Brachial-to-radial systolic blood pressure amplification in patients with type 2 diabetes mellitus

Brachial-to-radial-systolic blood pressure amplification (bra-rad-sbpamp) can affect central sbp estimated by radial tonometry. patients with type 2 diabetes mellitus (t2dm) have vascular irregularities that may alter bra-rad-sbpamp. by comparing t2dm with non-diabetic controls, we aimed to determine the (1) magnitude of bra-rad-sbpamp; (2) haemodynamic factors related to bra-rad-sbpamp; and (3) effect of bra-rad-sbpamp on estimated central sbp. twenty t2dm (64±8 years) and 20 non-diabetic controls (60±8 years; 50% male both) underwent simultaneous cuff deflation and two-dimensional ultrasound imaging of the brachial and radial arteries. the first korotkoff sound (denoting sbp) was identified from the first inflection point of doppler flow during cuff deflation. bra-rad-sbpamp was calculated by radial minus brachial sbp. upper limb and systemic haemodynamics were recorded by tonometry and ultrasound. radial sbp was higher than brachial sbp for t2dm (136±19 vs 127±17 mm hg; p<0.001) and non-diabetic controls (135±12 vs 121±11 mm hg; p<0.001), but bra-rad-sbpamp was significantly lower in t2dm (9±8 vs 14±7 mm hg; p=0.042). the product of brachial mean flow velocity × brachial diameter was inversely and independently correlated with bra-rad-sbpamp in t2dm (β=−0.033 95% confidence interval −0.063 to −0.004, p=0.030). when radial waveforms were calibrated using radial, compared with brachial sbp, central sbp was significantly higher in both groups (t2dm, 116±13 vs 125±15 mm hg; and controls, 112±10 vs 124±11 mm hg; p<0.001 both) and there was a significant increase in the number of participants classified with ‘central hypertension’ (sbp⩾130 mm hg; p=0.004). compared with non-diabetic controls, bra-rad-sbpamp is significantly lower in t2dm. regardless of disease status, radial sbp is higher than brachial sbp and this results in underestimation of central sbp using brachial-bp-calibrated radial tonometry.