Aortic calcification is associated with the difference between invasive central and cuff-measured brachial blood pressure in chronic kidney disease.

Abstract

Chronic kidney disease (CKD) is associated with accelerated vascular calcification and increased central systolic blood pressure when measured invasively (invCSBP) relative to cuff-based brachial systolic blood pressure (cuffSBP). The contribution of aortic wall calcification to this phenomenon has not been clarified. We therefore examined the effects of aortic calcification on cuffSBP and invCSBP in a cohort of patients representing all stages of CKD. During elective coronary angiography, invCSBP was measured in the ascending aorta with a fluid-filled catheter with simultaneous recording of cuffSBP using an oscillometric device. Furthermore, participants underwent a non-contrast computed tomography scan of the entire aorta with observer blinded calcification scoring of the aortic wall ad modum Agatston. We included 168 patients (mean age 67.0±10.5, 38 females) of whom 38 had normal kidney function, while 30, 40, 28, and 32 had CKD stage 3a, 3b, 4, and 5, respectively. Agatston scores adjusted for body surface area ranged from 48 to 40,165. We found that invCSBP increased 3.6 (95% confidence interval 1.4-5.7) mmHg relative to cuffSBP for every 10,000-increment in aortic Agatston score. This association remained significant after adjustment for age, diabetes, antihypertensive treatment, smoking, eGFR and BP level. No such association was found for diastolic BP. Patients with advanced aortic calcification have relatively higher invCSBP for the same cuffSBP as compared to patients with less calcification. Advanced aortic calcification in CKD may therefore result in hidden central hypertension despite apparently well-controlled cuffSBP.