Can Clinical Predictive Models Identify Patients Who Should Not Receive TAVR? A Systematic Review

Background

One third of high- and prohibitive-risk TAVR patients remain severely symptomatic or die 1 year after treatment. There is interest in identifying individuals for whom this procedure is futile and should not be offered.

Methods

We performed a systematic review of the highest reported stratum of risk in TAVR clinical predictive models (CPMs). We explore whether currently available predictive models can identify patients for whom TAVR is futile, based on a quantitative futility definition and the observed and predicted outcomes for patients in the highest stratum of risk.

Results

17 TAVR CPMs representing 69,191 treated patients were published from 2013 to 2018. When reported, the median number of patients in the highest stratum of risk was 569 (range 1 to 1759). Observed mortality for this risk stratum ranged from 9% at 30 days to 59% at 1 year after TAVR. Statistical confidence in these observed event rates was low. The highest predicted event rates ranged from 11.0% for in-hospital mortality to 75.1% for the composite of mortality or high symptom burden 1 year after TAVR.

Conclusion

No high-risk TAVR group in currently available TAVR CPMs had an appropriate event rate and adequate statistical power to meet a quantitative definition of futility.

Aortic Valve Regurgitation: Pathophysiology and Implications for Surgical Intervention in the Era of TAVR

Aortic insufficiency (AI) or regurgitation is caused by the malcoaptation of the aortic valve (AV) cusps due to intrinsic abnormalities of the valve itself, a dilatation or geometric distortion of the aortic root, or by some combination thereof. In recent years, there has been an increase in the number of studies suggesting that AI is an active disease process caused by a combination of factors including but not limited to alteration of specific molecular pathways, genetic predisposition, and changes in the mechanotransductive properties of the AV apparatus. As the surgical management of AV disease continues to evolve, increasingly sophisticated surgical and percutaneous techniques for AV repair and replacement, including transcatheter aortic valve replacement (TAVR), have become more commonplace and will likely continue to expand as new devices are introduced. However, these techniques necessitate frequent reappraisal of the biological and mechanobiological mechanisms underlying AV regurgitation to better understand the risk factors for AI development and recurrence following surgical intervention as well as expand our limited knowledge on patient selection for such procedures. The aim of this review is to describe some of the putative mechanisms implicated in the development of AI, dissect some of the cross-talk among known and possible signaling pathways leading to valve remodeling, identify association between these pathways and pharmacological approaches, and discuss the implications for surgical and percutaneous approaches to AV repair in replacement in the TAVR era.