Brachial Artery “Low-Flow Mediated Constriction” Is Associated with Myocardial Perfusion Defect Severity and Mediated by an Altered Flow Pattern during Occlusion

Introduction: The relationship between low flow-mediated constriction (LFMC), a new proposed measure of endothelial function, with cardiovascular disease severity and its hypothesized stimulus, that is, low flow, has not been comprehensively evaluated. The study evaluated association between change in brachial artery diameter during constriction with severity of myocardial perfusion defect (PD) and alterations in different components of flow profile. Methods: Brachial artery responses to occlusion were assessed in 91 patients and 30 healthy subjects. Change in anterograde and retrograde blood flow velocities (delta anterograde blood flow velocity and retrograde blood flow velocity), anterograde shear rate and retrograde shear rate (delta ASR and RSR, respectively), and oscillatory shear index (delta) during forearm occlusion at 50 mm Hg above systolic pressure, from baseline was calculated. Myocardial perfusion was evaluated in patients using exercise single positron emission computed tomography and % myocardial PD was calculated from summed stress score. Results: LFMC emerged as independent predictor of defect severity after correcting for age and gender (p = 0.014). Sixty-seven patients (73.6%) and 15 healthy subjects (50%) showed constriction during occlusion. In stepwise backward regression analysis, RSR contributed 35.5% and ASR contributed 20.1% of the total 63.9% variability in artery diameter during occlusion. Conclusion: The results suggest that LFMC is independently associated with myocardial perfusion severity and is “mediated” by an altered flow profile during occlusion.

Download Full-text

Influence of prostaglandins and endothelial-derived hyperpolarizing factors on brachial and popliteal endothelial-dependent function in young adults

Journal of Applied Physiology ◽

10.1152/japplphysiol.00698.2020 ◽

2021 ◽

Vol 130 (1) ◽

pp. 17-25

Author(s):

Jennifer L. Petterson ◽

Myles W. O’Brien ◽

Jarrett A. Johns ◽

Jack Chiasson ◽

Derek S. Kimmerly

Keyword(s):

Blood Flow ◽

Young Adults ◽

Shear Rate ◽

Brachial Artery ◽

Popliteal Artery ◽

Lower Limb ◽

Low Flow ◽

Flow Mediated Dilation ◽

Artery Blood Flow ◽

Dependent Function

We compared changes in upper- and lower-limb artery endothelial-dependent vasodilatory and vasoconstrictor responses between control, prostaglandin inhibition, and endothelial-derived hyperpolarizing factor inhibition conditions. Neither prostaglandins nor endothelial-derived hyperpolarizing factor influenced flow-mediated dilation responses in either the brachial or popliteal artery. In contrast, endothelial-derived hyperpolarizing factor, but not prostaglandins, reduced resting brachial artery blood flow and shear rate and resting popliteal artery diameter, as well as low-flow-mediated constriction responses in both the popliteal and brachial arteries.

Download Full-text

Exercise intensity modulates brachial artery retrograde blood flow and shear rate during leg cycling in hypoxia

Physiological Reports ◽

10.14814/phy2.12423 ◽

2015 ◽

Vol 3 (6) ◽

pp. e12423 ◽

Cited By ~ 5

Author(s):

Erika Iwamoto ◽

Keisho Katayama ◽

Koji Ishida

Keyword(s):

Blood Flow ◽

Shear Rate ◽

Brachial Artery ◽

Exercise Intensity ◽

Leg Cycling ◽

Retrograde Blood Flow

Download Full-text

Elevation in blood flow and shear rate prevents hyperglycemia-induced endothelial dysfunction in healthy subjects and those with type 2 diabetes

Journal of Applied Physiology ◽

10.1152/japplphysiol.00936.2014 ◽

2015 ◽

Vol 118 (5) ◽

pp. 579-585 ◽

Cited By ~ 14

Author(s):

Arno Greyling ◽

Tim H. A. Schreuder ◽

Thijs Landman ◽

Richard Draijer ◽

Rebecca J. H. M. Verheggen ◽

...

Keyword(s):

Type 2 Diabetes ◽

Blood Flow ◽

Shear Rate ◽

Endothelial Function ◽

Brachial Artery ◽

Interaction Effect ◽

Healthy Subjects ◽

Local Heating ◽

Oral Glucose

Hyperglycemia, commonly present after a meal, causes transient impairment in endothelial function. We examined whether increases in blood flow (BF) protect against the hyperglycemia-mediated decrease in endothelial function in healthy subjects and patients with type 2 diabetes mellitus (T2DM). Ten healthy subjects and 10 age- and sex-matched patients with T2DM underwent simultaneous bilateral assessment of brachial artery endothelial function by means of flow-mediated dilation (FMD) using high-resolution echo-Doppler. FMD was examined before and 60, 120, and 150 min after a 75-g oral glucose challenge. We unilaterally manipulated BF by heating one arm between minute 30 and minute 60. Oral glucose administration caused a statistically significant, transient increase in blood glucose in both groups ( P < 0.001). Forearm skin temperature, brachial artery BF, and shear rate significantly increased in the heated arm ( P < 0.001), and to a greater extent compared with the nonheated arm in both groups (interaction effect P < 0.001). The glucose load caused a transient decrease in FMD% ( P < 0.05), whereas heating significantly prevented the decline (interaction effect P < 0.01). Also, when correcting for changes in diameter and shear rate, we found that the hyperglycemia-induced decrease in FMD can be prevented by local heating ( P < 0.05). These effects on FMD were observed in both groups. Our data indicate that nonmetabolically driven elevation in BF and shear rate can similarly prevent the hyperglycemia-induced decline in conduit artery endothelial function in healthy volunteers and in patients with type 2 diabetes. Additional research is warranted to confirm that other interventions that increase BF and shear rate equally protect the endothelium when challenged by hyperglycemia.

Download Full-text