Cognitive dysfunction in congestive heart failure: transcranial Doppler evidence of microembolic etiology

Cognitive symptoms are common in patients with congestive heart failure (CHF) and are usually attributed to low cerebral blood flow. In the present study, we aimed to evaluate global cognitive function (Mini Mental State Exam MMSE) in relation to both cardiac function (evaluated by echocardiogram) and cerebrovascular hemodynamics (evaluated by transcranial Doppler TCD) in CHF patients. In 83 patients studied, no correlation was found between echocardiographic parameters and MMSE scores. In contrast, a significant correlation was found between right middle cerebral artery (RMCA) mean flow velocity and MMSE score (r=0.231 p=0.039), as well as between RMCA pulsatility index and MMSE score (rs= -0.292 p=0.015). After excluding patients with a previous history of stroke, only RMCA pulsatility index correlated with MMSE score (rs=-0,314 p=0,007). The relationship between high cerebrovascular resistance and worse cognitive scores suggest that microembolism may be responsible for a significant proportion of cognitive symptoms in CHF patients.