Accuracy of Estimated Central Systolic Blood Pressure and Augmentation Index in Patients With Type 2 Diabetes Mellitus

Abstract

It has been suggested that transfer functions to estimate central aortic systolic blood pressure (SBP) and central BP waveform parameters (i.e., augmentation index) may be less accurate in patients with type 2 diabetes mellitus (T2DM). However, these observations have not been confirmed in a large sample, which was the aim of this study. Consecutive patients with and without T2DM undergoing coronary angiography at the Royal Hobart Hospital had BP recorded at the ascending aorta and radial artery with a fluid-filled catheter. Radial BP waveforms were processed using the SphygmoCor Cardiovascular Management System (CVMS) transfer function (AtCor, Sydney) to estimate central BP. Two invasive waveform calibration methods were used: 1) aortic mean arterial pressure/diastolic BP (MAP/DBP); and 2) radial SBP and DBP (SBP/DBP). between-group analyses were performed unadjusted and adjusted for age, sex, hypertension, hypercholesterolaemia, body mass index, and coronary artery disease. Data from 64 patients with T2DM (61±11 years, 73% male) and 186 patients without T2DM (62±8 years, 70% male) were analysed. There was no difference in the accuracy of estimated central SBP between groups when compared with invasive aortic SBP from MAP/DBP calibration (T2DM –1.8±6 mmHg vs –1.1±5 mmHg; p=0.37; adjusted p=0.59) or radial SBP/DBP calibration (T2DM –1.2±9 mmHg vs –2.0±9 mmHg; p=0.57; adjusted p=0.66). Augmentation index was not significantly different between patients with and without T2DM 0.8±12% vs 3.7±14%; p=0.13, respectively). Estimated central SBP and augmentation index do not appear to be less accurate in patients with T2DM when waveforms are calibrated with invasive BP.