Elevated blood viscosity in patients with borderline essential hypertension

Area of Science:

• Cardiovascular Physiology
• Hemodynamics
• Blood Rheology

Background:

• Total peripheral resistance (TPR) is a key factor in borderline hypertension.
• Blood viscosity is a significant determinant of TPR.
• Understanding blood viscosity in hypertension is crucial for managing cardiovascular risk.

Purpose of the Study:

• To compare components of blood viscosity in patients with borderline hypertension versus normal subjects.
• To investigate the relationship between blood viscosity and blood pressure levels.
• To identify the rheological factors contributing to increased blood viscosity in borderline hypertension.

Main Methods:

• Comparison of blood viscosity components (hematocrit, plasma viscosity, red cell aggregation) between 25 borderline hypertensive patients and 25 normal subjects.
• Assessment of blood viscosity under various experimental blood flow conditions.
• Measurement of plasma fibrinogen concentration.

Main Results:

• Blood viscosity directly correlated with systolic and diastolic blood pressure.
• Hypertensive subjects exhibited higher blood viscosity compared to normal subjects.
• Elevated venous hematocrit, plasma viscosity, and red cell aggregation (due to higher fibrinogen) were observed in hypertensive patients, contributing to increased blood viscosity.

Conclusions:

• Even mild elevations in arterial pressure are associated with increased blood viscosity.
• Increased blood viscosity in borderline hypertension is a multifactorial rheological issue.
• Hematocrit, plasma viscosity, and red cell aggregation are key contributors to altered blood flow resistance in hypertension.