Comportamento hemodinâmico durante estresse mental em mulheres com hipotireoidismo subclínico

Abstract

Patients with subclinical hypothyroidism (SCH) have a higher risk of cardiovascular mortality. One possible explanation for this outcome may be a worsening of vascular function. However, the effects of SCH in hemodynamic response during mental stress physiological maneuver are not known. We hypothesized that women with HSC have impaired peripheral blood flow and peripheral vascular conductance during mental stress. We evaluated 20 women with SCH (SCH Group) and 21 euthyroid (Control Group) women, matched for age (37±11 vs. 38±10 years, p=0.699) and body mass index (26±5 vs. 25±5kg/m2, p=0.462). The muscle blood flow (MBF) (venous occlusion plethysmography), heart rate (HR) and blood pressure (BP) (Dixtal2023) were evaluated simultaneously during 3 min-baseline followed by 3-min of mental stress test (Stroop Color Word Test). Forearm vascular conductance (FVC) was calculated by dividing MBF by the blood pressure mean. Student t test and ANOVA were used, adopting significant p<0.05. The SCH group had greater TSH levels (7.57±3.17 vs. 2.10±0.88 mU/L, p<0.001). In baseline the groups HSC and Control were similar to HR (67±8 vs. 67±10, p=0.126), systolic blood pressure (130±11 vs. 128±10 mmHg, p=0.851), diastolic blood pressure (70±7 vs. 68±6, p=0.527), mean blood pressure (90±8 vs. 88±7, p=0.664), MBF (2.50±0.79 vs. 2.55±0.71ml/min/100ml, p=0.905) and FVC (2.80±0.90 vs. 2.92±0.88 units, p=0.952). During all mental stress test the groups SCH and Control increased significantly HR (time effect, p<0.001), BP (time effect, p<0.001), MBF (time effect, p<0.001) and FVC (time effect, p<0.001) compared with baseline. However, MBF and FVC were significantly lower in SCH group during first (MBF: 3.66±0.96 vs. 4.66±1.61 ml/min/100ml, p=0.018, effect size=0.78; FVC: 3.95±1.08 vs. 5.19±1.96 unidades, p=0.010, effect size=0.81) and second (MBF: 3.55±1.01 vs. 4.62±2.27 ml/min/100ml, p=0.018, effect sixe=0.65; FVC: 3.75±1.07 vs. 4.92±2.37 unidades, p=0.020, effect size=0.68) minuts of mental stress test. In conclusion women with SCH compared to euthyroid women have preserved HR and BP, however impaired MBF and FVC during mental stress.