Cardiovagal and adrenergic function tests in unilateral carotid artery stenosis patients—a Valsalva manoeuvre tool to show an autonomic dysfunction?
Background: The stability of an arterial baroreflex depends also upon the integrity of the afferent limb. For its quantification, we can use a noninvasive test such as baroreceptor sensitivity estimation during Valsalva manoeuvre. The aim of this study was to evaluate potential autonomic dysfunction in patients with unilateral severe carotid disease and compare the results to the results obtained from an age and gender matched group of healthy volunteers.
Methods: We evaluated dynamic changes during Valsalva manoeuvre (Valsalva ratio, cardiovagal and adrenergic baroreceptor sensitivity, sympathetic indexes and its dynamic ranges) in 41 patients (29 males; 62.9 ± 7.4 years) and compared the results to results obtained from volunteers (62.8 ± 7.0 years).
Results: Valsalva ratio between the patients and control group revealed no significant difference, as well as cardiovagal and adrenergic baroreceptor sensitivity. Sympathetic indexes, except for sympathetic index 2, reflecting the sympathetic vasoconstrictor baroreceptor response in late phase 2 of Valsalva manoeuvre (7.1 ± 13.1 mmHg in patients vs. 11.4 ± 10.2 mmHg in control group; p = 0.012) showed no significant differences between the studied groups. The most prominent dynamic range between the groups was within the sympathetic index 2.
Conclusion: With some Valsalva manoeuvre test results, we were not able to show severe autonomic dysfunction in unilateral severe carotid stenosis patients except for lower vasoconstriction response within the late phase 2 of the manoeuvre.of uncomplicated and well-treated hypertension and no stroke or a transitory ischemic attack. Notice (arrow in picture b) a lower level of the blood pressure, not approaching to a baseline level at the end of phase 2 as it is a case in a normal Valsalva manoeuvre (arrow in picture a), probably due to a missing sustained sympathetic peripheral vasoconstriction. BP blood pressure, SBP systolic blood pressure, DBP diastolic blood pressure, HR heart rate, 1/min beats per minute, mmHg millimetres of Mercury, s seconds
Fig. 3: Comparison of sympathetic indexes SI1–SI3 obtained with Valsalva manoeuvre between both studied groups (a). Comparison of dynamic ranges of indexes SI1, SI2 and SI3 (b). Dynamic range (mean ± standard deviation) of SI2 (DR-SI2) exceeds the dynamic range of SI1 (DR-SI1) and SI3 (DR-SI3). SBP systolic blood pressure, SI1 sympathetic index 1, SI2 sympathetic index 2, SI3 sympathetic index 3, mmHg millimetres of mercury, DR-SI1 dynamic range between sympathetic index 1 in patients and control group, DR-SI2 dynamic range between sympathetic index 2 in patients and control group, DR-SI3 dynamic range between sympathetic index 3 in patients and control group