Assessing the Accuracy of Systolic Aortic Pressure Estimation From a Brachial Cuff Alone: A Comparison With Radial Tonometry.

Background: A novel method for estimating central systolic aortic pressure (cSAP) has emerged, relying solely on the peripheral mean (MBP) and diastolic (DBP) blood pressures. We aimed to assess the accuracy of this Direct Central Blood Pressure estimation using cuff alone (DCBPcuff = MBP2/DBP) in comparison to the use of a generalized transfer function to derive cSAP from radial tonometry (cSAPtono).

Methods: This retrospective analysis involved the International Database of Central Arterial Properties for Risk Stratification (IDCARS) data (Aparicio et al., Am J Hypertens 2022). The dataset encompassed 10,930 subjects from 13 longitudinal cohort studies worldwide (54.8% women; median age 46.0 years; office hypertension: 40.1%; treated: 61.0%), documenting cSAPtono via SphygmoCor calibrated against brachial systolic BP (SBP) and DBP. Our analysis focused on aggregate group data from 12/13 studies (89% patients) where a full BP dataset was available. A 35% form factor was used to estimate MBP = (DBP + (0.35 × (SBP-DBP)), from which DCBPcuff was derived. The predefined acceptable error for cSAPtono estimation was set at ≤ 5 mm Hg.

Results: The cSAPtono values ranged from 103.8-127.0 mm Hg (n = 12). The error between DCBPcuff and cSAPtono was 0.2 ± 1.4 mm Hg, with no influence of the mean. Errors ranged from -1.8 to 2.9 mm Hg across studies. No significant difference in errors was observed between BP measurements obtained via oscillometry (n = 9) vs. auscultation (n = 3) (P = 0.50).

Conclusions: Using published aggregate group data and a 35% form factor, DCBPcuff demonstrated remarkable accuracy in estimating cSAPtono, regardless of the BP measurement technique. However, given that individual BP values were unavailable, further documentation is required to establish DCBPcuff's precision.