Ambulatory tonometric blood pressure measurements in patients with diabetes

Arterial tonometry is a novel technique for measuring ambulatory blood pressure (AMBP). The watch-like device BPro(®) (HealthSTATS International, Singapore) captures radial pulsewave reflection and calculates brachial blood pressure (BP). In this study we investigate if arterial tonometry is applicable and reliable in patients with diabetes.

We compared tonometric (BPro) to cuff-based oscillometric and auscultatoric BPs (Takeda model TM2421, A&D Medical, Tokyo, Japan) in 25 Caucasian patients with type 1 or type 2 diabetes. Patients were seen twice within 2 weeks. At visit 1, a 15-min rest was followed by the recording of three cuff-based BPs and 2-min continuous tonometric BPs. At both visits 24-h AMBP measurements were recorded with the BPro device.

At Visit 1, auscultatoric BP (mean±SD) was 136±19/72±8 mm Hg versus 138±19/78±8 mm Hg with the tonometric device. Visit 1 AMBP was 131±20/76±9 mm Hg versus 131±12/75±9 mm Hg at Visit 2. Mean 24-h AMBP, daytime BP, nighttime BP, and dipping at the two visits were similar (P>0.40). Linear and intraclass correlations coefficients between auscultatoric and tonometric systolic and diastolic BP were r=0.86 and 0.65, respectively (P<0.001 for both), and r=0.83 and 0.77, respectively (P<0.001 for both). The mean differences between devices were 1.9±10 and 5.5±6.6 mm Hg for systolic and diastolic BP, respectively.

In patients with diabetes tonometric and cuff-based BPs are comparable, and tonometric AMBPs are reproducible and feasible.