Aortic blood pressure (BP) has been shown as a stronger predictor of target organ damage than brachial BP. Whether pre-treatment aortic BP is a better determinant of early anti-hypertensive response than brachial BP is not known.

We analysed the pre and post treatment haemodynamic data on untreated hypertensive subjects (n=290) aged 51±0.6 years, who had received in random fashion ; ACE inhibitors, angiotensin receptor blockers, calcium antagonists & nebivolol (vasodilators) & non-vasodilating agents ; atenolol & thiazide diuretics. Data were analysed using JMP Version 7.1.

Baseline aortic systolic BP showed a better correlation with reduction in either brachial or aortic systolic BP compared with brachial systolic BP. In subjects < 50 years, baseline aortic systolic BP showed a stronger correlation with brachial systolic response(r=0.38, p<0.0001) than brachial systolic BP(r=0.28, p<0.001). Baseline brachial systolic BP showed a poor correlation with reduction in aortic systolic (r=0.19, p<0.05) compared with baseline aortic systolic BP(r=0.37, p<0.0001). In those >50 years, pre-treatment brachial(r=0.46, p<0.0001) and aortic (r=0.47, p<0.0001) systolic BP showed similar correlations. Baseline aortic systolic BP showed a better correlation with BP response to vasodilating anti-hypertensives (r=0.42, p<0.0001) than non-vasodilator agents(r=0.36, p<0.0001). In multiple regression analysis, gender, vasodilator agents and baseline aortic systolic BP emerged as independent determinants of brachial BP response with no significant contribution from brachial systolic BP.

Aortic BP is a better determinant of BP response than brachial BP, especially in young hypertensive patients and particularly to vasodilating antihypertensives and may guide choice of initial anti-hypertensive agent in the young patient.