P86 Blunted Cerebral Microcirculation Oxygenation During Exercise in Newly Diagnosed Hypertensive Patients: Links with Indices of Macrocirculation and Arterial Stiffness

Abstract

Purpose/Background/Objective

Hypertension has been considered as one of the most common modifiable risk factors for stroke and cognitive impairment. Decreased cerebral perfusion and oxygenation, as a result of capillary rarefaction and microvascular impairment of brain vessels, have been suggested as potentials underlying mechanisms. However, there is no study investigating whether these parameters are present in newlydiagnosed hypertensive patients (HP), without any co-morbidities. Thus, we examined (i) whether functional activation of the human cerebral cortex during handgrip exercise is altered in newly diagnosed HP and (ii) whether cerebral oxygenation correlates with different markers of arterial stiffness.

Methods

Forty-five newly diagnosed HP and 36 normotensives underwent an exercise protocol, consisting of a 3-min-rest, a 3-min-handgrip exercise (30% MVC), and a 3-min-recovery. Continuous-near-infrared-spectroscopy (NIRS) was used to monitor changes in cerebral-[O2Hb]. IMT, Augmentation Index, Central-BP and PWV (Sphygmocor) were assessed.

Results

No significant differences were detected between groups in age, BMI, sex, MVC and force maintained during handgrip. During handgrip, cerebral[O2Hb] increased in both groups; however, hypertensive patientsexhibited a significantly lower average response than normotensives [1.6(1.1–2.7) vs. 2.4(1.4–3.2)mM], respectively, p < 0.05 and a lower peak [O2Hb] [4.2(3.3–6.2) vs. 5.9(4.3–9.2), p < 0.01]. Significant negative correlations were found between cerebral-[O2Hb] and aortic BP, AI, and PWV.

Conclusions

Hypertensive patients exhibited a blunted cerebral [O2Hb] response during handgrip exercise compared to their normotensive counterparts. This blunted increase in cerebral oxygenation during exercise was present in patients with recent diagnosis of hypertension and without evident TOD and correlated with macrovascular stiffening, indicating a cross-talk between micro- and microcirculation.