Aortic Calcification and Central Blood Pressure in Patients With Chronic Kidney Disease

Aortic Calcification and Central Blood Pressure in Patients With Chronic Kidney Disease

Aim and background:

This study will seek to identify physiological and biochemical factors explaining and predicting a higher than expected central (aortic) blood pressure (BP) in patients with chronic kidney disease (CKD). The basic hypothesis of the study is that the degree of aortic calcification is an important component of elevated central BP, which, in turn, is important for the organ-damage and increased risk of cardiovascular disease associated with CKD.

Methods:

Adult patients with varying degrees of CKD undergoing scheduled coronary angiography (CAG) at Aarhus University Hospital will be included in this study.

During the CAG procedure, systolic and diastolic BP is determined in the ascending part of aorta by a calibrated pressure transducer connected to the fluid-filled CAG catheter.

Simultaneous with the registration of invasive aortic BP, estimation of central BP is performed using radial artery tonometry (SphygmoCor®), while a corresponding brachial BP is also measured.

Prior to the CAG, a non-contrast CT scan of aorta in its entirety will be performed to enable blinded quantification of calcification in the wall of aorta and coronary arteries.

Furthermore, echocardiography, resting BP measurement and a range of blood- and urine samples will be performed.

Inclusion Criteria:

• Age >18 years
• Patient referred for planned CAG at the Department of Cardiology, Aarhus University Hospital (AUH)
• eGFR constantly either >60 ml/min or <60 ml/min in at least 2 separate blood-sample measurements over at least 3 months.
• Signed informed consent-form.

Exclusion Criteria:

• Antihypertensive treatment changed within the last two weeks prior to the CAG.
• Severe aortic valve stenosis (<1 cm) as central hemodynamics may be altered
• Maximum number of patients in CKD-group already reached.
• Atrial fibrillation or other cardiac arrhythmia making radial Pulse Wave Analysis (PWA) estimations impossible.
• Known significant stenosis of a. subclavia or a. brachialis
• Bilateral arteriovenous-fistula (even if one or both of these have been surgically removed) as this may significantly affect the pulse-wave form.