Abstract 3049: Impact of Arterial Load on Left Ventricular Diastolic Function in Patients Undergoing Cardiac Catheterization for Coronary Artery Disease
Background: Although altered left ventricular (LV) diastolic function is associated with worse outcomes in various populations, including patients with chronic heart failure and those with coronary artery disease (CAD) and even community-dwelling subjects, no specific treatment for diastolic abnormalities has been established. Animal and human studies have shown that an acute increase in LV afterload adversely impacts on LV early diastolic relaxation, but little is known about its chronic effect on LV diastolic function.
Methods: We examined the relationship between various components of LV afterload and indices of LV diastolic function (relaxation time constant [Tau] and end-diastolic pressure) in 320 consecutive patients (age 66±9 years; males, 76%, LV ejection fraction, 0.67±0.09) who underwent left-sided cardiac catheterization for the evaluation of CAD. Arterial load was measured by effective arterial elastance (Ea, a ratio of LV end-systolic pressure to stroke volume), systemic vascular resistance index (SVRI, a ratio of mean aortic pressure to cardiac index, converting to standard units) and augmentation index (AI, a ratio of augmented pressure to pulse pressure in the ascending aorta).
Results: Ea (r=0.13, P<0.05), AI (r=0.30, P<0.001) and SVRI (r=0.24, P<0.001) correlated with Tau. AI (r=0.23, P<0.001) and SVRI (r=0.18, P<0.01) correlated with LV end-diastolic pressure. In the multivariate linear regression analyses including heart rate, traditional cardiovascular risk factors, medications used and the severity of CAD, AI, but not Ea or SVRI, was significantly associated with LV diastolic function indices (standardized parameter estimates of AI with Tau and LV end-diastolic pressure, 0.14 and 0.16, both P<0.001).
Conclusions: Increases in arterial load, particularly increased AI, adversely impact on LV diastolic function in CAD patients. Arterial wave reflections may be a therapeutic target to improve altered LV diastolic function in this population.