Background: Taking into account coronary artery biomechanics is fundamental to understand the pathophysiology of myocardial perfusion. Coronary artery pulse wave velocity (CoPWV) is a new marker for assessing coronary artery stiffness using a pressure wire (J Am Heart Assoc. 2017). In the presence of a stenosis, the translesional pressure may be influenced by coronary artery stiffness. Fractional flow reserve (FFR) represents a common way to assess stenosis severity by evaluating translesional pressure ratio. It is thus conceivable that CoPWV may modulate translesional pressure ratio and thus FFR.
Aim: To study the independent impact of coronary arteries stiffness evaluated by CoPWV on FFR.
Methods: In 39 patients with an indication of FFR measurements on an intermediate coronary artery stenosis, CoPWV was evaluated. 58 coronary arteries were assessed. Associations were assessed by univariate correlations after log-transformation in case of skewed variables; independent predictors of FFR were assessed by multivariate linear regression including univariate determinants with p value<0.1.
Results: Patients characteristics were as follow: 29 (74.4%) men, 27 (69.2%) hypertensive, 16 (41%) diabetics, 25 (64.1%) smokers, 21 (53.8%) with a history of coronary artery disease. Mean FFR was 0.78±0.08. Mean coronary artery stenosis was 71±13%. Mean CoPWV was 10.4±6.3m/s. A better correlation was found between FFR and CoPWV (see figure) than between FFR and angiographic coronary stenosis severity, respectively r=0.514 p<0.001 and r=- 0.243 p=0.069. On the contrary, CoPWV didn't correlate with angiographic coronary stenosis severity.
Among all tested variables including, cardiovascular risk factors, angiographic coronary stenosis severity, reference vessel diameter, angiographic calcifications, systemic blood pressure and heart rate, CoPWV was the strongest independent predictor of FFR β=0.457 p<0.001. Angiographic coronary stenosis severity wasn't a determinant in multivariate analysis.
Conclusion: CoPWV is a strong determinant of FFR. This new parameter may influence the hemodynamic behavior of a stenosis. It may explain the discrepancies between anatomical and functional assessment of a coronary artery stenosis.