The Inter-Arm Diastolic Blood Pressure Difference Induced by One Arm Ischemia: A New Approach to Assess Vascular Endothelia Function

OBJECTIVES To evaluate whether inter-arm diastolic blood pressure difference (DBPl-r) induced by one arm ischemia correlates with flow-mediated dilatation (FMD). METHODS Bilateral arm BPs were simultaneously measured with two automatic devices and right brachial artery diameter (D) was measured by ultrasound technique in 108 subjects (56 hypertensives and 52 normotensives). Following baseline diameter (D0) and BP measurement, right brachial artery was occluded for 5 minutes. The diameter was measured at 1, 1.5 and 2 min, and bilateral BPs measured at 3, 4 and 5 min after occlusion release. Their averages were recorded as post-D and post-BP, respectively. The difference between post-D and D0 (ΔD) was calculated as the percentage increase of artery diameter (ΔD/D0). The BP difference between left and right arms was calculated as BPl-r, and the difference of post- BPl-r and baseline BPl-r was recorded as the net change of BPl-r (ΔBPl-r). RESULTS At baseline, bilateral SBPs and DBPs were similar. Right arm ischemia induced significant DBP decline only in the right arm (68.8±12.7 vs 72.6±12.0 mmHg, P<0.05), which led to an increase of ΔDBPl-r (4.00±3.75 vs 0.78±4.47 mmHg, P<0.05). A positive correlation was seen between ΔD/D0 and ΔDBPl-r (r = 0.744, p<0.001). Furthermore, the correlation between age and ΔDBPl-r (r = -0.358, P<0.01) was similar to that between age and D/D0 (r = -0.398, P<0.01). Meanwhile, both ΔDBPl-r and ΔD/D0 were significantly lower in hypertensive patients than in normotensive patients. CONCLUSION The inter-arm DBP difference induced by one arm ischemia may be a potential index for clinical evaluation of vascular endothelial function.