A18474 Aortic Pulsatility, And Not Mean Arterial Pressure, Is An Independent Determinant Of Left Main Coronary Artery Disease

Abstract

Objectives: Left main coronary artery(LMCA) disease is prognostically the most important lesion in the coronary tree.LMCA differs from the other coronaries in having a high elastin content. Aortic pulsatility (AP) eliminates the effect of cardiac output and vascular resistance and is shown to be an independent predictor of cardiovascular events in CAD.As the left main is an elastic vessel,we hypothesized that aortic pulsatile stress may be an independent determinant of disease in this artery,independent of mean arterial pressure(MAP). Methods: This was a prospective cohort study in patients undergoing coronary angiography between the years 2011 and 2016(n = 4633, 25% female) at King Abdul Aziz Cardiac Center, Riyadh, Saudi Arabia. Aortic systolic and diastolic BP were measured in the ascending aorta. MAP was obtained by direct integration of the BP curve.AP was calculated as PP divided by MAP.CAD was defined as > 50% stenosis in atleast one of the major coronary arteries.AP in patients with LMCA disease was compared to those with non-obstructive, 1, 2 and 3-vd as well with LMCA and 3-vd. Results: Six percent of the study population had LMCA disease(mean age 60 ± 11 years,25% female).LMCA disease was associated with higher PP(69 ± 22 vs.58 ± 18, p < 0.0001)despite similar MAP(94 ± 16 vs. 94.5 ± 14, p = 0.92)compared with non-LMCA disease.AP was significantly higher(0.72 ± 0.30) in LMCA disease compared with;3-vd (0.63 ± 0.32);2-vd(2-vd(0.61 ± 0.28),1-vd(0.58 ± 0.31)and non-obstructive CAD (0.52 ± 0.26) (p < 0.0001).In a stepwise regression model,AP was an independent predictor of LMCA disease(R2 = 0.68,P < 0.0001), adjusted for age, gender, BMI and MAP. Conclusion: Stiffness of the LMCA, independent of MAP, may play an important role in the pathophysiology of plaque formation, hitherto overlooked.