Overall Males n = 874 n = 213 Ln-RHI 0.67 [+ or -] 0.32 0.63 [+ or -] 0.31 Ln-RHI < 0.51 293 (33.5) 35.2 Ln-RHI < 0.44 (1Q) 223 (25.5) 25.6 Females p value n = 661 Ln-RHI 0.68 [+ or -] 0.33 0.055 Ln-RHI < 0.51 33 ns Ln-RHI < 0.44 (1Q) 25.4 ns Values are expressed as median [+ or -] 1SD; Ln-RHI: logarithmic
reactive hyperemia index; 1Q: first quartile.
Post-occlusive
reactive hyperemia (PORH), an index of microvascular function was calculated as (peak cutaneous blood flow--baseline cutaneous blood flow)/baseline cutaneous blood flow x 100 (12).
Although the exact mechanism is unknown,
reactive hyperemia is thought to occur due to the build-up of vasodilator metabolites such as endothelium-derived nitric oxide following vascular occlusion, which decreases vascular resistance leading to increased blood flow to the ischemic tissue [47, 48].
Microvascular vasodilator response indices, improving the reproducibility of the method [16] were calculated: delta
reactive hyperemia ([DELTA]RH) as PUrh-PUb; percent change of
reactive hyperemia (% RH) as ([DELTA]RH/PUb)x100; the velocity of PORH microvascular response (Vrh) calculated through dividing of delta
reactive hyperemia by the time to peak blood flow ([DELTA]RH/t).
To explore the relationship between CHD and vascular endothelial function, CHD outpatients were recruited from our hospital and received the non-invasive detection of endothelial function (
reactive hyperemia index, RHI) with Endo-PAT2000 Diagnostic System.
Major finding: Rosuvastatin failed to improve pulmonary function overall, but significantly improved peripheral vasodilator function in patients with elevated hsCRP levels at baseline, indicated by a final
reactive hyperemia index of 2.8 vs.
In the Framingham Heart Study offspring cohort increased aortic stiffness was associated with higher forearm vascular resistance at baseline and during
reactive hyperemia, and with blunted flow reserve during hyperemia (39).
A transient increase in skin blood flow after ischemia is regulated by a protective mechanism called
reactive hyperemia [4850,56-57].
The diameter of brachial artery was measured by 10 MHz transducer in longitudinal section on 2-1,5 cm above the elbow bend before and after tests with
reactive hyperemia through 30-90 seconds.
HEPA filtration was linked to a 9.4% increase in the
reactive hyperemia index (RHI), a marker of endothelial function, and a 32.6% decrease in C-reactive protein, a marker of inflammation.
After analyzing their data, the researchers found portable HEPA filters reduced the average concentrations of fine particulates inside homes by 60 pc and woodsmoke by 75 pc, and their use was associated with improved endothelial function (a 9.4 pc increase in
reactive hyperemia index) and decreased inflammation (a 32.6 pc decrease in C-reactive protein).
This blood flow occlusion produces an ischemia-induced
reactive hyperemia and, upon occlusion release, an increase in shear stress.