Patients With Alzheimer Disease Have Altered Transmitral Flow

Abstract

Objective. There is considerable epidemiologic evidence that Alzheimer disease (AD) is linked to cardiovascular risk factors and associated with an increased risk of symptomatic left ventricular (LV) dysfunction. Formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. The vortex formation time (VFT) is an index of optimal conditions for vortex formation. We hypothesized that AD and its associated cardiovascular risk factors impair diastolic transmitral flow efficiency and, therefore, shift the VFT value out of its optimal range. Methods. Echocardiographic studies were performed on 45 participants in total: 22 patients with AD diagnosed according to the American Psychiatric Association's criteria and 23 age-matched individuals as a control group with cognitive function within normal limits. Results. The echocardiographic ratio of the early to atrial phases of the LV filling velocities was significantly lower in the AD group (mean ± SD, 0.67 ± 14) when compared with the control individuals (0.79 ± 0.14; P = .003). The interventricular septum diastolic thickness, left ventricular posterior wall diastolic thickness, and right ventricular end-diastolic diameter were significantly higher in the AD group (P ≤ 0.04). The mitral annular diameters in the control and AD groups were nearly identical (P = .725). The time-velocity integral of the E wave had a lower value in the AD group than in the control group (P = .05), whereas the VFT was significantly lower in the AD group (P = .018). Conclusions. Our study suggests that patients with AD have impaired transmitral flow efficiency of diastolic filling, as measured by the VFT, compared with agematched control individuals. Key words: Alzheimer disease; blood flow velocity; diastolic function; vortex formation.

Altered diastolic function and aortic stiffness in Alzheimer’s disease

“…However, our findings were associated with statistically significant impairment of diastolic parameters in the AD group when compared with the ND group. Similar to our findings, Belohlavek et al19 found that patients with AD have altered mitral inflow parameters and vortex formation time. However, they did not evaluate for the more sensitive tissue Doppler parameters for diastolic functions that we observed in our study.…”

“…Hypertension, diabetes, stroke, and atherosclerosis have been shown to increase AD risk 7,24,25. During the aging process, heart, arteries, and brain suffer the continuous cumulative consequences of hemodynamic and mechanical stresses;19,26–28 further, the myocardium undergoes structural changes including interstitial fibrosis and cellular disarray, which affects the diastolic functions negatively as a result of aging 29–31…”

Cerebral blood flow in Alzheimer’s disease

“…Impaired left ventricular diastolic filling efficiency, as assessed by vortex formation time and detected by echocardiography, was significantly decreased in AD patients compared with NDC subjects 48. These findings suggest that intraventricular blood conveyance is suboptimal in AD and that left ventricular diastolic dysfunction is related to cognitive deficits 48. Decreased pulse pressure could be part of the pathogenesis of AD and/or synergistically contribute to the development of this neurodegeneration, given that oligemic and hypoxic changes in the AD brain may also result from destruction of the vasoactive brain centers that regulate cerebral perfusion 49.…”

“…Subclinical dysfunctional heart disease may result in decreased cardiac output that may lead to lower pulse pressure in AD patients. Impaired left ventricular diastolic filling efficiency, as assessed by vortex formation time and detected by echocardiography, was significantly decreased in AD patients compared with NDC subjects 48. These findings suggest that intraventricular blood conveyance is suboptimal in AD and that left ventricular diastolic dysfunction is related to cognitive deficits 48.…”

Is Alzheimer's disease amyloidosis the result of a repair mechanism gone astray?

“…Numerous cross-sectional and longitudinal studies, using various imaging and ultrasound techniques, have shown that in AD there is an statistically significant reduction in total and regional cerebral blood flow when compared to age matched controls [24-32]. Echocardiographic investigations demonstrated that AD subjects exhibited a statistically significant diastolic dysfunction revealed by increased transmitral vortex formation time [33]. Likewise, duplex Doppler carotid ultrasound showed a consistent and significant decrease in diastolic flow along the path of the carotid artery in AD patients, suggesting a loss of arterial elastic capacity [34].…”