Background: The blood pressure (BP) in the ascending aorta can be estimated non-invasively by pulse wave analysis using commercially available devices such as the SphygmoCor. However, this device has not been validated for use in patients with chronic kidney disease (CKD).

Objectives: Comparison of non-invasively obtained estimates of central BP with invasively measured central BP in CKD patients.

Methods: Patients with stable CKD stage 3–5 corresponding to an estimated glomerular filtration rate (eGFR) under 60 ml/min undergoing elective coronary angiography were included. Central BP was estimated by the SphygmoCor using four different calibrations: Invasive aortic diastolic and mean BP (invasive), systolic and diastolic brachial BP (sys-dia), brachial diastolic and mean arterial BP (form factor 0.33) (ff-0.33), and brachial diastolic and mean arterial BP (form factor 0.4) (ff-0.4). Brachial artery BP was measured simultaneously with a validated oscillometric BP device.

Results: Forty-nine patients, 65% males, age 61±13 (mean±SD) with a median eGFR of 18 ml/min (range 5–59 ml/min) were enrolled. Invasive BP was 150.8±22/ 75.4±11 mmHg while brachial BP was 147.3±19 /86.0±10 mmHg (mean differences: −3.6±9.3/10.6±7.9 mmHg (P<0.012).

Mean differences (invasive minus estimated central BP) with the four calibrations used were: −5.9±6.1/1.3±1.0 mmHg, P<0.001 (invasive); −16.0±9.3/11.5±8.0 mmHg, P<0.001 (sys-dia); −17.5±10.5/11.5±7.9 mmHg, P<0.001 (ff-0.33); −7.5±10.2 /11.6±7.9 mmHg, P<0.001 (ff-0.4).

Conclusion: In CKD patients, we found a systematic difference between estimated and invasively measured central BP. Surprisingly, brachial systolic BP was very close to invasively measured central systolic BP and was even more accurate than estimates based on calibration with invasively obtained BP.