Relationship between coronary flow velocity and vascular stiffness

Background: It has been hypothesized that an increase in stiffness of great
vessels is associated with reduced coronary blood flow. Animal studies are
conflicting, and no human evidence, particularly by non invasive technique,
has been provided.
Objective: To assess the relationship beteween arterial wall stiffness measured
by a non-invasive new tool „e-tracking, Aloka, Japan”, and basal coronary
blood flow evaluated in the left anterior descending artery (LAD) by
transthoracic doppler echocardiography.
Methods: We studied 34 patients, mean age 52.8+/-15.1, 21 men, without
history of coronary artery disease and with negative echo-stress. We used
an Aloka (Japan) alfa-10 prosound echo-machine. LAD doppler velocities
have been recorded at the distal segment of the vessel by phased array
transducer. The following parameters have been evaluated: ratio between
diastolic peak velocity (D) and systolic peak velocity (S), (D/S); ratio between
velocity time integral of diastolic component (VTI-D) and velocity time
integral of total flow (VTI-Tot), expressed as percentage (VTI-D/VTI-Tot %).
Parameters of vascular stiffness have been evaluated by „e-tracking” with
the same echo-machine, at the level of the common carotid artery just before
bifurcation.
The following parameters have been evaluated: Beta (stiffness parameter);
AI (augmetation index); PWV (pulse wave velocity). The value of blood pressure
(systolic and diastolic), evaluated in the left arm, have been included in
the system for evaluation of these parameters.
Results: Our results showed an inverse correlation between vascular stiffness
parameters and coronary blood flow velocities (p<0.01), Table 1.
Conclusion: Our data, obtained by non-invasive methods, show a negative
correlation between vascular stiffness parameters and coronary blood flow
velocities patterns. These preliminary data needs of further studies to be
confirmed.