P6.07 A STUDY TO DETERMINE IF THE REFLECTED WAVE TRANSIT TIME FROM BRACHIAL SUPRASYSTOLIC WAVEFORM ANALYSIS IS REPRESENTATIVE OF LARGE ARTERY STIFFNESS

Abstract

Background: Aortic stiffness is clinically important, but measurement can be time consuming. The ‘reflected wave transit time’ (RWTT) is thought to represent aortic stiffness and, since this can be measured quickly by brachial cuff oscillometry, could be a useful new test. This study aimed to compare RWTT with directly measured aortic (as well as brachial) stiffness in non-diabetics and also diabetics where there would be an expectation of increased stiffness (lower RWTT). Methods: Aortic and brachial stiffness were recorded using tonometric pulse wave velocity (PWV; SphygmoCor) in 68 non diabetic (age 54.9±8.6 years,64.7% male) and 20 patients with type 2 diabetes (T2DM; age 60.5±9.6 years,55% male). RWTT was measured using brachial cuff oscillometry and suprasystolic waveform analysis (Pulscor®) as the time between the first and late systolic waves. Aortic PWV was also calculated from path length/RWTT in a subgroup of 69 patients. Results: T2DM patients had significantly higher aortic PWV (9.6±2.7 vs 7.7±1.6 m/s, p=0.005), but no difference in brachial PWV (7.6±1.1 vs 8.1±1.4 m/s, p=0.14). RWTT between T2DM and non-diabetics was not significantly different (0.16±0.02 vs 0.17±0.02 s, respectively p=0.12). There were no significant correlations between RWTT and aortic PWV or brachial PWV in either T2DM or non-diabetic groups (r>−0.05, p>0.05 all). Furthermore, calculated aortic PWV was not significantly related to actual aortic PWV (p>0.05). Conclusions: While brachial artery cuff oscillometric waveform analysis offers potentially useful clinical information, the transit time of pulse waves is not representative of large artery stiffness and, therefore, needs to be measured directly.