Delirium Is Under-recognized and Underestimated Following TAVR, Putting Patients in Peril

Dutch researchers are warning that delirium is an often unheeded and underestimated adverse event among patients undergoing transcatheter aortic valve replacement. Data from their retrospective, single-center study show not only that roughly 1 in 7 patients appear to develop delirium after TAVR but also that delirium is independently associated with longer hospital stays and, after transfemoral cases, higher mortality.

“I think [delirium] is overlooked because this issue is quite new in the TAVR world,” lead author Masieh Abawi, BSc, of University Medical Centre Utrecht in the Netherlands, told TCTMD. When he first presented delirium data at last year’s EuroPCR meeting, he was taken aback by the strong reaction from cardiologists. “I think in the future there will be trials [looking at] delirium especially in the field of protection devices,” he predicted.

Abawi first became interested in investigating the incidence and impact of post-operative delirium in TAVR patients after reviewing the surgical literature, where risk of delirium is higher among patients who undergo surgical valve replacement on top of CABG than among patients undergoing CABG alone. “We’d also seen some patients in our department after TAVR [develop] delirium, and I was curious as to how high the incidence of delirium might be,” he said.

In all, 270 patients underwent TAVR between November 2011 and December 2014 at the University Medical Centre Utrecht. Two were excluded for having known Alzheimer’s disease, but among the remaining patients, Abawi et al found 36 (13.4%) with post-operative delirium diagnosed by a trained geriatrician according to established criteria. None of the patients had delirium prior to their valve procedures.

Predictors of post-op delirium included current smoking, carotid artery disease, atrial fibrillation, older age, and, most notably, transapical or transaortic valve delivery. Although delirium typically resolved with a few days, a delirium diagnosis was associated with a range of complications (including bleeding, stroke, and atrial fibrillation, among others) and longer hospitals stays, even in the absence of complications. At a median follow-up of 16 months, patients who had developed delirium following transfemoral TAVR were nearly three times more likely to have died than were transfemorally treated patients who did not develop delirium (HR 2.81; 95% CI 1.16-6.83), although no such difference was seen among the non-transfemoral TAVR patients.

True Incidence Unknown

To TCTMD, Abawi observed that the 13.4% rate of delirium in their series likely underestimates the true incidence of this syndrome in TAVR patients. The vast majority of delirium cases are hypoactive, he noted. While these can be correctly identified with the proper tools, many nurses and doctors tend to dismiss delirium symptoms like decreased consciousness as grogginess or sleep.

Moreover, while older patients were more likely to develop delirium in this series, young patients who developed the syndrome also experienced prolonged hospital stays and increased mortality. On multivariate analysis, nontransfemoral TAVR was independently associated with delirium, regardless of age and other factors.

Abawi believes cerebral protection devices will likely play an important role in reducing the risk of delirium caused by microemboli, although he acknowledges that this remains to be established. He and his colleagues have unpublished data correlating MRI lesions in the brain with increased risk of delirium. “That doesn’t mean that MRI lesions are directly causing delirium, because delirium is a multicomponent syndrome, but we think that because of the high atherosclerotic plaques in the region of valve and aortic root, the brain lesions could be the cause of delirium, or at least one of the causes,” he commented.

Of note, conscious sedation in Abawi et al’s series was typically used for the transfemoral patients, while most nontransfemoral cases underwent general anesthesia—a known risk factor for delirium. In an accompanying editorial, David Wood, MD, of the Center for Heart Valve Innovation in Vancouver, Canada, predicted that the risk of delirium post-TAVR may shrink as more and more cases are done transfemorally, and under conscious sedation.

That said, Wood continued, Abawi et al should be commended for focusing attention on an often overlooked condition that warrants further study. Indeed, whether “fully awake” procedures, via transfemoral access, can decrease or eliminate the risk of delirium is one of the questions being addressed as a secondary endpoint in the ongoing multicenter Multidisciplinary, Multimodality, but Minimalist Approach to Transfemoral Transcatheter Aortic Valve Replacement (3M TAVR) study.

Abawi, for his part, would like to see delirium’s incidence and prognostic importance addressed in a dedicated study, particularly as TAVR trials move into younger, lower-risk patients. As the surgical literature shows, delirium is relatively common in younger and middle-aged patients and has been linked not only to increased mortality but also to the development of cognitive decline and dementia.

“If you want to perform TAVR in younger patients or lower-risk patients you should mention that delirium is one of the very devastating complications of the TAVR, and there should be [more of] a focus on this syndrome,” he said.   

Sources:  
1. Abawi M, Nijhoff F, Agostoni P, et al. Incidence, predictive factors, and effect of delirium after transcatheter aortic valve replacement. J Am Coll Cardiol Intv. 2016;9:160-168. 
2. Wood DA. Could a “simplified” transcatheter aortic valve replacement procedure eliminate post-operative delirium [editorial]? J Am Coll Cardiol Intv. 2016;9:169-170.

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