4.6 Elevation in Central Blood Pressure During Exercise is Predominantly Driven by Forward-Propagating Waves: A First in Man Invasive Exercise Study

• Published in: Artery research Vol. 6; no. 4; p. 148
• Main Authors: Schultz, M. G., Davies, J. E., Black, A., Roberts-Thomson, P., Hughes, A. D., Sharman, J. E.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2012; Springer Nature B.V; BMC
• Subjects: Blood pressure; Cardiovascular disease; Conference Abstract; Flow velocity; Hypertension
• ISSN: 1872-9312; 1876-4401; 1876-4401
• DOI: 10.1016/j.artres.2012.09.030

Introduction Exercise hypertension independently predicts cardiovascular mortality, but little is known on exercise central haemodynamics. This study aimed to determine contributions of arterial wave travel and aortic reservoir characteristics to central blood pressure (BP) during exercise. We hypothesised exercise central BP would be principally related to forward wave travel and aortic reservoir function. Methods Invasive pressure and flow velocity were recorded in the ascending aorta via sensor-tipped intra-arterial wire in 10 participants (age 55±10 years, 70% male) with normal left-ventricular function and free from obstructive coronary artery disease. Measures were recorded at baseline and during supine cycle ergometry. Using wave intensity analysis, dominant wave types throughout the cardiac cycle were identified (forward, backward, compression and decompression), and aortic reservoir and excess pressure were calculated. Results Central systolic BP increased significantly with exercise (19±12 mmHg, P<0.001). This was associated with significant increases in early systolic forward compression waves (15×10 6 ± 18×10 6 W.m −2 s −2 , P = 0.025) and forward decompression waves in late systole (9×10 6 ± 5×10 6 W.m −2 s −2 , P<0.001). Despite significant augmentation in BP (+10%, P = 0.023), backward (reflected) waves did not increase in magnitude (-1×10 6 ±2×10 6 W.m −2 s −2 , P = 0.241). Excess pressure rose significantly with exercise (16±9 mmHg, P<0.001), and reservoir pressure integral fell (-5×10 5 ± 5×10 5 W.m −2 s −2 , P = 0.010). The change in reflection coefficient negatively correlated with change in central systolic BP (r = −0.682, P = 0.030). Conclusion Raised exercise central BP is principally driven by increasing aortic forward wave propagation generated by left ventricular ejection, and not wave reflection. These findings have relevance to understanding the pathophysiology of exercise hypertension.