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La técnica de análisis de onda de pulso en la determinación del riesgo cardiovascular

Fri, 01 Apr 2005 00:00:00 GMT

La técnica de análisis de onda de pulso en la determinación del riesgo cardiovascular Clara, Fernando Mario; Cayrol, María L.; Scandurra, Adriana Gabriela; Meschino, Gustavo Javier; Garzillo, Miriam G.; Moyano, Eduardo; Introzzi, Aníbal R. En 76 voluntarios de edades y condiciones diversas se efectuó un estudio de riesgo cardiovascular al que se le incorporó la técnica de análisis de forma de onda de pulso radial mediante registros incruentos de variación del diámetro arterial. Esta técnica se basa en el estudio de reflexiones de la onda de presión generadas en discontinuidades del sistema arterial y lechos arteriolares, cuyos retardos y amplitudes dependen de parámetros arteriales afectados por el envejecimiento y las enfermedades cardiovasculares. La calidad de los registros, obtenidos mediante tecnología propia, resultó similar a la lograda mediante tecnologías de mayor costo. Se brinda un panorama de sus posibilidades como herramienta para evaluar riesgo cardiovascular basado en las experiencias realizadas durante el estudio. Se obtuvo un patrón de variación de la forma de los registros con la edad. Los jóvenes presentaron una onda sistólica angosta y una onda diastólica de gran amplitud. Al aumentar la edad, la onda sistólica se fue ensanchando y la onda diastólica se fue reduciendo. En algunos casos la edad arterial no coincidió con la biológica mientras que en otros se observó la presencia de reflexión sistólica, potencial factor de riesgo. En individuos hipertensos se distinguieron diversos grados de deterioro de las propiedades elásticas arteriales, aun en los casos que presentaron niveles similares de presión arterial.

Spectral Analysis of Radial Pulse Wave for Non-Invasive Assessment of Arterial Aging

Wed, 01 Jan 2025 00:00:00 GMT

Spectral Analysis of Radial Pulse Wave for Non-Invasive Assessment of Arterial Aging Clara, Fernando Mario; Basso, Fabricio; Azpilcueta, Rodrigo; Meschino, Gustavo Javier The radial pulse wave (OP) provides a valuable reflection of arterial system dynamics, offering insights into vascular aging. This study aimed to evaluate vascular aging by analyzing the spectral characteristics of the OP and determining the system's resonance frequency and its relationship with age, uti- lizing the four-element Windkessel model, which accounts for distal compli- ance. Pulse wave recordings from 100 healthy males aged 18 to 65 years were analyzed. Fourier analysis was applied to identify the frequency of maximum gain of the Windkessel model, analyzing the specific spectrum of the diastolic oscillation and using Lagrange interpolation for the accurate determination of this frequency. The Diastolic Pressure Augmentation (DPA) was also measured, examining its dependence on harmonics and age. Results indicated that fre- quency of maximum gain remained stable with age, averaging approximately 3.5Hz. Conversely, DPA decreased linearly with age at a rate of 0.11 mmHg by year. The third harmonic was identified as the principal spectral determinant of DPA for normal heart rate. The arterial system's behavior was consistent with an underdamped response, with resonance persisting across all age groups. In conclusion, while the resonance frequency of the arterial system remains con- stant with aging, its gain diminishes due to a reduction in distal compliance. Spectral evaluation of the OP offers a non-invasive, functional indicator for ar- terial aging, complementing traditional assessment methods.

The Diastolic Oscillation Amplitude Used as an Arterial Aging Indicator

Tue, 04 Apr 2023 00:00:00 GMT

The Diastolic Oscillation Amplitude Used as an Arterial Aging Indicator Clara, Fernando Mario; Alfie, José; Adriana, Scandurra; Fita, Mariana Introduction: The compliance of the distal arteries depends on their vasoconstrictor tone and distensibility and is sensitive to endothelial function and aging. C2, a component of the Windkessel model, is a measure of distal arterial compliance, and establishes the magnitude of the pressure rise during early diastole. It is calculated from the diastolic portion of the radial pulse wave using sophisticated analyses. C2 is used as a cardiovascular risk indicator since it decreases with aging, high blood pressure, and diabetes. Here, we propose an alternative method to assess the distal arteries distensibility by measuring the amplitude of the oscillation that occurs at the beginning of diastole. Methods: Peripheral pulse wave was evaluated noninvasively by applanation tonometry in 511 individuals (264 women) aged between 13 and 70 years. Diastolic amplitude (DA) was measured as the peak-to-peak amplitude of the diastolic oscillation. Radial augmentation index (RAIx) and pulse wave velocity (PWV) were also calculated. Results: DA decreased approximately 2% per decade of life between 16 and 70 years from 19% to 7%, and was higher in men than in women (p<0.0001). Linear regression analysis identified RAIx as the strongest predictor of AD (p<0.0001), followed by age and height. Sex modified the age-related decrease in DA (p< 0.001). By applying the method to measure DA from previously published data, we found a strong linear correlation with C2. Conclusion: DA decreased linearly with age in a reciprocal manner to the increase in radial augmentation index, was greater in men than women, and was independent of blood pressure and heart rate, as previously reported for C2. We propose that measuring DA could provide an alternative index to evaluate distal arterial compliance and aging.

Spectral Analysis of Arterial System Resonance

Wed, 01 Jan 2025 00:00:00 GMT

Spectral Analysis of Arterial System Resonance Clara, Fernando Mario; Alfie, José; Blanco, Gustavo; Casarini, Alfredo Introduction: The Windkessel model simulates the radial pulse wave. When the aortic valve closes, instead of a pressure decrease during diastole, there is an initial increase due to a resonant response. The aim of this study was to explain this phenomenon based on the spectral analysis, and determine how it is affected by aging. Methods: The Fourier spectrum of resting pressure wave was analysed in a healthy set of 49 young individuals (26.9±7.3 years) and 51 adults (53.4±10.3 years). To explain the results, the Windkessel was considered a low-pass filter composed by distal compliance Cd, aortic inertance L, and peripheral resistance Rp. Results: The spectrum obtained showed a maximum amplitude between 3 and 4 Hz, evidencing resonant behavior in that frequency range. Linear regression of diastolic pressure increases revealed that it depends mainly on the amplitude of the 3rd harmonic of the spectrum (p<0.001), for normal heart rate values. Conclusions: The arterial system resonates at a frequency close to 3.5 Hz, generating the oscillation responsible for the diastolic pressure increase. The resonance frequency remains constant with age, however, the oscillation amplitude, related to small distal artery compliance and endothelial dysfunction, decreases by more than 50%. The resonant configuration of the arterial system results from an evolutionary development that allows diastolic pressure to be increased for approximately 300 ms, using the energy stored during systole. Spectral analysis allows the assessment of aging of the arterial system, and could be useful in evaluating the effects of cardiometabolic diseases on small arteries.