Carotid-Femoral, Oscillometric and Estimated Pulse Wave Velocity

Correlation Between the Values of Carotid-Femoral, Oscillometric and Estimated Pulse Wave Velocity

What is the purpose of this research? This research aims to compare three different methods of measuring pulse wave velocity, which is the main parameter used for assessing arterial stiffness. This parameter is as important as blood pressure in predicting future cardiovascular risk.

The investigators intend to compare carotid-femoral pulse wave velocity, which is the gold standard for measuring arterial stiffness, with brachial pulse wave velocity measured using a device similar to a blood pressure monitor and a mathematical formula validated in a large European population.

Who is eligible for this survey? Anyone aged 18 or older who has been invited may participate, provided they sign an informed consent form.

Where will the field research be conducted? The research will be conducted at a health center specializing in the treatment of hypertension. This center is a reference for outpatient blood pressure monitoring in the city of Uberaba (MG), Brazil. Patients enrolled in the study will also be included in the Hypertension Center of the Faculdade de Medicina de São José do Rio Preto (FAMERP).

Which procedures will be performed by research participants? All participants who consent will answer some questions about their demographic and health information. A trained nurse will measure their weight, height, and blood pressure after a 5-minute rest, and then measure carotid-femoral pulse wave velocity. The participant will lie down on a bed and the nurse will place a sensor on the middle of their neck and the groin. The device will automatically deliver the parameters. At least three measurements are required for each participant. Measurements normally take between 10 and 15 minutes. Then, participants will wear a device to record blood pressure and pulse wave velocity for 24 hours. The nurse will fit the cuff around the participant's arm and attach the monitoring device to a belt around their waist. The device will take measurements every 20 to 30 minutes. 24 hours later, the participant must return to the research venue to have the equipment removed.

What are the risks and adverse events of the procedures? There are no known risks or adverse events (AEs) associated with carotid-femoral pulse wave velocity measurements. The risks of this research are minimal, limited to discomfort during the AMBP recording, which occurs at a low frequency. However, excessive arm pain, allergic reactions, and edema may occur. To minimize these risks, a nurse will be available via telephone to aid all participants during the AMBP recordings.

Hypertension is one of the leading causes of cardiovascular morbidity and mortality worldwide and is strongly associated with myocardial infarction, stroke, heart failure, and premature death. In addition to elevated blood pressure levels, vascular alterations such as arterial stiffness have emerged as important markers of cardiovascular risk. Carotid-femoral pulse wave velocity (cfPWV) is currently considered the gold standard non-invasive method for the assessment of aortic stiffness and has consistently demonstrated independent associations with cardiovascular events and mortality.

Over recent decades, alternative methods for pulse wave velocity (PWV) assessment have been developed. Oscillometric brachial cuff-based devices can estimate PWV through proprietary algorithms derived from blood pressure waveform analysis. The Mobil-O-Graph system is one of the most widely studied oscillometric devices and has shown associations between brachial PWV (brPWV) and cardiovascular outcomes in different clinical settings.

In parallel, estimated pulse wave velocity (ePWV), calculated using mathematical equations based on age and mean blood pressure, has emerged as a simple surrogate marker of arterial stiffness. Previous studies demonstrated that ePWV predicts cardiovascular events and mortality independently of traditional cardiovascular risk scores and even independently of measured cfPWV in some populations.

Although both oscillometric PWV and equation-derived PWV have shown prognostic value, uncertainties remain regarding the degree to which these methods reflect true aortic stiffness when compared with directly measured carotid-femoral PWV. Since oscillometric algorithms and ePWV equations are strongly influenced by age and blood pressure, further studies are necessary to better understand their relationship with the reference standard method.

The present study aims to evaluate the agreement and association between carotid-femoral pulse wave velocity, oscillometric brachial pulse wave velocity, and estimated pulse wave velocity in adults undergoing ambulatory blood pressure monitoring as part of routine clinical evaluation.

This is an observational cross-sectional study conducted in a specialized cardiovascular center in Brazil. The study population includes adults referred for ambulatory blood pressure monitoring (ABPM) for investigation or characterization of blood pressure abnormalities.

Participants undergo office blood pressure measurement, anthropometric assessment, 24-hour ABPM, carotid-femoral pulse wave velocity evaluation, and oscillometric brachial pulse wave analysis under standardized conditions.

Arterial stiffness is assessed using the Complior Analyze device according to current recommendations for non-invasive evaluation of aortic stiffness. Ambulatory blood pressure monitoring and oscillometric brachial PWV measurements are performed using a validated oscillometric device programmed for daytime and nighttime recordings according to guideline recommendations.

Estimated pulse wave velocity is calculated using validated equations derived from the Reference Values for Arterial Stiffness Collaboration based on age and mean blood pressure values.

All participants also underwent routine laboratory evaluation requested by the attending physician at the time of referral for ambulatory blood pressure monitoring. Blood samples collected under fasting conditions included measurements of total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglycerides. Laboratory data obtained from routine clinical care were collected and analyzed for research purposes as part of the present observational study.

The primary objective of the study is to evaluate the agreement between cfPWV, brPWV, and ePWV. Statistical analyses include correlation and agreement analyses between pulse wave velocity methods using standardized statistical approaches.

The study is observational and non-interventional. All procedures are performed within the context of routine clinical care, and all participants provided written informed consent prior to inclusion in the study.

Inclusion Criteria :

- Individuals older than 18 with an elevated office blood pressure :

• suspected hypertension diagnosis or
• uncontrolled hypertension under treatment

Exclusion Criteria:

24-hour ABPM recordings presenting:

• less than 70% of the expected measurements or
• fewer than 20 valid awake or seven valid sleeping measurements or
• fewer than two valid daytime and one valid night-time measurement per hour