Post-TAVR Cognition Improves in Some Patients and Declines in Others, With Few Signposts to Guide the Way

In the largest series of patients studied to date, transcatheter aortic valve replacement was associated with improved cognitive function postprocedure in nearly 40% of patients. Almost 13%, however, experienced cognitive deterioration.

And while certain preprocedural characteristics were identified that might be useful in predicting mental gains, no such factors could be identified for patients who had a decline in their functioning.

Speaking with TCTMD, the study’s lead author, Andreas Schönenberger, MD (Bern University Hospital, Switzerland), pointed out that the focus of TAVR outcomes to date has centered on cardiovascular and to a lesser degree renal outcomes.

“For me as a geriatrician, cognition is a very important part of the functioning of the whole body and the brain is an important organ too,” he said. “If there is relative cognitive deterioration after TAVI, this is a major problem. The result of the TAVI might be good because perhaps the dyspnea is improved or heart failure symptoms are better, but if you a relevant proportion of patients that have cognitive deterioration, they perhaps have to go to the nursing home anyway. So it is really important to look also at cognitive function.”

The study was published online last week in Circulation: Cardiovascular Interventions.

From the Heart to the Brain

Studies linking TAVR and cognition changes have been mixed. The largest series to date with 111 patients, by Ghanem et al, found that cognitive function was preserved in most but that 9% experienced declines. Smaller studies have also reported a mix of improvement and deterioration. In the DEFLECT III study of the TriGuard cerebral protection devices (Keystone Heart), patients experienced a more than two-fold increase in recovery of normal cognitive function (MoCA score > 26) at 30 days, but this was in patients whose procedures included neuroprotection. More recently, investigators have been zeroing in on delirium as an underestimated problem post-TAVR, one that is linked both with cerebral ischemic lesions on MRI as well as subsequent dementia.

In Schönenberger et al’s series, 229 TAVR patients, all of whom were 70 years of age or older, underwent cognitive testing using the Mini Mental State Examination (MMSE) both prior to and 6 months after their valve procedures. At 6 months, cognitive deterioration, defined as a decrease of 3 or more points on the MMSE, was seen in 29 patients (12.7%). However, among 48 patients with MMSE scores lower than 26 at baseline, 18 (37.5%) saw improvements of 3 points or more following their TAVR procedures.

In a subset of 8 patients who’d experienced significant cognitive declines (MMSE score reductions of ≥ 5), medical record reviews identified causes in six cases including postprocedure delirium in two patients and progression of renal failure, progression of heart failure, postinterventional stroke, or preexisting cerebrovascular disease in one patient each.

On the other side, patients with significant mental gains were found to have preinterventional aortic valve area that was significantly lower than that of patients who showed no improvement. This observation bolsters those of previous studies hypothesizing that improving valve hemodynamics can lead to better brain function.

“Our study is the first adequately-powered study to provide evidence that TAVI results in cognitive improvement among patients who had impaired preprocedural cognitive function,” Schönenberger et al write. “Our analyses also suggest that patients with low aortic valve area are particularly prone to cognitive improvement after TAVI because of the hemodynamic improvement after successful intervention.”

Predicting Improvement

Asked how cognitive risks and benefits could be discussed with patients before TAVR, Schönenberger acknowledged that the lack of preprocedural predictors of worsening cognition make this a complicated conversation. He believes, rather, that it is the peri- and postintervention factors that physicians should pay attention to. No cerebral protection devices were used in this series of patients, senior author on the study Stefan Stortecky, MD (Bern University Hospital, Switzerland), confirmed. Whether these devices have any impact on cognition is unknown and is a focus of ongoing studies. Postintervention delirium, however, is something that physicians can be more alert to, particularly since it seems to be more common in patients who have some degree of cognitive impairment preintervention.

“In these patients, you should really do all the measures recommended in the guidelines to prevent delirium, which is a very effective way of also reducing the risk of cognitive deterioration after TAVI,” Schönenberger said.

The large proportion of patients who experienced better function is even more striking, he suggested, noting that some referring physicians may not send a patient with aortic stenosis for TAVR evaluation because of their cognitive state, when in fact it may be improved by the procedure.

“This is one reason why I always claim that geriatricians should be part of the heart team,” he said. “They can help predict whether a patient could improve after TAVR regarding his or her cognition.”

Commenting on the paper for TCTMD, Alexandra Lansky, MD (Yale University, New Haven, CT), called the findings of both improvement and deterioration post-TAVR “consistent with what’s been published before.”

She also agreed that delirium is a clear warning sign and that any patients who develop delirium after TAVR should get a full work-up for stroke and be evaluated by a neurologist. “The neurologists are attuned to this, but I don’t think the cardiologists are,” she commented.

What’s not clear is the degree to which cognitive deterioration, which has been seen in earlier studies, can be linked with specific types of brain injury on imaging—something she believes needs further study. There is also a growing body of work looking at periprocedural factors—longer procedures, more postdilatation, positioning and repositioning of the valve—and how these may increase the risk of stroke and, potentially, cognitive decline.

“There is now more intensive research and better series, larger series, trying to better understand what causes stroke and other subclinical findings on imaging, so the evidence is building,” Lansky said. “But the challenge with this whole field is that it’s all so new. We’ve fixed the valve, we’re improving mortality and cardiac outcomes. Now we need to get a better understanding of the neurological outcomes.”

 

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