Invasive Assessment of Central Aortic Blood Pressure, Differential Impact of Beta Blocker vs. Non-Beta Blockers and their Correlation with Severity of Coronary Artery Disease in Hypertensive Patients Undergoing Coronary Angiography

Abstract

Background: Non-invasively measured brachial arterial pressure is accepted as the standard method for blood pressure measurement. However, systolic pressure varies throughout the arterial tree such that central systolic pressure is actually lower than corresponding brachial pressure. The aim of the study was to evaluate the differential effects of commonly used antihypertensive drugs on central aortic pressure measured invasively. Methods and Results: This was a prospective, single-centre and observational study. During the time period November 2009 to November 2010, a total of 170 patients with chronic stable angina and systemic hypertension were enrolled. Detailed medical history and physical examinations were performed. Laboratory investigations were noted. Brachial and central aortic pressures were recorded and compared. Demographic and clinical parameters were comparable among patients in different antihypertensive therapy groups. Mean systolic blood pressure (SBP) difference and mean pulse pressure (PP) ratio values between beta blocker and non-beta blocker groups were significantly different, (p<0.0001) and (p=<0.0001) respectively. Mean central SBP difference and mean pulse pressure ratio values between beta blocker arm and beta blocker combination groups arm were significantly different too, (p <0.0001 and p=0.0005 respectively). Mean SBP difference and mean PP ratio were also significantly different for beta blocker monotherapy as compared with non-beta blocker drugs individually. In each antihypertensive therapy group, moderate and severe coronary artery disease groups had significantly higher central PP levels. Conclusion: Different classes of antihypertensives have differential impact on central blood pressures. Central systolic and pulse pressures cannot be inferred accurately from brachial blood pressures. Thus, there is potential for under treatment or overtreatment of hypertension based on brachial blood pressure targets