PP.20.06: REFLECTED RATHER THAN FORWARD WAVE PRESSURES ACCOUNT FOR BRACHIAL PRESSURE-INDEPENDENT RELATIONS BETWEEN AORTIC PRESSURE AND END-ORGAN MEASURES. (June 2015)

• Record Type: Journal Article
• Authors: Norton, G.; Sibiya, M.; Booysen, H.; Raymond, A.; Millen, A.; Maseko, M.; Majane, O.; Sareli, P.; Libhaber, E.; Woodiwiss, A.
• Is Part Of: Journal of hypertension. Volume 33(2015)Supplement 1
• Publication Date: 2015-06
• Subjects: Hypertension -- Periodicals; Hypertension -- Periodicals; 616.132005
• DOI: 10.1097/01.hjh.0000468318.07557.0c
• Languages: English
• ISSNs: 1473-5598

Abstract

Abstract : Objective: Aortic blood pressure (BP) predicts outcomes and is associated with end-organ measures independent of brachial BP. Whether this is accounted for by the impact of aortic forward or backward waves on variations in aortic-to-brachial BP amplification is uncertain. We aimed to determine whether brachial BP-independent relations between aortic pressure and cardiovascular damage are better explained by reflected (backward)(Pb) or forward (Pf) wave pressure effects. Design and method: In 1174 participants from a community sample we assessed aortic pulse pressure (PPc), Pb and Pf using radial applanation tonometry and SphygmoCor software with wave separation analysis being conducted using a triangular aortic flow wave. End-organ measures were determined from left ventricular mass index (LVMI, n = 786) (echocardiography), aortic pulse wave velocity (PWV)(n = 1019), carotid intima-media thickness (IMT)(n = 578) and transmitral early-to-late LV diastolic velocity (E/A)(n = 779). Results: Independent of mean arterial pressure, central aortic pulse pressure (PPc) and both Pb and Pf were independently associated with end organ measures (p < 0.0001). With adjustments for brachial PP or systolic BP (SBP), PPc remained independently associated with end organ measures (p < 0.01 to < 0.0001). Moreover, with adjustments for brachial PP, Pb remained independently associated with LVMI (partial r = 0.09, p < 0.01), aortic PWV (partial r = 0.30, p < 0.0001), IMT (partial r = 0.30, p < 0.0001), and E/A (partial r = -0.31, p < 0.0001). With brachial SBP rather than PP as an adjustor, Pb retained independent associations with end organ measures (p < 0.0005 to < 0.0001). In contrast, with adjustments for brachial PP or SBP, Pf was not independently associated with LVMI (partial r = 0.06, p = 0.13), aortic PWV (partial r = 0.05, p = 0.09), IMT (partial r = 0.07, p = 0.10), or E/A (partial r = 0.06, p = 0.09). Adjustments for Pb, but not Pf markedly diminished the relationships between PPc and end-organ measures. Independent relations between Pb, but not Pf and end-organ changes were attributed in-part to Pb accounting for most of the variation in brachial-to-aortic PP amplification. Conclusions: Brachial BP-independent relations between aortic pressure and end-organ measures are largely attributed to an impact of reflected rather than forward wave pressures accounting for aortic-to-brachial BP amplification.