title: Estimated aortic blood pressure based on radial artery tonometry underestimates directly measured aortic blood pressure in patients with advancing chronic kidney disease staging and increasing arterial stiffness.
abstract: Central blood pressure (BP) can be assessed noninvasively based on radial tonometry and may potentially be a better predictor of clinical outcome than brachial BP. However, the validity of noninvasively obtained estimates has never been examined in patients with chronic kidney disease (CKD). Here we compared invasive aortic systolic BP (SBP) with estimated central SBP obtained by radial artery tonometry and examined the influence of renal function and arterial stiffness on this relationship. We evaluated 83 patients with stage 3 to 5 CKD (mean estimated glomerular filtration rate [eGFR] 30 ml/min/1.73 m(2)) and 41 controls without renal disease undergoing scheduled coronary angiography. BP in the ascending aorta was measured through the angiography catheter and simultaneously estimated using radial tonometry. The mean difference between estimated central and aortic SBP was -13.2 (95% confidence interval -14.9 to -11.4) mm Hg. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (cf-PWV) and was significantly increased in CKD patients compared with (versus) control patients (mean 10.7 vs. 9.3 m/s). The difference in BP significantly increased 1.0 mm Hg for every 10 ml/min decrease in eGFR and by 1.6 mm Hg per 1 m/s increase in cfPWV. Using multivariate regression analysis including both eGFR and cfPWV, the difference between estimated central and invasive aortic SBP was significantly increased by 0.7 mm Hg. For the entire cohort brachial SBP significantly better reflected invasive SBP than estimated SBP. Thus, tonometry-based estimates of central BP progressively underestimate invasive central SBP with decreasing renal function and increasing arterial stiffness in CKD patients.
authors.affiliation: Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark. Electronic address: rasmcarl@rm.dk.
authors.forename: Rasmus K
authors.initials: RK
authors.lastname: Carlsen
authors.affiliation: Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Christian D
authors.initials: CD
authors.lastname: Peters
authors.affiliation: Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Dinah S
authors.initials: DS
authors.lastname: Khatir
authors.affiliation: Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Esben
authors.initials: E
authors.lastname: Laugesen
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Bøtker
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Simon
authors.initials: S
authors.lastname: Winther
authors.affiliation: Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Nephrology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Niels H
authors.initials: NH
authors.lastname: Buus
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta / Q000503:physiopathology; D062186:Arterial Pressure; D001795:Blood Pressure Determination / Q000379:methods*; D001916:Brachial Artery / Q000503:physiopathology; D015331:Cohort Studies; D017023:Coronary Angiography; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008365:Manometry / Q000009:adverse effects*; D008875:Middle Aged; D063177:Pulse Wave Analysis; D017534:Radial Artery / Q000503:physiopathology; D051436:Renal Insufficiency, Chronic / Q000150:complications*; D013599:Systole; D059289:Vascular Stiffness
keywords: blood pressure; central blood pressure; chronic kidney disease; generalized transfer function; invasive blood pressure; pulse wave velocity