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RESUMEN El diagnóstico de muchas de las enfermedades neurológicas no transmisibles requiere de la práctica de una resonancia magnética, la cual no se encuentra disponible en regiones rurales o remotas. Es importante realizar esfuerzos destinados a encontrar pruebas diagnósticas portátiles que sirvan como tamizaje para la identificación de personas que necesitan ser sometidas a una IRM. Como parte del Proyecto Atahualpa, hemos invitado a todos los participantes ≥60 años para la práctica de una IRM de cerebro y aproximadamente el 80% de las personas han aceptado el procedimiento. Por lo tanto, tenemos la oportunidad única de probar la validez de pruebas no-invasivas que puedan ser utilizadas como substitutos de resonancia para identificar candidatos a hacerse dicho examen. Hasta la fecha, hemos estudiado el valor del índice tobillo-brazo, la confiabilidad de la relación neutrófilos-linfocitos, la exactitud de la presencia de retinopatía hipertensiva y el valor del Doppler transcraneal para la detección de personas con enfermedad de pequeño vaso cerebral. Los individuos con índice tobillo-brazo anormal tiene 4 veces más riesgo de tener un infarto lacunar silente que aquellos con índice normal. Una relación neutrófilos-linfocitos elevada es pobremente sensitiva pero altamente específica para detectar personas con por lo menos un marcador de imagen de enfermedad de pequeño vaso. Los individuos con retinopatía hipertensiva Grados 2-3 tienen casi 4 veces más riesgo de tener hiperintensidades de sustancia blanca que aquellos con retinopatía Grado 1 o sin retinopatía. Finalmente, la correlación del índice de pulsatilidad de las arterias intracraneales para detectar marcadores de enfermedad de pequeño vaso es pobre. Seguimos en la búsqueda de una prueba económica y confiable que permita la identificación de sujetos aparentemente sanos, con riesgo de desarrollar eventos cerebrovasculares catastróficos.
ABSTRACT Diagnosis of many non-communicable neurological diseases require the use of MRI, which is not readily available in remote rural populations. Efforts should be directed to find portable screening diagnostic tools that may help identify candidates for MRI screening. In the Atahualpa Project, all participants aged ≥60 years have been invited for the practice of MRI, and about 80% of them have underwent the procedure. Therefore, we have the unique opportunity to test the accuracy of non-invasive exams to be used as surrogates to MRI for identifying candidates for the practice of this exam. To date, we have assessed the value of the ankle-brachial index ABI), the reliability of the neutrophil-to-lymphocyte ratio (NLR), the accuracy of hypertensive retinopathy, and the value of transcranial Doppler (TCD) to detect individuals with cerebral small vessel disease. Individuals with an abnormal ABI have 4 times de odds of having a silent lacunar infarct than those with a normal ABI. A high NLR has a poor sensitivity but is highly specific for detecting persons with at least one imaging signature of small vessel disease. Individuals with hypertensive retinopathy Grades 2-3 are almost four times more likely to have moderate-to-severe white matter hyperintensities than those with no- or only Grade 1 retinopathy. Finally, the correlation between the pulsatility indexes of major cerebral arteries with imaging markers of small vessel disease, as assessed by TCD, was poor. We are still in the search of some non-expensive and readily available biomarker that allow the identification of apparently healthy persons at risk of suffering a catastrophic cerebrovascular event.
RESUMEN
BACKGROUND: Diagnosis of cerebral small vessel disease (SVD) is a challenge in remote areas where MRI is not available. Hypertensive retinopathy (HTRP) has shown to correlate with SVD in different ethnic groups, but there is no information from indigenous Latin American people. We assessed the usefulness of retinal photographs to detect cases with SVD among Amerindians living in rural Ecuador. METHODS: Atahualpa residents aged ≥60years with arterial hypertension or prehypertension were identified during a door-to-door survey. A confocal line scanning laser ophthalmoscope was used to identify and grade HTRP (according to the Keith-Wagener-Barker classification). MRIs were read with attention to the presence of white matter hyperintensities (WMH) of presumed vascular origin and lacunar infarcts. Using logistic regression models, we evaluated whether HTRP was independently associated with neuroimaging signatures of SVD. RESULTS: Of 323 eligible candidates, 241 (75%) were enrolled. MRI readings revealed moderate-to-severe WMH in 49 (20%) cases and lacunar infarcts in 29 (12%). HTRP Grade 1 was noticed in 90 (37%) individuals and Grade 2-3 in 42 (17%). After adjusting for demographics and cardiovascular risk factors, multivariate analyses showed a significant association between Grades 2-3 HTRP and moderate-to-severe WMH (OR: 3.87, 95% C.I.: 1.64-9.13) but not with lacunar infarcts (OR: 2.22, 95% C.I.: 0.83-5.92). CONCLUSION: Amerindians with HTRP Grades 2-3 are almost four times more likely to have SVD-related subcortical damage than those with no- or only Grade 1-HTRP. Retinal photographs might allow recognition of people who need further investigation and therapy.