Early Detection of the Hypertension-Mediated Brain Damage Using the Clock-Drawing Test

Abstract Background The hypertension-mediated brain damage is more frequent than cardiac or renal damage, but early silent brain damage is not routinely included in the evaluation of patients with hypertension. Consequently, hypertensive patients with early brain damage are unidentified and their cardiovascular risk underestimated. If we consider cognitive impairment as a surrogate of vascular brain damage, a cognitive test implemented in the routine clinical evaluation of hypertensive patients could detect early cerebral small vessel disease. The aim of the study was to estimate the prevalence of cerebral, cardiac and renal organ damage in hypertensive patients and evaluate the usefulness of the clock-drawing test for brain damage detection. Patients and Methods Multicenter, multinational, cross-sectional study in patients with essential hypertension seen in four centers in Argentina and one center in Uruguay. Organ damage was assessed by means of glomerular filtration rate (GFR, Cockcroft-Gault equation), left ventricular mass index (LVMI) and the clock-drawing test. Results A sample of 441 patients (mean age 63.2 ± 11.8 years, 53.2% female) was included. Of all participants, 60.5% presented impairment of some marker of target organ damage. The heart (elevated LVMI) was affected 32.8% and the kidney (reduced GFR) in 20.4% while silent brain damage (abnormal clock-drawing test) was observed in 38% of all patients. In addition, abnormal clock-drawing test was seen in 47.2% of hypertensive patients with cardiac and/or renal damage, and in 30.7% of patients without cardiac and/or renal damage. Conclusion Silent brain damage was more prevalent than pre-clinical cardiac and/or renal damage. The clock-drawing test turned out to be a useful tool in routine clinical practice to detect early brain damage expressed as mild cognitive impairment in hypertensive patients.