Objective: Indices of arterial stiffness and aortic pressure are usually assessed by applanation tonometry. The more recently introduced oscillometric device is simpler to use. Several studies have investigated the agreement between these two devices, but not in populations with elevated levels of arterial stiffness. Therefore, we evaluated the agreement in an elderly population with high risk of arterial stiffness.
Patients and methods: We included a subgroup of the B-PROOF study (n=344, mean age 73 years, 60% men), whose aortic pulse wave velocity (aPWV), aortic augmentation index (AIx), aortic pulse pressure (PP), and aortic systolic blood pressure (SBP) were assessed both with applanation tonometry (SphygmoCor) and with oscillometry (Arteriograph). We investigated agreement between the two devices using Pearson correlations and Bland-Altman analysis. We carried out a stratified analysis in participants with more pronounced arterial stiffness (SphygmoCor aPWV>12 m/s).
Results: The oscillometric method produced higher values of AIx, aortic PP, and aortic SBP (P<0.01) than applanation tonometry. aPWV values were lower (P<0.01) and were not correlated (r=-0.06, P=0.92), whereas AIx measurements (r=0.35 P<0.01), aortic PP (r=0.57 P<0.01), and aortic SBP (r=0.68 P<0.01) measurements were correlated. Bland-Altman analysis showed insufficient agreement between the two devices, especially in those with elevated levels of arterial stiffness (aPWV>12 m/s).
Conclusion: Particularly in the elderly with elevated levels of arterial stiffness, measurements of aPWV obtained with oscillometry and applanation tonometry show poor agreement. Also, AIx, aortic SBP, and aortic PP show clearly less than optimal agreement.