Estudo ultrassonográfico da hemodinâmica cerebral de pacientes com doença de Parkinson e fatores de risco para doença cerebrovascular

Abstract

Background: The association between unfavorable functional outcomes in patients with Parkinson's Disease (PD) and the concomitant presence of Cerebrovascular Disease (CVD) has been the subject of increasing investigation. This study aimed to analyze the cerebral hemodynamics of Parkinsonian patients with risk factors for CVD, considering different clinical phenotypes, using transcranial color Doppler ultrasound (TCDU). Methodology: This analytical, observational, cross-sectional, and singlecenter study included TCDU exams in individuals diagnosed with PD. Patients who met the research requirements were selected. Hemodynamic variables, such as mean flow velocities (Vm), resistance index (RI), pulsatility index (PI) of the middle cerebral artery, and apnea index (AI) for the assessment of cerebrovascular reactivity (CVR), were all quantified. For clinical evaluation, standardized functional scales were used, including UPDRS III, Hoehn & Yahr modificada, and MoCA. Some patients also underwent brain MRI to quantify the degree of white matter lesions. The participants were subdivided into two groups based on vascular risk factors: one group with two or more risk factors (PDvasc) and another with less than two (PDnvasc). Additionally, a parallel analysis of motor subtypes was conducted, considering the Rigid-Akinetic and Tremor-Dominant phenotypes. Results: TCDU exams were performed on 97 individuals with PD. After applying the inclusion and exclusion criteria, 64 patients became eligible for analysis. Among the evaluated patients, approximately 50% showed alterations in CVR. The analysis revealed that the PDvasc group had a 4.7 times higher likelihood of presenting significant alterations in CVR compared to the PDnvasc group (p=0.007). The mean velocity of the middle cerebral artery after apnea was significantly lower in the PDvasc group (p=0.030), and the AI was also lower in this group (p=0.015). On the other hand, the RI and PI were considerably higher in the PDvasc group, with p=0.042 and p=0.001, respectively. Additionally, the Fazekas score, indicative of subcortical lesions, was higher in the PDvasc group (p=0.0047), suggesting a greater burden of cerebrovascular lesions (n=20). Regarding motor subtypes, alteration in CVR was observed in 64% of patients with the rigid-akinetic phenotype, compared to only 36% in the tremor-dominant group (p=0.024). The odds ratio analysis revealed a 3.18 times higher chance of CVR alteration in patients with the rigid-akinetic phenotype. The average AI value was significantly lower in the rigidakinetic phenotype (p=0.001), which supports a more pronounced vascular reactivity impairment in this group. The mean velocity after apnea was also significantly lower in individuals with the rigid-akinetic phenotype (p=0.0084), while the PI was substantially higher in this phenotype (p=0.0295). Conclusions: The data suggest that the presence of two or more vascular risk factors significantly impacts cerebrovascular reactivity in patients with PD, compromising their cerebrovascular function. Additionally, patients with the rigid-akinetic phenotype show more intense vascular impairment, which may be associated with a less favorable functional prognosis. Future prospective studies should explore the interaction between cerebral hemodynamics and neurodegeneration, aiming to identify prognostic markers and more effective therapeutic strategies for this patient group.