P166 AORTIC PULSATILITY, AND NOT MEAN ARTERIAL PRESSURE, IS AN INDEPENDENT DETERMINANT OF LEFT MAIN CORONARY ARTERY DISEASE

Abstract

Introduction: Left Main Coronary Artery (LMCA) disease is prognostically the most important coronary lesion. LMCA differs from the other coronaries in having high elastin content. Aortic Pulsatility (AP) is an independent predictor of cardiovascular events in CAD. We hypothesized that pulsatile stress may be an independent determinant of disease in the LMCA. 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. We excluded patients with acute myocardial infarction, cardiogenic shock and significant valvular disease. Aortic systolic and diastolic blood pressures (BP) were measured in the ascending aorta. Mean Arterial Pressure (MAP) by direct integration of the BP curve and Pulse pressure (PP) as difference between systolic and diastolic BP. AP was calculated as PP/MAP. CAD was defined as > 50% stenosis in any major vessel. Results: Six percent of the 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 (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) even when adjusted for potential confounders, including MAP, age and gender. Conclusions: LMCA disease is independently associated with high AP. Considering aortic pulsatile stress to be an independent cardiovascular prognosticator, stiffness of the LMCA may play an important role in plaque formation, hitherto ignored.