Hem 7131

The intravital capillaroscopy was performed with final 136× magnification on 19-inch display (Videocapillaroscopy: XS3000, JIANNENG Optical Instrument Lmt.com, An Hui, China; Display: Phillips 19S4QAB, Suzhou, China). The skin of the dorsum of the middle phalanx of the left hand was examined. Four microscopic fields (0.66 mm² per field) centered on an ink spot at each site were recorded continuously for 5 min to detect intermittently perfused capillaries, images and videos were coded and stored with Videocap 8.14 software (DS-Medical, Milan, Italy). Capillary density in the resting state was counted during a 15-second period, during which visible perfused capillaries (continuously and intermittently) were counted. We applied venous congestion (VC), with the digital cuff (OMRON, HEM-7131, Japan) inflated to 60 mmHg for 2 min, to expose a maximal number of non-perfused capillaries. Using the same visual fields that were used during resting state, the capillaries were counted in the 2-min recordings.
Skin capillary density (SCD) was counted offline to determine whether a capillary was present or not by a single-experienced investigator who was blinded to the group assignments from a freeze-framed reproduction of the videotape and from the running videotape, as well as the hypertensive status and blood pressure data of the study subjects.

Brachial BP were recorded in both arms, using an electronic device (OMRON M3, HEM-7131), with adequate cuffs for normal and large arms. Three measures were performed on both arms at three minutes intervals, in seated position after a rest of at least 15 minutes. On each arm, BP was defined as the average of the last two measurements. sIABPD ≥10 mmHg was defined as the absolute value of the difference for SBP between the left and right arms greater than or equal to 10 mmHg [9 (link)].