Treating Aortic Valve Stenosis for Vitality Improvement: The TAVI Study

Abstract

Background: Degenerative aortic valve stenosis (AS) is the most common valvular heart disease among the elderly. Once cardiac symptoms occur, current guidelines recommend aortic valve replacement. Progressive degeneration/calcification reduces leaflet mobility with gradual cardiac output (CO) impairment. Low CO might induce abnormal brain-aging with cognitive impairment and increased risk of dementia, such as Alzheimer's disease or vascular dementia. On the contrary, cognitive improvement has been reported in patients in whom CO was restored. Transcatheter aortic valve implantation (TAVI) has proven to be a safe alternative to conventional surgery, with a similar mid-term survival and stroke risk even in low-risk patients. TAVI is associated with an immediate CO improvement, also effecting the cerebrovascular system, leading to an increased cerebral blood flow. The correlation between TAVI and cognitive improvement is still debated. The present study aims at evaluating this relationship in a cohort of AS patients where cognitive assessment before and after TAVI was available.

Methods: a total of 47 patients were retrospectively selected. A transcranial Doppler ultrasound (TCD) before and after TAVI, a quality of life (QoL) score, as well as a mini-mental state examination (MMSE) at baseline and up to 36 months, were available.

Results: TAVI was associated with immediate increase in mean cerebral flow at TCD. MMSE slowly increase at 36-months follow-up with improved QoL mainly for symptoms, emotions and social interactions.

Conclusions: this proof-of-concept study indicates that TAVI might induce cognitive improvement in the long-term as a result of multiple factors, such as cerebral flow restoration and a better QoL.

Keywords: aortic stenosis; cerebral flow; cognitive decline; quality of life.

Figure 1

Transcranial Doppler evaluation: (A) The transtemporal window with Willis circle visualize at color Doppler. A representative measurement of PSV and EDV is reported in (B) (pre-TAVI) and (C) (post-TAVI). The average PSV value pre-procedure was 50.21 ± 18.5 cm/s. This value increased significantly (p < 0.0001) in the post-procedure measurements, reaching a mean value of 62.9 ± 19 cm/s (D). Significant variations occurred in the measurement of End Diastolic Velocity (EDV), which changed from a mean of 20.05 ± 11.1 cm/s to 24.4 ± 16.1 cm/s post-procedure (p < 0.005; (E)). The resulted mean cerebral flow (MCF) was also significantly improved from 30.11 ± 13.2 cm/s to 37.2 ± 15.9 cm/s (F). * = p < 0.01; one-way ANOVA with Tukey’s post hoc test.

Figure 2

TASQ score graphical representation before and after TAVI: a significant improvement was observed started from 3 months after the procedure for physical symptoms (7 ± 1.7 vs. 7.8 ± 2.1, p = 0.04) and from 6 months for physical limitations (14.7 ± 2.9 vs. 16.4 ± 5, p = 0.04). These improvements involved physical symptoms, physical limitations and social limitations from 12 months up to 36 months. The overall summary significantly improves at the evaluation performed at 24 months (54.7 ± 12.6 vs. 63.4 ± 25.9, p = 0.04), remaining fairly steady at 36 months. TASQ physical limitations and emotional aspects greatly improved over time. Health expectation was almost unmodified up to one year after TAVI (3.9 ± 1.9 vs. 4.4 ± 1.8, p = 0.19). Starting from two-years follow-up, a significant improvement was observed (2.9 ± 2.1 vs. 4.4 ± 1.8, p < 0.01) up to 36 months. (# = p < 0.05, * = p < 0.01; one-way ANOVA with Tukey’s post hoc test).

Figure 3

MMSE evaluation: The mean MMSE score before TAVI was 25.15 ± 1.89. No significant changes were observed at 3 (25.22 ± 1.85, p = 0.8 vs. baseline) 6 (25.24 ± 1.84, p = 0.8 vs. baseline) and 12 months (25.4 ± 1.77, p = 0.5 vs. baseline) after the procedure. The MMSE score post TAVI improved significantly by two-years follow-up to a mean of 26.13 ± 1.28, p = 0.0047, vs. pre-TAVI, mean Δ 0.98. After this initial rise, the post-TAVI MMSE score remained fairly steady, at around an average of 26.28 ± 1.17, p = 0.001, vs. pre-TAVI, mean Δ 1.13 up to three years post-procedure (* = p < 0.01; one-way ANOVA with Tukey’s post hoc test).