Effects of baroreflex activation therapy on arterial stiffness and central hemodynamics in patients with resistant hypertension

Background: High central blood pressure, augmentation index and pulse wave velocity are independent cardiovascular risk factors. Little is known of the effect of baroreflex activation therapy on central hemodynamics. Method: In this prospective clinical trial, radial artery applanation tonometry and pulse wave analysis were used to derive central aortic pressure and hemodynamic indices (i.e. augmentation pressure, augmentation index, pulse wave velocity, systolic and diastolic pressure time integral, subendocardial viability index) at baseline and 6 months after starting baroreflex activation therapy in 25 patients with resistant hypertension. Results: Apart from peripheral blood pressure reduction, 6 months of baroreflex activation therapy significantly reduced mean central aortic blood pressure from 109.7 +/- 20.5 to 97.4 +/- 18.8mmHg (P<0.01) and aortic pulse pressure from 62.9 +/- 18.6 to 55.2 +/- 16.0mmHg (P< 0.01). Aortic augmentation pressure and augmentation index at a heart rate of 75 b.p.m. were significantly reduced by 4.3 +/- 7.9mmHg (P +/- 0.01) and 3.5 +/- 6.8% (P +/- 0.02). Additionally, pulse wave velocity decreased from 10.3 +/- 2.6 to 8.6 +/- 1.3 m/s (P< 0.01) 6 months after starting baroreflex activation therapy. Systolic pressure time integral was significantly reduced (P +/- 0.03), whereas subendocardial viability index remained unchanged. Conclusion: Apart from peripheral blood pressure, baroreflex activation therapy reduces central blood pressure, augmentation index at a heart rate of 75 b.p.m. and pulse wave velocity in patients with resistant hypertension, suggesting strong potential to reduce cardiovascular risk.