happening within the arteries from one beat to the next.
Information Provided by HD BP Monitors
A primary metric is Central Aortic Pressure (cBP), which is the pressure at the aorta, the major artery connected directly to the heart. This measurement is significant because it reflects the actual load being placed on vital organs like the heart and brain. Since pressure increases as it moves from larger arteries near the heart to smaller ones in the arm, brachial pressure is often higher than central pressure.
One parameter is Pulse Wave Velocity (PWV), which measures how fast a pressure wave travels through the arteries. A higher velocity can suggest increased arterial stiffness, a condition where the arteries are less flexible. Another metric is the Augmentation Index (AIx), which quantifies the contribution of reflected pressure waves to the central aortic pressure.
Potential Health Insights
Some research indicates that central aortic pressure is a more accurate predictor of cardiovascular events, such as heart attacks and strokes, than the pressure measured in the arm. In one study, 41% of hypertensive patients who had controlled brachial blood pressure were found to have uncontrolled central blood pressure, suggesting their risk was underestimated by standard measurements.
Metrics like PWV and AIx give insight into arterial elasticity, which is a marker of vascular health. Tracking these detailed parameters could allow for a more comprehensive understanding of an individual’s cardiovascular risk profile than is available from a standard reading.