NON-INVASIVE CENTRAL BLOOD PRESSURE ESTIMATIONS IN PATIENTS WITH OR WITHOUT CHRONIC KIDNEY DISEASE: A PILOT PROJET

Abstract

Objective: Central systolic blood pressure (SBP) is a better surrogate for hemodynamic strain on the myocardium, brain and kidneys. In the context of chronic kidney disease (CKD), where the blood flow to the kidneys is reduced and there is a higher degree of aortic stiffness, estimation of central BP through non-invasive methods needs to be validated. The aim of our study is to determine the accuracy of brachial and central SBP, as measured and estimated by two devices, towards the invasively measured aortic BP, in CKD patients compared to patients without CKD. Design and method: This is a multicenter pilot study taking place at the hospitals Hotel-Dieu de Québec and Sacré-Coeur de Montréal. Patients undergoing non-urgent coronary angiograms are undergoing evaluation of non-invasive and invasive BPs simultaneously in supine position. In brief, intraarterial aortic BPs are recorded in the aorta within 3 cm of the aortic valve for every heartbeat for 30 seconds then averaged. Non-invasive central and brachial BP measures are recorded concurrently to the intraarterial aortic BP recordings with WatchBP central and Mobil-o-graph. All measurements are recorded on the contralateral arm used for angiography. Results: In 34 subjects (29% female, mean age 64.2 ± 8.7). In the CKD group (n = 8, eGFR < 30 ml/min/1.73m2) and the control group (n = 26, eGFR> 30 ml/min/1.73m2). Brachial cuff-SBP underestimated aortic SBP in CKD (-10.0 ± 19.6 mmHg) but overestimated aortic SBP (3.9 ± 16.3 mm Hg) in the control group. Mobil-o-graph estimations are more precise than the brachial BP in CKD (0.0 ± 10.1 mmHg) but not in the control group (6.5 ± 14.7 mmHg). WatchBP Central SBP estimations are also more precise than the brachial BP in CKD (1.2 ± 10.8) but overestimated aortic SBP in the control group (13.4 ± 18.9). Conclusions: The preliminary results indicate that brachial SBP underestimates aortic SBP by in CKD as compared to controls, and that estimation of central BP by both devices provide a better estimate of aortic SBP in CKD than in controls. These preliminary results suggest that the use of central BP estimations could be beneficial for the management of hypertension in CKD.